If someone has 310 rwhp, approx how much hp is at the crank?

 

I depends. Losses from the flywheel to the wheels vary depending on the efficiency of the drivetrain. Automatics tend to stink up a bit more power than manuals and the overall losses vary from model to model.

The rough rule of thumb I've read is around 12 - 15% loss for manuals and 15 - 20% loss for automatics, but individual results may vary.

Using the 15% loss figure, 310 RWHP would convert into 356.5 flywheel horsepower.

Keep in mind that the SAE net standard automakers use is also done at a consistent temperature and tightly controlled proceedure, so comparing an individual RWHP test, under different conditions, converted to flywheel horsepower, will only give you an approximate number for comparison.

 

ah, thanks for the info.