M3 Feels Qucker..What the hell??

Gents, I just collected my 2000 996 today which is fitted with the X51 kit and PSE. The first time I drove it was after I bought it and I have to say, it doesn't feel that quick... This evening, a friend brought over his newly acquired E46 M3. I drove that and it feel a good degree sharper off the mark than my car...What is going on?? I had the car PPi'd yesterday, so I know that the 996 is running pretty much as it should...I am feeling a little down!

Hmm...not sure...my 02 feels a bit faster than the M3s I've driven before...

X51??? Are you for real?

Was the parking brake on?

what octane fuel ? if you are not running 92 it will detune and run like crapola.

It is a Euro car so I am running 95 Octane. No question, the M3 fealt sharper...Is the 996 power delivery more top-end?

I am affraid so. The car has a factory fitted X51 kit.

You should race your friend.

The P-car has a very short first gear. Besides, Porsche never designed this to be a dragster. It is designed to be a complete sports car, i.e. acceleration, braking, handeling and cornering, not just straight line acceleration.

guys, there will ways be someone with better and faster who fuqin cares if the M3 feels quicker seriously find a new hobby

You should copy this post, and just use this in all of your future posts here, since you seem to always say the same thing. "OMG someone mentioned the M3 in a bad-light, and they are comparing their 996's to it!!! I better go do something about it before it's too late!!!!" Just take it easy their, Benjamin.

I have an M3 and I must say when I tested the 996, it did feel less frenetic in acceleration than the M3. My seat o' pants accelerometer says that M3 starts pulling at a lower RPM than 996. (Maybe I was a little bit shy in someone else's 996 rather than my own M3?) Maybe then M3 would feel faster, even if the typical milestones like 0 to 60 and 1/4 mile all show an edge to the 996. Anyone have the torque curves of the 996 and M3 engines for comparison? But, the 996 is a better handling and overall a more dynamic car, especially when the roads turn twisty.

In Europe fuel octane is calculated using a different method than in the US, so 92 US = 98 Euro. You will probably notice a difference if you use 98 octane instead of 95. I have never used anything but 92 octane in my P-cars in the US. But I did run the cheap gas in our X5 4.4 after Katrina hit. Performance suffered badly. I have stuck by 92 octane (i.e. euro 98 octane) for all cars since.

Was the X51 even available on the Mk I's?? I thought it was only available on the 3.6l Mk II's.

It definitely was in Germany. I still have a German 2000 996 broschure and the X51 powerkit was definitely an option.

What about the US market? How much power did the German market model make?

I don't know about the US, but the X51 that was sold in Germany had a parts list similiar to the X51 sold in the US for the 3.6l cars (heads, manifolds, etc.) and if I recall correctly added 20hp.

The M3 probably felt "quicker" because you rev it harder and it's exhaust note screams a bit more (the well known "rasp"). A 996 with X51 should certainly be faster, both in a straight line and on curves. It's all perception. Both great cars.

Porsches are a lot like Harleys. It's about the total driving/riding experience. Harleys don't handle, stop well and are pretty slow but they are really a hoot to ride. I have a bunch, have had for 37 years, have a Buell and a Gixer too. If the P car doesn't meet your expectations sell it and move on. I feel bad for you.

Buell..did someone say Buell.. whats yours ? I have a 1998 S1 White Lighting, in Black.

'96 S1, Carbon Black 9k miles, bought new. White Lightning heads, pistons, CR raised to 11:1, lighter exhaust valves, I hand ported the heads, V&H exhaust, HSR 42mm Mikuni carb, modifyed suspension and front brake and other stuff. Much faster than stock, and my 996 but still slow. Fast isn't everything unless you're racing.

don't get your panties in a bunch bud u know i love u how much more fap fap fap fap do you want around the 911 carrera? the M3 is right up there with it in pure performance specs... hence, it's not at alls urprising to me that someone could determine by their **** dyno that the M3 feels as fast and sometimes perhaps even faster. it's cool to love your car, but let's be candid and honest here v. being all drugged up on 911 crack. there's just as fast and just as pleasing and as much passion, and faster and better - just be happywith what u got and i certainly am, but i aint' driving around these parts thinking my ride's better than anyone else's really. M3, Sti, honda s2000, maserati coupes etc etc etc i put my mouth where the money is and i have a 911 in the garage v. the m3. that should already tell you which car i love more, but i understand the m3 is fantastic in its own ways and has a passionate following as the 911. keep an open mind suckas

I think the M3 feels faster because it is faster

In the past I was a test driver for a company that contracts with various automobile and parts companies. I have driven thousands of cars at the limits and had the data to support or disprove my butt dyno. The bottom line is that butt dynos are very inaccurate. There have been times that certain cars feel faster simply due to the sound and feel of the engine, even though the data suggested otherwise. The stock 996 is a smooth and fairly quiet car which can be misleading. Whether the 996 or M3 is faster isn't very important. It is hard to disprove that if all aspects of performance are observed- the 996 is a superior auto.

I agree: butt dynos are inaccurate. But it's an important part of our appreciation of what cars we love and why. it just so happens that unless one is a total gear geek and can convince the brain to override the senses in favor of a set of memorized specs and performance data, the butt dyno is what we use to determine what we like or dislike about a car. (now there are some who don't even CARE what butt dynos say, and only go for a car because of prestige, exclusiveness, me-too fad worship....but that's another story.) It is true that often pure performance data can contradict a car's feel. That's when kudos go to the manufacturer and the engineers of a sports car: those who understand what makes a great sports car will make more out of less. A well-balanced car (i.e. 996) can feel more nimble, more spirited even though its HP and torque are lower than another bigger beast with poor setup that inspire no driving confidence (i.e. Viper). The verdict is also very personal. Sometimes a car feels faster because it grunts (or in an M3 it rasps) more to the liking of one's ears. Maybe someone likes to shift at a certain RPM and one car suits the driving style more than others. In that case, what's more important: what the results of R/T 0-60 or 1/4 mile tests, or how the car feels pulling away at one's home-turf stoplight or zipping down one's favorite stretch of road? That is a decision for the individual to decide. I'd say if the performance data is the only thing that matters, there would not be a lively forum like this, everyone would have to agree that owning a Dodge Viper is way better than owning a 996, end of story, Porsche aficionados are losers.

Not according to magazine testing....

I went right from an E46 M3 to X51-equipped 996, and the Porsche is definitely faster. The X51 moves peak power up the RPM curve, though - stay in it and once you hit 6,000 RPM, the advantage will be obvious. The M3 weighs 300-400 pounds more than the X51 996, and has 12 fewer HP and 12 fewer lb-ft of torque...do the math.

DId you have the sport button on the M3 when you drove it? If so, the quicker throttle response may be what you felt, but the stop watch does not lie and an X51, properly driven, is faster.

agreed ! slow donkey bikes Buells are I love mine. for me the fun is in building fast.. mine is top secret custom head work/cams/valves/Stainless Specialties Race muffler/Air-Tech Airbox/K&N/Mikuni HSR42/Buell Race module = 101 RWHP CRG Bar end mirrors/V-Rod head lamp/Crossroads Billet racing pegs/custom all black painted body work/Liquid flames medalions, fender/flyscreen,tank and undertray all under 6 coats of clear/2000 front rotor & Ferodo 911 race pads/cut down and black painted M2 rear fender/black powder coated 99 swingarm, primary and cutdown cam cover's/X1 chin fairing/banke oil tube/banke rearsets/banke frame brace/x-roads bars/Sharktooth Billet rear pulley/EuroComponents Underseat Tray/powdercoated forks/polished tripple clamps/custom springs fork valving 3rd place 2001 Orlando Bike Show 2nd place 2002 Orlando Bike Show 4th place Rats Hole Bike Show Leesburgh Bike Fest 2002 2nd place Orlando HD show 2003 2nd place Rats Hole Chopper Show Daytona 2003 2nd 2003 Orlando Biketoberfest Show 2nd place Orlando HD show 2004

The porsche has 345 hp?

With the X51 power package, the 3.6L does.

A stock Mk I has 300 hp (296 for the '99). The x51 for this car (Europe only) adds 20 hp. A stock Mk II has 320 hp and the X51 kit adds 25hp (345 hp). Stock Mk II's have been tested in the high 12's in the 1/4 with 0-100 times as fast as 10.1 seconds without the x51 kit (published times). If there is a faster time for a stock e46 M3 I have never seen it. Keep in mind the C2 is significantly lighter than the M3. Additionally the C2 (while down on hp without the x51) makes more torque. When it comes to handling it's just no contest. The M3 drives like a sports sedan (one that understeers quite a bit). The 996 is pure sports car and the handling (especially with some of the optional Porsche suspension options) really shines. Need more proof, go for a test drive of both cars or just look up some "Ring times".

Always blows my mind when people talk about horsepower as an explanation for a car's acceleration from a standing start. It's torque, folks. That's what moves a car off the mark. And an in-line 6 is the most naturally torquey configuration for a normally aspirated engine at a given displacement. BMWs always feel 'right there' off the line (and, actually, the M54 variants feel even more lively to me than the M3's S54, which is tuned for higher rpm performance). If you want that shove in the back when the light turns green, a normally aspirated Porsche might not be your cup of tea.

I'll trade you my M3 for your PCar

Porsche 911 is faster than the M3.

True, however, torque and hp tend to go hand in hand. Lots of torque can only get you so far if you don't have any horsepower. Torque=the push you feel in your seat. HP=how long you feel that push. You can have gobs of torque, but with no horsepower, you still won't be that fast--otherwise we'd all be driving deisels. This is a dumb example, but, look at a Cayenne Turbo (hp=500, torque-516) vs VW Touareg TDI (hp=310, torque=554). If torque were all that mattered, they should be quite close in acceleration (I'm assuming the wts are similar). 0-60 in the Touareg is 7.5 secs, CTT? 5.1 sec. It's not as simple as just torque. This goes back to my previous point, the M3 and 996 have similar power numbers--M3 hp=333, tq=268, 996 (no X51) hp=320, tq=273. The 996 is lighter, therefore it will be faster. It may just "feel" faster because of the noises and the revs.

The original post was about what 'felt' faster off the line. That's torque. Torque is the measure of an engine's ability to overcome inertia. Horsepower is a measure of what total 'work' an engine can do, which in practical terms means speed (since the work required to move an object through the air rises exponentially with speed). The other concept missing from your analysis is where in terms of rpm those peak numbers occur. My last BMW made 90% of its peak torque by just over 2,000 rpm. That 'feels' fast because you don't have to wait for it, and it's characteristic of an inline 6. Opposed and v configurations don't naturally have that characteristic, but they tend to be happier and more powerful at higher rpms. So when you're comparing the two cars, don't just compare the numbers. Compare how soon the peak numbers are available... that's what 'feel' is all about.

I just learned that the x51 was not available on the US Mk I's ('99-01). Additionally, it will not function properly on our cars if you try to retrofit it. The x51 was only available in the US on the 3.6l in the Mk II's.

Agreed...I forgot about the RPM issue...here are the complete numbers: 996 (3.6): hp=320 tq=273@4600 rpm M3: hp=333, tq=268@4900 I took a look at some dyno curves, and you're correct, the BMW's tq curve seems to stay relatively flat, above 200 ft-lbs the entire time. The porsche starts below 200 and builds.

The above points about the importance of torque are well taken; the 996 has slightly more torque than the M, but most importantly weighs about 400 pounds less - that's what makes this a no-contest, whether 0-60 or whatever. Hell, even my girlfriend (unprompted) noticed the difference right away, from the passenger seat.

I agree with BruceP: my M3 feels faster off the line than the C4S I test drove because its torque kicks in around 2000 RPM and stay pretty flat into the 6000s. Redline for the S54 engine is 8000RPM. But I have no doubt that Carrera will get to 60, to 1/4 mile, to 100mph faster. M3 feels faster (pushes harder) in the initial launch. I think the butt dyno we refer to is really a butt torque meter.

Diablo99 In your first posts you are asking advice for a car that your brother is going to buy. Then you refer to "we" like the two of you are going to buy it. The latest is that you bought one. Has your brother bought one? If so how does yours compare to his? Or are you asking info on behalf of your brother? A little confused here...not that it really matters but it's almost like a hint of trolling here. If that's not the case forgive me, but even used Porsches are expensive, and I can't believe someone would buy one without driving it beforehand. And if they had any reservations regarding performance that they found questionable, going ahead with the purchase seems foolish. If you bought it without trying it first, you have more money than sence and can afford the loss. If not you learned an expensive lesson.

0-60 between the two is much closer in my opinion. The 996 can suffer from bad wheel hop when you launch it. The M3's (at least the ones I have driven) don't seem to have this problem. However, the 996 seems to have the definate upper hand as speeds climb (in addition to much better handling).

The original post was about what 'felt' faster off the line. That's torque. Torque is the measure of an engine's ability to overcome inertia. Horsepower is a measure of what total 'work' an engine can do, which in practical terms means speed (since the work required to move an object through the air rises exponentially with speed). The acceleration of any car is dependent upon three factors: car's weight, its torque power band, and of course its gearing. Since we are concerned about torque at the wheels, it's important to keep in mind that gearing will also have a huge impact on how fast a car accelerates. Torque at the wheels is equal to engine torque times the gearing of the tranny and rear axle. HP is important because it tells us how much torque the engine is producing at the upper ranges of the RPM range. Historically Porsches have traditionally either outperformed or at least held their own against cars with far more HP because of the factors listed above.

I intentionally left out gearing to keep the discussion simple, but yes, it is the third factor along with mass and available torque at a given rpm. I think your comment on "how much torque the engine is producing at the upper ranges of the RPM range" is correct in essence, but not technically. Horsepower is quite simply the amount of work an engine is capable of. For a road going car, "work" means overcoming wind resistance more than anything else. HP, in fact, isn't measured, it's calculated as a function of torque, ie: HP = (torque x rpm)/5353. An amusing bit of trivia comes from this equation: You'll see lots of guys soberly debating and bragging about the point where their torque curve and hp curve cross over, some claiming it's a good shift point. This is actually bollocks. Every reciprocating engine has its torque and hp curve intersect at exactly the same rpm: 5353.

my c4s feels faster off the line than the M3... in fact, it feels more powerful all around, but again, it's deceiving... looking forward to lining up next to an m3 and go from a roll for curiosity's sake and stay away from all this qb RACING going on here

Care to explain that scientifically for me?

Rob, is 93 octane not available in the Atlanta area. In MS 93 is available in almost all areas. I�m doing a DE at Road Atlanta next month and would like to keep running 93 octane. Lee

Is this a test, or are you skeptical?

Yeah, I think it's bull. Torque curve is a function of the characteristics of breathing, not the layout.

For torque, I can't see how the crankshaft cares which side the pistons are on. The boxer configuration is more balanced, if anything. By the way Bruce, how many horsepower does your horse have?

Okay, here is the best I can do for you: To be exact, inline 6 cylinder engines, having no primary or secondary imbalances (they're 'perfect' in this regard) are naturally extremely smooth. That smoothness allows engineers to design them for torque, which usually means a longer stroke. Long stroke engines are more prone to vibrations and imbalances, for obvious reasons, so choosing the inline 6 configuration is the best way to minimize it and build an engine that will last. This is the reason, I believe, that so many industrial diesels, such as in tractors, are inline 6s. As to whether torque curve is a function of breathing, that's poppycock. How much and how soon torque is produced, all else being equal (and forgetting external stuff like flywheels and gearing), is totally a function of engine layout (both the configuration and the ratio of stroke to bore). That's just how it is, and no I can't explain it. But what I can tell you is that at a given displacement and with the same valvegear etc, the inline engine will have more torque than the opposed engine, and the long stroke engine will have more torque than the short stroke one. On the more general question of how engine configuration affects torque, here's some fun reading for you: http://www.epi-eng.com/ET-PistonExcit.htm

No, sorry. The inline 6 is the most balanced engine configuration there is. Perfect primary and secondary balance. It has nothing to do with the distribution of mass. It has to do with how evenly spaced the firing intervals are with respect to crank rotation. There are other reasons to build opposed engines: packaging is one, another can be less drivetrain inertia, which you want in a high performance engine, but if all you cared about was smoothness (and the durabiility that goes with it), you'd pick an inline 6. My horse? Probably 1 hp, I guess. But the rules don't apply to him. He's not a reciprocating engine. He's a hay eating, farting, pooping, temperamental, butt kicking engine. And scary fast off the line. My Porsche may not have perfect harmonic balance, but it's never opened its door and dumped me out on the highway...

OK, but that has nothing to due with the shape of the torque curve.

Take another look at your reference. It considers inline, opposed, and 60 degree v-6 all balanced. Which has nothing to do with magnitude of torque output, just the smoothness of the engine. Isn't your horse essentially a 4 cylinder?

wrljet, my understanding is that it does. Inline 6s generally have quite flat torque curves, where opposed engine designs are more inclined to be peaky. Again, I think this is why so many industrial engines are configured this way. Obviously, there's lots a designer can do to mitigate this with other tricks, but I believe that a flatter torque curve is inherent in the inline 6 layout.

My wife is nagging me to get going for a dinner date... I'm not sure what they mean by 'balanced' in the reference, but if you Google around a bit, you'll find a number of references to the fact that only the inline 6 cylinder engine has no primary or secondary imbalance. I'm sorry I can't explain it any better, but it is a fact. Actually, my horse is four-wheel-drive. I'm pretty sure he just has one cylinder. Gotta go while I'm still married...

93 is readily available. I don't recall seeing a station without it.

Yes it is. In fact 87, 91, and 93 are the usual variants. I only mentioned 92 because one of the previous posts did, and I was just trying to be consistent. My point was that the octane calculation method is different between US and Europe (or Germany anyway). So the high octane pump fuel in Europe is 98 octane which is equivalent to our 92/93 octane in the US. HTH

actually it is available... it's called the "European powerkit....".... very similar to X51; and you can have the kit installed on a 3.4... Steve Weiner sells them at Rennsport systems... serious upgrade with good results

Interesting. Link please.

I agree. Can you post more info?

On the M3 /996 debate: I owned a 2002 E-46 and would not argue the M-3 is faster off the line (hope I don't get killed here). I had a 964 at the time and sold it in favor of the M-3. I tracked the M-3 for 2 years, then bought a race car (964, of course). I now have a street 996. Although I never did it, I'm sure in my mind that the track times will be faster in the 996; and not because it's faster, because I don't believe it's as fast as the M-3! The braking and handling of the 996 are heads above the M-3 to me. On the same tracks, I had to back my brake points a full mark to 1.5 marks back to get the M-3 to stop, and that's with pretty aggressive pads on the M-3. Plus with the 996, I feel the road so much better and really feel much more in control. I'm sorry, I'm just a Porsche guy to the core.

I believe Ray S meant that it wasn't offered as a factory option by Porsche on the pre-02 3.4l cars. If an aftermarket tuner imports the parts and sells them to be retrofitted to the stock engine, that is another matter.

First job of the day, drive the car until all that 95-Octane crap is out of the system. Fill with Shell V-Power. Drive it until that tank is almost empty. Refill with V-Power again. You now have a tank of almost pure 99-Octane gas. Next - reset your engine control unit as follows: Turn the ignition to on. All dash lights on but the engine OFF. Disconnect the battery negative lead under the bonnet. Leave for a half hour - Don't lock yourself out of the car!. Re-connect the battery, fire up the car and leave to idle for a while. You can re-input your radio code and get your 1-touch window operation set up again whist you do. Now drive the car for a few miles some slow, some faster. Within apprx 20-30 miles you will have a totally different car, fully calibrated to 99-Octane gas. Now go for it - you will fall for the car again! Never fill up with 95 again except in emergencies. Follow the instructions above if you have to. Ian

And the BM M3 is known for having good brakes. (at least in those circles) Bill

Really now. Ask me sometime and I'll tell you all about it.

It is not similar to an X51, it is an X51. I bought mine from Steve, and I don't think he has any more. And it is not a bolt on, by any stretch of the imagination.

Note to ianwallwork... So using the Shell V-Power would be the same (almost) as running 100 Octane??? That would be a dollar a gallon cheaper, for me!!

Ok, how do you have it? I have it on very good authority that this option was never offered in the US.

Not quite. You have to pay attention to the details. ianwallwork is in Manchester, UK. As I pointed out earlier in the thread, the calculation used for octane rating is different in Europe than in the US. Euro 98-99 octane is approx. equivalent to 92-93 octane in the US.

Oh, sure. I tell you, you tell a freind, they tell a freind, and soon, everybody knows. That is true. Steve has had this on his shelf since 2000 or so. I really think it was a kit that somebody put together, since it didn't come with a DME, which probably wouldn't have much use to me anyway. But it does match up part for part with what is outlined in the service manual. It also includes the highly sought after oil pickup kit like the one PMNA used to sell.

Well, for what it's worth, Road and Track (I believe it was them) lapped a Cayenne Turbo around a race track faster than an M3 a couple years ago. They did it on the same day, in the same conditions.

The Cayenne Turbo also lapped a Lotus Elise faster around a road course recently, what say you? The M3 is an awesome ride and so is the Lotus Elise and so is the 911.

So.

That's correct - 98 RON Euro gas is approx the same as 93 Octane US. Th original poster said he was in a Euro car using 95 Octane which is the standard low-grade Euro rubbish equivalent to approx 90 Octane US. Shell V-Power is rated at 99RON (Euro) min. Shell states that it is typically 99.6. This would be the equivalent to 95-ish US and show quite a significant gain over 95 Euro / 90-ish US. Porsche state that their engines produce rated power on 98 RON (Euro). Any less and they pull timing. Ian

ok... didn't compare the parts list but at the same time I didn't want to say it was the same kit.. and yes Steve had a few of them and it is *major* surgery... and yes it was *NOT* offered as a dealer option on any 3.4 cars... so how do u like the kit after Steve isntalled it.... do you feel that much of a difference.... some nice new parts in that kit should make a diff no? regards, P.

This is the X51 kit that my car has: - new intake manifold with modified cross-section (material: sand cast aluminium ); - new intake pipe supports adapted to the form of the intake manifold; - new exhaust manifolds with larger cross-section and optimized flow behaviour; - new cylinder heads with optimized, CNC-milled inlet ducts; - new camshafts with larger valve stroke on the inlet side and modified inlet and outlet timing; - inlet valve springs adapted to the enlarged valve stroke; - modified partition box in the oil pan; - modified maps for the DME control module; - new underside panel in the transmission area; - all cars get a third radiator. I am not sure how to add a picture, but if someone can add one I can mail them a picture of all of the parts.

Feeling and actual power are two different things. When I did a power pull with a 3.2 liter NSX vs a SMG E46, the NSX was faster, but when driving the cars around the E46 felt faster. Simply because the NSX has a very dismal torque rating compared to the highly tuned individual throttlebody inline 6. On a track car I would prefer less torque and more power simply because during a corner I don't want the balance of the car to be thrown off by the power of the engine. Maybe that is what the Porsche engineers wanted.

I agree with BruceP: inlines are the only engines I've seen that can equally match the torque and hp in high hp applications. The only downfall I see with inline engines are the upper limit of the RPM powerband. It seems to cut out at 7k. V engines all have some sort of resonance problem (primary the lower RPM if the engine can rev over 9k). The Pcar flat opposed engines are the closest thing to an inline engine. This is to be used for discussion only and not to be relied upon.

Yep. Real high performance cars are always biased toward HP and away from a flat torque curve. Even BMW does this. You'll notice that the M3 has more HP than torque, where BMW's bread and butter 6s are the reverse. Toyota's F1 engine, if memory serves, produces about 730 hp but only 202 ft/lbs of torque, less than our cars. You can 'feel' torque, but it's HP that wins races.

Not sure why we're arguing over split seconds here, but hey, it's fun. Based on my experience putting about 12K miles on an E46 M3, it doesn't feel quicker than my porky C4S. In fact, the C4S feels nimbler, and pulls harder all around, yet I know that if an E46 M3 decided to punch it, I won't be overtaking it at all in the straights or in the turns. It's that close between a Carrera and the M3. Now we all know it's not just about performance specs... the 911 kills the M3 in all sensory depts and I would not pick even the more powerful V8 M3 over my 996 C4S because, again, I've come to quickly learn that There Is No Substitute. P.S. The brakes on the P-car don't bite nearly as hard as the overboosted M3 brakes. I prefer the feel of the P-car as I feel like I have better control over how hard I want to stop. M3 takes just a light push and wham you're slowing down whereas the P-car, if you want to wham stop, well use that left leg muscle and hammer down and it will hammer down.

Again, the configuration has nothing to do with the *shape* of the torque curve. Modern BMW 6-cyl motors happen to have a very sophisticated Vanos system which results in high low speed torque and high HP on the top end. This has nothing to do with the straight-6 basic configuration. Bill

Agreed - man, so many wannabe starting QBs in this town!

M3 is and C2 are about even, in a straight-line. M3 is FASTER than C4S. Any former M3 owner will tell you that, right Ben?

Not sure - I think it's about the same in the straights - I will have the oppty I'm sure in the future to do a little roll-on with the friend I sold my M3 to. I love the throttle response on the M3. It's instantaneous, razor sharp. One of my loves on a sporting car/sports car. So it certainly does apply its power very well along with that M diff in the back.

Using my seat o' pants dyno, I think my wife's 335i Twin Turbo is just as fast as my P in a straight line. As Ben mentioned, I'm not a big fan of the brakes going from off to on without much room to modulate. -td

I'm sorry, but that is absolutely false, on two counts. I really urge you to do some digging before you make these pronouncements. VANOS and Dual VANOS were meant to PRESERVE the flat torque curve of the inline 6 when they added a multivalve head (multivalve engines are not naturally torquey down low, so need help with engineering tricks like this). In the M52-TU engines, for example, the secondary cam profile kicked in at 3500 rpm, long after most of the engine's torque peak had been achieved. It was to give the engine more top end, the thing an inline 6 is less good at than an opposed configuration. I don't know if you're a Wikipedia kind of guy or not, but if so, this might help you get started on some digging into this: http://en.wikipedia.org/wiki/Straight_6 Otherwise, do some Googling around car mag sites and the like. Wherever you see a mention of "inline 6", you're sure to see the phrase "flat torque curve". It's practically a cliche. And as sure as the world is round, it's a fact.

OK, you can have the last word. Mine is "you don't know what you're talking about."

Thank you for the gracious offer. Here's my last word: You're an intellectual coward. I've explained and cited and tried to back my point of view up as best time and resources will allow. I'm happy to be proven wrong (though this time I'm extremely sure of myself). But all you've done is deny and not offer a single scintilla of contrary evidence or logic. That makes you a waste of my time, and casts serious doubt on the value of any advice or opinion you might have to offer on this board. Any fool can bleat, "you're wrong".

OK, fine, I'll keep going. Normally you tune an engine for good low end, good top end, or a happy medium. Historically (before variable valve timing) this was all that was possible. Tuning this shape of the torque curve is done by selection of camshaft profiles, tuning of intake and exhaust plumbing. Race engines are tuned for maximum HP, which comes from having peak torque at a high RPM. Tow trucks benefit from lawn mower cam timing and a peak at a low speed. You couldn't have it both ways. This made peakier engines like the old 911S motors harder for people to use in normal traffic, etc. And of course the bore vs. stroke ratio comes into play here. Vanos and other variable cam timing schemes (along with intake tracks with internal valving, etc) allowed engine designers to put both setups in one engine, so it keeps good torque up and down the RPM range. This is possible with ANY basic multi-cylinder engine configuration. It has nothing to do with an inline 6 vs. a V-8 or any other setup. (as far as Wikipedia goes, well those articles are written by people like me and you and are worth what you pay for them) Bill

Yes, you can engineer your way around these things in any engine configuration. Forced induction is probably the utlimate example of that. Nothing you've said here is wrong, and having owned three 6 cylinder BMWs, I'm very familiar with VANOS (which ALL felt livelier off the line than my 996, BTW). You're saying engineering can overcome the natural tendency. But I wasn't talking about what is possible if you throw enough computers at the problem. My original premise was and is that all else being equal, a flat torque curve is more characteristic of an inline 6 engine than of any other configuration. It's just a fact. And if I am to ignore Wikipedia (sometimes a wise thing to do), then please tell me why your opinion should carry more weight? Sorry, Hoss. It's just a fact. You're getting physics mixed up with engineering.

[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/images/smilies/popcorn.gif

Please ensure that your cell phone is turned off during the performance.

What is all this livelier off the line feeling add up to, Bruce? Man, this Rennlist is def the best free entertainment reading on the www

Say what?

Exactly

Yes, I understand your claim, and it is simply wrong. Cite some academic research papers and/or SAE publications to support it and maybe I'll be convinced.

Actually, since it's you that chose to challenge this, I believe it's you that ought to prove me wrong. So far, your evidentiary submission has been bupkus. Zilch. Zero. Just some anonymous guy on the internet arguing the world is flat and demanding that I prove otherwise. Anyway, if I were to play your silly game, the problem for me is that it wouldn't be research papers you'd have to read, it would be textbooks. Because what I'm talking about is a long accepted principle of physics, not some recent discovery or theory. Ridiculous. Okay, bored now.

No, seriously, kid, what are you on about?

Well, hopefully people see through your ridiculous claims.

You're doing all this QB auto engineer analysis to prove why 'my inline 6 feels livelier' schtick when in fact, my 3.6 boxer feels livelier than the uber I6 in the E46 M3 no worries, bruce, just trying to stir things up here no need to call me a kid!

If yours was factory fitted, how do you have a picture of the parts?

Steve didn't install it. He told me he had two, he sold one early on, and I bought the other one last fall. The difference was noticeable and measurable on the track in terms of lap time and top speed down the back straight, but marginal. The car had a serious lean spot at 6000 rpm, most likely due to the configuration of the intake. Remember my comment about the DME. Tuning by protomotive took care of the lean spot and hopefully took better advantage of the components of the kit.

Not the exact parts that went into my car, but a picture i found on pistonheads.com. My car has the X51 option code and this was further confirmed in the PPI last week...

That is so weak. If you were here, I'd propose putting money on it. Be interesting to see if you'd be as brave face to face. Because you could not be more comprehensively wrong. Let me know when you find those WMDs.

Love those butt dynos, because you can never argue with them, and facts never get in the way.

Ah. Then you can just post the link.

Be aware the difference will be most dramatic in the triple digits. Additionally a C4S is not the best car to run with. It's heavy and has additional driveline and aero drag (it has a lower top speed and slightly slower acceleration than a C2) Futhermore, your sexy new wheels (with huge rubber) will also hurt your acceleration.

Nice crack. OK, you said we could ignore the tuning effects of cam profiles, VANOS, intake tracks, etc. So follow along with this... Take a generic Straight 6. No fancy VANOS. Ordinary cam. Individual intake with a simple carb and individual single pipe exhausts on each cylinder. This way there are no tuning effects from. This engine has some given shape to its torque curve. OK, the engine just described is exactly like having 6 separate individual one-cylinder engines connected together. Each one of them has a torque curve with the same shape as the original 6-cyl engine, just 1/6th of it. The overall torque curve of the original straight-6 has nothing to do with its inline 6 configuration. Any engine made up of those same single cylinders with the same bore and stroke, same stroke to rod length ratio, same cylinder head chambers, valves, CR etc. and intake and exhaust as the original engine will have exactly the same shape to its torque curve. Be it a flat 4, V-8, 9 cylinder radial, or whatever. Bill

Here Enter the Porsche of your choice and the E46 M3 and compare their performance at either the Nurburgring or the Hockenheim short course. This is as close to apples to apples data you're going to get. Cheers,

By your logic, every engine would have one cylinder and be "tuned" to order. Sorry, but this just isn't going anywhere. Inline 6s are naturally biased to flatter, broader torque curves. It is by no means the only thing that determines the shape of a torque curve, but it is the primary factor after displacement and stroke. It's famously characteristic of BMWs, and is the reason the original poster THOUGHT he was experiencing a feeling of more power in the Bimmer off the line: More available torque at lower rpms. Technologies like variable valve timing exist precisely because engine configurations each have their own natural strengths, but few consumers will put up with an engine that is only good at one thing. Why don't you find a real live expert that you trust, ask them, and let this thread die. I'm quite comfortable I know what I'm talking about, and I don't really need to win this debate.

I am not going to step on anyones toes but I have heard all my life that I6s produce more torque than V6s of the same displasement as Bruce P stated. I DO NOT know if it is true or just a coincidence and that I am not claiming Bruce is right. Could be simply all the I6's had small lift/duration cams, small-high velocity runners for the intake/exhaust with a longer crank stroke over the comparable displacement V6's, all could explain the higher low-end torque. What I think is the actual reason that this is always said is the fact that I6's generally have LONGER STROKES than V6's. The E46 M3 engine has a 0.6" longer stroke than a 3.4L M96 engine just for reference explaining some of the low-end grunt the M has.

Wow you sure get worked up about this stuff. I've been aware of straight-6's being naturally balanced, and they are very smooth, but I didn't know they produced flatter torque curves than other engines. I looked around online and googled various combinations of "straight 6" and "torque curves" and such, but couldn't find anything that actually explains why. Can you point us to a link with technical information that tells why? You are so confident and sure of yourself, but you don't know exactly why that is. Did you just see that on some random website - like some "car guy" said so and therefore it must be true? Where did you get your information from that makes you so confident, if whatever info you did get didn't explain the reasons to you either? I read somewhere that one of the advantages of the boxer configuration was low center of gravity, and torque. I just read that somewhere, like you did, and like you, I can't explain why. Since I can't explain why, I'm not gonna regurgitate random information if I can't actually back it up. "No really, you gotta believe me!!! seriously I'm right and you are all wrong!!! I just don't know why but it's some technical thing that is beyond me. Now shut up because I'm right and bow before my knowledge!!!"

This is a logical argument. To refute it, you must use facts to logically refute the argument. Anything else is blowing smoke. As far as the long stroke myth goes, read this. http://findarticles.com/p/articles/m...9/ai_n15614621

check it out...E46 M3 & 2002 C2 996 comparison http://www.track-challenge.com/main_...mparison_e.asp Porsche vs M3 1 0

that comparison chart is QB racing at its worst

What's "QB"?

Another amateur. That stroke = low end torque is no more a myth than that the earth is round. What too many bench racers on boards like this refuse to accept is that all engineering involves conscious, intelligent compromises. For a dragster, instant torque is obviously important. But at current trap speeds, top end is now moreso than ever, too. Engine design naturally causes these objectives to be opposing, and there will be guys who claim superiority on the strip by focusing on either of them. Your dialectical principles are also flawed (as, incidentally, is your grammar and, apparently, your Google skills). Strictly speaking, my friend does not need to provide a logical argument to win. He needs to provide proof. That "logic", not coming from an engineer, is just another WMD hunt, and there is an unlimited quantity of logic in the world that can be used to defend anything and, in the minds of fools, prove it. Believe what you like, guys. Sitting in traffic styling for the ladies, it won't really make much difference.

Never heard of it, either. Quarterback is all I know it as. WTF IS IT, BEN???

We had a conversation on E46 fanatics about a half-year ago, I gave the M3 and C4S about an even shot and you TOTALLY BLASTED ME. Come to think of it, you blast a lot of people for A LOT of things. Kinda funny how the C4S's got faster, cause you now own one...

Autozine talks about 6 cylinders being the best for balance because of firing impulses relating to piston/counterweight locations.

are you going to tell your mom on me now cuz i hurted your feelings wahaha but what i said stands true. in the straights, the c4s is the slowest of the 996s and really in a straight line race which any monkey can do from STL or Seattle, there are no such "skills" involved.

Hehe, there's your answer, straight from BEN! M3 will dust the C4S, in the straights. Nah, not gonna tell my mom about this one. Just thought it was funny how 6 months ago, you BLASTED me for saying I had a chance of beating an M3 in a straight line, but I had to get a REALLY good run/timing. Now you say, you're not sure which is faster/pulls harder, you'll have to get your friend to run in his M, to find out. Typical BEN, typical! OH, and btw, I disagree with you. I was a new 911 driver at that time and I did NOT have the skills yet, to get a good 0-100 run. It think it takes good timing and a lot of seat-time to get a q/m run down, in a 911. Anyone on this board will tell you, it takes more skill to get timing down on a 911 than most other cars.

WHAHAAH yea yea I'll eat a little bit of crow on this one, but I didn't blast you man... I said it in a very brotherly way. man up, handle it. btw, wtf do you do for st. louis university? or wherever it is that u work

Right on Ben. You know I repect you bro. Also, love having you around!! IT Manager, Washington University - School Of Law. 9 years and counting.

Gotta have a little Westside gangsta flavor up in this place.... adds levity to the 911 scene.. G G G G unit! If it weren't for work, I would never ever think to visit STL or Nashville, but I gotta say.... Nashville, esp vanderbilt was a blast and i'm sure Wash U's got a great atmosphere. sweet.

Since you only seem to be able to resort to insults instead of intelligent debate, try this on for size. I am an engineer with 27 years of experience, 2 degrees, 7 patents, and 25 technical papers. Now go play in your sandbox.

No, I respond in kind. To me, "you don't know what you're talking about" is an insult, too, and opens the door to another level of dialogue. I didn't start this. I made a statement which, whether you think is true or not, is widely believed to be so. The onus on someone who disagrees, therefore, is not simply to disagree. That's kid stuff. The onus on them is to say, "You and the car magazines you read have this wrong, and here's why." I didn't find the answer given persuasive. Yes, it was 'logical', but so is this: I was on an airplane yesterday. Therefore, gravity is a myth. Logical, but superficial and naive. The truth is that man in his ingenuity engineered a way around gravity, just like car companies engineer their way around the inherent compromises in things like engine configuration. That does not prove the basic physics wrong. Anyway, I'm not going to compare imaginary credential penises with you, especially when your "torque myth" comment speaks so eloquently. Not sure what kind of engineer you're claiming to be, but the ones I know are more critical thinkers than this. Now you can go back to your PlayStation.

long stroke engine are considered by many to have larger torque because the crankshaft has a larger diameter and therefore more mechanical advantage leveraging the force on the crown of the piston. Tell me in your infinite wisdom, what possible difference this makes after going through the cars transmission? Torque and horsepower are like amperage and wattage. Amperage means nothing without voltage (corresponding in this example to RPM). The only real meaningful quantitiy is horsepower (wattage). People in the car business use phrases like "lots of torque" to mean the engine has a broad power band. Tourque by itself is meaningless. A motor in a forklift has gobs of torque at 0 rpm. How much work is it doing at 0 rpm? None. How much work are your flapping gums doing? 0.

Well, first of all Dr. Science, we're leaving drivetrain out of the equation. There is no argument that a hamster wheel can lift a supertanker if the gearing is right. You are correct, leverage is the reason long stroke engines produce more torque. You are incorrect that it's the crankshaft diameter that provides the leverage. It's what that crankshaft is driving that provides the leverage. Did you sleep through Newton? You are wrong about horsepower, if I'm reading you correctly. Horsepower is a derived number, it's not measured (again, HP = (torque x rpm)/5353). Torque is the opposite of meaningless, a stunning statement that I have to assume I'm misinterpreting, because it's otherwise asinine. And, I must add for Mr. Choi's benefit, for most drivers most of the time, torque matters massively more than HP. I don't know what magazines you read, but I have never confused "lots of torque" with "a broad power band". I well understand the difference between how much absolute torque an engine produces and how much of it is available at a given rpm.... the genesis of this thread. I have not once said that torque is work. I explicitly said that HP is work. The reference to electric motors is unhelpful and irrelevant, since everyone knows that electric motors produce 100% of their potential torque instantly. They just don't produce much horsepower. Yet they use them in locomotives. Hmmmm...

You are incorrect, The diameter the lower connecting rod rotates around is the only reason the longer stroke engine produces more torque at the crankshaft. This thread is labeled "M3 feels quicker...etc" or did I get that wrong too? Last time I checked both cars had transmissions. Let me check that again... Yup, both my 996 and wife's 330i have transmissions, what a surprise. I read textbooks, not magazines. Horsepower is work. The ONLY thing that moves your care is WORK. Horespower = work =watts. 1HP=746 Watts (wow, and I didn't even look it up). I can't believe you didn't look this stuff up before posting. I also took way more physics than you, obviously; because you are conducting this disscussion on a very low technical level. I'll say it again, torque by itself means NOTHING. Only POWER is meaningful in moving the car. Now go get your GED. (hey, I wouldn't be an *** if you weren�t an *** first).

Read more carefully, there, Hoss. This was a theoretical argument about the putative bias of the inline 6 cylinder engine configuration to broad, flat torque curves. I stipulated several times that if you allow drivetrain and fancy valvegear into the equation, the discussion is completely moot. Horsepower does not equal work. Horsepower equals work over time. I'm sure you realize this, and you were typing in the heat of the moment. Power as a separate concept from both torque and HP is a new one on me, I'm afraid. A foot pound of torque is the twisting force necessary to support a one pound weight on a weightless horizontal bar, one foot from the fulcrum, which sounds to me like "power". HP, given the critical dimension of time, sounds to me more like 'work'. Yes, I'm conducting the discussion on a low technical level. I think that's appropriate for the environment and the subject at hand. What matters to people here is the driving experience so, past a certain point, the technical explanation is unwelcome, I think. Given the same mass, same gearing, engines with more available torque at low rpms 'feel' faster off the line than engines with less, regardless of either their peak HP or peak torque. It just seems to me undebatable. And congratulations on your "way more physics". Do you have that on your business card? Geez, I would. It's impressive.

fellas we have a d!ck measuring contest on our hands and not sure if i want to be a judge

No, I'm dickless. I'm not an engineer. I've never even driven a train (though I have always fancied one of those hats).

I believe Ben meant "armchair" racing or "magazine racing"

Again, if you are going to assert technical statements LOOK THEM UP FIRST. Ok, lets start at the beginning. Work is force x distance. In this equation, force is torque, and distance is rpm (or angular velocity). Horsepower times time is ENERGY, this is what the electric company charges you for (similar to the gas you put in the tank). You can have INFINITE torque, yet accomplish nothing with it (1/4 mile in... never seconds). It is a kind of colloquialism that we even say a car "feels" torquey. What we really mean is the car has lots of power at low rpm. I am weary of this.

OK, gonna wade a bit into this: From Webster's: Horsepower n. A unit of POWER equal to 745.7 watts or 33,000 ft-lb per min. Torque: n. The capability or tendency of a FORCE for porducing torsion or rotation about an axis. A turning or twisting FORCE.

... and no wonder. Happy to let this die whenever you like.

NO!!! I was just about to pop up a new batch of popcorn , I even invited friends!!

I haven't forgotten my highschool physics or my Mechanical Engineering degree from 1973, so I'll post this once: Force = Mass x Acceleration. Torque is a FORCE. A rotational force. Nothing has to move for torque to be present. Think of a stuck bolt you're trying to loosen. Work = Force x Distance through which it is MOVED. No movement, No work. just FORCE Power = The time rate at which work is applied. Working in English Units, HP = (torque lb-ft x RPM)/5252 Now who wants to stay after class and write this on the blackboard 10,000 times? Cheers,

I'm still waiting for BruceP to tell us why inline-6's give a flatter torque curve than other engines. He hasn't said anything except his opinions and he can't tell us why - just that we gotta believe him. Waiting for a link to a credible website or something that will explain it in technical terms...

Would you understand if I did? Look, my friend established that he would only buy academic research. I can produce over 200,000 Google hits - everything from magazines to blogs - where the writer says something like, "the naturally flat torque curve of an inline 6", but I can't produce evidence to his standard. This is because the subject has not warranted "research" (to use his word) in decades. So, two things: First, he can't produce evidence that meets his own standard. This isn't a debate, it's McCarthy-esque bullying. Second, why on earth would I risk whatever credibility I might have bringing evidence to the table that doesn't meet his standard over and over again only to get shot down every time just cuz he says so? It's not fun, it's not mature, it's not productive. I wouldn't waste my time on hypocritical bench racing wannabes at all except that I have this genetic defect that I don't like to give up. So if you want to get all Lord of the Flies and jump on this dogpile ten pages in, go right ahead. It doesn't say much for you, but it's a free country. What would be super cool would be if you were to CONTRIBUTE. Geez, I wish someone would start an oil thread....

Look, dude, I have a PhD in six cylinder engines from the University of Bite Me, have published seven hundred books on the subject, including War and Peace and If I Did It, and hold the patents on the wheel, aspirin and the Clapper. I don't need any attitude from you.

Didn't you also fly that hot air balloon around the world in 40 days without refueling? I think I saw you near Albuquerque. -td

Well, you spent lots of time trying to convince everyone that it's true, when all you had to do was say, "Look, the evidence is right here". Why argue and argue and not post anything to back it up? I'm actually curious about this topic, and I did read thru everything. I'd love to know the why's and the how's. I've long known that the straight-6 is the most balanced, but never heard it also produced the flattest torque curve, so I kept hoping that you'd post something other than, "I know it's true and you need to believe me. I just don't know why". I'm just asking why you think it's true, since you were obviously presented with clear evidence at one point or another - or was it just anecdotal evidence by some car-dude? You must have seen something somewhere that explains it, and I'm curious and would love to read it. You can't just say, "well I have the evidence but I don't want to provide it because you guys wouldn't understand anyway" - yet you've put lots of energy into the argument and haven't backed it up with anything meaningful. Instead you are just getting upset that people aren't believing you and taking your word for it. Seems like the time is right to just give us the technical information you are holding back.

You are correct, but modesty forbids...

If you spend some time on this board, you'll see that once one of these bunfights gets going, there is no evidence that will satisfy the jackals. Look at the poor bastards that got all excited about plenums, or the lost souls that dare to put whatever oil Porsche tells them to into their cars. Certain folks, in the anonymity of cyberspace, fearlessly dismiss any source you can imagine like Torquemada himself (hey, wait, that's funny!). A few pages back, I cited a very simple little article on Wikipedia. It wasn't cited as a defence for my case, nor was it presented as prima facie or comprehensive. On the other hand, it was a pretty simple, rational, well articulated article. My friend dismissed it IMMEDIATELY without reading it, because it didn't agree with his view of the world. THAT's when I knew it wasn't worth trying. Nothing short of a Marshall Macluhan moment (Annie Hall... great scene) is going to do the job, here. So I'm afraid you aren't going to bait me any further. You and me, eye to eye over a beer, I could persuade you easily. In this environment, secondary evidence is just so much chum. Find me a peaky inline 6 cylinder passenger car engine currently in production. Just one. Ain't none. Why?

I read that wiki article, and it was good - but didn't say why straight-6's have flat torque curves. I'm not trying to "bait" you into anything. You're just making claims and trying to convince people, but have zero evidence to back it up. Why not just post a simple link with some technical explanations so we can check it out and we'd be satisfied.

Because with the possible exception of some BMWs, they are mainly used in truck and low performance applications where it makes no sense to design/tune them for high rpm usage. Most firms abandoned them for packaging and other reasons before too many people got worried about high specific outputs, etc. Bill

Look, this is unwinnable. There is no 'simple link'. And I reiterate that you haven't demanded the same of my esteemed colleagues. Why not just let it go? Inline 6 cylinder engines have no primary or secondary imbalances. That is a scientific fact. This means they can be designed with a bias to torque without them shaking themselves to pieces (or without the need for balance shafts). Same reason they're used in industrial applications: big, readily available torque on a stable platform. Now, add the benefits of one head, one manifold, one header (because exhaust is a critical component in determining an engine's torque curve)... But when I've got opponents who are even willing to deny that long stroke engines are torquier than oversquare engines, and then glibly demand that I prove otherwise, what is the point? When you have people claiming, straight faced, that any engine can be tuned to do anything, what's the point? Where the hell would I start? Contrary proof is all around us, but does not happen to be conveniently packaged on an easy-to-read web page authored by a papally infallible source. And there is no will, here, with certain folks to have a genuine debate.

All true. Inline 6s began to die because of Detroit's marketing of the V8 in the 60s. Front wheel drive finished the job, because of packaging, as you say. They are mainly used in truck and low performance applications, just as you say, BECAUSE THOSE APPLICATIONS DEMAND AVAILABLE TORQUE AT LOW RPMS, for the love of pete, and an inline 6 is the cheapest way to get it because it needs no engineering bandaids. BMW tried to play the high specific output game with engines like the S54, and it was a nightmare for them. They were asking the engine to do more than it naturally could. This is why they're slowly abandoning the configuration. The fact is that I could walk away from a 996 in my Dinan z3 2.8 from a standing start... for about half a block. This was the point of my original post. It felt quick off the line, but the Porsche would eat it up and spit it out once it was rolling.

The secondary imbalances don't present a problem at low speeds. And here you go talking about "designed" with a bias to torque, after you keep insisting it's an inherent quality of the straight-6 configuration. (which in my previous posts I have to clearly demonstrated is simply not the case) Inline engines are cheaper for big industrial applications. That's why they are often used. Bill

People in the car business use phrases like "lots of torque" to mean the engine has a broad power band. Tourque by itself is meaningless When you are talking about cars, you have to consider Torque and HP. Torque is obviously important because a car's maximum acceleration will occur at its peak torque output at any given gear. HP is important because having a car that builds maximum torque at 3K and falls off precipitiously won't be of much use to car enthusiasts. HP is critical because we must focus on torque to the wheels, and a car with a high HP engine will still be producing a lot of torque at high RPM which will enable the driver to take advantage of the gearing advantage which you have in the lower gears. So even though the engine torque will be falling, it will be more than offset by the gearing advantage of the lower gear. Torque at the wheels = engine torque X gearing. Another way of looking at this is that I'd rather be in first gear at 7500 RPM where my hypothetical engine may only be generating 210 lb/ft of torque than second gear at 4500 RPM where my engine may be making 280 lb/ft of torque. Since a six speed transmission may have a gear ratio of 3.31: 1 in first gear and a 1.95: 1 in second gear, you want to stay in first to redline to take advantage of the 3.31: 1 gear ratio. So bottom line is that you have to consider torque and more imprtantly torque RPM range, HP, gearing, and of course the weight of the car when considering how fast a car can accelerate.

Horsepower is proportional to torque x rpm. What else is there to say? Saying you want maximum horsepower at a given rpm is the same as saying you want maximum torque at that rpm. You can't have horsepower without torque, and you can't have horsepower without rpm.

Horsepower isn't really "measurable". Engine Dynos measure torque, and horsepower is merely a number gotten from an equation that shows how much work your engine can do with that torque over a period of time. Horsepower is all about rpm's - it's just milking all the possible work that your engine's torque can do for you. Maximum G-forces on acceleration will always be felt at the peak of the torque curve, not the hp curve, since you aren't adding anything new into the equation once you go past the torque peak. Obviously it's best to wait until you get the maximum work from your engine before shifting into a lower gear ratio, so you want to use all of the engines rpms before hitting the next, less efficient, gear.

Secondary imbalances don't present a problem at low speeds? Better not tell every contemporary V6 designer on the planet, who invested all that money in balance shafts. They'll be pissed. Inline engines are cheaper for big industrial applications. Yes. You are abso-freaking-lutely correct. This is because industrial applications demand lots of torque at low rpms, and an inline 6 is the cheapest way to get it. That's because an inline 6 naturally gives it to you without a lot of fancy engineering. With respect, I don't think you've "clearly demonstrated" anything. I haven't seen a credible third party explanation of how any engine can be designed to have any characteristics, as you argued a few pages ago. I haven't even seen a response to my challenge, find me a peaky inline 6 passenger car engine in production today. Nothing. Nada. Just bafflegab and belligerent denial, with a soupcon of self-contradiction. But I'll give you this: You've almost worn me out. That's saying something. Anyway, I'm going up to my country place tomorrow. I think I'll spend some time on the old John Deere... I'm sure I can get 150 mph out of it if I just "tune" it right.

Hp is proportional to torque x rpm. Am I repeating myself? Am I repeating myself? Here is another one. Hp IS work. It is not RPM. It is not torque. It is.... WORK. I'm going to bed now....

Almost correct. HP = (rpm x torque)/5353. For the third time. For the third time. And it is work. Work over time. Equivalent to raising 33,000 lbs. one foot over a period of one minute. Nighty night.

Hey genius, Read what I wrote again and I said the same friggin thing. I said hp is merely a number gotten from an equation based on torque. Torque peak will give you the peak hp number. Yes HP IS work. Where did I say it wasn't? How can you get "work" without using rpms? Did I say torque is work? hp is a measurment of how much work you can do with the torque your engine makes. Go bang your head against the wall and go to bed and learn to read.

The first time you wrote "5353" I figured it was a typo and gave you the benefit of the doubt. The correct figure is 5252. It's 33,000 / 2Pi

I said it first, and you tell me I am repeating YOU? ok Copernicus, think about this one. The torque peak rpm point is NOT necessarily; in fact, hardly EVER where the maximum horsepower is made. no wonder the Japanese and soon the Chinese are / will be eating our lunch.

You guys are arguing about matters that are covered in detail in High School Physics. The maximum torque is made at relatively low RPM in well designed engines and be definition, the HP is still low. An engine with a great torque power band like the Cayman S for example, will make its maximum torque at 3K RPM and maintain it until around 6K RPM. A car's maximum acceleration occurs when the engine is at its peak torque output, and of course that will occur in first gear where the gearing is at its highest numerical value, i.e., where the torque to the wheels is at its highest. In the case of the CS, at 3K RPM the HP is only 154: HP = 270 X 3000 / 5252. So in the case of the CS, it will not accelearte any faster than it does at around 3K RPM where the engine is only producing 154 HP. As the engine passes 6K RPM, engine torque will begin to decline but HP will continue to increase until it hits its peak at 295 at around 7000 RPM where the engine torque has fallen by almost 50 ft/lbs. So on a test drive, it's pointless to go beyond 4K RPM on most cars if you are trying to get a feel for how quickly the car accelerates. Nevertheless, I wouldn't be surprised if most people believed that a car will accelerate fastest at its peak HP, and therefore they feel they have to take a car to or near redline to experience its maximum acceleration.

So why are you quoting me?

Correct. Typo, and thank you. I was simplifying the horsepower equation with the "one foot over one minute" thing, as I'm sure you realize. You're being pedantic to make some kind of point, I assume.