How Do You Game a Dyno w/ a 996?

We are all looking to quantify whether various modifications work on our cars. While there are some dyno tests out on the market for various modifications, many of the dynos are conflicting. Most importantly, we generally don't see dynos which start with a base case and then incrementally add modifications to show the incremental improvement of each. This leaves us all scratching our heads especially if the data conflicts with dyno results from various testers. So here is a question for those with dyno experience. How do you game a dyno w/ a 996? What are the games that can be played?

There are lots of different types of dynos and all have different quirks. The only dyno that Ive seen be highly accurate is an engine dyno. Chassis dynos have modifiers in equations to calculate their values.

A good article by Motortrend on Dyno # https://www.motortrend.com/how-to/gh...el-horsepower/

Dynos really can't be compared. You never know how the operator is performing the test. The gear used to do the testing on a chassis dyno can make a notable difference, as well as the carbon monoxide contamination of the test cell, engine and gearbox oil temperature, and dozens of other factors. At FSI they have stand- alone engine and chassis dynos, so engines can be tested separately from cars, then the car can be tested. The engine and chassis dyno cells are separate but 20' apart from each other for back to back testing being able to occur the same day if the planets align. Some dynos are hub units that replace the wheels (dynapack) and others like Mustang and Dynojet use the vehicles wheels and tires. We've never seen numbers that cross well between these different manufacturers, but the data if using the same dyno and same software is very close all over the world when compared. As an example, a dynojet 248 is the most widely used chassis dyno, and the same car can be tested 2,000 miles apart and get very close results if tested using the same Winpep software generation and update. Compares that same car between a dyno jet and a Mustang and the results are drastically different. If you throw a dynapack into the mix then the numbers really change. What matters are dyno tests that are performed back to back on the same dyno, with the same operator, the same testing regimen and as few variables as possible. As Raby says, dyno graphs don't mean much since he watches most people's eyes go straight to the peak numbers, and they missed the most important part of the test completely. Few people understand that HP is a derivative of torque being multiplied by RPM, so they discount the pieces of the puzzle that are most important. The dyno is a tool, and like most tools some people are proficient with them, and others are not. Some people keep testing an engine to get the biggest peak values, and others look for average HP and torque by throwing away the highest and lowest values, then averaging the rest. FSI does the latter, and when I've been present for testing there it is much different than any other test I have experienced. Raby has the peak values turned off on his software for most tests, because he is concerned with everything else.

By being in direct contact with some tuners, going to their shops where the Dynos are I have picked up a few hints from them. Porsche 911 rear engine platform. Lid up or Lid down, doesn't seem like much, but take a look at your engine with lid up. Now imagine two 36" diameter fans on pedestals blowing outside air right in the direction of the opening of your air box, compared to lid down, now fans. up to 5 hp difference (average 3.5) as told to me by tuner. I was floored to learn this, I thought a everyone did them the same, nope. Warm dyno or cold dyno, on a rear wheel only dyno, depending on what time of year and what part of the country you live in, the mechanism needs to be warm along with the lubrication of the dyno itself, or the dyno will pull down HP for its own consumption. Just a couple things I have learned.

Rear wheel alignment is constantly overlooked in chassis dyno tests. Camber settings that favor the track can easily cost 10 WHP, especially in cars with a diff upgrade.This is because the wheels/ tires contact the rollers at an angle that sucks down power. The use of fans to provide clean air is standard, else the exhaust just gets sucked right back into the intake as dirty air. FSI's engine dyno pulls intake air from outside the test cell, and the exhaust system enters a chamber behind the dyno that goes to the outside. Doing this with a chassis dyno isn't as easy, unless the test car is a dedicated "mule" that has the rear exposed for these kinds of factors to be accounted for.

I don't know what "mods" you are considering, but for a normally aspirated Porsche motor the only mod that really has a benefit is a bump in displacement. Even that hs its limits. Most bolt-on mods really do nothing. Yes, you might get 15 more horse power, but 15 horse power, or even 30 on a 300 horse power engine is not significant to anything but your bank account. Any "boost" is really going to be subjective. Aftermarket suppliers want you to buy their products and any claims are going to be difficult (if not impossible) to actually prove. As others have pointed out, testing rear-wheel power is difficult due to environmental factors, equipment, and operator. In my mind the best way to get more out of your ride is to take your money and invest in training. The car is just a tool and most of us (myself included) have a long way to go before they outgrow their tool. I do get a kick with the trend to add more technology into today's cars. There is little doubt that the wizardry improves lap times, but no evidence that it makes a better driver. It just depends on your goals, I guess.

Folks, thanks for your responses. This is the exact kind of info we need to hear about and understand. This thread is most definitely not about what parts work and don't work. Please keep the info and thought stream coming!

Comparing dyno graphs that aren't from the same dyno on the same day is hard (and even that can't necessarily be trusted because of some of the factors mentioned previously). The only way that they are truly useful is for comparing changes you make to your own car and then re-testing it on the same dyno. A good example of this is my Turbo. On my neighborhood dyno, I put down 555hp to the wheels. If I went to another shop and dyno'd it, it could read anywhere from probably 530 to 570 even though I changed nothing on the car.

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Really good points That is why Rennlist is so damn good!!! Now, does that make anyone wonder if a car with a LSD might not put out the same dyno graph, all things being the same. What about rear wheel weights, lightweight wheels or really heavy street wheels OH NO, now more questions to ponder

And what gear are the dyno run, I always do direct drive 1:1 .

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Dynamic weights make a difference on an inertia dyno, but not as much on something with a brake (eddy current or water) like a Dynapack hub dyno. The dynapack is more user dependent though, since you can load the drive system for steady state testing, and etc. They Dynojet seems to be the best across the board from many perspectives when it comes to testing on different days at different locations, getting similar repeatable results. At one time NASA (sanctioning body) only used dyno work from a Dynojet to classify cars for HP: Weight ratio. I am not sure if that is still the story today. This was because they needed repeatability from shop to shop/ operator to operator so cars could be properly and fairly classed. The issue with something like a Mustang or Dynojet is wheel spin, but that usually only happens on boosted cars, or insane NA engines. FSI has had some issues "planting" the rear wheels on some R- 43 Series engines on a dynojet as they approach 500HP. It is pretty easy to see wheel spin on the dyno if you look at the data recovered as a text file, rather than a graph. Wider tires help to put down more of the power, but they have more resistance on the rollers as a caveat when you don't need the grip.

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One of my favorite business quotes...ever: “I realize that I have not succeeded in answering all of your questions…Indeed, I have not answered any of them completely." "The answers I have found only serve to raise a whole new set of questions, which only lead to more problems, some of which we weren’t even aware were problems." "To sum it all up…In some ways I feel we are as confused as ever, but I believe we are confused on a higher level and about more important things…”

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Well said........... I am going to miss this forum!!

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You don't have to leave, you know.

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The bold is... bull ****. Dyno graphs do mean a lot both as a validation tool, and a calibration one as well. Some people have had a car or two or 3 on a dyno. Some of us know why you would want to calibrate an ECU on an engine dyno or an eddy chassis dyno as opposed to an inertia. Some know how to look at average HP as you refer to and the shape of the torque curve. Some even know to question what the weather correction and smoothing are set to, what's the AFR, what gear the test was run etc.... And, peak numbers are important, where they occur in the RPM band is an important characteristic of an engine and will show the user the best RPM range to use to maximize the AVG output. Totally not surprising that FSI turns the peak numbers off. The "you are too stupid to understand it if we showed you" mentality is unique to the Porsche world with regards to its highest profile engine builder.

Really? It�s a 300hp car at best, and keeping it alive at that horsepower level is challenging at this point. What are you really going to gain with a header, intake, or tuning change, maybe 25hp? Be happy it runs well, and doesn�t burn oil and live with that, and spend time on maintenance items.

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This is interesting. Size of the rear wheels, camber and having a limited slip differential all may rob results from a dyno. Not to mention the usual suspect of hot air.

No doubt there are even more variables to think about with dyno testing that havent been mentioned yet which will influence dyno results. Don't be shy. This information helps to better inform and most importantly set the proper expectations. We too easily throw around the concept of "dyno" without truly understanding it.

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I am not sure if this is Charles N. posting this. But thank you, to whom every is. Since you have gone into so much detail in letting us know your methodology for dyno testing , maybe you could also share the answers to these additional questions. Based on the history of posts in this forum, I previously would have thought asking questions like this were obtrusive, but since you have already shared so much. Thank you in advance. 1) When you run a dyno on a rear wheel on a 996, do you run with lid up or down? 2) Answer to number one notwithstanding, what is the reason? 3) Have you ever tried it the opposite way? 4) What was the difference?

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I agree, with all the historical posts and threads on the 996 forum, let's peel back the onion! There is no lack of professionals and customers of professionals who can share what they have seen or experienced. This is a fascinating thread.

An LSD wouldnt change a thing compared to an open diff as both rear wheels will be spinning at the same speed hence no speed difference between left and right wheel therefore no locking action irrespective of type of LSD. Should they not be turning at the same speed one tyre will be slipping relative to the drum surface and the whole measurement is skewed and void.

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The answer to this is fairly simple. If the facility has poor airflow (not enough fans to simulate actual driving conditions then lid open. the opposite if they have great airflow in the facility.. FYI most do not have great airflow as it's an expensive piece... Heat soak is a killer for Dyno.

Well, I�d argue that by blowing high speed air into the engine bay, you could actually cause AIT to drop, thereby increasing air density and HP. The air could be cooling the intake manifold as well. Secondly, many drag car racers have known for a long time that max HP can occur when the engine temp is below recommended operating temp. So for example, you might run dyno pulls where water temp is closer to 140F or 160F than 180F or 200F. This comes with at least 2 caveats: you still want high cylinder head, cylinder bore, and exhaust temps, as high temps there generate maximum HP as long as it doesn�t impact proper combustion (predetonation). And the other caveat is oil temps. You want low viscosity, which often means higher oil temps, or else you can run a lighter weight oil to �cheat.� I�d guess the best way to get the balance here is to have a fully warmed up engine, but before the dyno pulls, the engine has been shut off for maybe 15 mins with fans blowing into the engine bay. The oil should be hot, but the engine should have cooled down a bit.

Seems that there are yet more variables to the dyno. With all these variable, someone who knows what their doing who is testing a product to see if it improves output could actually game it to test lower on the initial baseline test and to make the new product look even better claiming a 5 or 10 hp gain. Mind you i am not suggesting this is being done in the industry.

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you have to find a way to recreate the airflow from the roof, down the back glass and over/ in the decklid. Mine for example would require a fan blowing fresh air over the decklid or you can just pop the decklid and have a fan blowing in the general direction from a distance. I mean you already have a fan inside the engine bay that uses air temp and I believe intake temp to turn on and off as well.. the ironic thing about my dyno session is everything was the exact same except the ambient temperature was warmer� 95 degrees inside the shop� unless you find a dyno shop that has a simulated wind tunnel than things have to be changed. also search around on YouTube for 996 dyno runs and you will most with decklid open especially with fixed wing�

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The dyno shop who did mine, did lid down. The similar to the way he dynos front engine 1000+ HP Procharger Drag Cars, hood closed. I guess it is going to be a little different all across the country.

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Bet it is. Seems that the key is to be consistent with how you do it, such as with lid up or down. As an example, if you want to game it during the baseline runs, you would keep the lid down, turn down the cooling fans and run the dyno. Then if you were adding new parts or tuning, you would then open the lid and turn up the cooling fans to show more dramatic gains from the base.

Ok with so many variables and differences in Dyno type HOW do we create a similar beginning chart for all to follow so we can have at least close results from dyno runs otherwise we all are just spinning our wheels

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too hot around here this summer to run things with hood down.. all the places around here are hood up...

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just stick with a baseline from the dyno place you choose and keep all the variables as close as possible... Weather ( temp and humidity), Dyno tech, his settings, fan placement, time that car has sat and cooled off, etc... that will keep things on an even playing field

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Finger Lakes Region of New York Goes from -20 to 100 all over the board

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Generally speaking, you can only compare two cars if both cars have a baseline dyno and then an "after" dyno for the changes you're testing. Ideally, you want all four dynos to take place on the same brand of dyno with similar conditions for both runs. It still wouldn't be a "perfect" comparison, but it would be about as close as you can reasonably get.

Decklid up or down matters a lot based on the style of the intake inlet. A stock air box will usually perform best with the decklid down and having some fresh air in the general vicinity. Open element air filters will usually perform better with the lid open, since they tend to induct a lot of hotter air that radiates into them. The differences I've seen or only a couple HP between open and closed. It is easy to see if dirty air is a factor, since plots with the dirty air will show a richer fuel mixture, as the available oxygen is displaced by carbon monoxide. I know that FSI overlays MAF readings on plots which can be used to create further observations. On road testing can use the MAF readings to turn the car into a driving dyno with just a little effort. I know the FSI engine dyno cell only uses intake air that is pulled from outside the roof of the test cell after passing through the CFM meter and then into the intake The exhaust dumps into an insulated chamber behind the engine, then goes outside via huge fans.

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Good information, it is good to get this kind of information from people who walk the walk , not just talk the talk , thank you What kind of dyno do you folks have your facility?

Good information, it is good to get this kind of information from people who walk the walk , not just talk the talk , thank you What kind of dyno do you folks have your facility? QUOTE=NYoutftr;18312411] Did this ever get answered? I apologize if I missed it. Since you have recently enlightened us with all of your dyno experience, I thought the question was valid. What kind of dyno(s) does your facility use? How many dyno runs have you personally performed? Btw, I think most of us look forward to your contributions. Being a Rennlist Sponsor, I would have thought it appropriate for you to introduce yourself and give us a little bio. I say that, because you are so through and assertive with your words. Most of long timers here have a general idea who is posting and their background, just by years of communication. I will go first if you are uncomfortable with introducing yourself. My name is David D. from the Finger Lakes Region of Central New York. I am mid 60s. Ecommerce business owner Just sold a modified 996.2 after 8.5 years of ownership. Never operated a dyno, had a couple of my personal cars dynoed. Been around performance cars my entire life. Rebuilt my first engine at 14 years old Ford 428, put rings, rod bearings, Crane cam, etc. My first pass in a drag race was a couple weeks after getting my License at 16. 1974, just turning 16 1979, just turned 21 with Sportsman Drag car ,I built. 2017 Dyno pulls on engine I modified 2018 up Esses at WGI I think if people knew of your experience as it relates to topics you post about. There might not be any doubt, that you can Walk the Walk, not just Talk the Talk. Just my $.02 Thank you again for the enormous amount of information have shared. David D. NYOUTFTR Apalachin, NY

delete duplicate

Since we are always discussing performance gains and dynos, it may make sense to get this thread going again to see if we can add more information for everyone's benefit.

Time to resurrect this thread. Some interesting info.

https://www.dragzine.com/tech-storie...-with-dynojet/ ​​​​​​​

So how much does using racing fuel add to the dyno?

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Unless the naturally aspirated engine suffers from pre ignition, nothing. How much power can be gained by recalibrating the timing to actually take advantage of the higher octane, I don�t know. This assumes stock compression ratio. You may want to read up on octane and why you need it.

It's a rhetorical question.

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To what end ?

Good article from The Drive on race fuel vs pump fuel. https://www.thedrive.com/sponsored/4...l-vs-pump-fuel

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Race gas doesn�t do anything unless you are octane limited. A M96 running stock compression is not. Maybe there would be a benefit to race gas under track conditions when temps are substantially higher for insurance, but it�s not going to make you more power.

I hear you. So why run it then? Don't a few tuners run racing fuel settings?

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Dont know, if they do - there are 2 reasons I can think of why, both have already been mentioned. 1. You want to ensure under hard use that you have provided as much headroom above the pre ignition scenario as possible. 2. You could alter the ignition timing to see what gains could be afforded with the additional pre ignition protection. If you wanted an M96 that would reap the benefits high octane fuel has to offer then you either need to add static compression or variable (turbo/supercharger).

Engine Masters on the Motor Trend channel ran a LSx (I forgot which LS engine, 1,2, or 3) on a dyno with 87, 93, and race gas (104 octane, perhaps). The engine actually performed better with 87 octane because it was tuned from the factory to run with 87 pump gas. It made very little, if any, gains with race fuel. Compression ratio is a major factor determining what octane an engine needs (parroting this statement as I am not an engine builder and do not even play one at work!).

As an example, FVD software adjusts for octane. See reference under Adaptability section. https://www.fvd.net/us-en/FVD9966182...lash-tool.html

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In that same page they talk about modifying boost pressure - for that, you’re going to want to have the octane accounted for. They are saying their SW adjusts for octane through the knock sensor, this is the same thing your ECU does from the factory by the way. If you are convinced that race gas is going to give the stock compression M96 guy any real meaningful gains after everything I have relayed - I can’t help you other than to tell you, you’re wrong.

Just asking questions on a topic that hasn't been explorered for quite awhile on the 996 forum. Goes hand in hand with tuning and ultimately if it can influence a dyno. While I have run racing fuel many times at Road America, I didn't measure its effects on my car with a data retrieval system nor dyno it. Sure seemed to make the car respond quicker, but it may just have been that I paid big bucks for the fuel and wishful thinking. A brand new 996.2 starts with ~250-260 HP at the wheels. Less when its 20 years old. Fuel is part of the dyno conversation. As is software, headers, cats, intake, plenum, differential, camber, temperature, lid up or down, etc.

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Thanks for this. What would be cool to see from them is the data that shows how they came up with the correction factors for atmospheric conditions. In thinking about calibrations and offsets this becomes the critical thing to get right. Nitpicking about the blanket statement that all DynoJet's are identical, there is still some base level calibration that exists. Maybe they do this through design, for example, drum weight on all machines is within 0.1%. Maybe they could make a statement like: each machine is within +/-1% of the others. The electromagnetic load control is very cool, but, it would also need some kind of calibration from time to time. Think about our starter cables and how they wear out due to running high current through them. Same thing could happen here over time. But again, maybe the design is such that time is really long, like decades. I don't know, this is pure conjecture on my part about how the system can wear. I have no experience with these big machines. They are much much larger than the machines I have and understand on our manufacturing floor. The machines we have are quite small and sensitive, controlling positions to 0.1um. Motors and grippers wear out on 6-12 month basis. Maybe I'm overly sensitive because of this. But it would be nice to see correction factor calibrations. That would be cool data.

We’re not talking about ISO cal standards Paul - I agree that there are going to be differences that build up through wear / tear and cal stuff. That all said as far as my experience observing dyno graphs, dyno jet is the one that seems to be most prevalent and most consistent but every test output should be viewed critically. Of course, take it for what it’s worth.

Yep. I get it. Through their software control and updating, DynoJet remains in control of inputs and outputs from the machine. It seems someone would need to go to extra work to game the machine, for example, externally heating the atmospheric monitors...

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Exactly.

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Here is a typical Dyno Corection Calculator that has SAE, STD and MSA correction factors. There are other correction standards used but these are the main ones. The operator choses which one to use or to use none at all... @golock911 if you are serious about learning about Correction Factors then get this 106 page book written by Patrick Hale . https://dragracingpro.com/books

Isn't that interesting.

I am not sure on a M96, but on older SBC or BBC, the higher octane fuel, would allow more advanced timing that would give a little bump in torque Any way I miss this forum Just went over the New Year mark without the thrill of looking forward to a spring with a 996 Had to look at some old videos, lol Here is a terrible way to treat a 996, this was years ago, first day with the mods and new tune You Tube

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We need to get you back into a 996! Yeah, my butt dyno felt a little bit more response and kick with the racing fuel. But no data to confirm. Looks like we got the answer to gaming a dyno in the Jake Raby thread. Seems that the easiest way to do it is to adjust the inputs for the calculation. Sad and funny at the same time. Also tells us that the absolute numbers are irrelevant in comparison. However, dynos can still be useful in measuring against a base case to see what incremental improvements are realized over the base, as well as improving the curve if possible with tuning. Doesn't suprise me. Even when I had mine dynoed 10 years ago, I didn't care about how high the number was, I cared about the incremental improvement. So did my indy.

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Skip, as always, appreciate your knowledge. Saw your MAF thread resurface and started reading thru it early this am. Hope it stays active. Good stuff. Gotta dust off my durametric software and get the data into your calculation.

Here are some charts made using the Correction Factor calculator that Skip refers to above. I'm trying to show how the correction factor moves around with given temperatures, Barometric Pressures, and Humidity. All the graphs use the same Y axis scale for easy comparison. This first chart shows the relationship with temp and pressure. Correction factor goes up as temperature goes up. Correction factor goes down as Barometric pressure goes up. The other way to say this is the engine on the dyno will show lower horsepower at higher temp and higher horsepower at higher BP. 8% difference between a stormy day and a sunny day. 7% difference between a 50F day and a 90F day. The charts show how humidity has a much larger effect on engine performance at higher temperature. The first chart, at 50F, shows the 3 humidity values are close together across the range of BP's. But below, at 90F, the humidity change is having a greater effect. From these charts we can start to discuss putting error bars around each of the dyno plots. I've used 50F and 90F as likely boundaries for testing. Most tests will end up in between. The boundary barometric pressures are from the lowest and highest recorded values in Chicago

Nice work Paul. Hopefully your work begins a process of understanding and level setting on dynos for all of us on Rennlist.

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Great data. That shows a lot effort on your part, well done. While reading it, I think back to the shops that I have been in that have a dyno, years ago. They were generally over in a shaded part of a building or an area with no windows. Was that to control temp and humidity more consistently? Back years ago, the octane debate was not so much a tuning issue, but more of how the engines were configured. Then the timing. Like others have mentioned compression. I don't know about the M96. But in SBC & BBC, there would be an entire range of pistons available. From 8:1 for engines with blowers, 10:1 for street cars running pump gas, up to 12.5:1 using Octane over 100. Back then Sunoco 260 was 100 Octane at the pump. Then we could mill the surface of the heads to reduce the volume of the combustion chamber. Most if us would then "CC" the heads. A process in the 1970s, when done by 17 and 18 year old teenagers skipping school, would consist of using a dumore grinder to grind and polish the combustion chamber, but paying careful attention to consistency. Us back yard boys, would use a piece of plexiglass with a hole drilled in it. Use a beaker from high school chemistry class. Place the plexiglass on the head surface, use the beaker to pour grape koolaid through the hole and fill the c.c. with valves in and a plumbing plug in the sparkplug hole. Grind and polish to each c.c. was the same, checked by the volume of koolaid from the beaker to reach the top of the hole in the plexiglas. Head gasket thickness would be the next step. All the while needing to keep in mind the lift and duration of the camshaft, the pushrod length and rocker arm ratio to make sure valve to piston clearance was maintained. Sorry, went down memory lane. Us boys in our senior year in high school could build race engines that could scream to nearly 8000 rpm using race fuel. But would struggle doing a book report in English class.

I guy I knew that had one of these Ford engines would just let the valves float at 8000 RPM instead of worry about any rev limiters. He would also shift while keeping his right foot to the floor. I think some new cars are like this: no lift shift. I think the GT3 might have it. Of course, computers now control what was, in the old days, wear and tear on the valvetrain.

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The 69 Boss 302 was the first car out of Detroit to come with an "engine govenor" ( ie. rev limiter)....It was the first thing Hot Rodders by-passed on them because they could tell the engine was still increasing in power when the "govenor" kicked in..lol

Anybody have confirmed rear wheel horsepower and torque numbers directly from the factory on the 996.1 and 996.2 when new. Porsche factory document referencing the numbers would be great. Reputable magazine, publication, book or source would be second choice. It's about time we establish a factory baseline when these cars were new.

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That was a time for some hocus pocus from the car manufacturers. Late 1960s to 1971. False information on horsepower from those massive power plants. Many articles now have been done using brand new parts to assemble complete engines for the purpose of dyno testing. Biggest Pinochos went to Chrysler for the 426 hemi with 2x4 carburetors, factory advertised 425, dyno over 600, next was Ford 429 Nascar motor 820-S "Shotgun" , came in Boss 429 and Mercury Cyclone, dynoed over 550. Chevrolet LS6 factory rated at 450, well over 500 That was for purpose of insurance rates, back when the 996s were made Porsche was controlling the horsepower very carefully so they could justify the optional equipment, for things like X51, costing more than $10k. It would be nice to see some of these garage queens get tied down to a dyno and see what they produce at the wheels

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When I was wrenching on milk trucks in the early 70's almost all of them had governors. Some of the vehicles were from the 1950's. It was a pretty common item on fleet vehicles. Seems like a weird thing to put on a performance car.

I imagine that Jake Raby knows how much a factory fresh engine put out. He has both crank & chassis dynos and has tested about every combination including stock, and done so for decades. Hopefully this info will be included in his upcoming book. If I recall correctly he has said he often sees 250hp at the wheels for M96, but I don't remember if that was an older engine nor whether 3.4 or 3.6. But my estimate based, on my bad memory, is the "typical" 996 M96 puts out 245-260hp at the wheels. Also the factory reports hp in DIN PS(Deutsche Industrie Normen Pferd Starke), not SAE HP. DIN HP is about 1.4% higher than SAE HP. So to "game" your dyno HP figures, report it in DIN like the factory does. Multiply your SAE crank hp by 1.0139.

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Looking forward to the book. Hope it's an encyclopedia of data. Your numbers from memory match mine.

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I heard this quote from Jake at least once, "all this data will be in my book..." I can't wait until it's available!

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ALL car nowadays have rev limiters performance or not ...The old truck governors are way different than modern rev limiters, but the 69 Boss 302 was called an "engine governor" was was just a little metal box mounted on the fender with 4 wires going to the coil.. You can buy them now in the replica style that look original but are "dummy" and don't do anything...

Just an FYI from today: Back in June I tested a 997.1 Stage II+ using the FSI Dynojet with Winpep 8 software. The owner could not take delivery of the car right away due to overseas work, so we finished the test loops and parked it. He asked that we store the car for him until now. We forgot to get the dyno videos of the test session, which was done just before the car was parked in storage. The car has been driven just enough since June to keep the battery maintained. Today I strapped it back on the rollers and the dyno plots that I gathered on a nice day in January overlaid atop those that were collected on a 92 degree day in June. The Dynojet weather station does a great job of keeping the playing field leveled when it comes to tests being done in wildly different conditions. My experience with the prior Winpep software wasn't the same, and my experience with a Mustang dyno in regard to this was less than favorable to say the least.

Just watched this video from Banks. Everything you need to know about a dyno including how to game it simply explained. Good tie in to what has been explained by our expert contributors. You Tube