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      02-18-2013, 12:13 AM   #1
M3takesNYC
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Power trumps torque: Here is the proof

I have realized through reading the posts that there is a ton of talk about the lack of torque and the fact the arguement is made frequently that "given the same horsepower, the car with the higher torque is faster" etc. Rarely do you have a true apples to apples comparison to illustrate that truly it is simply horsepower that matters.

I found this old video tonight. I actually for god knows why, I was watching youtube review on the new Dart. I give it to dodge, they are doing great marketing and catch commercials! Within 5 minutes I got bored of that and looked for some M videos. This old "shootout: Sibling rivalry" came up.

E92 m3 6-speed with 414hp/295foot pounds vs. Dinan 335 with 408 horsepower/450 foot pounds

Both 6-speeds, both weigh 3600 or so pounds per their spec sheet. They did slalam, a laptime and a quarter-mile. M3 won in everything but what I thought was relevent to this torque vs hp talk was the quarter mile. That is a purely straight-line race which if anything should give a car with low-end torque the advantage, especially given it has the same horsepower as the m3.

However as you see in the results the m3 is faster in a straight line from a standstill despite being down 150 foot pounds of torque and having equal horsepower, equal transmission and equal weight.

Now I am not sure how anyone can refute the claim that it is truly horsepower that dictates acceleration for a given weight.

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      02-18-2013, 12:43 AM   #2
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Oldie but a goodie!

The 335 uses the same transmission as the M3? That's news to me...
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      02-18-2013, 12:48 AM   #3
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I always preferred the higher power to the higher torque.
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      02-18-2013, 01:48 AM   #4
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I'm not sure if one video of a race is "proof", plus DINANs tuning is pretty tame...the Proceede, COBB guys are laying down some impressive numbers..

Ran the COBB on a 335 sedan and use to pull on M3s consistently..its at the higher end where the M3 has the advantage. So in that respect hp trumps tq.
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      02-18-2013, 01:59 AM   #5
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Interestingly, Willow Springs/Rosamond is over 2,000 ft in elevation, where an FI engine would be advantaged vs NA.
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      02-18-2013, 02:13 AM   #6
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Quote:
Originally Posted by PrimoM3
Oldie but a goodie!

The 335 uses the same transmission as the M3? That's news to me...
No. I believe the 335 uses a ZF-sourced transmission. Looking it up now to confirm though.
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      02-18-2013, 03:57 AM   #7
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Given the same horsepower, the car with higher torque is RARELY faster, often times it will be slower.
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      02-18-2013, 06:17 AM   #8
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Itt: people who don't understand physics
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      02-18-2013, 07:09 AM   #9
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As most of you know, torque and hp are not completely independent of each other. Hp is actually a mathematical calculation based on torque and engine speed. Most turbo motors, make "big torque", but are limited in their engine speed and their ability to produce that torque for any length of time. Hence the feeling that they "run out of breath" at high rpms. This is especially true for the smaller turbos that most manufacturers use to spool up quickly. Bigger turbos of course, suffer from more turbo lag, and are less beneficial off the line, and lead to a very surging type of power delivery. The M3 produces "only" 295lb ft of torque, but it can keep producing near that level of torque over a huge rev range.

When tuners modify a turbo motor ECU to give more boost, you will notice that this always results a greater peak torque, but that peak torque is very short lived. It goes back to that old notion of "the area under the curve". The M3 can keep making torque even at high rpms, hence the high calculated hp.
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      02-18-2013, 07:10 AM   #10
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This has been debated to death. Peak torque by itself is pretty much a meaningless number. As a single number, peak power provides a much better appreciation of an engine's capability to accelerate a car. Especially when comparing power to weight.

In this test, both cars have very similar power to weight, and they come out with only 0.1 second difference in the quarter mile. Expected...

However other variables also come into play, like the shape of the power curve, gearing, tire slip, aero and tire drag. A combination of these is probably the reason why the M3 came out faster despite the Dinan having the slight advantage from a power to weight perspective.
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      02-18-2013, 07:26 AM   #11
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power is a function of torque.
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      02-18-2013, 09:32 AM   #12
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Quote:
Originally Posted by LarThaL View Post
As most of you know, torque and hp are not completely independent of each other. Hp is actually a mathematical calculation based on torque and engine speed. Most turbo motors, make "big torque", but are limited in their engine speed and their ability to produce that torque for any length of time. Hence the feeling that they "run out of breath" at high rpms. This is especially true for the smaller turbos that most manufacturers use to spool up quickly. Bigger turbos of course, suffer from more turbo lag, and are less beneficial off the line, and lead to a very surging type of power delivery. The M3 produces "only" 295lb ft of torque, but it can keep producing near that level of torque over a huge rev range.

When tuners modify a turbo motor ECU to give more boost, you will notice that this always results a greater peak torque, but that peak torque is very short lived. It goes back to that old notion of "the area under the curve". The M3 can keep making torque even at high rpms, hence the high calculated hp.
Said best right here.

The best way horsepower vs torque was explained to me was: "Horsepower = Torque * Engine Speed"

And as far as performance of the M3 engine, it certainly is under-rated if you just look at the peak power of it. It is very smooth and delivers that power over a much longer period of time.

The Math gurus need to crunch a new formula to rate an engine which incorporates how much power was generated over a given amount of time. Maybe some kind of weighted horsepower figure.
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      02-18-2013, 09:59 AM   #13
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Quote:
Originally Posted by e1000 View Post
Given the same horsepower, the car with higher torque is RARELY faster, often times it will be slower.
I must admit to being a little pissed off that they didn't show the quarter mile trap speeds of the two vehicles. By implication (based on the test driver's comments), the Dinan suffered off the line, but had the better trap speed.

In theory, comparing two cars with equal power to weight, the car with the better torque to weight numbers will likely win, since it will likely be making a bit more average power to weight over the race distance (i.e. - more power after each shift). This would tend to show up in terms of a better trap speed, but other factors might be more important in terms of ET.

I'm not picking a fight, but am genuinely curious about your statement. Do you have some examples?

Bruce
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      02-18-2013, 10:01 AM   #14
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Quote:
Originally Posted by Nautik View Post
Said best right here.

The best way horsepower vs torque was explained to me was: "Horsepower = Torque * Engine Speed"

And as far as performance of the M3 engine, it certainly is under-rated if you just look at the peak power of it. It is very smooth and delivers that power over a much longer period of time.

The Math gurus need to crunch a new formula to rate an engine which incorporates how much power was generated over a given amount of time. Maybe some kind of weighted horsepower figure.
The exact formula is hp =(torque in lb-ft * rpm)/5250. If you look at ALL power and torque graphs, they all cross around 5250 rpm. This is where power in hp and torque in lb-ft are numerically the same.
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      02-18-2013, 11:44 AM   #15
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
I must admit to being a little pissed off that they didn't show the quarter mile trap speeds of the two vehicles. By implication (based on the test driver's comments), the Dinan suffered off the line, but had the better trap speed.

In theory, comparing two cars with equal power to weight, the car with the better torque to weight numbers will likely win, since it will likely be making a bit more average power to weight over the race distance (i.e. - more power after each shift). This would tend to show up in terms of a better trap speed, but other factors might be more important in terms of ET.

I'm not picking a fight, but am genuinely curious about your statement. Do you have some examples?

Bruce
i disagree. Cars with high torque values compared to their power output typically have early peak torque, which then trails off. Perfect example of this is the N54/N55. (Blue line)



Of course, with the N54/N55, this is due to the turbo's being optimized for a certain rev range, and once it gets past this range, the fun tapers off quickly. This reflects the driving characteristics of the car, a strong initial shove and then that acceleration tapering off in the high rpm range.

While that's all happening on the 335i side, The M3's torque curve looks like this.



The almost completely flat torque curve means that the S65 pulls right up until rev-line.

I know what you're thinking, "but that's a FI vs NA car, surely this is a symptom of being turbocharged!"

Not so, take for example, the M156 6.3L AMG engine. Again, relatively high torque vs the horsepower it produces.



Again, we see the drop off occur starting at 5.5k rpm.

Why does this happen? This happens because regardless of FI or NA, horsepower and torque will always have a relationship with one another, and if a high amount of torque is created in the early to mid range, the engine will have to slump at the end. The answer to this of course, is what M did with the S65, and what Ferrari likes to do. Cut the peak torque to achieve an almost completely flat torque curve.

From there, you and I both know why the torque number itself means little to nothing. Throw in the proper cogs and the equivalent hp/low torque engine will almost surely run away with the race.
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      02-18-2013, 11:56 AM   #16
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God I really need a framed picture of the S65 dyno plot! I have looked at ferrari's, MB, lambo's and NOTHING gives you the absolutely perfect delivery of power like this engine! If this was put in a 3200 pound car, it simply would be the absolute best car. Essentially the GTS I guess.

Still love it!!

The point of this thread was to show people who say that torque wins any contest is silly. As everyone is saying HP is derived from torque and are really not seperable terms. But this was a really clear easy illustration of a drag race in two cars with essentially the same hp but wide variance in torque and essentially the cars were equal in a straight line with the slight edge to the car with lower torque (it was even heavier!)
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      02-18-2013, 11:59 AM   #17
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The key is the area under the torque curve and not the peak torque.

Having a car with high RPM's (M3, F430, GT3, etc) allows greater torque multiplication via gearing, which allows more work over time.

Having a car with more RPM's to work with allows it to have a mechanical advantage. The higher torque/lower HP car will pull away initially. As the car with higher torque/lower HP shifts into 2nd, the lower torque/higher HP car will start pulling away, because it's still in 1st gear. In 1st gear, it's putting down much more overall torque.

That's why a F430 can achieve a trap speed of 120 mph for a relatively low torque car. The above is also the reason F1 race cars have a pretty low torque of 300, but a HP of 900 and a redline of 19,000.

The thing slowing the M3 is it's weight.
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      02-18-2013, 12:17 PM   #18
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Quote:
Originally Posted by M3takesNYC View Post
God I really need a framed picture of the S65 dyno plot! I have looked at ferrari's, MB, lambo's and NOTHING gives you the absolutely perfect delivery of power like this engine! If this was put in a 3200 pound car, it simply would be the absolute best car. Essentially the GTS I guess.

Still love it!!

The point of this thread was to show people who say that torque wins any contest is silly. As everyone is saying HP is derived from torque and are really not seperable terms. But this was a really clear easy illustration of a drag race in two cars with essentially the same hp but wide variance in torque and essentially the cars were equal in a straight line with the slight edge to the car with lower torque (it was even heavier!)
Correct, for a high performance car, the S65's torque curve is pure fantasy land to the eyes on an engineer.
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      02-18-2013, 12:33 PM   #19
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Something not right here. Torque and Power graphs should cross around 5000-5500 rpm, unless there is something that I am not accounting for??
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      02-18-2013, 12:33 PM   #20
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Quote:
Originally Posted by HighandDry View Post
The key is the area under the torque curve and not the peak torque.

Having a car with high RPM's (M3, F430, GT3, etc) allows greater torque multiplication via gearing, which allows more work over time.

Having a car with more RPM's to work with allows it to have a mechanical advantage. The higher torque/lower HP car will pull away initially. As the car with higher torque/lower HP shifts into 2nd, the lower torque/higher HP car will start pulling away, because it's still in 1st gear. In 1st gear, it's putting down much more overall torque.

That's why a F430 can achieve a trap speed of 120 mph for a relatively low torque car. The above is also the reason F1 race cars have a pretty low torque of 300, but a HP of 900 and a redline of 19,000.

The thing slowing the M3 is it's weight.
Its actually the power curve that is meaingful and only looking in the area within the 2-3k RPM's worth of the powerband which the car is in during maximum acceleration. ie. Looking under 6k for the m3 is useless when comparing its full-out performance. Daily driving ability is different but all out performance you look at power under the curve in its powerband which is really 6-6.5k to 8400.

Higher revs does not increase performance because you can stay in the revs for longer as the powerband is simply adjusted quite far to the right in a high-revving car. An F1 car never dips below 17000 RPMS's so its not like the advantage is there because it can sit in second gear from 11k-19k RPMS.

If you compare and bench race a 335, you look at its powerband where its gearing allows it to be during max acceleration which is about 4.5-6.5k RPM's so a span of 2k RPMS roughly. Compare that with the area under the curve of power for the m3 which again is really only a 2k RPM span, so no difference in total number of RPMS available to play with, but rather the effect the RPM's are having on the power output. Within the 6k-8500 RPM range the m3 uses its high-revs coupled to a weaker torque to produce its power which is illustrated by the power curve.

A 335 takes its relatively higher torque (given its power) and uses the lower amount of revs coupled with the higher amount of torque to produce its power curve during those peak 2.5k worth of band. The total area of those 2 curves (power curves) is indicitive of its maximum output during its powerband during maximum acceleration.

Go to youtube and watch an all-out sprint with someone video taping the RPMS's and you notice when all-out a 335 never dips below 4500-5k rpms and the m3 never below 5500-6k. They both only have about 2k-2.5k worth of RPMS to rev through so the m3 is not using more revs to stay in the band longer.
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      02-18-2013, 12:43 PM   #21
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Quote:
Originally Posted by LarThaL View Post


Something not right here. Torque and Power graphs should cross around 5000-5500 rpm, unless there is something that I am not accounting for??
They scaled HP and Torque on different scales.
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      02-18-2013, 04:32 PM   #22
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They scaled HP and Torque on different scales.
+1
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