S4 power loss

[Dippy]

Can anyone confirm that the power loss between the flywheel and the wheels for S4 4-wheel drive is about 25%?

[wazza]

Thats what they use at G-Force for the 996TT and Skylines.
I remebersomeone saying AmD use 27%

[Carps]

I seem to remember that whenever I have had cars rolling road tested they calculate the transimission losses by driving the rolling road in order to drive the transmission (ie, running the system backwards) and making some calculation based on that. I have heard of figures from 18% up to about 30% but no specific figures for the S4. You have to remember that you will also need to take into account wheel and tyres combinations in order to get accurate losses for a specific vehicle.

[jeffw]

My recent rolling road produced a loss figure of around 31%.....

[Dippy]

Thanks Guys,

My RR plots from AmD worked out about 25%, but I suppose I have to allow a +/- 5% variance.

I'm playing with the VAG-COM "butt dyno". I need a very long flat road with no cars on it, so looks like I'll have to go out in the middle of the night!

[wazza]

I know a good one [img]images/graemlins/033102bigblink_1_prv.gif[/img]

[Dippy]

Is it a secret?

[wazza]

No secret, but I'm not going to broadcast it to the world...