Colinj

Work out my power at wheels from BHP figure? I have 245.6bhp at fly

Cheers

SteA

I think the accurate answer is that you cant (unless of course it was measured on an engine dynamometer, so a direct measurement was taken from the flywheel).

Wherever you got it rolling roaded should have the at wheels figure because that is what they measured, they then use some sort of equation to guess the figure at the fly. I'm not a techie so may not have explained properly, but this site is a bit more illuminating:

http://www.dynamometer.fsnet.co.uk/index.htm

Colinj

Any idea on rough transmission loss then? Ive been told 30-40%!!!

Taken from that site:

Another reply!!!

To: burgerman@ntlworld.com
Sent: Saturday, May 22, 2004 10:02 PM
Subject: Re: email from the Dyno Information pages


Thanks for the reply. I am talking car. 267bhp measured at the wheels. Roller guy reckoned 30% loss on fly wheel BHP any thoughts
Cheers Chris

One third of your power (approx) is 89bhp!

If you REALLY lost 89 BHP as "waste" power it would show up as heat!
Into the oil and castings...

To convert this to watts multiply by 760...
Result = 67540 watts apparently went as heat!!! That would run a small town...
Your transmission would have melted, the oil boiled away in a massive cloud very quickly...


I suggest you get him to study physics?


Burgerman.

SteA

Dont know if its right, but would make more sense to have a figure that isnt a % of your overall power, otherwise a 600 bhp 4wd measured at the wheels could have 900 bhp at the fly which seems unrealistic at the very best. I could give you an idea if you had a 200sx I'm sure some other scooby owners will chip in soon....

Colinj

Ok mate thanks for your input

Im having a discussion with a mate, he fancies his chances against me in his Punto GT with 150bhp(130 at wheels he says), my scoob with 246bhp, he says I have 40% losses and a fair bit more weight.

What you think?

SteA

40% sounds unrealistic, I would make a wild guess at a 40-50 bhp loss???

I suppose it depends a lot on the power to weight of both cars, but the obvious question.... would he still fancy his chances in the wet