Full Spec, G45, Gearbox questions...

[Matty!]

How Do

Late this year I am planning on pulling the polo apart for the full works, rods, oversized pistons, ported head, cam ect ect.

I am also thinking about going down the G45 route... and I get all excited about this prospect but then the big black cloud of worry on the subject of the gearbox brings it all back down to earth which almost forces me to can the project altogether.

I track my car, and with a G45 and full spec I am expecting to see around 190bhp-200bhp easily, is this territory likely to threaten my gearbox going bang ? I will be having it rebuilt removing the gripper and placing a Quaife in instead.

I am trying to keep away from the Golf gearbox option at the moment, as to run it requires alot of fabrication which isnt my strong point.

[benh999]

I've always been told that the torque from supercharged rather than turbo charged is what tends to kill boxes?

Is there no way of strengthening these boxes? 

I remember a few years back companies who cryogenically treated parts claiming to make them stronger?

Ben

[hayesey]

I think if you have 190bhp with a g-lader doing track days then you're going to need to learn to rebuild gearboxes

A turbo is slightly more forgiving because there's a more progressive build up of power than the instant punch of a g-lader.  But really when you get to 200bhp you're so far beyond what these gearboxes were ever designed for that turbo or g-lader, you're likely to have to do regular rebuilds and repairs.

I remember a few years back companies who cryogenically treated parts claiming to make them stronger?

you're talking serious money for stuff like that though, might as well pay for someone to convert it to an 02 box.

There's no answer really, if you want a high powered g40 then you're going to have to live with the fact that you've gone way beyond the limits of the drivetrain. 

[Yoof]

I think if you have 190bhp with a g-lader doing track days then you're going to need to learn to rebuild gearboxes

A turbo is slightly more forgiving because there's a more progressive build up of power than the instant punch of a g-lader.  But really when you get to 200bhp you're so far beyond what these gearboxes were ever designed for that turbo or g-lader, you're likely to have to do regular rebuilds and repairs.

I remember a few years back companies who cryogenically treated parts claiming to make them stronger?

you're talking serious money for stuff like that though, might as well pay for someone to convert it to an 02 box.

There's no answer really, if you want a high powered g40 then you're going to have to live with the fact that you've gone way beyond the limits of the drivetrain.

O RLY?



Ultimately if you make the weakest point in the torque path the tyres, the drivetrain has an easier life. Once you start running sticky rubber, or using slicks, everything gets a workout.

There's not many options available for the 085, Claus-Bernard (sp?) gears are limited to 250Nm, and are very expensive, Gemini/Ricardo sequentials won't give you change from £10k second hand.

The 02J conversion is a fair amount of work, but ultimately the cheapest way of getting a reliable gearbox in with a PY engine. Endless ratio options, cheap diffs, and they're dirt cheap (a 5th of the price of a G40 box!)

If you're serious about tracking the car, it's the only way to go for peace of mind 

[Karlos the jackyl]

As yoof said , this is a good mod , the bonus is you can also convert to hydro clutch quite easily as well.