Awkw Vs Rwkw Vs Flywheel/engine Kw

[Piggaz]

What I've always wanted to know is what are R34 and R33 GTR drivers talking about when they say their car has XXX RWKW? Surely they aren't taking the driveshaft out of the transfer case to get these readings, and to my knowledge only the 32's AWD can be disabled by pulling a fuse. Is there a way to disable AWD in a 33/34 GTR?

Yep. Pull the shaft.

[usmair]

yeh some tuners take the front diff out when tuning on the dyno

mine was done like that, which is why my reading was in rwkw

[kawasakirider]

Is it because they don't have an AWD dyno available? If I had an AWD car I'd prefer an AWKW figure.

[GoldZilla]

Is it because they don't have an AWD dyno available? If I had an AWD car I'd prefer an AWKW figure.

Pretty much. Those tuners who do have an AWD dyno will use it to measure awkW.

[GTRAAH]

My R32 GTR with only an Exhaust after the catalact convertor did 203 kw at the rears, Evrything else was stock

that 206kw shit they talk about is bullshit ! the gtr is in another league comparing them to evo's and wrx's is quiet and insult to the makers..

hense

now with the R35 THEY MADE IT VERY CLEAR THEY DONT EVEN WANT TO COMPARE THE GTRs TO THESE CARs, BUT INSTEAD: PORSHE, FERRARI, LAMBO etc...

Edited December 25, 2011 by GTRAAH

[luke gtr]

And flywheel to wheels loss also comes with some controversy. Some claim about 25% loss from flywheel to wheels, but personally I guess it is mostly a fixed amount, not a simple%...otherwise a 1000kw car would be loosing 250kw in the drivetrain

In rebuttal to this;

I've heard that autos are around the 15-20%

Manuals around 10-15%.

And I would think a percentage COULD be relevant.

The faster the motor turns, and gearbox and diff, the more oil will be squeezed through the oil pump, and squeezed from the gears.

It's like a boat through water, the liquid can't move out of the way as fast, and it requires more power/torque to displace.

This is my thoughts on the matter, unfortunately, I've never done or had the opportunity to do testing.

Would love to find out though.

Thanks for reading my rant.

[Piggaz]

My R32 GTR with only an Exhaust after the catalact convertor did 203 kw at the rears, Evrything else was stock

that 206kw shit they talk about is bullshit ! the gtr is in another league comparing them to evo's and wrx's is quiet and insult to the makers..

hense

now with the R35 THEY MADE IT VERY CLEAR THEY DONT EVEN WANT TO COMPARE THE GTRs TO THESE CARs, BUT INSTEAD: PORSHE, FERRARI, LAMBO etc...

Cool Story!

[MBS206]

In rebuttal to this;

I've heard that autos are around the 15-20%

Manuals around 10-15%.

And I would think a percentage COULD be relevant.

The faster the motor turns, and gearbox and diff, the more oil will be squeezed through the oil pump, and squeezed from the gears.

It's like a boat through water, the liquid can't move out of the way as fast, and it requires more power/torque to displace.

This is my thoughts on the matter, unfortunately, I've never done or had the opportunity to do testing.

Would love to find out though.

Thanks for reading my rant.

Under the laws of physics energy can not be created or destroyed, it may only change state.

Therefore to lose 250kws you need it to become another form of energy other then kinetic... That normally means sound or heat...

While 1000kw cars may be noisy, they are not producing 250kw of noise... Nor are they boiling diff and gearbox oil or melting metal parts... Hence they can't be making 250rwkw in heat either...

They're not storing so no potential energy and I don't see them getting brighter, therefore they're not pitting it out in light energy...

Since there is no other energy forms available... They must be putting most of that power through in kinetic energy...

Most losses are caused from drag, primarily from bearings, which have a set coefficient of friction, meaning that it's primarily a constant loss, not a percentage loss.

Autos and manuals do "lose" different amounts of power purely from the design of the trans and torque converters/clutch. The main part of this is the torque converter, as it is designed to slip a kittle and use a liquid to transmit power, this means you end up losing power in the form of heat in this scenario, but only a bit.

[NYTSKY]

The loss is a fixed amount, NOT a percentage.

/END THREAD.

[a20089]

The loss is a fixed amount, NOT a percentage.

Though more correct then the straight % loss this is also incorrect. There's certainly a lot of car forums quoting their theory's but little facts, it seems very hard to point to real facts without going through the science which would send most car forum people to sleep. Duncan first post probably was as close as simple reality can get.

I refer to a Wheels magazine comparison of quoted KW and tested RWKW, between high output falcons and commo's. There was common theme of 40-50kw loss between 240-310kw, lower loss for the less powerful in general.

So if we say 40-50kw is a fixed amount, what happens to cars that output less then 40kw, there has been a few in years gone by. Do they not move?

In reality the formula would be closer to a parabolic equation with a high % for low power cars and getting less % for high powered cars. Certainly different cars have different power loss due to differing designs and maintenance. 300rwkw approximatly equals 350fwkw.

Again you can't tell some people, most in the ford forums still quote the old 30% that went out years ago. Sure my 300rwkw car has 400fwkw??? sure....

[France]

In reality the formula would be closer to a parabolic equation with a high % for low power cars and getting less % for high powered cars. Certainly different cars have different power loss due to differing designs and maintenance. 300rwkw approximatly equals 350fwkw.

I think that is that case as well. i don't think it follows a set % or a fixed number.

[Duncan]

lol this thread is as regular as xmas.

[blk94r33]

Area under the curve....

[HOT_R33]

My 2 cents,

Owning a R33 Vspec and having 500+ runs on the Advan Performance 4wd dyno under my belt, we have noticed a few things.

1. Peter will only tune the GTR in RWD due to the attessa interfering with the amount of 4 wheel power delivery ( almost every run it's slightly different based on how the attessa feels at the time).

2. Based on the same tractive effort, the 4wd kw figure seems to vary by about 5-10kw on almost every run. This is also spaced days apart on the same tune so heat soak is not a factor here. The RWD figure on the same tune remained within 2-3kw every run.

3. My GTR's 4wd mode generally saps about 15kw from my peak power figure (within the variable bracket I stated at item 2.) It's simple physics as was said before, there is always going to be some power loss to the treads and more so when the engine is trying to drive 2 drive shafts and 4 axles instead of 1 shaft and 2 axles.

IMHO it's not the peak power you make in these things that's important, it's all about the torque you can produce to keep the 4wd system accelerating right up through the rev range which makes all the difference...

Fun too :-)