MAF value = Horsepower potential

The Mass Air Flow of an engine is directly related to the horsepower potential. The power production process all starts with amount of mass air the engine can inhale, then the DME calculates the required fuel at 12.6:1 ratio for best power. The power "potential" can be calculated by using the Mass Air Value alone,( injecting more fuel will lower power output without more air mass). Sure there are many variables that effect the actual power output like number of valves per cylinder, combustion chamber shape, flame travel, time at TDC, rod/stroke ratio, cam profile, ignition timing, displacement, but when comparing our 996 engines those variables will be the same. While the above variables do effect Mass Air flow, they are not something that most of us will alter, except maybe displacement with a "big bore" kit, or maybe ignition timing with an aftermarket tune for some. So why would we even care about the max Mass Air Flow Value? Because if your Max MAF value is low, your engine does not even have the "potential" to make the desired power. If I stick a potato in one of your tailpipes, you will not have a good Max MAF value and power. Max MAF values can be used to evaluate displacement increases, intake plenums, TB, headers, exhaust, cats, anything that has to do with air flow into and out of the engine.If on an engine Dyno and you see an increase in Max MAF value(potential), but no increase in "actual power" you will have to ask "why not !!"..Any increase in Max MAF value SHOULD also produce an increase in "actual power"... Back in the 70's 80's we would have given our left nut for a MAF sensor to measure actual mass air flow. That kind of stuff was only found in laboratories of the manufactures. Some speed shops had flow benches for heads but that's about it. We would change cams, heads, intakes, carbs,headers in all combinations and have to go to the track to see if it was better or worse.. I tried to keep this background section short as to not stir any debate and focus on collecting data from others that may be helpful to some who are interested in this kind of stuff. The thick film MAF on our cars is very accurate at measuring actual Mass Air Flow and can be monitored easily with a bluetooth OBDII LM327 and a Torque app on your phone. Here is my Max MAF value as displayed in Torque in grams/second. 213.4 / .75 = 284.5hp Year: 1999 miles:174,000 Displacement : 3.4 Max MAF : 213.4 g/s Intake air temp : 62F Ambient temp : 57F Barometric pressure : 28.9hg Altitude : 660ft Intake sys : custom short ram Exhaust : headers, stock cats and mufflers other mods: none

Interesting stuff. It�s surprising to me, that the M96 in its stock form seems to be just about maxed out regarding easily findable extra power (like many other stock engines of today).

Under what conditions is the max maf measured. Isn’t it throttle position and rpm dependent? I could assume WOT at max rpm?.

You are correct about power in relation to airflow. The more airflow, the more torque can be made. Designing higher airflow across a wider range of RPMs can generate more power across an RPM band for a faster car overall, even if that engine has less peak horsepower than a narrow band engine. Designing more airflow within a narrow band can actually generate more peak power than a broad band engine, but the car may not be faster than a broadband car unless the gearing is set just right. Designing peak airflow higher up in the RPM band almost always increases horsepower, since HP is directly related to RPM. I guess it would be good to check to see if my OBDII records peak airflow values (I know it does real-time). It�s possible that our engines can have peak airflow but not make peak power (incomplete combustion, bad rings, bad valve guides, bad timing). But as you said, if our engines aren�t able to flow to peak airflow, it�s impossible to make the advertised HP.

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Yes, but it would certainly have to be at WOT. I�m not sure if peak airflow is at the torque peak or HP? Or could it even be above the peak HP RPM?

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Peak Torque and Peak Volumetric Efficiency happen at the same time, Peak Mass Air Flow and Peak Horsepower happen at the same time higher in the rpm range..

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That�s what I was thinking, but then I was thinking that it might be possible to spin the engine a little faster, giving up some efficiency, but still moving more air and fuel into the engine?

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Nope. After Peak Torque and VE are achieved, they start to fall, gradually at first, then after Peak MAF and HP is achieved, they fall at a greater ratio than the increase in RPM, therefore a less grams/second of Mass Air will be inhaled. Hopefully other forum members will spend the $20 bucks and record their Max MAF values, temps, altitude, intake/exhaust setups, mods, ect. We should see some interesting trends start to emerge..

Spot on Porschetech. I�m in and will see if my app records that data and post. Should be interesting.

Spot on. You could piggyback your ECU to maximize performance. Porsche ECU is too limited for that. especially optimizing the performance overall the whole rpm range

My understanding is that the Torque Pro app won’t work on iOS devices, I have OBD Fusion app set up on my iPad. As an experiment this morning I played around with it just idling in the garage and I can’t get the MAF gauge to read. I don’t know if this a quirk of the app or of the iOS version, or if I’m doing something wrong. Also interesting to note that the data logger will plot MAF over time, (note the spike with I rev’d the engine) it’s just the gauge that isn’t reading. Any. Ideas?

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It might be a configuration issue. I use the Dash Command app on iOS and the MAF gauge works fine. I don't know about Torque Pro, but the standard Torque app works on iOS.

I’ll check out dash command. The standard Torque app is a scam for iOS. Check the reviews, it doesn’t work.

I use Dash Command for IOS. It works but is a bit clunky.

After some tweaking I am now able to get MAF reading on my system. Just a software glitch I guess because all I did was delete that gauge and reinstall it. Now I need to figure out how to get it to save the max reading. This is a snapshot at idle

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Man, that really sucks. It's rock solid on android (my phone at least) and a really well-built app.

All the data comes straight from the DME over OBDII protocol. I don't care which bluetooth adapter/app/OS you use, use the one you are most familiar with or have on hand. As long as the MAF, temps, altitude,ect. can be retrieved. You can even use Durametric over the Porsche protocol, but it is a LOT more cumbersome with the cable/laptop and all. When I go on long trips or just spirited drives and "hooligan runs" with my Porsche buddys, I have my phone mounted and Torque app running for additional gauges and info I can easily flip through to keeps tabs on everything..I usually monitor fuel trims, 02 sensors, MAF, IAT, and coolant temp since the dash gauge is so inaccurate, and I have a separate oil temp gauge.

Porschetech: can You get oil temps that way? Would be an easy soution if possible.

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No, you can't get oil temps through OBDII protocol, it can only be gotten through Porsche specific protocol on 996,(ie Durametric/Piwis). That's why I have a separate oil temp digital gauge..

Ok, I got my OBD Fusion system issues sorted out, thanks to super support from their tech service dept. I emailed them my questions about 3:00 pm SUNDAY and had their response before 9:00pm SUNDAY NIGHT. I can highly the app to anyone wanting to use an iOS device. Now on to the hard data: car:1999 C2 3.4 coupe miles: 3000 on rebuilt engine all stock intake, exhaust, cats, mufflers max rpm: 6930 max MAF: 197.1 g/s ambient temp: 45*F barometric pressure: 30.18 in hg altitude: 2248 ft

Thanks for the info Porschetech3 I've got an OBDII device and piwis but prefer to use the OBDII device as it's portable. So I'm guessing I just fire up torque pro so a few pulls when the engine is warm and it will record Max MAF? Should be interesting to see!

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If the Torque app works like Dash Command, you pick which data items you want to log from a menu.

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Yea, on Torque just fire up the app, (connected to OBDII bluetooth), select gauge type (half dial (needle)) (has min/max), then PID( MAF) do a couple pulls in 2nd or 3rd to capture Max value..

What exactly are you trying to with all this data?

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The Data should speak for itself . Like mentioned earlier, if enough data is collected, some "interesting trends" is expected to emerge. With all the sensors and computer, you basically have a rolling "engine laboratory" at your fingertips. I can't think of any other factor you would want for evaluating engine performance. Of coarse each data set will need a correction factor back to SAE standards of (sea level,60F) similar to what NHRA uses for World Records at different tracks in different parts of the country, or like Dyno companies use to set-up dyno's at different parts of the country to be able to compare readings.

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In other words, you have no idea.

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OH I have some idea, if I thought all our engines (after correction for altitude,temp) would have the same power potential even with different exhaust, cats,mufflers, intakes, filters, mileage ect, then I would think it would be pointless.

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Looking for a factory freak?

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You mean like looking for a 1969-S DDO Lincoln penny......

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Wow. I know what this is. Haven't heard it spoken out loud since I was a kid in the 80's though. lol D.

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x2 lol! I like what you're doing here Ptech3. I'll add my data when the car comes out for the new season.

Point or no point I like what's going on here

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I guess everyone isn't information and Data junkies like we are. I am still envious of you having your own PIWIS !! lol We had 2 nice PST2's at the shop before I retired. When PIWIS came out, on the last update for PST2 there was a software "bomb" hidden in the software that after a month disabled the PST2 making them useless. It was such a shame because even though it was much slower than PIWIS, it had several features/functions that on a 996 were not included in PIWIS. A couple very smart Techs figured out how to turn them back on, but was quickly shut down by Porsche lawyers... I understand Porsche wanting to keep the information/data proprietary, but thank God for OBDII !! At least they are forced to give the public that easy to get Data, and most people just take it for granted. The point to this was to collect a lot of this valuable Data on these specific engines to find trends, evaluate performance gains/losses, that can be used by it's self or in combination with Dyno tests. I think I may have misjudged this subject, just let it die.... Thanks to Coopdoc for posting his Data and others who were intending to do so, but I don't think we will gather enough data?

Is this DATA something one can get with a Durametric?

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Yes.

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I'm all for whats going on here I love data! It is handy having a PIWIS, there is a whole world of PIWIS and even people building their own PST2 Bosch units as well! Although whats missing in PST2 that PIWIS doesn't have? I've always read that PIWIS has everything + more?? Don't let the tread die - shame on those who aren't on board!! I'll post my data next weekend as my car is in storage. I'm actually quite curious to see what value comes out...

I've only had a 996 for about 3 weeks and a Durametric for a few days but as soon as I figure out how to extract this data I'll post mine.

Don�t let is die Ptech! I will post my data as soon as I can get a chance for a good pull. Disregard the Debbie Downers on this forum. This is fun stuff. Dan

Are you looking for safety margins in the programming?

I just bought a foxwell scanner. If it can record this data I'll be submitting it soon.

I'll play too Did some pulls on an uphill slope and collected the following from the Torque pro app. Mine is a '03 996 all stock except sport cats from Carnewal and mufflers from Fister. 91 octane pump gas in CA. A/C off. Year: 2003 miles: 78k miles Displacement : 3.6L Max MAF : 252.5 g/s Intake air temp : 102F Ambient temp : 56F Barometric pressure : 29.4hg Altitude : 666ft Max VE: 98% Edit: more pulls. Got 312.8 g/s while intake air temp was at 77F. Not sure how consistent the max MAF numbers are. Max VE at 102%. For simplicity, I entered 3600 cc in torque (which is used to compute VE I believe.)

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I agree, That's a HUGE jump in MAF, with only a 25F drop in IAT. I have been monitoring my MAX MAF ( in Torque Pro ) for for about 5 years, and it has always been within 4-5 g/s, something strange going on here..

I wonder if it's related to the sampling rate. I use the OBDlink bluetooth adaptor, which returns 8-12 PIDs per second. Do you know your sampling frequency? Would be nice if someone can log MAF using Durametric, which has a much higher sampling rate.

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Check your Error count in the app, it should stay at "0".. I have my app set for "faster communication" and "no MPG calculations" which is suppose to give the fastest sample rate, but I don't know the actual rate, where do you get that rate? Yes, Duratmetric/Piwis/PST2 all would be a lot faster sample rate than any bluetooth, but the bluetooth is so convienient, I hope there are not inconsistency's.. BTW I am using ELM327 Bluetooth device EDIT : found the sample rate data menu, I'll get the sample rate tomorrow

I don't recall clearly now but I think I observed that sampling rate when doing data logging using Torque with the OBDlink scanner. I don't think I have any issues with my setup because I can see the very clear O2 sensor voltage pattern with great resolution.

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You can attribute 5% from the temperature difference alone. At least that�s what I calculated.

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I agree, but that 312.8 g/s isn't plausible,.( unless you have a Jake Raby 4.0 Stage 3 engine)

Right. 312.8 g/s is physically impossible. Did some Torque logging and got some more believable numbers: Coolant temp: 194 F rpm: 7142 IAT: 91.4 F MAF: 241.5 g/s mph: 31 mph VE: 100%

Ordered this "splitter". I should be able to run Durametric and OBDII/ Elm327/Torque Pro at the same time. Should be easy to compare values since the values should be identical. https://www.ebay.com/itm/Ultra-Low-P...72.m2749.l2649

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So 241.5 / .75 = 322? Spot on with the brochure??

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Um, I don't think that will work because both scanners will then try to talk to the DME/Alarm on the same K-line on pin 7 on the OBDII port. I don't think the DME can talk to both at the same time. BTW, sadly Durametric can only read the MAF value (or any sensor value) at ~10 times per second (best case). The Torque pro probably reads the MAF much less frequently than that. especially if you log other PIDs at the same time too. I have not monitored the max MAF values long enough to be confident about the consistency of this max MAF value for my car. The 241.5 g/s was observed in a Torque log which logged the MAF readings in time during a drive. I picked up the max 241.5 manually and saw the readings immediately before and after it are all "smooth", as opposed to a sudden spike to 241 g/s..

I'll give it a try with my Snap-On Ethos Pro this weekend. I need to find a low-profile OBD extension like that splitter. It's kind of a PITA to drive with the cable run across my lap. I keep knocking it loose with my left knee. I wish the OBD port was on the other side of the steering wheel!

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its because y'all drive on the wrong side of the road! Mines in the passenger side footwell haha

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Could be. The OBD port is required to be within 2 feet of the steering wheel. Wish it could be in the middle. That makes it a lot easier to deal with the scanner's cable. Although the newest Snap-on scanners have a wireless feature. But I prefer a cable, no batteries to deal with, or having to remember to recharge yet another device.

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Just run it up between your legs.

I'm still trying to figure out exactly what the hell is the point of this thread. What is the end game?

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The end game= What is the power potential of YOUR car? How much did that 3.8 conversion increase the potential? Did that IDP plenum increase the potential? Does those High flow cats increase the potential? IS your cats clogging up decreasing your potential? Did that BMC air filter increase potential? IS your air filter dirty causing loss of potential? Did that 80mm TB increase your potential? ect. If you can't see the advantage in knowing this stuff, or have any interest in it, I don't know what to tell you.

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The short answer is it establishes a baseline from which you can measure the efficacy of changes, hopefully in terms of performance improvements. Could be simple changes like a new air filter to �the sky�s the limit�. If it doesn�t matter to you, then there�s really no point in doing it, but it could also point out impending problems, like clogged cats, etc before CEL gets lit, that should be addressed before it leads to more serious problems. Just my thoughts, and I have had this capability to do this for several years on every vehicle I�ve owned since the dawn of OBD2, but I�ve never done it before. Maybe I�m one of those guys it just doesn�t matter to!

Here is a link to a correction calculator using "Motorsport Standard Atmosphere" for correcting for altitude, intake temperature, humidity, barometric pressure. It uses Motorsport Standard Atmosphere, Barometric pressure isn't critical. The altitude, intake temperature and humidity are the most critical and will make the most difference. To compare data sets from different parts of the world, in different weather conditions. Using Coopduc's data set and assuming a relative humidity of 50% for NC,and since there is no intake air temp data, assuming 75F, IAT , the correction factor is 1.136. 197.1 g/s / .75= 262.8 x 1.136= 298.5bhp Using my data set with a relative humidity of 50%, the correction factor is 1.041 213.4/ .75 = 284,5 x 1.041 = 296.1bhp http://www.wallaceracing.com/weather-corr.php

Thanks for the explanation, sounds to me like bench racing.

Bought torque pro over the weekend but just didn't get to take my car out I will soon

Wish I saw this thread before removing my K&N intake to install a 3.8 intake from a 997. I'll post my "number" later. I have the stock 3.8 intake, ported GT3 TB, IPD plenum, BBE headers, and fabspeed Maxflos. (3.4L)

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Nope, not bench racing, I just enjoy the technical aspect of measuring the power out put of our engines under different conditions/scenario's. Do you like to "bench race"? Want to share some of your interests on this subject? Dyno time is expensive, has it's variables/inconsistencies, but is a great "tool". Timed "track runs" is also costly, has it's variables/inconsistencies, but is a real world test of power/performance, and is a great "tool". MAF measurement is about as good as it gets for power measurement, and has to be accurate/consistent or else nothing about the power production will be accurate/consistent since fuel/timing all are dependent on MAF. IF MAF output is not accurate/consistent then even Dyno measurement, timed track runs ect. will not be consistent. 33 years ago I took a "Pinto" 96hp engine to 525hp (T88-series EAO/OHC, manufactured by Ford of Germany) and set some Records with it, and it was featured in a national magazine. It took a lot of thinking "outside the box" and not listening to the naysayers. People would ask me how I got so much power from the little 2 liter engine, I would say "if you want 100 extra horsepower, find 1 horsepower in 100 extra places" , although I found much more than that, it got the point across.

I received the low profile extension cable today. Unfortunately my car is stuck in the garage. Roofers dropped the new roofing material today and I can't get my car out now. Luckily I'm working from home again tomorrow, and the rest of the week. I'll take the car out probably Wednesday evening and get some MAF numbers.

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Your lucky, roofers in Alabama are starving. It's been raining here for about a month !! Floods everywhere, 23 people died in Tornado's yesterday in Opelika !!!

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Whats the formula for the MAF in Litres? I guess I could just convert Litres to Gallons. You guys have to start using litres!! Haha Sorry to hear that

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If you are using Torque Pro, there should be an option in settings for MAF grams/second. When you are referring to Mass Air Flow you have to use "weight", either in lbs/min or grams/second. Liters, Gallons, and CFM are "volume" and not to used for MAF, even though there is some conversion between them, it can get confusing, since Mass = volume x density..

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Ahh I thought the G was gallons not grams! Got it - I've got Torque pro Thanks

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Did another pull today and got the same max MAF reading 241.5g/s so it' quite consistent. Per Porschtech3's computation 241.5/0.75 = 322 hp. Right on?! 2003 Porsche 996 C2 manual Coolant temp: 174 F rpm: 6702 IAT: 96.8 F MAF: 241.5 g/s mph: 63.4 mph VE: 102%

BTW Porschetech3, have you tried the max hp (rwhp) and torque dynos from the Torque Pro (pulls on a straight and level road from a dead stop)? I usually got ~270hp/234ftlb. If we assume 15% drive train loss, that's 317hp and 275ftlb, which are also very close to the spec 320hp/273ftlb.I use 3.6L and 1,517kg in the vehicle profile.

Ahsai, it would be cool to see your 3.8L readings. Coming soon?

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x2 Did the timing chain get fixed yet?

Yeah, timing chain was fixed a couple of months back. Now doing paint correction in the garage. With all the rain I have not been driving it. Also need to restore the headlights (again). They turned yellow after I restored then a yr ago so this time I plan to put xpel films on them. Will definitely try to see what numbers I get on the 3.8.

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Yes I was thinking the same thing, would be nice to add that 3.8 conversion data to the thread. I have not tried the rolling Dyno feature in Torque Pro because my DD is a Tip and I know it has a ton of loss, but since it seems to accurate, I'll give it a go and post the Data for Tip power loss. Did a pull going over to my sons house a couple hours ago. year ; 1999 C2 3.4 MAF: 213.5 ambient temp; 47F IAT; 55.4F altitude : 660ft humidity : 35% Baro :30.2

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Well there's a bit of that aspect to it, but it's also practical. Let's say you baseline your car. Now you make a change. You want to know how much of that change (different MAF values) was due to the change vs. the fact that yesterday it was 40F and 10% humidty and today it was 60F and 40% humidity. This is about putting some science down that we can all do without renting dyno time. Poor man's dyno.

221.25g/s. I forgot to log RPM. Doh! Odometer must've been at like ~6900 RPM before I changed gears.

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lol...What engine do you have? Don't forget to get all the other data, IAT, altitude, humidity ect...

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This is true, but the advantage over renting Dyno time, is that I drive every day and this is right at my fingertips. I always end up taking it to redline at some point during my drive. So the more Data you log, the better your base-line, and the better you can evaluate changes.. Also look at my IAT temps, cool air, you wont get that on the Dyno !!! I think that is one reason our cars do poorly on the Dyno..

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3.4L I'm using Bluedriver. I don't think I can monitor altitude and humidity. Using a weather app, it's 58F and 85% humidity. Basically sea level since I was on Pacific Coast Hwy.

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OK cool, I was going to say, if you are using an Android, most Android phone you can get altitude and Baro from the GPS, or download an app for them.. BTW, how many miles on your 3.4? Any mods? EDIT : I see your Mod list above, but mileage?

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I�m guessing everyone�s figures won�t take into account all sorts of losses, such as oil pump, accessories, etc.? I mean the actual HP an engine produces is probably higher than what can be measured at the crankshaft unless these accessories are included in the crank-based dynamometer. But our numbers are airflow with fuel delivered, so won�t our calculated/measured numbers going to be higher than what a dyno would measure? I�m not talking about transmission and diff/driveline losses, just other engine losses like crankshaft, piston ring friction, crankcase pressures, camshaft chains, valves and valve springs, etc.??

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You are absolutely correct, our measured numbers are for absolute power with no losses. No losses from alternator, power steering, water pump, friction, drivetrain ect. We should probably come up with a new name for it since it is a new way of measuring power/potential out of the many ways that already exist. Here is a link to an article on some of the ways horsepower is calculated/corrected. https://www.dynomitedynamometer.com/...horsepower.htm

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I'm not sure of exact mileage. The Porsche dealer put in a re manufactured motor in late 08/ early 09. Roughly 70k miles

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My sample rate for my setup is 5 times per second for the ELM327 and Torque Pro, but I'm monitoring MAF.IAT, fuel trim long and short, 02 sensors, coolant temp, throttle position, timing, all on different flip through screens. 5 times per second seems to be enough to be consistent if doing a 3rd gear pull, may not be fast enough for a 1st or 2nd gear pull.

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Yeah, mine is not much faster. Mine does 6~8 PIDs per second so when I monitor 6~8 PIDs, on average each will update only about once per second, which is quite slow. BTW, I think the way Torque Pro works is it only queries for the PIDs that are relevant to the current screen you're on so the fact that you have other PIDs on other screens should not slow it down. If you turn on logging for the run, you will see the log spits out about 10 rows per second. Each row will have the readings of all the PIDs you selected but then their values change at most once a second even though you know they change constantly in reality (e.g. rpm during a pull).

Logged a quick run with my foxwell today. Outside temp is 62, local elevation is just under 600 ft. Quick 2nd gear run had .46lb/s at an IAT of 75. In grams that's about 208. Car is a 2000 C2 6 speed with IPD competition plenum and tb, AWE headers, speedtech mufflers, catless X-pipe. I'm going to try a 3rd gear pull and see what that nets.

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NIce, thanks..

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It�s a lot closer to GROSS than anything else. I�m guessing there isn�t much more than 20-25 HP to run the accessories and internal engine components (assuming AC is off)?

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Correct again, this method of measuring is more closely related to GROSS HORSEPOWER (mechanical horsepower not metric horsepower), but should be given a different name like Mhp or Mhpp (Motorsports Horsepower) or ( Motorsports Horsepower Potential), what y'all think? The expected change in air flow from bolt-ons would be 7.5 g/s per 10Mhp. With over 5k views there seems to be enough interest, just need to put out a little effort to help the community. Don't be concerned to take the engine to redline, if it can't go to redline it isn't healthy anyway.

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Internal like cams and pistons?

[QUOTE=Imo000;15698121]Internal like cams and pistons?[QUOTE] Yes....

This measurement is meant to examine the properties of AIR FLOW, which is where the power process begins. This measurement is not influenced by the conversion to mechanical power where many influences have to be factored in. There are numerous measurements and methods for the conversion to mechanical power and this is not one of them, but rather a method measuring the whole potential BEFORE the conversion takes place. Just this past weekend I diagnosed my granddaughters 2007 Sebring with a stopped up catalytic convertor. It had a drastic reduction in power and overheating. The inability to flow air out caused the lack of power by not being able to inhale more air, and the lack of air flow caused combustion chamber temperatures to peak. There is no more accurate or better way of measuring Mass Air Flow than a MAF sensor. Alpha-N and Speed Density are less accurate methods and only advantages are simplicity and easy to tune to a "close" value for custom applications. What are y'alls opinion on calling this method Mhp or Mhpp? (Motorsport Horsepower) or (Motorsport Horsepower Potential)

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I like MHPP! Will try and get my values this weekend. Have been a bit busy to get out unfortunately

How about "air-fuel horsepower", which indicates hp generated directly by air-fuel combustion with the assumption of certain fixed AFR and AFR->hp conversion. Nothing to do with any mechanical loss and engine design.

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Yes, "air-fuel horsepower" would be a good descriptive name for it and could include other fuels like Methanol, Ethanol,Nitro, ect. at their appropriate AFR for combustion, it could apply to all fuels since we are measuring the total mass air flow. Although each fuel would need it's own conversion formula as there is different amounts of energy in each, but with accurate MAF readings it would be simple. Along the same lines could be "chemical horsepower" or "atomic horsepower" all descriptive of the method/process before the conversion to mechanical horsepower.

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We have one vote for Mhpp, how about "Molecular Horsepower"???

Maybe something related to the total energy content of the air/fuel mixture. We already have GGE ( https://en.wikipedia.org/wiki/Gasoli...lon_equivalent ) and BTUs, but how those convert to actual horsepower need a converter, and we need to subtract the efficiency of the engine (since our engines might only be 20-35% efficient at transferring heat to usable power).

Personal opinion here based on a technical background: You won't be able to put together an accurate measurement of real horsepower based on MAF for a variety of reasons, many of them mentioned here. Just because my car pulls, say, 240g/s at standard elevation, humidity and temperature doesn't mean your car that pulls 240g/s at the same standards is getting the same horsepower. What this measurement is GREAT for is checking the relative effectiveness of a change in parts. BUT there are some caveats. Change your tune? It will likely change the air-fuel mixture. You could get more or less power at the same MAF. Change your pulley? You could get the SAME MAF reading at the same RPM (in fact you should be able to) but your power at your rear wheels will be slightly higher because you've reduced parasitic losses. So, like I said before, I'll eventually get one of these OBD-II readers and start monitoring this, but it's relative to my car and my car alone. I'll watch it so that if adjusted/normalized MAF drops, I can go see why (dirty air filter? need new spark plugs?)

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I agree, I didn't come by the .75 conversion factor lightly. It may be off by a few % but that is the best I could do. And that is on our M96 engines running on gasoline only. Also the Motorsport Standard Atmosphere correction factor needs to be used so that we can compare MAF readings from someone at 50F, 30%, humidity, 5000ft alt. in Colorado to someone at 75F, 85% humidity,100ft in Baton Rouge.

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I agree with a lot of what you are saying here, and somethings we may be just be looking at it differently or through different lenses. For instance if I say the glass in half full, and you say the glass is half empty, and the glass has .5 liter of a 1 liter glass, we are both right. I would not say that changing the pulley would make more horsepower, I would say that changing the pulley will "save" horsepower or not loose as much horsepower. I would say that if we both had " identical" M96 engines ran at the same elevation, temp,humidity, and both pulled 240g/s, that they both would have the same horsepower. But you had an M96 and changed to a longer duration camshaft, it would pull more than 240 g/s and would create more horsepower. This measurement is about air flow into and out of the engine, without regard to anything below or after the head gaskets. There is an old saying the racing community that I have always lived by "horsepower is made from the head gaskets up, durability is made from the head gaskets down".. Again, we are not talking about rear wheel horsepower , net horsepower, gross horsepower, SAE horsepower, imperial horsepower, metric horsepower, flywheel horsepower ect.

�I would say that if we both had " identical" M96 engines ran at the same elevation, temp,humidity, and both pulled 240g/s, that they both would have the same horsepower.� i can generally agree agree with that. But it once we get to two different cars with different mileage, you can�t tell if one is lower on power (but same MAF) or not. The point being MAF only measures air. Not fuel. And can�t tell you how well that fuel was burned. And how much blowby resulted in lost power. I still maintain that it�s AWESOME to test changes on an single engine where you change a single variable at a time.

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I can see your starting to grasp the concept, good. In this context, we are not measuring or looking at anything below or after the head gasket(ie power loss or to more specific, mechanical power loss). It is actually good that a high mileage engine with blowby will not show in the MAF because that would be a power loss, and we are not looking at power loss. (mechanical power loss that is). And there are other means to measure blowby. As far as the AFR-complete combustion goes, you are correct the MAF doesn't measure fuel, BUT, the DME "depends" on MAF to inject fuel to the millisecond to produce the correct AFR for best power or most complete combustion. Otherwise the DME would just give it it's best guess. To keep confusion down is why we should give it different name, and limit discussion to components above the head gaskets, IE air flow. Ok I'll go ahead and give it a name "Motorsport Horsepower Potential"... This is to used to evaluate components ABOVE the head gaskets that effect Motorsport Horsepower Potential, which WILL effect rwhp, real hp, and all the other hp's..

"I still maintain that it’s AWESOME to test changes on an single engine where you change a single variable at a time. " I agree, any changes should be done one at a time, with before and after measurements. I would also say if I designed a hotter cam and got 50g/s more mass air flow 50/.75= 66.66Mhpp, and you put the same cam in your car, that you would also get 66.66 more Mhpp...... The DME will see the 50g/s more MAF and inject the appropriate fuel and the result will be more mechanical horsepower, rwhp,( or any other horsepower measurement).

Just watched mine on an hour long cruise. Highest number i got from MAF g/s was 281

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281/.75= 374.66 Mhpp without correction Is this a 3.6? or larger? Do you feel this is accurate or a spike/glitch? What OBDII/software device are you using? Is see your in Florida, so altitude will be near sea level.

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04 c4s. Stock 3.6. Only bolt on's like fabspeed intake and exhaust and a RSS underdrive pulley. All other mods are suspension and wheels. Plan on adding ipd plenum and gt3 intake at some point. Readings stayed consistant over the hour drive. Using torque pro and a bluetooth dongle. May grabe my snap on verus one day to get a better graphing display. I doubt the refresh rate on the bluetooth is worth a damn.

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Ahh, the Fabspeed intake, could you measure the inside cross-section of the area at the MAF sensor? I'm suspecting it is smaller than the stock cross-section of the calibrated Porsche stock MAF housing. I have no problem with the designing and installation of different intake systems, and have done so, but they MUST have the same cross-section area at the MAF sensor or a specifically calibrated MAF sensor for the housing size. Otherwise the g/s will not be accurate. Smaller housing size will show more g/s than actual, larger housing size will show less than actual g/s. I suspect this is why FSI does not approve of any aftermarket intake systems.

Did two pulls on the 3.8 (3rd column) and here are the numbers compared with the 3.6 (2nd column) Engine: 3.6L, 3.8L Atm. pressure: 1008mb, 1009mb Intake temp: 36C, 47C MAF: 241.5g/s, 244.25g/s Coolant: 174F, 198F rpm: 6702, 6665 Speed: 63.4mph, 66.5mph If we fix 241.5g/s for the 3.6 and adjust the 3.8 number with atm. pressure and temp, the 3.8 should get 250g/s (relative to the 3.6 under similar conditions). So the 3.8 sucks in ~3.5% more air than the 3.6 at about 6.6k rpm.

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Nice !! I got a 6.1% increase for the 3.8 after MSA correction 241.5 x 1.106 = 267.0 g/s (MSA correction, 660ft,96.8F,50% humidity) 244.25 x 1.161 = 283.5 g/s (MSA correction, 660ft,116.6F,50% humidity) 283.5 - 267.0 = 16.5 / 267.0 = 0.061 x 100 = 6.1%

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Thanks for pointing out the MSA correction factor. The elevation was actually at 144ft. From the MSA calculator, I got 1.083 and 1.135 241.5 x 1.083 = 261.54 g/s 244.25 x 1.135 = 277.22 g/s => 6.0%. Close enough because the actual cc were 3,596cc for the 3.6 and 3,824cc for the 3.8 and that's 6.3% increase in displacement.

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Yep, it all adds up, science/math doesn't lie !!

A pattern starts to emerge indeed. For those using the Torque pro app, my experience is you cannot rely on the "max MAF" recorded. It may record the spurious excessive values, which are physically impossible. If you use logging to log the rpm, MAF, IAT etc, and manually inspect the logged values to pick up the max, you will get a much more consistent maximum.

Obviously couldnt pay to much attention while um....moving at a higher rate of speed. But 2nd gear pulls get up to 265. 3rd gear @7k hit 286 Maf g/s. Reset multiple times and repeats same results. Tried with snap on verus and same results. Have not checked the fabspeed diameter at the maf yet.

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Yes this is definitely interesting !! Please measure the ID of the MAF housing when you get a chance so we can confirm. Also what was the Intake Air Temperature and humidity at the time of these pulls? They can make a big difference..

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Is your logging showing spikes? Or does it just move up smoothly then smoothly tapers after the max..

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just emailed fabspeed asking the ID. not sure of intake temp. Wasnt looking for it. But ambient temp was 63 degrees and car was just started minutes before this run. Couldnt tell ya humidity either. But it was dry out side and night time. Weather app says 50% relative humidity if that is any help.

Density of air @96F = 1.144 kg/m^3 (1 atm and 50% humidity) ​​​​​​Air flow rate @7,000 rpm = 3.596L/6 x 3 x 7,000/60 = 209.8L/s Therefore, mass air flow rate = 209.8 x 1.144 = 240g/s One will need a turbo or serious ramp air/intake tunning to get higher than this number under the same conditions. ​​​​​​

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Ok yes that helps. These are near perfect conditions that need hardly any correction. Near seal level, near 60F has no correction, and 50% humidity only makes about a 2g/s ( 0.010) correction, so we just need to confirm the ID of the Fabspeed which I suspect to be around 3.250in..

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Yes I agree,I'm sure our engines are well over 100% VE at max torque (4600rpm 3.4 and 4250rpm 3.6) and probably hold pretty close to that even up till 7k thanks to the tricks of vario-cam and the intake tuning flaps on ram air tuning. If you look at the 4.0 RS, it can pull over 390 g/s at 8250rpm with its dual vario-cam and 2 intake tuning flaps ( I have watched it on a PIWIS at Barber Motorsports Track). That's some serious VE !! That's Turbo VE on a NA motor..All this magic happens ABOVE the head gaskets also, all the goodies in the bottom end just keep it from going "boom". My calculations for the 4.0 RS engine pulling in 390 g/s is 124% Volumetric efficiency at 8250 rpm..

Did a few pulls on my 2002 986 3.2 about an hour ago. Car pulls strong for a 3.2, good torque down low..And I agree with Ahsai, logging is better than recording, just don't put but two or three PID's at a time though, use RPM , MAF , then do others on a separate log. Car: 2002 986 Displacement : 3.2 Mileage: 22k MAF: 202.75 IAT: 78.8F Ambient temp: 55F RPM: 6961 Humidity 32% Altitude : 660ft Baro 30.0 in/hg

Ok, I was able to use Durametric to log my 3.8L numbers. I did a few runs and used the correction factor for each run. I got ~282 g/s (corrected), which is very close to the Torque pro value (277 g/s corrected) Durametric is quite accurate because I got ~6 readings per second (vs once per second for Torque pro).

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my kids decided my measure tape would be fun to play with and now it magicly disapeared. Cant get a perfect measurement. Looks like the factory piece is 3.75 inches. I believe the fabspeed unit to be 3.5. i emailed fabspeed but it looks like they respond quickly when your gonna buy something but not so much when you have a tech question.

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The factory's air box/maf housing looks big just looking at it, but I just measured it with an inside mic to be sure ( been a while since I had done that) . the ID right at the sensor hole is 3.322..

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Yea, Fabspeed may have some explaining to do if they used a different size ID and are playing games with the DME. I just measured the stock air box/ maf housing , it does look bigger just looking at it, but using an inside mic right at the sensor hole is 3.322in..

I'm usually so into data like this and have been trying to find the time to do some pulls! Fingers crossed i'll get some time this weekend. @Porschetech3 any interest in my using my PIWIS vs TorquePro to get the values? Or are we trying to keep the data consistent with the same app/similar readers?

Considering these cars are Metric, why not post all measurements in that?

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I try to stay with g/s and F because that's what posted by the OP. Also those are the default units used by the Torque pro app. Durametric uses kg/hr and C by default.

Porschetech3 may know this. I've read the factory info about it but still do not quite get it. In Durametric/PIWIS, there are two values returned. One is called "Mass Air Flow (HFM)" and the other "Mass Air Flow". These valuaes are different (not by alot) most of the time. I believe the former is what is measured by the hot film MAF sensor while the latter is including other flows such as the evap flow. No idea how the extra flows are measured after the MAF sensor. Perhaps derived from actual AFR the O2 sensors see? The former correlates perfectly with the voltage signal of the MAF (another value reported by Durametric) while the latter does not entirely, especially at lower call flow rate. Does anyone have more info?

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If you could do both, that would be great !! Am mainly interested in accuracy, but you are elite in that you have PIWIS, not many people has that. The different bluetooth devices, apps, phones may have problems with sample rate, or spikes, but the data comes from the DME, so the data should be the same, but slow a sample rate will cause it miss the max maf, and a spike will, well be a spike. You can recognize a spike by running a log, the spike will be out of place, slow sample rate can be countered by doing pulls in 3rd gear so that max maf will be available for a longer period of time.

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g/s and kg/hr are both metric. Fahrenheit and inches aren't. I can understand using Fahrenheit since most of you Mericans have no idea how to relate to Celsius, just as the rest of the planet doesn't know how to relate to Farenheit but, why use inches when all those parts were made to metric dimensions? Most Americans know how to relate to millimeters because they were forced by the auto industry so just use it.

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The Mass Air Flow (HFM) is the actual value from the MAF sensor.(HFM= Hot Film Module) The Mass Air Flow other value is the default map in the DME, the DME uses this map if the MAF is unplugged or has a total failure, it also uses this map to check on the MAF performance. If the MAF sensor value gets to far from the default map, it sets a code. The air from the evap system is not measured, but is predicted and adjusted for when the purge valve is active. The air from the AOS has already been measured, and the blowby is recycled.

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Thanks. That makes sense. The value I reported was the HFM so that's the correct one for this thread then. So one can plot this measured vs spec'ed values and check if the MAF is healthy (i.e. expect a 45 degree straight line in the ideal case).

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You're asking a much bigger question than this thread

Just want to share some cool Excel plots you can do from Durametric log for my 3.8. This one is the measured air flow (kg/hr) vs rpm plot. From the vehicle speed measurements (6 samples per second), assume a weight of the car you can compute the rwhp and torque (measurements were done on almost flat roads). If you look at the upper envelope traced out by the dots, you'll see that these are pretty close to the IPD plenum dyno plot.

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Because I'm "old school" and all my precision Micrometers are USA made! Precision doesn't care whether you use English or metric units, just how well you use them.. 3.322in = 84.37mm is that better for you?

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Well, I have found that the default map reacts slowly compared to the actual MAF sensor. Sudden changes in air flow are not picked up by the default map, or at least not displayed quickly, it is Alfa-N map and uses TP,RPM,IAT to calculate/display mass air instead of directly measuring it. I have found that actual MAF can deviate quite a bit without setting a code, so use it with a grain of salt.

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I love these maps !! You can see a couple of "kicks" in there from the ram air tuning at about 4100 and 6100. Ahsai, what were your temps during the above maps? Can you calculate your VE at 4100 rpm? I have done it and see some serious VE, see what you come up with.

I'll give it a try with the PIWIS when I can - was being held back because my laptop battery has degraded but a new one just got delivered so I should be good to go!

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Make sense and thanks for the explanation. Yeah, I'm actually surprised how good they line up with the stock dyno plot with only a 6Hz sampling rate. Of course we have to take the numbers with a grain of salt because the numbers are very sensitive to my assumptions: 3,400lb and the roads were flat. However, I'm surprised how well the SHAPE match the dyno plot.

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I'll also have to figure out how to get the data! Guessing it will be under DME > Actual Values - keep you posted!

Hi Dan, To do logging with Durametric, it's a bit more involved. I'll summarize the steps here: - Go to DME Actual values - Check the parameters you want to log (best to limit it to less than 10 or so) - There's a small tab right above the list of parameter that says logging option or something like that - Pick "Fast" and "Digital only" - Save the config file, which remembers which parameters you picked so next time you only need to open this configure file as opposed to manually checking all those parameters again - Click "Start" to start logging - When you're done logging, click "Export" and save the log to a csv file - Click "Stop" Next time you log, just click recall the same config file and then click "start" to start logging.

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That reminds me, I need to order a new laptop battery also, mine went flat last time (I was going to use Durametric to log), before I got out of the neighborhood. Ahsai's instructions are great for us using Durametric, but you are using PIWIS and honestly I can't remember (Alzheimers?) the steps. Hopefully you can figure it out, or maybe it will come back to me. Ahsai, what were your temps during the above maps? Can you calculate your VE at 4100 rpm? I have done it and see some serious VE, see what you come up with.

Thanks Ahsai and Porschetech3, steps for PIWIS are: DME > Actual Values Input Signals > Measurements > Select Values > Data Logger (start) Seems to be able to map to 1/10th of a second: I love PIWIS... haha

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Yes and it's better for everyone else that lives outside of the US.

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It goes up smoothly to MAX then goes down abruptly because usually that's where the redline is and I had to shift up. Intake temp was around 45C and here's the VE plot of my 3.8. You were right about the bump at ~4k and 6k rpm.

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Looks like the VE is about 110% from 4k-6k then falls to 95% from 6k-7k.

Yes. The VE could be lower across the board because this is a 3.8L with 3.6 stock intake above the head gasket. Will be interesting to see the same plots for the stock 3.6. Hopefully sometime next week.

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Glad to help out my neighboring countrymen. Here is a handy link to phone app for you and others when we "Mericans" use things like miles, gallons, lbs, oz, dollar, acre, PSI, Fahrenheit ect. https://play.google.com/store/apps/d...d=kr.sira.unit

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As well as drive on the other side of the road!! :-p

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I'll admit, I'm to set in my ways to ever get used to shifting gears with the wrong hand !! lol

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Always makes for some "interesting" driving in other countries!!

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I bet it does !! I'd be missing shifts going and coming..

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I wasn't too bad actually, although last time I drove a LHD was a Renault SUV haha.

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I miss not having access to PIWIS, going to have to get one in the future..

Well i have done dozens of runs and every time low 280's is my max number. Still havent heard from fabspeed in regards to ID at the maf. Even PM'd them thru here and nothing. I noticed 1st to 2nd redline only get me to 260. 2nd to 3rd redline gets me the 280. 82 degree temps and 24% humidity. I had to keep getting out of it @ 120mph so thats the most i could find out.

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282 g/s is a great number for a 3.6 even with the fantastic weather conditions you are having in Florida at this time, hence the need to verify the ID compared to the calibrated ID of the stock air box. I think fabspeed knows what we are looking at as is reluctant to respond..Someone may have to physically do a precise measurement. It doesn't surprise me that 1st 2nd gear will not display the max maf. The MAF is increasing so rapidly that sample rate has a huge effect. 3rd gear slows down the MAF increase enough it can be displayed. Thankx for posting your numbers !!

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The foxwell has a few different places to access the MAF values. I did a quick pull this evening and came up with 230.5g/s. IAT was 67.

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That's a good number for a 3.4, 230.5g/s / .75 + 307.33 Mhpp ( no losses from oil pumps,WP,Alt,PS,ect. , and especially from drive train) With MSA correction for altitude (600ft) IAT (67F) your correction number for this pull is 1.047 230.5g/s x 1.047 = 241.33g/s / .75 = 321.77Mhpp (corrected for comparison to other corrected values).....Now, if we could just break that down into how much for each change from stock like plenum, TB, AWE headers, catless x-pipe ect. Hopefully with more data from others we can dial in on some things...

For those curious in why I'm interested in the ID of the fabspeed intake or any other MAF housing, let my propose a scenario. I'll use (IF?) to denote an unknown hypothetical. The stock air box MAF on 996 99-04 housing measures 3.322in., to compare flow to a different size housing, we use the radius to the fourth power.. So, 3.322 / 2 = 1.661, 1.661 to the 4th power = 7.611 (IF?) we had a MAF housing that measured 3.250..3.250 / 2 = 1.625, 1.625 to the 4th power = 6.972 7.611 - 6.972 = 0.639 / 6.972 = 0.091 x 100 = 9.1% So on a calibrated MAF of 3.322 that flowed an actual 250g/s the (IF?) 3.250 MAF housing would report 9.1% higher or 274.72 g/s. (uncalibrated-over-reporting) The DME would see the over-reporting and over-fuel by 9.1% or 1.96g/s or 2.62cc per second or 157cc per minute. This over-fueling would cause the AFR to be 11.46:1 instead of the desired 12.6:1 for MAX POWER.. 250g/s @ 12.6 AFR = 19.84g/s fuel 274.72g/s @ 12.6 AFR = 21.80g/s fuel So you can see why if useing the OEM MAF sensor and DME, you MUST use a housing of 3.322 ID...( 84.37mm ) Probably why Jake Raby only approves of the OEM intake??

Right. IF the diameter of the intake is smaller than stock, the MAF will over report the intake air rate like you explained. However, the closed loop fuel control (per inputs from thr O2 sensors) should pull fuel to maintain the optimal AFR, right? The MAF will be just like a bad over-reporting sensor to the DME and the DME will be able to adapt. Perhaps we can ask if Mbren has negative FRA and RKAT in the order of -10% or so?

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Well, the fuel control per narrow band 02 sensors will pull fuel to maintain Lamda 1 (Stoichiometric, AFR 14.7). However narrow band 02 sensors only work very near 14.7 and cannot adapt fuel mixture to 12.6 (best power) for WOT. At WOT the DME goes open loop, ignores narrow band 02sensors (since they are not valuable anyways at AFR's near 12.6:1) and relys on MAF since pulling fuel would be dangerous. Newer systems that use LSU4 wideband 02 sensors, like used in 996 Turbo and 997 ,can adapt mixtures over a broad range from 17:1 to 10:1 and even at WOT, like what you are thinking "Perhaps we can ask if Mbren has negative FRA and RKAT in the order of -10% or so?" yes, it would be interesting.

Yes, I agree in the WOT scenario, where the DME goes to open loop fuel control. It just wasn't clear to me you were talking about WOT.

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i should i have taken a screen shot of thoses as well. I have them on the next screen. I have monitored thoses as well during these runs and i always stay within 4 or 5% +/-. At idle it is +/- 0 to 2%. I will admit i am surprised by this. I would have expected that a car of this age surely would have some leaks somewhere. But long term is almost always 0 and short term is as described.

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Interesting! Remember that I also got some very high spikes like 312g/s in one of my runs so I decided to use logging instead so you can see all the values leading up to the max and also the values after the max. That way you can tell whether the max is a spike. I remember I got these spikes at the point of shifting right after WOT.

Here is a short drive. Engine @ operating temps. You can seen the high and low parameters on the gauges. This snapshot was @ idle.

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Very nice and healthy. Based on my computation, your VE is 116%, which is awesome!

I have brought home my Snap On Verus. I can get screen shots with it. It has a much higher sample rate and amazing graphing. The only problem is for some reason with porsche it wont put all the pids on one screen so i cant always get what we want to see at the same time. It puts them into like 4 different groups.

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That would be very interesting to see. I can only get Durametric to return ~6 readings per second for each of the sensor I picked.

Stock box fabspeed

Realized thoses pics might be confusing. Both have the measuring tape inserted where the MAF goes in. Stock box has a rubber boot so i could remove it and easily get a pic of the cross section. Because of the design of the fabspeed it is impossibe to get an inside view of the cross section so the pic is taken from where the maf goes in.

So they have the same diameter? Hard to tell from the pics.

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looks like it to me!

Happy to see my camshaft deviation @ 3.31 bank 1 and 1.43 bank 2. And oddly enough i can only measure the MAF in voltage and kg/hr. No g/s and snap on

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Very healthy. Yes, Porsche DME only reports the MAF in voltage and kg/hr natively if queried by a Porsche/equivalent scanner. You can see my plots in post #134 are also in kg/hr. Mine is a 3.8 and yours is pulling 280g/s or 1,000 kg/hr!

Ok. This data provided by snap on. RPM: 7294 MAF: 994 kg/h (276 g/s) IAT : 96.8 ALTITUDE CORRECTION FACTOR : 1.01 OUTSIDE AIR TEMP : 74F COOLANT : 188F OIL TEMP : 194F Graph was smooth as can be and the highest recorded MAF was just before closed throttle @ 7294 rpms. also monitored on torque pro and results were very very close. and as previously posted - highest numbers were obtained at the 2nd to 3rd shift not 1st to 2nd.

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Very nice. Wish I had roads here for a 120mph pull. Oh wait, 2nd to third. That's what I've been doing too. You mentioned you had Feebspeed intake and exhaust. Do you have the stock headers?

Im just confused though. The purpose of this thread was horse power possibility. Doing the math. That put my car 360 to 370hp unless i am missunderstanding this thread. While i agree my car is quick. Its still a factory 04 c4s cab built with around 320 horse. Yes i got fabspeed maxflow mufflers, fabspeed comp intake and RSS underdrive pulley. But potentially 40hp from that?

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Yes. Stock headers and cats.

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Yes you are correct, the purpose of the thread is horsepower potential Mhpp using Mass Air Flow . The math doesn't lie. The Mhpp (corrected for weather) will be higher than manufactured rating of 320hp by about 5% because there is "no Loss" from oil pumps, scavenge pumps, friction, Alt, water pump, PS, and of course especially drivetrain. So the bone stock 3.6 M96 with factory rating of 320hp will have a Mhpp of 336Mhpp because there are no "mechanical power loss" and only "thermal power loss". Your Mass air flow of 282g/s / .75 = 376Mhpp, that's a 40hp increase and is why we are very interested in evaluating the fabspeed intake as to how much is actual increase in Mass air flow and how much is "over-reporting" due to smaller cross-section and not being calibrated to the MAF sensor. Is that metal sleeve on the fabspeed intake going all the way down to the cross-section? Due to the design and position of the sensor hole, it may be difficult to measure the cross-section. It's just like coming off a chassis Dyno with an impressive number on a near stock car and wondering where that number came from !!

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Yes it is.....guess the fabspeed claim is truthfull. But i am sure there will still be people to say its a lie

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Could be ?!! Math/science doesn't lie !!

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too bad someone with a dyno in the central florida area wouldnt be willing to prove or disprove this! 😁

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My saying is " If the results differ from the theory, believe the results and invent a new theory" !! Math/science doesn't lie !!

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That's impressive. Is it this setup? https://www.fabspeed.com/porsche-996...BoC8BAQAvD_BwE

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yupp!

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Nice! Now you have your baseline, you can probably evaluate the IPD plenum better in the future.

Well the IPD will have to wait a little. My Porsche fund just dropped a whole lot. It would figure that after i just did the water pump with LN tstat and OE coolant (with Ahsai amazing flush write up) the left rad would decide it was at it end of life cycle. I just ordered a pair of these!

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Also wanted to point out that i DID get oil temps using my Snap On scanner. I could not get it with my Torque pro app

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Yes because the Snapon scanner also use Porsche specific protocol to communicate with the DME. If a scanner reports cam deviation and oil temp, it uses Porsche specific protocol. I think more scanners are capable of doing that now e.g. icarsoft scanner.

too bad it won't show ignition over rev counts. Not that i really care. Just figure it would be nice to compare as everyone always post about it.

Fabspeeds response to my asking the ID @ the MAF. "The oval part of the competition air intake is 3.6� x 3.1� "........

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Is it oval shaped at the cross-section where the sensor hole is? 3.6 x 3.1 = 3.350 circumference, that's only 0.028in larger than the stock MAF housing. A 0.028 larger than calibrated MAF housing would result in a slight "under-reporting" of the Mass air flow. So if that measurement is precise your flow numbers are plausible, if not slightly "under-stated".by 3%..very interesting !! 3.350 / 2 = 1.675rE4 = 7.87 3.322 / 2 = 1.661rE4 = 7.61 7.87 - 7.61 = 0.21 / 7.61 = 0.03 x 100 = 3%

I would believe it could be oval. The MAF is located right at the end of where the two "intakes" meet.

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Is there a "divider" inside where the two intakes meet? Does it extend near the MAF sensor? I'm loving the design, and looks like the flow numbers are plausible, and the fuel trims being near 0 back that up... They say on the web site that it interferes with SAI and engine comp. fan on the 99, that's a shame, but looking at it I can't see why it would interfere..

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Just speaking from opinion i would expect to see dividers up to a point. It would be needed to help tunnel the air and not making it just a huge disturbance. I wish fabspeed would join this thread!

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I agree about the dividers. It would also be beneficial to have "air straighteners" in there before the MAF sensor also to keep turbulence from skewing the MAF reading. I see fabspeed responding on the exhaust sound thread, and I'm sure they have lots of flow data (?) when designing the intake, but the guy responding on the threads may not be a designer with answers to our questions.

I responded to them and asked them to join our conversation. will see what happens

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Since this thread is about "MAF value = Horsepower potential" and they have designed a MAF housing/intake system, if they will divulge flow data and method of calibrating/verifying the MAF housing to MAF sensor accuracy, then they are welcomed !!! Using MAF value to evaluate IDP plenum, GT3 TB, camshaft design, or just air filter, or even exhaust systems, for flow gains or losses is very straightforward. But using the fabspeed intake/MAF housing to evaluate "itself" is quite a conundrum, with the only supporting data is the physical measurements and fuel trims indicate that it is not "over-reporting" or "under-reporting" except by 3% according to their ID information of 3.6 x 3.1 oval shape housing.

I'd sure like to see the inside that FS collector.

Perhaps i will put my OE housing back in over the weekend to see what the difference will be. Truth be told i am lazy and don't want too. But if they don't join the discussion maybe that data can help something.

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I have visioned it in my head, and to be honest it causes me more questions than answers. But I am pulling for it to all be supported by the Math/Science and be more actual Mhpp. I want to find as much Mhpp and in as many places as possible ...

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I know the feeling, I was lazy today. I did my "spring cleaning" on my washable K&N dual cone air filter. The dishwasher does a great job, just make sure the wifey/GF is gone shopping for a few hours... Yes, it would be important data !!

best i could do

The divider (or whatever we sre going to call it) is 5 inches away from the MAF

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Thanks !!! I'm loving the design !! Air, being a compressible fluid, has much the same flow dynamics as water ( a non-compressible fluid), if you envision water flowing through the intake, you can see how air will react through there..

Excellent, thanks for taking the time Mbren1979. I look forward to seeing more testing!

2003 C4S 59k miles . Bone stock. I got a chance to do a pull yesterday and recorded a max of 232 g/s in 2nd. I didn't think to get other variables at the time and wasn't in a position to go any faster or do more than that one, but it's a data point.

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232g/s / .75 = 309.33Mhpp ( uncorrected for altitude and weather) Thanks for posting your data !!

Did a pull today on my 99 3.4 using Durametric instead of Torque Pro.(was waiting on a new laptop battery, long story). Logged 721 kg/hr at 6840rpm, 107F IAT, 79F ambient, 660 altitude 721 kg/hr = 200.27 g/s 200.27g/s / .75 = 267.02Mhpp 267.02Mhpp x 1.134 = 302.84Mhpp ( corrected for weather and alt.)

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68,400 rpms? I wonder how many ignition over revs thats going to be!

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At least the rod didn't let go !!!

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Yeah, but i bet your IMS is gone!

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lol,,175k still going,(original) yea, I play the odds !!

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I have a flip phone, so it's Durametric for me. Any instructions on how to use it for this? I wish Durametric provided an instruction booklet with their tool...

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Yes, for Durametric, select actual values, then select RPM, Mass Air flow, and IAT, then select LOG in the top right, then start. Then do a pull to red-line in 3rd gear if you have the road/room, or 2nd gear if 3rd is not possible. Then press stop. You can go through the log and find the max-MAF value along with the RPM and intake temp. Will also need the ambient temp, and your altitude to do corrections, most GPS's have altitude, and the baro/humidity really don't effect much using the MSA correction.

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Thanks Doc. I'm at sea level and have one stretch of road that I could do this safely before I end up in the ocean...Or I could take her to the drag strip

One important step. Make sure you select the highest sampling rate.

which value i should take in Durametric? Do I need some recalculation? Did not log the rpm though I measured a max air flow of 258.3 kg/hr Is this equivalent to the so called g/s value you measured in your Torque app? Anyway my testing conditions Did now 3 runs all around the same value: 256, 258, 262 Measured in 3rd gear Ambient temp 13.5�C (56F) Air Intake Temp 17�C (62F) barometric pressure 1008.5 hPa (756 mmHg) Alt: -3m under sea level (-10ft) Rel Humidity: 65% Car is a 2002 996 C2 3.6 with 124.000miles Intake mods: IPD intake plenum, hot AOS vent line relocated to airbox exhaust mods: 200 cell Top Gear cross-over cats; Cargraphic Sound mufflers

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That MAF number looks like g/s instead of kg/hr, are you using a genuine Durametric? If kg/hr the value should be @600-700 Anyway 262g/s / .75 = 349.33 MHPP Since your IAT is at 62F and altitude is -10ft with 65% humidity the correction is 1.016 349.33 x 1.016 = 354.92 MHPP (corrected)

Are you sure the units in torque app are right? Just curious... where does the 0.75 factor come from. I am not that an expert. i would not mind a more scientific explanation. I am an (metallurgic) engineer so no problem with that. I used the website you mentioned; it gave me a correction factor of 0.95 what do we do different (did you notice the inchHg vs mmHg) to be conservative I would use the koerst value

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Yes I'm sure the Torque Pro App has the correct units. I have used Duratetric and Torque PRO for my 3.4 and get 721kg/hr in Durametric and about 200g/s in Torque Pro. They are correct. The .75 factor is a conversion from thermal energy to mechanical energy, it was not achieved easily. You can try to do your own if you want, but this factor is very good for our engines, and the best I could do. Did you use this calculator for weather corrections? http://www.wallaceracing.com/weather-corr.php What do you mean by "koerst value"?

I see this thread has been quite for months, but I just had to chime in. I just got Torque Pro ($5) and an $11 bluetooth dongle bluetooth dongle off Amazon, and am thrilled with the data available. Can't wait to run the MAF tests on my stock '99 996. I read this entire thread from top to bottom, and appreciate all the guidance here. Can anyone tell me if Torque Pro can run cam deviation?

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Torque Pro won't do cam deviations, but will do a lot of gauges to monitor engine. I keep my big screen phone dash mounted to use Bluetooth/Torque Pro for additional gauges to monitor. I have been wanting to do a Double Din head unit for additional gauges with Bluetooth/Torque Pro, but still on the fence on that one. I love gauges !!

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What is my cheapest means of measuring/monitoring cam deviations? Have you thought about an Android tablet mounted on center console?

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Yea, but I think Android Double Din head unit does the same as a tablet, I'm just still on the fence..

I have the Durametric. It reports actual engine torque in % Maximum. What is that maximum torque in N-m or ft-lb? I have scoured Rennlist and the Internet and can't find any reference to this.

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I'm not sure (or trust) how Durametric calculates torque, but the 3.4 engine is 350nm/258ft lb torque, and the 3.6 engine is 370nm/273 ft lb torque..

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Since it is labeled "actual engine torque" I am hoping that there is actually a torque sensor on the driveshaft. This could be acquired by measuring the angular twist of the shaft under load and knowing its diameter and the shear modulus of the steel.

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Yea..... but there is no such sensor there or anywhere else, and the DME doesn't put out a torque value, so , the Durametric is taking MAF, RPM, throttle angle, ect. to do it's own calculations...

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There is definitely not a sensor for torque. Even if there was a sensor to measure the physical torsion of the shaft, that torsion would be a function of the engine input torque vs the load on the shaft. Load is a variable as it would depend on drivetrain losses, the exact car weight (uphill/downhill), passengers, gas level, wind, air temp, etc. Most of those apps have you input the car type, and it uses either an approximation, or an actual value for weight of the car that you enter. Then it will calculate the engine 'force' based on the car mass and acceleration (F=ma) using the measured change in speed vs time. It converts to torque from linear force (using rpm), but that's just one more step. Sampling time will really matter here too, calculating a derivative (acceleration) from velocity vs time of 5-10Hz or so results in acceleration at 2-5Hz, and can be very noisy. So, the apps will apply some smoothing, which can have huge effects on the 'peak' value. Also HP/Torque calculations taken while driving should be with a grain of salt, because like I said, it will depend on the road slope, wind direction/speed (resistance), air temperature (density), road resistance, speedometer accuracy (tire size and wear), and other factors, all of which can have an enough of an effect to throw off the data. They sound minor, but 1% error (which each of those things can contribute) is already 3HP. It can be interesting to use programs like VirtualDyno, etc. from OBD WOT drive data, but one must only compare the same car/setup to itself, don't expect the HP/Torque numbers to mean anything real, and record runs that are as exactly consistent as humanly possible. And still expect error comparing runs. BTW. Thanks for resurrecting this thread! I had missed it, and I love good data. I like the proposed use of MAF data (plus IAT, rpm, altitude(air density)) because measuring and tracking how well the engine is breathing is a pretty fundamental measurement that removes alot of outside noise. My car is in pieces right now for a UAOS install and some other work, but when it's running, I look forward to collecting consistent MAF data. (and a new set of AOS vacuum / Blow-by pressure data: https://rennlist.com/forums/996-foru...w-by-test.html )

Hey Josh, every thing you just posted is spot on !! You have your head wrapped around the Physics and Dynamics of Automotive Performance very well as seen from this post and others,and have been a pleasure to work with on your UAOS ! Just curious as to what you are doing for a living, and hopefully it's in the Automotive Industry somewhere..Glad you enjoyed this old thread, it didn't get a lot of participation, but did provide a lot of "late night reading" for quite a few people..The Bluetooth OBDII Guages available in this thread are really sweet and nice to have to monitor your engine..

Thanks. A PhD in Physics helps; I'm not working in the automotive industry though, this is just the hobby. Actually, I've done much more data and analysis on my daily driver than I've managed on my 996. For some strange reason when driving the 996, I tend to forget about logging data (Bluetooth OBDII to TorquePro) and I come back home having collected nothing but a stupid grin.

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lol,, I know the feeling, my radio stopped working for a couple of months then just came back on by it's self, and I didn't even care !!

Had time to read the thread and collect the data. I didn't make entries for the conversion from mass air flow (i.e. chemical horsepower potential) to estimated mechanical HP (Porschetech3's 0.75 efficiency number), nor did I enter the Motorsports Standard Atmosphere conversion values. Maybe in the next version, but here's what's been provided so far, grouped by engine size: And here's SI units, if you're into that sort of thing... (which I usually am): I can post the text/xls if anyone is actually interested.

Nice bit of work. It's a shame we didn't get a bigger sampling of cars.

When it's possible to do so (aka when the snow melts) I'll do some pulls in my 996 Turbo. Obviously forced induction gives a volumetric efficiency of much greater than 100%. I actually have some Durametric logs already without the MAF signal though.

Nice chart Josh !! Even with the small sample looks like the big winners are the Fabspeed Competition Intake (Mbren1979 ), and Low altitude.......

OK, late to the game with data... 3.6L 2002 95.5k miles 7077 rpm 232 g/s MassAirFlow(HFM)(calc) 837 kg/hr MassAirFlow(HFM) 74F Intake 96 mph (154kph reported) 41F Ambient 74% RH 550 ft 29.93 inHg Barometer( how about those units... ) IPD 3.6L plenum, California crappy gas Seems in line with others. Maybe a touch lower. Measured with Durametric at fastest rate, 10hz

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Thanks for posting your Data !!! It will be very useful in the future !!

Adding injector duty cycle to this would be exceptional..

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Yep, now if we could just get more people off the couch and into the garage to post Data !!

My 35 year old leather sofa is really really comfortable. I must like you guys to get out of it to take this data... Here is tonight's run with injector time & duty cycle added 3.6L 2002 95.6k miles 6909 rpm 230 g/s MassAirFlow(HFM)(calc) 828 kg/hr MassAirFlow(HFM) 14.77mS Injection time 85.0% Injector Duty Cycle 55F Intake 94 mph 42F Ambient 69% RH 550 ft 29.85 inHg From my extremely short reading on duty cycle, 85% seems to be the target max. So I guess I'm happy. Road was a bit busy tonight. I only made the one pull in 3rd gear Here are the numbers for max RPM in 2nd gear 6996 rpm 232 g/s MassAirFlow(HFM)(calc) 835 kg/hr MassAirFlow(HFM) 15mS Injection time 87.0% Injector Duty Cycle 74F Intake 65 mph 42F Ambient 69% RH 550 ft 29.85 inHg At idle, 700rpm, the injection time is 2.36 to 2.39mS so the duty cycle is 1.3-1.4% You will notice the difference in IAT between 2nd and 3rd gear. The engine compartment cools significantly when above 65mph. I expect this is due to the spoiler opening up. Semi-educated WAG. I'm still always amazed at how strong this car pulls through the gears. I don't know how racers keep from over revving these engines. The power keeps going.

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Yep, almost 20F difference. That's why I keep my spoiler deployed all the time (plus I like the looks of it deployed YMMV). the factory air box takes a while to cool off after it gets heated up. My Custom Short Ram cools quickly at 40mph as there is no hot plastic in close proximity and all the hot air exits the bottom of the engine compartment at 40mph and above. The "Banshee Scream" I get from my Custom Short Ram with the "Sound Enhancer" added from 6K up makes me want to not stop revving all the time , I want to take it to 10k !! Getting off the 35 year old leather sofa to post Data is good for your Health !!!

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Do you have any pics of your intake setup? -Tom

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Just thought the same thing.

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I built a dozen of these in 2011 (before my heart issues). The "Sound Enhance" does the opposite of the Helmholtz resonator, instead of quietening the intake, it enhances it.. I got them from Keet Boon who was the Inventor and works for Mann+Hummel ( the big Kahuna in factory intake systems). The Custom Aluminum MAF Housings were made by a guy in Michigan who does aluminum fab work (to my specs).The Dual Cone Filter and the Rubber Elbow are off-the-shelf stuff; I made the clear Lexan shields (heated and bent/formed) , made some from aluminum, but I liked the see-through Lexan ones best..The sound is INCREDIBLE. especially on a 3.8 liter M96/7 !! It's best to used with stock exhaust , a loud exhaust interferes to me. Was a PITA to install, not a quick DIY like installing a K&N , Evoms , Fabspeed . The "Banshee Scream".. Aluminum "Banshee Screamer"

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Very clean set up, did you use a GT3 throttle body? Think I'm going to do the 997 airbox, and IDP plenum w/GT throttle body. It's nice to see more exotic set ups from time to time.

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Thanks, was a fun project..No GT3 throttle bodys, those pictured were 997 3.8 "S" models and were the best sounding, all it took was a road test to hear it and you would want it, all the cars are local.

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[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/images/smilies/smile.gif https://cimg5.ibsrv.net/gimg/rennlist.com-vbulletin/1106x711/7ntr8f08qukv2evby4ielq_thumb_241b_71bad5dd30b3a9b256f593f88cd157deb0c499d6.jpg

On the 996 Turbo, a lot of people who make big power seem to have a tendency to ruin MAF sensors. One theory is that these sensors max out at around 500 g/s. A lot of us just go to a MAF-less tune to get around this. On the 997 Turbo Porsche went to a dual MAF setup (one for each cylinder bank). Those of us with MAF-less tunes get to have fun noise maker intakes as well, such as filters on turbos or fender well intakes. My car sounds like a jet engine.

I�d do this if know exactly what software to get for an iPhone and what cable or bluetooth device to plug in. I�m technologically challenged but the results aren�t so hard to wrap my head around.

"MAF-Less" engine control systems are named either Speed Density Systems, or Alfa-N Systems. They are less sophisticated than "Mass Air Flow Systems" but are easier to Customize to run huge injectors and high boost pressures by manipulating values, a MUST for a very radical custom engine, also like you said more freedom for intake arrangements !!

From jdbornem's post 234 you can see that my original MAF numbers were on the lower end of the range for the 3.6L measurements. Being a stupid competitive male, I needed to try to improve this. So I cleaned the MAF and retook the data. As you can see, the airflow reading increased and the injector time changes along with it. I don't have any records for when the MAF was last replaced or cleaned. I would assume it's never been done. The car hasn't thrown any codes to indicate a problem. This was done simply to generate contrasting data. I would guess the small change seen, 3-4%, is likely a normal contamination decrease that is seen when running in clean air environments. One concerning point is the injector duty cycle. 95.5 seems a bit high. I did reset the trims a short time before this run, 15 minutes. Depending on how fast the computer learns, this may be a factor in the injector timing... The cost of getting this new set of data was a few extra counts on the overrev counter 1. I never run the car close to redline, except for these tests, and from now on won't.

We didn't have rev limiters when I was growing up. You would twist the motor until the power fell off, then shift to get back into the power. If you forgot to shift, the next thing would be "valve float" to intervene to stop the motor from turning up.. My 2.0 liter 525hp Race motor I built back in '86, I had to limit the RPM's to 11.5Krpm, I couldn't keep the flywheel bolted on past 12K .. !!!!

Update for new headers, 997 airbox, Soler throttle body and removed screens from deck lid. Runs today, 1 and 2 nearly identical. 2 pulls per run. All 4 runs peaked above 921 kg/hr at 7,000-7,200 rpm. 3rd gear. Durametric data. 3.8L rebuilt with Nickies, some head work, etc ; with 200 cell TG cats, Soler throttle body enhancements, Agency headers? (the ones on sale cheap last year), TG mild sport cans and Softronics tune. Helmholz delete, 997 airbox. 5w40 oil. Optimum engine and oil temp. 660’ alt 55% rh 108f IAT 30.41 in/hg 55f ambient MSA correction 1.089 7,200 rpm; 917 kg/hr or 254.7 g/sec uncorrected for MSA; 277.4 g/s corrected. 277.4 / .75=370 theoretical ponies. Ignition time 17.4-17.7 before limiter cut Previous run was 239.3/270.7 MSA=361 hp. Ignition time was 15.75-16.1 So my assumption is the engine likes the improved intake breathing and exhaust exit. And my 0-60 time dropped from 4.3 to 4.2. Wheee!

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Please post a photo of how the 997 airbox and Soler throttle body fit together in the engine compartment. Does the TB have a larger diameter than 996 stock?

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The throttle body exterior dimensions are the same as stock 3.6. The inner diameter is larger.

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Nice power gain and total !! It's hard to get a gain from these M96 engines, well done....

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With the new breathing in order, is it time for a new tune?

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No. The torque is impressive. The rear end already has enough trouble with squat on corner exit. The front washes out when I want to go full gas. Lord willing and the creek don’t rise and the engine stays healthy; I’ll put on Ohlins and do a zbomb on this car when the kids are too big to throw in the back (so two years or so). I’m gonna get a dyno run on the beast soon to see how the theoretical gibes with the physical.

Can anyone tel me what app I should by that works with an Iphone?

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It's not so much the App that matters with I-phone, but the Dongle you choose. I suggest the OBDLink MX+ Dongle, make sure it is the "+" version and not the standard LX or MX version ( standard LX or MX will NOT work with I-phone, they work with Android or Windows only)). It will come with it's own App, but can be used with Torque lite (free) or Torque Pro ($5) or DashCommander and many others. You can also leave it plugged in indefinably , it will turn off and on automatically, and not drain the battery.

Hey PT 3 do you ever sleep?

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LMAOoo , I was just thinking someone was going to mention that !! Actually I slept all day yesterday !!! My time clock is literally broken, there is no predicting when I will sleep or for how long, and when I will be awake, sometimes I'm awake all night long. It drives my kids crazy...lol But after 45 years of the 7:30 -4;30 grind on top of all the late night race car building and prep to 3am , once you stop that things go haywire...

Sorry for the ignorant post, but i'm wanting to get some baseline numbers and i'm socked in with loads of snow and cold weather that will keep it around for a while... can this data be acquired via durametric without actually 'driving', just 'revving', since this is just air flow and power 'potential' ? TIA !

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I suspect not. Wide Open Throttle without a load is probably not going to give you good numbers, let alone it�s probably not good for the engine. Look for a nice winter day where the snow and salt have disappeared. Your car will appreciate being driven anyway those rare days.

Yea, i had the same intuition as well... i think we're a few months out from 'clear roads' here in Colorado

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Yes, Durametric will do a good job at logging air flow data at all RPM's How many times per second the "refresh" of the data is important, so doing wide open throttle in 2nd or 3rd gear will allow the Durametric to get a good resolution for accurate data.. An ICE engine is merely an air pump, and the Mass Air Flow Sensor will measure the amount of air that is flowing at any given RPM. It can be used to evaluate the condition of your air filter ( if it is dirty or not) or to evaluate any changes in the air box, intake, cams, heads, headers, mufflers, ect.. It is important to have a NEW or known good MAF Sensor in the original size housing to be maintained throughout any tests/evaluations.. FWIW ; Most flow benches test at 28"wc , the actual running depression is ~56"wc ....56"wc= 10.04 psia @ sea level....28"wc=12.37 psia @ sea level IE. if you bolt on some cams and intake and expect to see a 50hp increase, then you should see a ~66.66 g/s increase in MAF Sensor air flow....

Hi Everyone, I am writing an app in this "vehicle data analytics for car enthusiasts" space that I think you will find very interesting. It uses the same Bluetooth ODB2 adapter approach but the software is built to be a lot smarter than existing apps in how it gathers, analyses, stores and presents data. It's born out of the exact same itch that PorscheTech3 has articulated many times in this post - I'm a data analytics software guy and a Porsche 911 owner. For anyone who is still interested in this thread (I am!) it would be great to share what I'm doing and get your thoughts on it.

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Start a separate thread and keep us updated. I love data.

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Sounds great! You have my attention!

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It's good to see a renewed interest in this subject after a year or so of non-perticipation.. Feel free to post your App developements here or to start your own thread , you have my support either way. I think a specific App will be very sucesssfull... The information that can be gathered/analized/presented is the same as that from a Dyno in regards to Air-Flow ... Air-Flow is the key ingrediant of an ICE engine ( esentially an air pump) in horsepower production .. "Actual" horsepower production can be broken down into two catagories, " Potential" and "Efficiency"... Potential::: The potential of any ICE engine to make horsepower is directly related to how much Air Mass flows through it.. Efficiency:: The efficiency of any ICE engine is determined by how well it uses the Air Mass that is avalible to it.....

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github link?

Got some Durametric data today, finally had several days of warm and sunshine got the streets scraped clear so i could get the car out for some runs... was good for both of us ! 2007 3.8L Stock, 3rd gear pulls Here's the data from four runs from MAF (hot film): 720.3, 727.0, 730.1, 734.2 kg/hr ... converted to: 200.1, 201.9, 202.8, 203.9 g/s 4,976' Elevation 44*F Amb air temp 46% RH 29.38 in/Hg (falling) 1.216 correction factor (from wallaceracing.com) Resulting theoretical HP values: (MAF g/s * 0.75 * correction_factor) 324.43 Min 327.83 Mean 330.66 Max

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Thanks for posting your data.....your MHP is right on par !!

02 cab with 90 k miles. motor seems to be in very good condition. no soot and no noises. I've only put about 1500 miles on it. It has the agency power (i think) short tube headers and 200 cell cats. otherwise all stock. I did two pulls to about 6800 rpm and have the following data. 6768 rpm @ 241 g/s, 6560 @ 226.25, 6114 @ 235 second run....6752 @ 238.5, 6550 @ 228.5, 6133 @ 227 Atmosphere = 45 degree 29.79 inHg 71%

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What is your Altitude ?? 241 g/s = 321.3 MHP ( uncorrected)

Updated the best I could. Some people post atmospheric corrections and some don't. Some add HP calculations after an assumed 0.75 efficiency. I have not recorded those things because the reporting is sparse. For many, there just isn't a complete data set. If I get time, I might look up a reliable source for the atmospheric correction, and add a line for that. Any advised references? I would just want it to be from the same source for everyone. It would give a more apples-to-apples comparison point. For you SI fetishist:

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@hatchetf15 Can you clarify your before/after runs here? I didn't see a separate post, and I can't figure out what the exact setup was for each. What hardware was on the "Previous Run" (239.3g/s), and exactly what was added or modified for this run (254.7g/s)? What were the temperature/atmospherics of your "Previous Run". So as of now, it's not on the table. Thanks!

Yes this is the newest weather correction designed by Patrick Hale specifically for Motorsports, much much newer than SAE........from the Wallace Racing Calulators page... http://www.wallaceracing.com/weather-corr.php

@jdbornem To help fill in some of my blanks ... IAT was 11.3*C and engine RPM at time of max MAF reading was 7,188

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Sure thing! The first run wasn�t submitted since I was trying out how to get the correct fields and data and update rates from the Durametric while driving. After I figured all that out, I did data runs on a later date. On practice pulls I had not installed Soler and Agency Power parts.The following is, indeed, the proper list for the data you posted to the chart: 3.8L rebuilt with Nickies, some head work, etc ; with 200 cell TG cats, Soler throttle body enhancements, Agency headers, TG mild sport cans and Softronics tune. Helmholz delete, 997 airbox. 5w40 oil. Optimum engine and oil temp.

Quotes source post: 18579968

600ft i figured out how to get more data points so I'll do that

More Durametric data from today, after having done the TB + Plenum + new air filter upgrade, this was on the way back from a 40 mile round trip... so there may still be some adaptation time/miles required. 2007 3.8L TB+Plenum, 3rd gear pulls Here's the data from two runs from MAF (hot film): 204.78, 205.53 g/s 4,976' Elevation 53*F Amb air temp 24% RH 30.00 in/Hg (rising) 1.226 correction factor (from wallaceracing.com) Resulting theoretical HP values: (MAF g/s / 0.75 * correction_factor) 335.97 Best run This is still old gas from late fall... i wonder if that has anything to give to this game. Albeit same gas as last time i ran these tests before the intake mods.

Re-ran after adding Soul sport cats. 202.56 g/s 48*F 22% RH 29.38 4,976' Same old gas. 1.218 correction 328.96 Best run. Consistent... just no change

Quotes source post: 18631676

Curious what headers you have? I have 200 cell cats, but still have stock headers on my 997.1 C2S, so while I'm interested in upgrading my headers I wonder if doing one of either headers or high flow cats already maximizes the MAF power potential. Then again maybe MAF power potential remains unchanged but more power is available to the wheels? idk...

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OEM sport headers, same as you... you can kinda see them in my 'build thread' here: https://rennlist.com/forums/performa...l#post18631791

Quotes source posts: 18632821, 18631791

Love your build thread, I've subscribed Nice headers, are those X51? Mine do not look like those though, I have the oem stock C2S headers that are like a shorty 3-into-1, like the ones pictured here: https://rennlist.com/forums/996-foru...4-996-a-3.html

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Pretty sure they're not X51 ... i've seen the spec sheet for this car's build and it doesn't have that option... but now you've got me curious!

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@Porschetech3 Where did you have the MAF housing made? I am interested in doing a custom project like that, to match my 997.1 C2S stock housing diameter.

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This was about 15 years ago, I measured the stock air box / MAF housing to get all the critical exact measurements and made a 3D drawing of just the housing portion, then added the connection for the "Sound Enhancer" and the Dual Cone Filter.. Then transferred the 3D drawing to the on-line E-Machine Service in the .stl format with all the dimension and metal material specs.... E-Machine then sends this to all their partnered machine shops for quotes.. Then you will get a number of quotes from machine shops and I picked one that I liked out of Michigan and had him make me a dozen of them... This is a good way to get certain custom parts made if you don't have someone already, or if your guy is just covered up with work ...

Few notes. 1) Measured MAF values are valid only if the MAF itself is new or nearly new. They do deteorate when they age and will thus be off. If your MAF is original it will be indicating ~10% less than the actual airflow is. This happens without any CELs or stored faults, but may be shown in fuel trims. I've had several 997.1 turbos for tuning and when datalogging stock car the worst had airflow of ~1200 kg/h. MAFs were changed and airflow magically returned to ~1370 kg/h, which btw equals stock 480 hp. 2) If you use logger that has a logging frequency less than 5/sec you might lose the peak MAF / RPM. Something like 1/sec will cause different values on every run, even if environmental conditions are equal. More is better here, unfortunately Durametric is quite crappy and it's the best commercially available so far. For newer ECUs we use VehiCAL and it can log 30-40 different variables at 10-20 Hz. 3) When logging use the highest gear you dare and preferably run uphill to get the engine loaded. Some cars / ECUs even restrict engine's max output on lowest (1-2) gears, so it's better to use at least 3rd. In Mexico. 4) @sealevel logged mass airflow converts to manufacturer's announced hp by g/sec / 0.8 or kg/h x 0.35. OTH logged maf reduces with increasing IAT, so for best numbers run when air is cold and engine is not heatsoaked. 5) MAF sensor must be calibrated to the housing it's used in. In other words if one changes housing's size from the original the ECU programming must be adjusted accordingly. Or the engine will run poorly. There must not be any airleaks between MAF and intake valves, or the engine will behave oddly with high fuel trims. If MAF and injectors are new & stock and still fuel trims are excessive there's a leak in the system.

@pete95zhn I agree with all said....thanks for dropping in.... BTW did you use to come in the 996 thread? or did I use to go over to the 997 thread...lol

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Just got the car on the dyno... and the best run file was 332.99 ... so this calculated power is pretty darn close !

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Yes it is , and works on the simplest of Physics.......less air = less power.....more air= more power.. I remember a time when all Hot Rodders would give their left nut for an accurate/simple air flow meter like our modern MAFs....even Pro track rats who would be at the track every time the gates were open, because elapsed time, as accurate as it is, has so many other variables...

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Not according to my wife when it comes to the fluid between my ears.

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Would be awesome if you could post the graph and mod list in the dyno thread here https://rennlist.com/forums/996-foru...s-allowed.html

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I'll do that.

I've recently been doing some data collection on the targa using a Durametric as we go through the (remote) tuning process with FSI. It got me thinking about this thread, and about what sorts of *potential* numbers I might be seeing. I have some of the data needed and can probably get the rest, but what I don't have is the Wallace Racing correction calculator. Unfortunately that site appears to be down altogether. At least for me; I'm getting 404 errors. Does anyone have an alternative calculator? Absent one of those, I've been seeing a lot of folks simplifying the process down to MAF g/s times 0.8. That's a ballpark number obviously, but using a standard value like that would at least give us consistent comparisons. EDIT: Never mind! The Wallace Racing site hasn't been updated for secure browsing (https:// versus http://) . Drop the "s" and the pages come up. Caveat emptor, yada yada. Now to go do another run or two using different collection criteria...

Yea, I would be interested in seeing some FSI big bore MAF flow numbers vs Stock MAF flow numbers also......thanks for taking the time to collect these...

Quotes source post: 19064535

I just loaded a new map. Gonna let it learn for a few miles and then do some 3rd gear pulls. Hopefully just a few days.

Yes the Wallace Racing Calculators is the best collection of Automotive Performance Calculators you will find anywhere on the net...and have been around for decades... The one to use for HP to Weather correction is this one http://www.wallaceracing.com/weather-corr.php Other very useful Calculators for Automotive use is here http://www.wallaceracing.com/Calculators.htm I must warn you that these are for "reference only" and to double-check and tripple-check with multiple sources before putting in "real world" use....

I finally got out to collect this data. 2004 C4S, 104k miles I actually bought, just out of interest, a 997.1 3.8 airbox, so I did 2 runs with my old stock 3.6 airbox, and 2 runs with the new 3.8 airbox. Both have pretty new filters (3.6 is about 2k miles old), (3.8 is brand new). I had to use the 3.6 snout on the 3.8 airbox in order to clear the SAI pump. I used the same MAF in both, I just transfered it over. These runs were back to back all within about an hour. I'm reporting here the better of each of the 2 runs. My car is stock, except for Top Gear 200 Cell Cats. For both runs: Ambient (F): 60 Humidity (%): 31 Barometric Pressure (inhg): 30.19 Altitude (ft): 715 Atmospheric correction: 1.037 3.6 airbox: RPM 6995 IAT (F) 74.0 MAF (g/s) 249.7 injector (ms) 16.70 injector duty cycle (%) 97.3 "HP" comparison point: 345 3.8 airbox: RPM 7047 IAT (F) 69.0 MAF (g/s) 239.4 injector (ms) 16.08 injector duty cycle (%) 94.4 "HP" comparison point: 331 Hmm, 3.8 airbox moved LESS air?

Updated aggregate results: Mixed/Imperial Units: Strictly SI Units: "HP" comparison point is calculated as: [MAF(g/s) / 0.75] * (MSA Correction Factor) Read footnote (2): This is a purely calculated value, and should NOT be mistaken for actually measured WHP. (even if the result from delirium45 is really close!!)

Has anybody actually measured the cross-section of the 3.6 air box compared to the 3.8 air box ?? IF they are "exactly " then same cross-section then yes.... IF the 3.8 air box has a slightly larger cross-section, then it will "report" a lower mass air flow, when in fact the "actual " mass air flow being the same... IF it reports a lower mass air flow, then it will also reduce injector time leaning out the AFR a bit also...( and looks like the injector time IS reduced)

Quotes source post: 19103192

I did measure the 3.8 before installing it. I'll post the numbers later after I can go find them. I have not precisely measured the 3.6 box after removing it. I was interested in that too.

Quotes source post: 19103196

Yea, a precision measurement at the MAF mounting point is a "must have" to relate the data to........

I think they're the same size. Interior opening, measured in two perpendicular directions: 3.6: 85mm 3.8: 85mm Depth from MAF opening: 3.6: 101.5 mm 3.8: 102.0 mm I may pull the 3.8 and remeasure these at the same time to get a better feeling for any real difference versus just error between these two measurements. I took the measurements more precisely than shown in these pictures. These pictures were just taken to show which directions I was measuring.

Quotes source post: 19103192

Based on my measurements, I think they are the same size, but do I understand correctly that if the 3.8 was larger, then it would be reporting lower mass air flow than actual (as you say), then the engine would be run lean. However, over time, if that were the case, I should see my fuel trim readings start to drift up to correct the AFR. Is this correct?

Quotes source post: 19103289

Well, we are actually talking about two different things that are closely related and even intermingled at times.. I'm just going to skim over a few things giving facts but in a broader more general way as to not get too deep in a never ending rabbit hole ,that may sound like contradicting if not taken literally and knowing that some things will overlap.. But if you need more clarification, or if I sound contradicting, just ask for more detail.. I was refereeing to the injector times in milliseconds at WOT,( open loop) and you are talking about fuel trims to correct AFR ( closed loop).. Our cars have narrow band 02 Sensors ( wide band Sensors were not yet invented) . Narrow band 02 Sensors are very accurate at 14-16 AFR and are tuned to 14.7 AFR ( also known as Stoichiometric or Lamda 1 ) which is the best ratio for the cats..and they switch high/low at ~.5v ..( whereas wide band 02 Sensors can read from 10-19 AFR) So, our cars under full throttle are in "Open loop" and ignore the 02 Sensors, but under idle or cruise loads they are in "closed loop" and use the 02 Sensors to adjust fuel trims to 14.7 AFR ( Stoichiometric/Lamda1) 14.7 AFR is the best ratio for the cats/emissions, and ~12.5-13 AFR is for power Most all MFG's tune their cars on the rich side under WOT as a safety margin..ours is no exception..This is done in the "fuel table' of the DME program. The fuel trim values are used to modify the fuel table by adding or extracting from the fuel table to get to Lamda 1 ( Stoich) ...or 14.7 AFR.. Now, under WOT the fuel trims are not used to modify the fuel table unless the fuel trim a positive value, if the fuel trim is a negative value a zero is used so that the AFR cannot be leaned out ( safety factor) ... So , to answer your question, if you are at a 0 fuel trim now and after driving it goes to a positive number , that number will be used to modify the fuel table, but if you are already at a negative number on the fuel trim and after driving for a while it becomes a less negative number fuel trim,, then a zero will be used and no change to the fuel table will be made for WOT..

Quotes source post: 19103345

https://en.wikipedia.org/wiki/Oxygen_sensor A variation on the zirconia sensor, called the "wideband" sensor, was introduced by NTK in 1992 [5] and has been widely used for car engine management systems in order to meet the ever-increasing demands for better fuel economy, lower emissions and better engine performance at the same time. [6] It is based on a planar zirconia element, but also incorporates an electrochemical gas pump. An electronic circuit containing a feedback loop controls the gas-pump current to keep the output of the electrochemical cell constant, so that the pump current directly indicates the oxygen content of the exhaust gas. This sensor eliminates the lean–rich cycling inherent in narrow-band sensors, allowing the control unit to adjust the fuel delivery and ignition timing of the engine much more rapidly. In the automotive industry this sensor is also called a UEGO (universal exhaust-gas oxygen) sensor. UEGO sensors are also commonly used in aftermarket dyno tuning and high-performance driver air–fuel display equipment. The wideband zirconia sensor is used in stratified fuel injection systems and can now also be used in diesel engines to satisfy the upcoming EURO and ULEV emission limits.

Ok correction ,,, wideband just had been " introduced by NTK" but "Bosch " had not yet supplied them to Porsche for the M96 996....24 years ago.....lol... So, again, our cars use the narrow band 02 Sensors.....

We all know @zbomb edited that Wikipedia page prior to posting.

Quotes source post: 19103345

So yes, I was aware of wideband vs narrow band, and that I know wideband has been around a while, I believe especially used on turbocharged cars. But I appreciate the reminder that at WOT, the cars run open loop; I didn't know that they will use the fuel trim only if positive. ​​​​My injectors are new, replaced about 2-3k miles ago, but if the numbers above (97%) are correct, it seems to mean that even if I got more air flow, and sought out a tune to take advantage of that, that I'm pretty much already injector limited at the top end. I might get more at lower RPMs, but shouldn't expect anything much at peak. I have no plans to do any of that, just thinking it through.

Quotes source post: 19103954

Yea, but your 3.8 box had you below 95% ... gives you a little more room to grow

Quotes source post: 19104032

Sure, like growing back to the 3.6 airbox! The 3.8 had 3.7% less injector time, but also had 4.1% less air! The result being... drum roll... 4.1% less calculated HP potential. ___________3.6______3.8_____delta MAF(g/s)___249.7___239.4___ -4.1% Injector(ms)__16.7___16.08___-3.7% I'm not making final conclusions here. I'll probably do some more data collections between the two before reaching a final conclusion. There are threads here claiming that for larger bore rebuilds, the 3.8 might be a better box to use, and that certainly may be true. I suppose it's possible that I'm just limited by how much air my stock 3.6 can pump? Not sure why the 3.6 would be better than the 3.8 in any case, but like I said... more data...

Quotes source post: 19103789

Yep, I have seen some pretty big "whoppers" on Wikipedia...but it was late last night and I didn't feel like "fact checking"at the time and thought Zbomb needed to feel like he got one.. But here is the Bosch Patent for the popular wide-band that every one is using and is used by all the aftermarket stand alone wide band kits... The patent was applied for in 1998 and was granted in 2004, and was first used in Carrera in 2005 on 997, and was first used in the 2001 Turbo... https://patents.google.com/patent/DE19815700A1/en

It just bothers me when people make **** up....

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Well, there is the proof/patent.......

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Which also shows you were wrong. The fact that you didn't know people were running widebands in the early 2K's is demonstrative that you were not playing with your little turbo fords then, if you were, you would have had a wideband in the car like the rest of us running a lot of boost did at the time. The innovate LM1 and AEM UEGO both came out around 2002, 2003.

Quotes source post: 19104440

No I was't wrong ,..even though I was going off just memory and not "trying to prove someone wrong".... The Bosch wideband you are referring too , was "Invented/patent applied for in 1998"...and not "granted" until 2004...But the 996/m96 was already being produced in 1997....so therefore " was not yet invented" is TRUE ...lol Edit:: and yes my TurboCoupe also had a Innovate WB with a Cobra Maf swap,EECIV with Quartehorse switchable chip to E85, double size Injectors, big Turbo, all the boost, ect.. all in the early 2k's

Quotes source posts: 19104452, 19103345

You said Here's the link to the SAE paper on wideband 02 sensors, it was written in 1992 . https://www.sae.org/publications/tec...ontent/920234/

Quotes source post: 19104468

So ? It was a "concept" ( not finish project) in 1992, but what I proved is that it was an "invention" in 1998......and that is simply what I said , but if you want to split hairs....show me an earlier patent for a Bosch wideband..

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You didn't say Bosch wideband... You said I don't know why you keep bringing it up other than a completely desperate attempt to not be wrong which to anyone with 2 working brain cells, you are... From the paper written in 1992:

lol, our cars don't even have wideband sensors, so just stop...lol Bosch is the OEM supplier to Porsche for these kinds of things, and is the only ones who matter, and if they didn't have it yet,, they didn't have it yet...if they would have had it perfected by 1997, it would have been on our cars, trust me...

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I never said our cars had wideband sensors.

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Then what in the world are you trying to prove?

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Wideband sensors were indeed invented before the 996 was. I think maybe what you meant to say was - wideband sensors had not yet been equipped on a Porsche... But you didn't - you said something had not been invented that clearly had.

Quotes source post: 19104575

It should have been understood that I was speaking about Bosch widebands....because Porsche only uses Bosch Sensors...always have and always will AFAIK

This bickering really doesn’t help anyone and it’s extremely childish the negativity only turns people OFF

What would you suggest I do when someone butts into a dialog I post?

Quotes source post: 15642176

wow never knew most of this

All I’m saying is I’ve done business with both of you guys and individually your both nice guys but this crap turns me off and I’m sure others so both your points get lost in the toilet water if you can’t ignore each other at least resist the urge spit flames at each so the rest of us can digest both of your valuable information/ideas

Quotes source post: 19104940

If it makes you like me less when I correct information thats wrong, whoever says it - I don't care if you like me at all..

It’s not the correction it’s the your tone everyone sees so to get the info we have deal with the bickering crap and I’m a big boy I know how to play in the playground with others

Quotes source posts: 19105245, 19103481, 19103510

Dude - give me a break, the tone.... if you have an issue with what I said above, you're 7 ply soft... I had no need to respond after this exchange until skip decided later he just couldn't deal with being wrong.

Quotes source posts: 19105283, 19104319, 19104319

No actually I thought you needed to win one since you lost so many, like the one where I said our cars Speedo would read 4-5 mph over, and you wanted to prove me wrong so you posted a whole thread to prove me wrong, but proved me right...Remember this ? https://rennlist.com/forums/996-foru...light=accurate See here.. But then I fact checked and found this... Our cars did not get this because it had not yet been perfected........ I don't care what other MFG's were doing or the sensors they use

Quotes source posts: 19103345, 19105413

First it was they weren't invented. Then it was they weren't perfected... Invented and perfected do not mean the same thing. Just a heads up. https://rennlist.com/forums/996-foru...l#post19105420 @EVOMMM - thats the nicest tone I have - thinking of ya bro.

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Yea but they are both true in this instance, Like Nick Saben says, its a process ..but does have a date. .from the Bosch patent. AbstractThe invention

And the drama continues yeah! thanks guys I’m so glad your thin skinned banter will improve our lives shame shame shame

Yea, I hate drama too....

Quotes source post: 19104064

@jdbornem This is very interesting. Appreciate you posting this info.

2002 911 targa 6-speed manual FSI 4.0 "Stage II" engine 997.1 3.8 airbox FSI X-pipe Porsche Sport Exhaust FSI ECU tune performed with all of the above installed RPM 6922 IAT 63F Injector Time 18.22 MAF kg/hr 974 MAF g/s 270.56 Elevation 700ft Ambient Temp 44F Relative Humidity 38% Barometric Pressure 30.42 in Hg Atmospheric correction factor 1.017 "HP" comparison value 366.87 'Poor man's dyno chart'. Engine load is a relative number generated by Durametric -- not directly associable to anything.

Quotes source posts: 19103192, 19103289

I just spent some time measuring the 997.1 3.8 airbox against the 996 3.6 airbox. Here is what I found. Cross-section at the MAF is identical. The difference I noticed in that area is that the MAF in the 996 airbox is ~50mm downstream of a wire mesh diffuser, whereas the 997 airbox has a plastic diffuser ~90mm from the MAF. It's hard to measure but the airbox volumes appear to me to be essentially equal. If anything the 996 airbox might have a bit more volume above (after, in terms of airflow) the filter. Air filters are identical so no difference there. By far the biggest difference I found was in the snorkel. The 997 snorkel has a noticeably bigger entry opening (about 8500 sq mm vs. 5500 for the 996 piece) and is beefier through the body. They both are the same size at the exit and can in fact be swapped around. Contrary to what I keep reading, the 996 engine cover bellows works just fine with the 997.1 3.8 snorkel. (Anyone want to buy a 997.1 engine cover air intake thingie?) 996 3.6 on right, 997.1 3.8 on left 996 3.6 snorkel inlet: 64mm by 86mm 997.1 3.8 snorkel inlet: 77mm by 110mm

Glad I held off buying one. So $400 gets you a better looking box but potentially no enhanced performance? Or am I reading this wrong?

^^^^ that is surprising, from jdbornem's data it looked like there would be a measurable difference...

Thanks for clarification. So what will it take to improve it. Tune?

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I think the story has been that they provide benefit to larger capacity engines. I have a 4.0 which is why I went with it. Plus it looks better. I was hoping you'd have insights regarding the diffuser location and/or larger inlet. Those are the two significant upstream differences I saw. For example it could be that the 996 3.6 airbox has plenty of extra capacity, and that the larger snorkel on the 997 airbox takes more advantage of it. Hopefully @jdbornem will be able to add something.

Quotes source post: 19109142

We have conflicting data so I dunno.....maybe jdbornem or wdb can swap it back and forth a few times and get a verdict

Think about all the money that folks will save if it comes down to the snorkel tube.

Quotes source post: 19109178

Not really because diffusers/air straighteners are suppose to just stabilize the air flow so no turbulence effects the MAF Sensor..and I would think the Porsche guy that flow tested would have made sure there was no turbulence with either....the larger inlet should have more potential but jdbornems data says less flow......so the only way to quantify is swap back and forth a few times to make sure the data is plausible.. And then as I have always said....." If the test results differ from the theory, believe the test results, and invent a new theory"...

A good thread to bump.

Quotes source post: 19819669

I'll second that

I can't believe it's been over a year since my air box test! Life got crazy this year. Maybe 2025 will be better?? I'll try to get back to the air box swap and retest a few times. No promises on timeline though.

Quotes source post: 19825131

Time flies when we are having fun !!!! Yes, 2024 has been crazy busy, I have not been able to do the things i like the most, like the scientific testing / developing / new problem solving .... I have been so busy building the UAOS and UIDS's I haven't had time for anything else... (((( not that there is anything else the M96 needs...it is pretty much developed out at this time, but you never know, there can always be something found that needs improved))) ...The only thing I know of at this time that needs improved is owner education ...I think there are more "new owners" occurring than ever before>>>

Another good thread to bump from Skip.

If I swap to a smaller throttle body (from a 986) on my 3.4L, will the DME automatically correct the fueling/ignition using the MAF? I'm wondering if the stock maps on the DME can scale down properly, avoiding the need for a tune. I remember reading somewhere that the larger displacement engines (like FSI 3.8L) can be run using the stock DME and MAF, so I guess that it should be able to accommodate the lessened airflow from a smaller TB...

Quotes source post: 20518916

You will not need to retune.....When the DME see's a lower air flow via lower MAF value, it knows what to do.... As an example also I put a 3.2 engine in a 2002 Boxster that came with a 2.7 and didn't change a thing and it ran like Raped Ape .......

Oh yeah, I now remember you've mentioned that Boxster before! Thanks for the good news, Porschetech3!