Question: how to calculate whp to hp?
Answer: Just use a regular calculator. Just to be clear, if you're assuming a 15% drivetrain loss (i.e. 100 HP at the crank = 85 HP at the wheels), then you need to take the WHP figures and multiply by 1.1765. In this case, 85 WHP * 1.1765 = 100.0025 crank HP. ^-- and that figure multiplied by WHP to get BHP.