Hp
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Hp
what is the proper way to calculate % loss if you know the crank HP and WHP? 
Now, I know of 2 ways, but dont know which 1 is correct. Lets say a stock Civic LX is claimed 115 crank, on a good day should dyno at 100WHP. Is percent loss: 115/100 = 1.15 minus 1 so 15% loss?
or: (115-100)/100 = 15%
in this case, it both came to 15% but in other cars it may not come out that way. Also if you have the percent loss and crank HP, how would you calculate the estimated WHP? thanks!
Now, I know of 2 ways, but dont know which 1 is correct. Lets say a stock Civic LX is claimed 115 crank, on a good day should dyno at 100WHP. Is percent loss: 115/100 = 1.15 minus 1 so 15% loss?
or: (115-100)/100 = 15%
in this case, it both came to 15% but in other cars it may not come out that way. Also if you have the percent loss and crank HP, how would you calculate the estimated WHP? thanks!
Joined: Dec 2001
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From: Milwaukee, Wisconsin, US
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divide the wheel horsepower by the crank horsepower. (assuming you know both)
wheel/crank = % of power that is MAINTAINED once you move the decimal over two places. so for example.
100/115 = .8695~ move the demical = 86.95% of power is maintained. Obviously this means about a 13% power loss.
another way to do it.
(wheel-crank)/crank = % of loss once you move the decimal two places to the right. (or multiply the answer by 100)
so ((100-115)/115))*100= % loss
just an FYI, the same car can dyno different losses on different days. you could dyno your car, and make 100whp. the next day you could dyno again and make 103whp. people tend to think that you can just assign a percentage loss for a single car or even a single type of car, when in fact, you can't.
wheel/crank = % of power that is MAINTAINED once you move the decimal over two places. so for example.
100/115 = .8695~ move the demical = 86.95% of power is maintained. Obviously this means about a 13% power loss.
another way to do it.
(wheel-crank)/crank = % of loss once you move the decimal two places to the right. (or multiply the answer by 100)
so ((100-115)/115))*100= % loss
just an FYI, the same car can dyno different losses on different days. you could dyno your car, and make 100whp. the next day you could dyno again and make 103whp. people tend to think that you can just assign a percentage loss for a single car or even a single type of car, when in fact, you can't.
Last edited by S2000man01; Jul 19, 2005 at 12:51 AM.
