Re: Where they measure hp from?

[Glenn Lawton <lawtonglenn@gsmai.com>]

Robert Paul Andrews wrote:
> measure HP...trans....anyone know what it is at the wheels

Phil Payne wrote:
> "At the flywheel" is the expression I'm used to.
 
Avi Meron wrote:
> subtract at least 15% or more...depends on the drive train etc.


Here are two more datapoints:

First, from the owners manual of the new G-Tech Pro I just
bought, it said 10-15%.

Second, from PowerHaus (a Porsche tuner in AZ 602 921 0921),
in their recent ad in European Car:

"Dyno Tests Updated, Real Horsepower Numbers"

	86 944T/2.8/PH		387 hp	484 Flywheel 
	86 944T/2.8/PH		341 hp	426 Flywheel
	89 944T/2.5/PH		329 hp	411 Flywheel
	87 930/3.3/PH		439 hp	549 Flywheel
	83 930/3.3/PH		409 hp	511 Flywheel

"The above #s were measured on a Dyno Jet Model 248E at
Pro Dyno Tempe, AZ. Horsepower to the rear wheels is the only
HP that really matters to you. All other #s are conversation.
There are a lot of high HP #s stated but not backed up
with Wheel Dyno proof, without Proof, those #s mean nothing."

It is clear that PowerHaus is only measuring HP at the 
wheels on the dyno, and using a factor to calculate up to
flywheel numbers. The factor they decided to use in each 
case is 20% (e.g. 329/0.8 = 411).

Glenn