hp loss

[Jason_Leone at amat.com]

<<I have wondered about this myself.  I have heard anywhere from 15%
to 25% in drivetrain losses.>>

Typically, expect a RWD front engine car to lose 20%. Expect a FWD front engine
car to lose 15%. I'd guess a RWD rear engine car would be closer to 15% than 20%
(ala Porsche). It depends on the individual drive train design, and the
materials used. The C5 Corvette has a pretty efficient drive train, for example.
Use of Aluminum and composites can greatly reduce rotating mass, and yield
better response and minimise losses.

You can calculate/test this by dynoing the engine on an engine dyno, then in the
car on a chassis dyno. That's not too cost effective though. The best solution
is using an accelerometer like the Vericom 2000. You can do coast down tests,
and it can calculate vehicle specific power losses based on known algorithms and
the vehicle data parameters entered. It's pretty accurate, and beats the old
"Gee, Wally...how much hp does a car lose?".

Jason
'93 SLC (15.1% loss)