Transmision loss

[Eat this 2]

rr day showed my car as havin great crank bhp/torque but i lost alot of it before it got to the road how do i reduce this loss and how much £??

iv heard about lightenin the flywheel is this expensive/effective

but i dont know what else would do it

[ingham 5]

transmisson loss could have been allsorts from low tyre pressures,brakes dragging ,worn gearbox,wheel bearings

check gearbox oil/tyre pressures

[Eat this 2]

wheel bearing theres a thought when i bought the car 1 was very noisy (read knackered) and i think maybe (& its a big maybe) another is starting to make a tiny amount of noise il check it where is the gearbox oil filler/dipstick pic would be great as i dont have a manual

[Guest Olly_K]

the biggest factor for transmission loss is the gearbox. yes tracking/tyre pressures/wheel bearings do play a part, but nothing like the gearbox. Lightened flywheel will help, but its best to get the whole bottom end balanced if you do.

The only other thing is straight cut gears, instead of dogleg ones........basically put in at the factory to stop gearbox "whine" but looses energy.

[Eat this 2]

sounds WAAAAAAAY too expensive for me lol

[anorak 0]

Just had a look at 3 RR results on my car from the last 18 months. They show transmission losses of 58bhp (yesterday) 41 (Feb this year) and 53 (March '03).

I did 2 runs in my 'Rado at Jabbasport on the same day and got a 6bhp difference in tranny loss, so you've got to wonder. :?

So personally I'd take the run down figures with a bit of a pinch of salt (likewise the corrected flywheel figures unfortunately).

The only actual measured reading that is comparable between cars is the power at the wheels. This time mine was down from 279 to 230, a big drop due to the fuelling problems no doubt.

The road wheel power will determine how quickly you can accelerate and what top speed you can do after all. It puts Minty's car much closer to mine at the moment - think his did 211bhp atw.

[Eat this 2]

that drops me down the list then hehe

[MarkGolf 6]

I got a lightened fly wheel and lightened pulley on the other end, will this help reduce loss?

[tandino 1]

Lightened flywheel and pulley will not affect transmission losses one bit - they will make the engine accelerate through the gears quicker as the rotating mass is lower but power is not affected by this...

Its friction rather than mass thats causing the high losses (or Stealths rr imho)...

Pete.

[cliveyp 0]

on both my 8V MK2 and my Corrado i was seeing transmission losses of over 40bhp. IIRC 8V was 82BHP atw, which gave me a tranny loss of 41bhp, and the Corrado was 141 atw which gave me a loss of 45bhp. With the Golf though, i've actually got a wheel figure of 154, which would explain why it feels quicker than the C, but it only show a loss of 31bhp!! Odd!

[anorak 0]

There's an informed explanation of transmission losses on

www.pumaracing.co.uk

The guy seems to know what he's talking about and uses data from a book written by a professor of automotive engineering.

His equations work on a maximum loss of 15% for front drive cars and look pretty undisputable.

That would give a flywheel power of 181bhp with 154 at the wheels and a loss of just 27bhp.

Rear drive losses are a fraction higher due to longer drive shafts and diffs and 4wd a bit more still.

It means I'm putting out 270bhp at the fly (as opposed to Stealth's feel good 300) which felt about right when I was struggling to keep up with a 300bhp Impreza on the straight at Donnington.

I think a lot of rolling road shops use the power loss figures to enhance the corrected power for customer satisfaction purposes. (Some more than others).