How much horsepower would a car need to run at the speed of sound. Assume car weighs 4514 lbs. Assume no wind. Assume no driveline losses. Travelling at the speed of sound (760 MPH --> 1116.4ft/sec) at sea level, What you need to know: HP = Fsum x V/hp F drag = 1/2 pv^2 CdA F rolling resistance = Crr x Weight F sum = F drag + F rolling resistance Cd = .398 A = 26.72 Ft^2 Crr = .015 p= .002377 slugs/ft^3