Can someone please explain the HP concept to me? I notice our car is rated @ 287 HP from the factory. The dyno results I see posted seem to usually be under that rateing, even with modifications. What gives?

 

The 287 rating is the factory rating at the crank although I have never seen that verified. Anyways, the reason that the dynos are lower is because of drivetrain losses. The accessories (AC, Alternator, etc) take HP to turn. Also the transmission, driveline rear axles, wheels, tires, etc. use alot of horsepower just to turn them let alone moving the car. Usually the total loss is around 15% give or take.

 

The engine is rated @ 287. All of the dyno numbers posted are horsepower measured @ the rear wheels. There is HP loss in the drivetrain due to friction etc.

 

Then too, altitude plays a big part in loss of HP. Figure 5-6% for every 1000 ft. Albuquerque is at 5094 ft. Before F/I with limited mods (i.e. Borla, Grounding Kit and CAI) I was at 226 rwhp. Now with SC I am at 334 rwhp.

 

Thanks guys. Very informative.