Flywheel power to rear wheel power?

[Shaun]

Does anyone know a basic conversion from engine HP to rear wheel HP. I realise that it will differ greatly between cars due to drive train losses, but a rough conversion would be appreciated.

Shaun.

[RB30-POWER]

Around 30% drivetrain loss is to be expected.

Auto will be more, manual will be less...

[FATGTS-R]

30% is probably about right for standard and mildly modified vehicles but this trend does not stay true for highly modified big HP engines.

e.g a GTR with 650rwkw. 650 + 30%= 845. I would say it would not have 845kw at Flywheel. Because that would be close enough to 200kw that has turned into heat. It would get pretty damn hot sitting in the seat I reckon.

[Cubes]

I'd say around 50-60rwkw, for a fairly mild rwd.

Realistically or more so logically I think we should base the loss on a fixed power loss + a very small percentage loss. The idea of the small percentage loss is that as power increases load increases on every bearing in the car, hence there is extra friction.

But who knows.

I say 50-60rwkw is a good estimate.

It kind of works out well. My RB20DET when dead stock made 115rwkw.

115+50 = 165rwkw. Dyno's also vary their readings so it may have made 110rwkw on another dyno. Its around the mark is what I am getting at.

Then there's the VX 5.7ltr Commodores that used to make 225kw at the fly, which showed as being ~165rwkw + 60 = 225kw.

So it does appear to be around the mark. Unless you jump on a hub dyno.