gearbox type

I need help. I have a mk1 and mk2 gti cars. In the mk1 i changed the gearbox to a diesel box, so i could get mor km/L. Now i am thinking of doing the same with the mk1. Witch type box do i need to get higer gear for more km/l , wil a GTD mk2 give a better km/L ?.
Regards Mike

everything and anything you need to know about mk1 or mk2 trannys and the gearing are here.
A2Resource

Briano1234 said

everything and anything you need to know about mk1 or mk2 trannys and the gearing are here.
A2Resource

Well it is not easy for a idiot as me to se what i need from the ratio list you gave me? If i just change the fifth gear, what box do i buy, or what golf model diesel fits? I think from what i have read that it has to be 0.756 ratio gear cogs? Best regards from Mike

The mk3 golf 8v gti has a rod change box, like mk1 but does about 23 mph per 1000 revs in 5th,  

abfmk1 said

The mk3 golf 8v gti has a rod change box, like mk1 but does about 23 mph per 1000 revs in 5th,  

So this box should work?

Yeah, I fitted one, although with a 2 ltr engine over 20 years ago , Couple of things I just remembered, I needed to fit the 90 mm cups from the mk1 box, The mk3 has 100mm.  Also had to use 16v friction plate as the splines are different, mk1 plate dosnt fit..