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Old 04-05-2012, 09:36 AM   #179
ZDan
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Quote:
Originally Posted by Deslock View Post
I'm not sure where you're getting that from, but the RX8 didn't make anywhere near 220 whp. By the simple weight & hp formula, 207 whp is needed for 3050 pounds and 95.5 MPH, and the RX8 didn't make anywhere near that either.
You forgot to add weight for the driver and some fuel. Try it again with 3250 lb. instead of 3050.

Mazda lied about the RX-8's hp, but not by THAT much!

[edit]Oh yeah, the formula is for flywheel power, not rear wheel. RX-8 rwhp ~185-190 from what I've seen.

Quote:
It's worth noting that formula only provides an approximation as it doesn't account for things like traction, temp, air density, and CoD (which is quite low for the FT86).
Especially for lower-powered cars, traction doesn't affect trap speed much.
Some mags correct 1/4-mile results for temperature and air density.
Minor differences in drag (Cd*A) won't change results much.

The equation *is* a quick/dirty approximation/estimate. But it's a very good one for getting in the ballpark.

Last edited by ZDan; 04-05-2012 at 10:35 AM.
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