HP vs RWHP question.
Le Mans Master
Joined: Oct 2002
Posts: 6,772
Likes: 1
From: Tampa FL
Originally Posted by DrValidus
HP and RWHP. What is the difference? Would someone be kind enough to explain?
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Factory hp ratings is FWHP (flywheel horsepower). This is the amount of power the engine itself produces.
In a car, the engine output is then routed through the clutch (or TC), driveshaft (torque tube), the transmission gears, and the rearend gears, and axles...all of which consume some power due to friction. How much loss depends on a lot of things, but 15-20% loss is the norm.
RWHP (rear wheel horsepower) is the actual power put down at the wheels after all the parasitic friction losses of the drivetrain. This is what a common chassis dyno measures, which is why you see rwhp numbers used much more commonly here than fwhp.
In a car, the engine output is then routed through the clutch (or TC), driveshaft (torque tube), the transmission gears, and the rearend gears, and axles...all of which consume some power due to friction. How much loss depends on a lot of things, but 15-20% loss is the norm.
RWHP (rear wheel horsepower) is the actual power put down at the wheels after all the parasitic friction losses of the drivetrain. This is what a common chassis dyno measures, which is why you see rwhp numbers used much more commonly here than fwhp.
Last edited by Y2Kvert4me; Aug 1, 2004 at 06:45 PM.
