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      04-07-2007, 03:03 PM   #18
swamp2
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Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

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Launch and drag

Tools such as this can do 30-60, 60-100 etc much more accurately than 0-X, the reason is is that wheelspin is required for the best time but of course just enough to get the momentum going and not so much to be loosing accelerative forces. This is extremely difficult to model and requires a myriad of factors such as weight distribution, suspension geometry, tire and pavement properties, etc., etc.

Air resistance scales with the square of velocity so at low speeds it is not so significant (even in 0-60) but for top speed it is one of the dominant factors. Leaving drag off because the software does not handle wheelsping is a fairly poor approximation that seems to give reasonable numbers but you are certainly "tuning" the software a bit to get an expected result. Here is the real question with similar aprroximations how close can you get to M5 or 335i times (I would not bother with Rs4 or Porsche times beacuse of the 4WD and rear engine effects which are quite large)?