Bhp At The Flywheel

sparkystav · January 10, 2008

It just varies with the rollling road i suppose, and what figure they decide or "make up" as transmission losses, The only true way to get a real figure is to attach straight to the engine.

Its not a set BHp thats lost through the trannie, its a percentage.

TDi suggested that through their knowledge 20% losses were expected so thats what we took them as.

Lee's came out at some like 188 on the RR at TDI so add the 20% and you get the 220ish figure.

Stav

loggyboy · January 10, 2008

Transmission losses are also going to vary due to condition of bearings, diff, gearbox etc etc. So one cars transmission losses could be completely differnt to another, even if they're the same car and similar spec.

mAltezza · January 10, 2008

ya but surely a m/t wouldnt loses as much power through transmission as auto?

so it doesnt seem right that its 20% for both, if you see what i mean,

sparkystav · January 10, 2008

Its just a guess at the end of the day.

RWHP is the only figure you can get accurately.

loggyboy · January 11, 2008

ya but surely a m/t wouldnt loses as much power through transmission as auto?
so it doesnt seem right that its 20% for both, if you see what i mean,

No real reason why it should, the way a gearbox changes gear, has little or no effect on the gearing itself. fuel economy on autos is effected by the changes, not the transmission losses.

Noel · January 11, 2008

@mAltezza, i can understand that you would like to know what bhp your car is putting out but lets look at some facts...

Tiptronic puts out less bhp than the Manuals as standard also has a lower rev limit, even experts with super dooper dynos don't want to test auto's as the results are not accurate... you say the car was tested in 2 gear when the correct gear ratio of 1:1 for the tiptronics is 4th i know you said this was to stop kick-down but it would still have kicked down to 1st unless it was a very easy build up to 4500... what advice were you given by the dyno operator regards the result? surely if he's on his game he would given you a proper printout....

end of the day I think how the car is running is more important than any figures from an inconclusive dyno

MacRs200 on here also has a tiptronic and had a camcon fitted and dyno-ed, maybe he can help you with you queries ... send him a pm, see what he says

mAltezza · January 11, 2008

ya i see what you mean, ya i do have a proper print out but it has no fly bhp,

well at the end of the day when i got there the first run without the filter and camcon it was 153.6 bhp at the wheels after fitting the filter and setting everything up with the camcon i left with 163.7 bhp, so it was just over 10bhp gain, suppose i can live with that,