Quote:
Originally Posted by aerobod
Yes, the torque curve (plateau in this case) is exactly the same until 5870RPM (as seen on dyno plots, for example from IND), so no extra work or performance is achieved until that point. The only extra performance is achieved in the extension of the torque plateau by 260RPM.
This is why the base M3/4 and M2 with weights within a few kg of each other in reality have the same acceleration when tested head to head. The useful extra work (bearing in mind the rev range used in each gear) is only 2% or less different between the engines, compared with the 4% power difference, assuming both engines are revved to 7200RPM.
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Measuring a cars power on a dyno which is at the wheels introduces parasitic losses and is not comparable to engine power which is rated at the crank. Dyno numbers also are useful as a baseline when tuning to see gains you are making in relative realtime. They are also useful when pitting two cars against each other under the exact same conditions. No two dynos will show the same results for the same car and the only way to usefully test the difference in power is to test two cars against each other on the same day, under the same weather conditions and using the same correction factors on the same dyno.