RWKW vS FLYWHEEL

[dmx_121]

What is the difference between rear wheel KW and Flywheel KW

i mean how do car manufacturers advertise i mean is a GTR 206kw rwkw or flywheel??????

[drunkenmaster]

the difference is everything between the flywheel and the rear wheels.

[4door_Sleeper]

What is the difference between rear wheel KW and Flywheel KW

i mean how do car manufacturers advertise i mean is a GTR 206kw rwkw or flywheel??????

KW at the flywheel are always more than at the rear wheels. The difference depends upon the type of transmission (4x4, Manual, Auto) and its condition the driveline. Many people quote between 20 and 30% loss of power between the flywheel and rear wheels. (Its a guess at the loss as no 2 cars would be exactly the same due to wear and tear)

[nmcmahon83]

In Japan, there used to be a gentlemans agreement between the car manufacturers that they would not advertise power greater than 280ps, or 206kW. I believe this has since gone out the window, but some still honour it (350Z for one).

[nmcmahon83]

To add: all powere figures advertised by car manufaturers are at the fly wheel. This is the most accurate measurement and they are advertising how much power the ENGINE makes.

[4door_Sleeper]

This is the most accurate measurement and they are advertising how much power the ENGINE makes.

Not sure it’s any more accurate. In Aust and USA and I am sure they try several new motors and play with the tunning fuel etc to get the highest figure possible to impress the bogans.

I'd love a dollar for every time a Holden owner laughs when I tell then I got 200KW on the dyno, to which they reply "thats nothing the ss commodore has XXXKW". Is it worth my time to explain the difference between the advertised engine figure, the real world figure produced by most cars that leave the factory, and rear wheel KW. Then there is the power to weight aspect as well as handling and power delivery ........

[adznight]

I'd love to be able to calculate the difference from the flywheel to the wheels. I'd like to know what 210kw at the wheels is at the fly on a GTT.

[Laurence]

Well until my car is pushed along by the flywheel directly to the ground I maintain that rwkW is not only the most easily measureable power, but also the most relevant as it is the power available to move your car along the road.

My favorite is people quoting the power to weight ratio of a motorcycle using the dry weight versus the flywheel power. It makes no sense at all.

[4door_Sleeper]

I'd love to be able to calculate the difference from the flywheel to the wheels. I'd like to know what 210kw at the wheels is at the fly on a GTT.

Multiply by 1.2

so 210rwKW = 252 fwKW (its close, but if you want to boast multiply by 1.3 and tell your mates you have 273 fwKW.)

Or convert it to horse power and get the big numbers - very popular with advertising gurus and Western Australians :Oops:

[KILL HSV]

What is the difference between rear wheel KW and Flywheel KW

i mean how do car manufacturers advertise i mean is a GTR 206kw rwkw or flywheel??????

does anyone know what the r32 gtr's actually make at the flywheel? when ppl ask me i always say umm.. about 230kw (guess)

so yeh would like to know cos i always thought the 206kw, for all the sports cars in japan was bs

[Cubes]

I don't really believe in the percentage drivetrain loss.

I used too. Until I did some reading and SK brainwashed me.. hahaha.

NOW.. I tend to believe that there is a fixed drivetrain loss (approx 55rwkw) + a very very small percentage loss as power increases. I have no idea what this percentage is but there has to be a very small percentage as when you increase load you also increase the friction upon the gears and bearings which is then transfered in to heat.

As a rough guide I tend to believe 55-60rwkw is around the mark, should it be a 500hp motor or a 300hp motor.

373kw is around 500hp... The place that worked on my head said they had a motor on the engine dyno making a solid 500hp. On a Dyno Dynamic dyno it made 317rwkw. This supports the fixed ~55-60rwkw drive trainloss.

Then you think about a stock R32 RB20DET.

160fwkw - 55kw = 105rwkw, mine made 110rwkw & 115rwkw on 2 different dyno's.

R33 Stock 187fwkw - 55kw = 132rwkw.

And the LS1 220kw 5.7ltr makes around 165rwkw.

The loss appears to be pretty much the same for most manual cars.

Its around the mark.