Drivetrain loss ratio

[AKKO]

Gents,

I've read elsewhere that anywhere from 25-35% drivetrain loss is typical for AWD vehicles.

Does anyone have any specific VR4 experience here that can confirm ~30% is also true for the VR4 platform ?

Cheers,
Chris

 

[uzz320]

If they really do have 206KW at the flywheel stock, then between 30 and 35% would be about right (http://ozvr4.com/forums/showthread.php?13411-A-few-tuning-results). I'm not sure that you would ever know for sure unless you found an engine dyno and put your motor on it to compare the figures to a wheel dyno.

EDIT: I can't imagine that anyone here would have had their engine on an engine dyno.

 

[TME_Steve]

It would be about that. A healthy stock MANUAL VR4 reads say 135atw on a mainline, hell lets call it 145 for a really good one, that'd be 70% of 206....

I also know that if you put a stock stagea on the dyno in awd it reads about 135, run it as rear and goes up to 155-160....

 

[uzz320]

Is hours supposed to be goes or has?

 

[AKKO]

Thanks for confirming gents.

 

[steveP]

The commonly used figures are as follows (and I use them in my Car Calculator):
- AWD 16% loss.
- FWD 10% loss.
- RWD 12% loss.

That means our cars should get about 163.04 kw at the wheels. Obviously that's not the case. I think the 206kw figure is misleading and is a generic figure used for most Japanese performance cars.


Edit: Sorry, forgot some of the forumula. Check below.

 

[jungle]

Commonly used figures- from where? Never seen figures that low before.
It was a gentlemans agreement between government and manufacturers not to exceed the the 280hp figure. Towards the end of the 90's the hp cap was largely ignored.

 

[Guest]

Results tend to show about Double that loss.

 

[steveP]

Sorry, I forgot a bit of the forumula.

It's the above figures, then minus 10kws.

- AWD = (power - 16%) - 10.
- FWD = (power - 10%) - 10.
- RWD = (power - 12%) - 10.

The only true way to know for sure is to get someone to dyno a stock engine at the fly.

 

[uzz320]

That would mean that a very good manual would only be producing 185KW at the flywheel (145 AWKW), and the average VR4 would be down around 165-170. I hope that isn't correct

 

[cyber_scriber]

Don't forget, you're all assuming that our 10+ year old cars are still producing 206kw at the engine today ...

 

[TME_Steve]

a good one will, stock 206kw evos make similar numbers, losses on other manual awds are similar as well.

When they were new, they claimed a flat 14 from a VR4. I tuned one that made 180atw and it ran a 13.2. That's a lot more power, I'm sticking with the 145....

 

[Kenneth]

Club VR-4 has used the following

Drive train loss = 24%
Torque converter loss = 7%

To calculate engine hp = whp / 0.76. If auto, whp / 0.76 / 0.93

The figures can be debated until the cows come home so there is little point arguing what it should be, best to just use the figures which have been "standardised" so at least you have some ability to make comparisons.

Better is to just give wheel (or hub) figures.

 

[TME_Steve]

Even tyres have friction loss, a third gear pull will make more than a fourth gear one....

 

[uzz320]

Just fixed a number below, became obvious when I calculated having over 2000HP lol

Club VR-4 has used the following

Drive train loss = 24%
Torque converter loss = 7%

To calculate engine hp = whp / 0.76. If auto, whp / 0.76 / 0.93

The figures can be debated until the cows come home so there is little point arguing what it should be, best to just use the figures which have been "standardised" so at least you have some ability to make comparisons.

Better is to just give wheel (or hub) figures.

 

[Kenneth]

Cheers for that. Ill blame being on my wife's laptop, half way around the world and having a damn cold
Have corrected the post

Just fixed a number below, became obvious when I calculated having over 2000HP lol