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      12-11-2012, 09:41 PM   #73
Remonster
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Drives: E90 M3
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Quote:
Originally Posted by swamp2 View Post
Why, because torque has very little to no bearing on how fast the car will be?
You must be joking, unless you're trying to imply that high RPM horsepower is what really matters but horsepower is just a function of torque.

We can assume the new motor will rev higher than 7,000 but probably not much more, with the M5's redline sitting at 7,200RPM, so they won't be able to make up for low torque with very short gearing like they have traditionally done. If you put short E92 M3 style gearing on a motor with a 7,000-7,500RPM redline, you would end up shifting way too often (assuming manual transmission, this isn't a big deal with a DCT).

So, if we know that the redline will be lower than the 8,400 of the current M3 and that the gearing will necessarily have to become taller, it comes down to weight savings and increased torque to get it to accelerate more quickly than the current car. As a result of this increased torque, we will obviously see an increase in horsepower. Since horsepower is defined as 550ft/lb per second, if the rumors of ~400lb/ft of torque are accurate we could see 380 horsepower by 5,000RPM (assuming the motor can maintain full torque at this RPM and isn't beginning to drop off too badly). An N54 / N55 is still making peak torque around 6,000RPM and I would think that one of the key goals for the new M motor would be even more high-rpm power. If that's the case, then a motor making 400lb/ft at 6,000RPM would also make 456 horsepower. I think we can safely assume a healthy horsepower bump over the S65 unless they use ridiculously tiny turbos or manifolds or something that would prevent the motor from making much torque above 5,000RPM.
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