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Model specific boards => Golf mk3 => Topic started by: jonnybravo on 11 December 2012, 07:34

Title: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: jonnybravo on 11 December 2012, 07:34
After having to nurse 3rd gear on my recent trackday I'm gonna be changing the gearbox, SO...... Rather than just swapping for another standard box I wanted to no would a diesel equivalent fit ( I'm guessing the diesel box would have lower ratios thus giving better acceleration ??)

Any help , tips or thoughts or even code numbers I need to research would be really helpful

Thanks
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: tweed on 11 December 2012, 09:01
Wrong way round I think
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: CJA321 on 11 December 2012, 09:17
Diesel box has a longer final drive i think.

Some people use them for the 20vt conversion for that reason
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: jonnybravo on 11 December 2012, 10:07
So using a diesel box would be pretty pointless then ?

Would a vr6 box make any difference or am I just pissing in the wind ?

Should I just source a standard box and updated clutch n be done with it then ?

Thanks
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: thai-wronghorse on 11 December 2012, 10:21
Im assuming this is to go on a 16v ? If so you'd be best off keeping the O2A gearbox and sticking in a 3.94 or 4.2 final drive and a lightened & balanced flywheel.  Acceleration will be improved dramatically.
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: Len on 11 December 2012, 10:22
Would help if we knew what you were trying to achieve by this!
Is it for a trackday car?
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: tweed on 11 December 2012, 11:07
I would rather a longer box for motorway driving
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: thai-wronghorse on 11 December 2012, 11:26
He has "trackday weapon"  beneath his username.
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: jonnybravo on 11 December 2012, 12:32
Yeah sorry for not making it clear the cars a mk 3 2.0 16v and seeing as the box has gotta come out I thought maybe a diesel box would have lower ratios ( for better acceleration , which is what I want )

And yeah it's a trackcar I've got
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: Len on 11 December 2012, 12:54
Quote from: thai-wronghorse on 11 December 2012, 11:26
He has "trackday weapon"  beneath his username.

Yea I did see that, which is why I asked just in case he had a sane Mk3 as well.
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: Len on 11 December 2012, 13:01
Quote from: jonnybravo on 11 December 2012, 12:32
Yeah sorry for not making it clear the cars a mk 3 2.0 16v and seeing as the box has gotta come out I thought maybe a diesel box would have lower ratios ( for better acceleration , which is what I want )

And yeah it's a trackcar I've got

Might be better to change the diff ratio
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: Wayne on 11 December 2012, 22:05
Quote from: jonnybravo on 11 December 2012, 10:07

Would a vr6 box make any difference or am I just pissing in the wind ?


VR6box will not fit a 16v as the bellhousing is a different shape.
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: hobbiniho on 13 December 2012, 19:51
basically the diesel box has longer ratios so you will lose acceleration but gain top speed if i fitted my caddy gearbox to my mates mk3 20vt then he could theoretically do ~180mph but the laws of physics would probably limit this somewhat  :grin:
Title: Re: Mk3 gti gearbox question ( diesel gearbox in a petrol car ???) questions
Post by: Len on 14 December 2012, 08:56
Yea ya cant go that fast on water! :laugh: