Had my engine tuned the other day, just wondering if these figures sound right. Managed 169.2kw at the fly and 154.2kw at the wheels, engine is basically stock, exhaust, extractors, cai. Its a 5lts v8 (vs) Thnx

that doesn't sound right. The back wheels figure should be around 30% less than the flywheel. How did you get the power figure at the flywheel?

Quote: Originally Posted by ijd that doesn't sound right. The back wheels figure should be around 30% less than the flywheel. How did you get the power figure at the flywheel? I dont know where you got the 30% figure from but depending on trans & diff it would be roughly be about 30hp or 21kw for that figure to work , example 1; a 1000hp engine with a [t400 & 9" diff]drive train = 30% of 1000= say 650 hp @ the wheels ? a loss of 350hp example 2: 500hp engine with a [t400 & 9"] drive train = 30% of 500= 325 @ the wheels a loss of 175hp useing the same drive train. why is example 1 loseing more through the drive train than example 2 useing the same running gear ? Because % dont work. You really need to know how much a t700 takes roughly 25hp & how much a b/w diff takes to drive. Figures i've used are only for the benefit of the example & not nesacerily correct but do show how you cant use a % to calculate hp or kw loss through the drive train.

25-27% through a manual 30% through an auto that is about the clearest guide you will get.

Quote: Originally Posted by Epitaph 25-27% through a manual 30% through an auto that is about the clearest guide you will get. Did you read what i just wrote ? Your saying you would lose 300hp on a 1000hp engine & 150 on a 500hp engine useing the same driveline ? What a load of crap !!! Percentages dont work full stop. Some original photos have not been recovered yet.

didnt you realise that i dont think what you said is correct? no offence but thats the most accurate way i've come across

Well explain it without just throwing a figure out there. An example for a 1000hp engine & an example for a 500hp engine both useing the same drive train. Then i can re-look at how i've been working it out maybe i'm wrong but what you have said doesnt explain anything as in how can too differently powered engines take different amounts of power to drive the same diff & gearbox ?

the way i see it there is more power there to be sacrificed.. do you think a bigger engine would only lose exactly the same amount of power as a small motor?

I thought 30% was "rule of thumb", with QuIkSiLvA figures there's SFA drivetrain loss which doesn't look right. QuIkSiLvA, the car was chassis dyno'd right, so you would have got the rear wheel figure on a printout and the flywheel figure was calculated? Please explain!!!!! lol

Why wouldnt it be if 1's 1000hp at the fly wheel & the others 500hp at the fly wheel regardless of engine make where is it loseing it ?

Quote: Originally Posted by QuIkSiLvA Had my engine tuned the other day, just wondering if these figures sound right. Managed 169.2kw at the fly and 154.2kw at the wheels, engine is basically stock, exhaust, extractors, cai. Its a 5lts v8 (vs) Thnx I read stock 5ltrs (VN's which are 165kw @ engine) should make around 160rwhp.. So going by that, yours is nice and healthy.

im so over dynos.. the readings are so gone these days its boring.. mine with the same mods as yours only made 115rwkw! then a vs came out on the same dyno and made 151rwkw, i once raced that vs and pulled away from it IMO unless u r doing mods and want to see what difference it back to back on same dyno, there is no reason or justification for getting a dyno readout Some original photos have not been recovered yet.

I would have to agree with Sinister on this. Some original photos have not been recovered yet.

dyno's are for wankers..

it really depends if the rear wheel dyno is read in shootout mode or reg mode. shootout reads 10% higher then reg which throughs a curve ball into equations. easiest way to work it out is to get the genuine not shootout rwhp and thats about how many kw at the engine. eg a 400rwhp car in shootout will read about 440 rwhp. its real kw at the engine will be about 400kw.

i would have to agree with the approximate 30% drivetrain loss for autos (t700) as my car pulled 117rwkw std(shootout mode) so thats a loss of 48fwkw which equates to spot on 30%

Yeah for the p1ssy hp you guy's are quoteing no wonder 30% works.

the figures are more "real life", how many 1000HP engines are out there on the street?

Quote: Originally Posted by ITSGMH the figures are more "real life", how many 1000HP engines are out there on the street? You missed the whole point if thats all you read Some original photos have not been recovered yet.

no I didn't miss the point, I know exactly what you're saying. 30% is a rule of thumb and is obviously not applicable to every application.