Flywheel & Rear wheel kW difference - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

VH-PBC · 05-06-2003, 17:20

I wanted to know if there is a formula or somewhat near that I can use to calculate the difference between the two.

Depending on what car the test is on will depend on the difference because of the mechanics of everything between the motor and the wheels

Factory figures come from the flywheel but figures from shops and many dynos are from the wheels.

Can anyone help?

Peter

XR8 Lamah · 05-06-2003, 17:55

I certainly don't know of an exact formula, but I think (someone correct me pls), that you generally reckon on losing 25% or so between the motor and wheels, usually a little more in an auto.

Like you said, every car / model is different, and I can't really see how any formula could claim to have good accuracy ( better than the above guesstimate anyways ).

Beyond this, even on the same car, different dyno's will produce wildly varying results anyway.

What are you trying to get from the formula ( I'd guess you want to know flywheel KW's after a mod ? ). Generally I'd say ( I think most ppl here would agree ), forget about the factory flywheel figure, and go with the dyno results, factory figures are good for impressing mates at the pub, but rwkw's will be what smokes that hsv at the lights :)

VH-PBC · 05-06-2003, 22:39

I did want to find out the flywheel kW after a mod because then you can brag about that

. But around the know-it-alls you talk about the actually figures, the end product is, the raw wattage.

gmanEA · 05-07-2003, 04:01

Good rule of thumb is flywheel kW is approx:
rwkw x 1.33

TA22-3SGTE · 05-07-2003, 06:53

There is no real accurate way other than putting the motor on an engine dyno .
Some work off 30% loss but this is bullshit , If you had a 600 hp motor that means you would lose 200 hp through the drivetrain which = 149000 watts of energy , The drivetrain would melt with this amount of energy being absorbed into it .

But a simple one to use that some work off is RWHP = FWKW

JC-XR8 · 05-07-2003, 07:08

Correct. RWHP = FWKW (approx) .The conversion is roughly the formula posted previously (RWKW * 1.33).

For a manual, you could work on around 20-25% loss as a rough figure. For an auto, it's more like 30-35%. Both of these are roughly the same as RWHP = RWKW.

galaxy xr8 · 05-08-2003, 01:44

Quote:

Originally posted by JCV8
Correct. RWHP = FWKW (approx) .The conversion is roughly the formula posted previously (RWKW * 1.33).

For a manual, you could work on around 20-25% loss as a rough figure. For an auto, it's more like 30-35%. Both of these are roughly the same as RWHP = RWKW.

Well going by that theory I come to 190KW(front) for mine,you sure about that.and that's after the mod's.