Kilowatt at the wheels

[AE86R]

lol jonny u the mannn

[af300e]

Why is it 30%?
100fwkw, 30kw to parasitic loss.
Same drivetrain, 200fwkw, 60kw parasitic loss?

Doesn't make sense. There is a small increase in energy converted to heat in the transmission/diff when more power is put through it, but it's nowhere near double the loss as these low power levels, the loss does not increase linearly.

I'd suggest the loss for t50/w5* boxes and t-g series diff is closer to a constant 20kw. Dyno results for stock motors seem to suggest this.

I spoke to a dyno engineer about this subject in length as the percentage thing has always had me stumped. He agreed, for most vehicles the loss is closer to a constant 20-30kw.

[Wally]

Mmm interesting point raised.

[AE86R]

jonny needs to answer that or sam q

[Wally]

I'd be keen to see the answer back to this.

As I used to always read about ~25% but this throws a spanner in the works... It makes some sense and could be pretty close right

[AE86R]

25% and 29.2% or 30% is fuck all really

[Wally]

Settle down tiger. We are all friends here.

[AE86R]

lol not taking any stabs just saying 4.2% is fuck all really

[slydar]

a dyno is a machined used for tuning and comparative testing. trying to work out your engine power level from a chassis dyno is pointless, as it is irrelevant.

there is no point in even knowing what HP your engine makes. taking your car to a dyno to check that it is making similar numbers to what other similar engines make on that same dyno has some relevance, as you will be able to determine if your engine/driveline ect is in good condition/performing correctly, and therefore make a better decisions on your next repairs/improvements.

i just dont understand why you even posted the thread? also these figures, be they percentage or rule of thumb kw figures for specific drivetrain loss are just every rough guides.

things like, tire type and condition and even pressure, diff ratio/condition/oil type, tailshaft uni condition and configuration/angle, transmission type and condition/oil used/oil level, ambient temperature, will all effect the reading. these are just a few of the variables..

stating that it is 29.2% is getting very close to being just plain un intelligent.

[AE86R]

i think every one likes to know hp - atw. there is no rough thumb rule on the whole interwebs and jonny took his time to write that up so i think it should be a basic guide..

29.2% is what is stated on many sites, and a few technicians have told me its that..