Kevin325isBMW

I think 15-20% for a FWD Honda is too much. I would estimate 12-15% For FWD, 15-18% for RWD, and 20-25% for AWD (I remember Sport Compact Car testing the Subaru WRX when it first came out and being surprised that thet 227hp engine rating was measuring 168hp at the wheel (a 25% driveline loss)).

Kevin

88crxSi

i dont know why you guys all say % drivetrain loss..

ok.. a stock 92 si hatch has 127hp (z6 motor). - that 13% or so drivetrain loss. means 110whp (wheel hp). Meaning the drivetrain used 17hp to turn all the gears axles pumps and the alternator. what makes you think it would take any more hp to turn all the same crap on a 500hp turbocharges beast?? still should have the same HP loss not percentage.

if your z28 has 200hp (example!) and takes 25% to drive the rear wheels u get 150whp. by using percentages a 1000hp z28 would only do 750whp?!?! nah!! probably 950 or so.

just keep that in mind

Kevin325isBMW

We all use percentages because it is the correct approximation method. For example a 500hp engine is ONLY at 500hp under peak load. Redline the engine with the car's wheels off the ground would require very little horsepower.

So if the engine is putting out peak power, it is transfering all that power through the drivetrain. Consequently the gears are all being forced together very tightly and the greatly elevated gear teeth loading does in fact create significantly more friction (hence power loss and heat generation) with the drivetrain.

Drivetrain losses are NOT constant. Higher load on the drivetrain = higher loss. Using a percent factor is the correct approach.

Kevin

88crxSi

gears forced together? they dont support each other, the shafts are supported by bearings and such..

if more power were forcing the gears tighter together eventually they would lock up.