What is the formula to convert wheel horsepower to flywheel horsepower on an automobile?
Question by Bobby Y: What is the formula to convert wheel horsepower to flywheel horsepower on an automobile?
For example, if the wheel horsepower of my car is 318, how would I approximate what the flywheel HP of my car is?
Best answer:
Answer by mark b
I would say that the best you can hope for is to look at similar models with the same drivetrain. all the different components can change your ratio just using a different length of drive shaft on rear wheel drive can make a small difference. a 3.75 or a 4.54 diff gear ratio can make a large differece. how rigid all the components are can all change those numbers. 318 horse on the ground would to me would be some thing over 400 hp. at brake hp. off the fly wheel. have a friend who has a quick change diff,it can go from 270 hp to 330 it is all in the ratios
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It has nothing to do with ratios. It has to do with transmission and tires mechanical efficiency, which can be estimated at about 0.8 for average manual transmission car and 0.75 for auto tranny car.
Just divide your number by 0.8 or 0.75 and you get the estimate of your flywheel hp.