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      04-21-2012, 10:25 AM   #45
catpat8000
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Drives: 2019 M5
Join Date: Mar 2010
Location: California

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A few points:

1. Why, when the numbers are so incredible, is everyone so quick to believe the dyno results? Dynos are excellent at measuring deltas but it's much more difficult to get accurate absolute values. Many, many things affect the outcome, not the least of which is the dyno's state of maintenance and the operator of the dyno. The most straightforward answer is that the dyno HP numbers publish by the magazine are bogus. We should be skeptical when things don't look right. Extraordinary claims require extraordinary proof.

2. The Porsche is AWD - how does this affect the dyno comparison with the other cars?

3. When you're looking at acceleration from a roll of 100 km/hr or higher, gearing will have very little effect on acceleration, if measured over a large speed range, like 100-200 km/hr. The reason is that while a higher geared car will pull harder in a specific gear, it is out of that gear more quickly and then the other car pulls harder for a while.

4. Aerodynamics will have a measurable effect on acceleration times at high speeds. Anyone know which car has a better coefficient of drag? Nonetheless, the single biggest factor which determines a vehicle's acceleration, once it is moving and at a higher speed (so traction isn't an issue) is the hp to weight ratio.

Pat
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