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Old 05-11-2011, 02:10 PM   #25 (permalink)
Dizon248
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Join Date: Feb 2011
Location: California
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Quote:
Originally Posted by Econ View Post
Bhp = whp*(1+.17)

Whp = bhp*(1-.17)

Estimation Obvsiously. Its not perfect.
You can't do that. When you use the 17% drive train lost, you can't convert back up 17%, you are using a different baseline and it will give you a different value.

So Whp = bhp*(1-.17) is right, but when you do Bhp = whp*(1+.17) you are multiplying by a different baseline. Try it. Say I have 300bhp and I multiply that by (1-0.17), I get 249. Now use 249 to multiply by 1.17, you get 291.33. You just lost 9HP from converting like that.

The right way is this, Whp = bhp*(1-0.17), solve for bhp now. bhp = whp/(1-0.17).

Summary

Whp = bhp*(1-0.17)

bhp = whp / (1-0.17)
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