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Gearbox!
Posted: Mon Jun 22, 2009 12:47 am
by turkpolo
Hi, i want to know how to make the gti gearboxes stronger? or can it be done?? bck in love with my polo so, i want to improve the power and the gearbox and clutch etc. Has any 1 got any suggestions???
cheers
Re: Gearbox!
Posted: Mon Jun 22, 2009 9:30 am
by tegwin
I looked into this issue some time ago…. The general consensus from the bearing experts was that, the bearings in there are already “top of the range”, so you can not easily upgrade the bearings.
The two “fail” points that I am aware of are the rivots on the diff and the 5th gear bearing which is a plastic “bush” rather than a bearing…
The rivots in the diff can be drilled out and high tensile bolts could be put back inplace… just make sure the heads don’t collide with anything in the box…
The 5th gear bush thing could be replaced with a decent bearing.. you may have to machine out its seat to take the bearing!
Increasing the lubrication of the box would help the bearings stay cool and smoother…. I believe the GTI box relies on splash lubrication inside… some more complicated modern boxes actually have oil galleries in the casting that feed the bearings directly…
You could (assuming there is enough metal) machine out all of the bearing seats and press in larger bearings, for what that is worth.
A while ago I was trying to find a broken/worn box that I could strip down to see why and where it had failed and then make adjustments appropriately, but I couldn’t find one.
The other option, if you desperatly wanted to keep the GTI and the 1.6 engine, would be to find a way of fitting as different box to the car... Assuming you can find one with decent ratios... you could machine/fabricate a bell housing to mate with the engine... but thats a lot of work for... little gain!
Re: Gearbox!
Posted: Tue Jun 23, 2009 1:16 am
by turkpolo
Thanks alot mate, that was more information than i had expected. It sounds like a big job and time aswell. Ill have to wait till it actually dies, than take it from there.
cheers
Re: Gearbox!
Posted: Tue Jun 23, 2009 10:21 am
by tegwin
The question you need to be asking is, what is special about the gearbox they used in the 6N2 rally car things... Im sure it would have been a similar casing, but radically different inside!
Re: Gearbox!
Posted: Tue Jun 23, 2009 10:55 am
by Redline
tegwin wrote:The question you need to be asking is, what is special about the gearbox they used in the 6N2 rally car things... Im sure it would have been a similar casing, but radically different inside!
The Group N 6N2 rally car gearboxes also came with a Limited Slip Diff according to the catalogue I've got. Shame they cost around €3800 back in 2002.
Re: Gearbox!
Posted: Tue Jun 23, 2009 1:53 pm
by tegwin
Do you have any other information on the box?
Is it a straight cut box? Hydraulic or cable?... I wonder if there are any used ones for sale.... That and a supercharger would transform the car
Re: Gearbox!
Posted: Tue Jun 23, 2009 4:18 pm
by Redline
tegwin wrote:Do you have any other information on the box?
Is it a straight cut box? Hydraulic or cable?... I wonder if there are any used ones for sale.... That and a supercharger would transform the car
It's hard to tell with it just being the parts catalogue. Does have various cut-away and exploded diagrams of the various gearbox internals though.
Can download a copy of it from here:
http://www.vwmotorsport.com/vwcat/vwcat.asp 9th one down "Polo GP GpN Catalogue"