GTT transmission loss

[PaulRobo]

Any one know it?

 

[James20VT]

doesnt seem a lot thats for sure!!

 

[Tom_16v]

I think my brothers had his worked out at 23%.

Not 100% sure, will get back to you when he gets home.

 

[PaulRobo]

Cheers.

 

[Tom_16v]

Ok, seems it was more like 30%

Hes had his car on the rollers @ 106.8bhp @ TW and it worked out to 139bhp @ the Flywheel.

Also had 170.4lb/ft Torque

 

[Ben j]

every car no matter if the model is the same is different. u can only get a rough figure unless u put ya own car on the rollers to know

 

[Rich-D]

Quote: Originally posted by Tom_16v on 09 April 2003


I think my brothers had his worked out at 23%.

Thats a bit too high...

 

[Rich-D]

Quote: Originally posted by Tom_16v on 10 April 2003


Ok, seems it was more like 30%

And thats 4wd territory!!!

 

[Rich-D]

The losses are not just from the gearbox though, there are things like CV joints, wheel bearings, wheels & tyres, etc... that affect the power from the flywheel to what you actually get on the road.

Somewhere around 15% for a GTT will be about right.

 

[PaulRobo]

I heard it was about 30 ish % somewhere else to, cant remeber where though.

 

[Tom_16v]

Well my brothers had a fair bit of engine work done & I think 139bhp is quite modest. I would have though it was a bit more like 145-150bhp.

Anyway, with 106.8bhp @ TW,

15% Loss = 122.8bhp

Only 2.8bhp more than standard and this car is a a fair bit quicker than standard.

I do think 30% seems high but it does seem to make more sense than 15%

 

[coolspot007007]

well when i took my 5 donor car up to RE it made 141 ATW he reckoned about 165-170 at the fly, which wasnt enough so i sold it.

 

[Rich-D]

There is a lot of debate about transmission losses and RR figures...


With 106.8bhp @ wheels, that is 125.65bhp @ fly with a 15% loss, which does sound low and I am wondering what size wheels & tyres he was running and if the tyre pressures were all correct?!

For the original figures of 106.8bhp @ wheels and 139bhp flywheel, that gives a transmission loss of 23% which is a little high, but believable, especially if hes running non standard wheels & tyres.