Power Loss

[niterydr]

John hit 516whp on elites fwd dyno
and he hit 403whp on rs motors awd mustang dyno
and the mustang dynos 'typically' run about 20% less, which would put him at about 483.6 whp in awd.. which would mean the awd adds approx 6% more drivetrain loss to the fwd numbers.
just some fyi.
so fwd being 9% and awd being 15% is good idea.
figure 10% more for the awd if your on a fwd dyno, and you should be good.
just my $.02.

[john]

What are your mods?

[Pushit2.0]

yep, well 420 on the first pull in 4th, then 401 in 3rd, spinning the tires both times at my peek power.

~John

[Shane@DBPerformance]

John didn't dyno on both dynos on the same day either though, so it it is hard to say exactly what the difference would be. Most of the people I have seen dyno 2WDs on both get about a 15% higher number on a dynojet or dynapack going off of Mustang dyno numbers.

It's hard to say if the drivetrain loss should be a simple percent though. I read some page a while ago with a more complex drivetrain loss formula that had some loss built into it. So that a car making a lot more power would actually have a smaller percent loss than one making a lot less power.

It's all just numbers though. If you took a 100% stock awd and put it on whatever Vishnu's dyno is you might think there is 40%+ drivetrain loss when going off the factory HP numbers(who knows if those numbers are correct either, they obviously weren't on the RX8s or SRT4s). Think of the heat that would be created in the tranny if 40%+ of all the power was dissappearing in it.

[JET]

Shane brings up a very good point. The loss is not going to be a straight percentage. It will be a give HP of loss, then the extra amount of drag created by the extra HP for friction on the gears because of the increased force put on the gears. Say a stock car has 25 hp of drivetrain loss plus 5% of its HP. If you use the same equation it will be a lot less total percentage on a higher HP vehicle.

[niterydr]

so you guys are saying that there is a cap to the hp lost through driveline?
Or you automatically lose set amount of hp and the rest is a percentage that varies with your power output.
Imo, you put down what you put down, race them to find out who has more power :).
unless you have an engine dyno, then you actually know how much power you really are making.