what is the % power drivetrain loss...

ertech · 11-16-2009, 02:00 PM

Hi got a type of gtech for my Iphone and it need to know the power drivetrain loss in % anyone know?
Thnaks

A930Rocket · 11-16-2009, 02:06 PM

I've always used 15% on a Dyno.

xbmwguy · xbmwguy's Garage

i had a mustang dyno back in the 90s and i saw 18-20 %

zcoker · 11-16-2009, 04:10 PM

Why is there always such a high percentage of drive train loss quoted for a Porsche when the engine is almost attached to the wheels themselves? I would figure this kind of percentage loss for a front engine car where the drive shaft travels way back to the rear end and then to the wheels.

911st · 11-16-2009, 04:56 PM

I believe 12-15% depending on the weight of the rear wheels and the weight of the clutch... but as a rule of thumb we usually use 15%.

ertech · 11-16-2009, 04:59 PM

Thanks all

tj930 · 11-19-2009, 10:39 AM

I saw 16% on my car - so, as a rough rule of thumb, when I see a RWHP figure, I divide by 0.84

mark houghton · 11-19-2009, 11:38 AM

I can't remember, but are the Porsche quoted HP figures for RWHP or flywheel HP? I think my '87 is rated at 282 bone-stock in the book.

strokher racing · 03-06-2012, 09:25 PM

Anyone else have feedback on drivetrain loss estimates?

Kraftday · Kraftday's Garage

13-15% for most 2wd wheel dynos.

fredmeister · fredmeister's Garage

Quote:

Originally Posted by Kraftday

13-15% for most 2wd wheel dynos.

Anyone know what to expect from a typical Dynapak dyno that bolts right to the hub? It should be lower than a wheel dyno.
Is there a way to calulate the loss on the dyno by running the car up and then putting it in neutral and measuring as it runs down?
Never having run a dyno this seems logical to me.