gearbox??

[BradGTV]

whats the differnece between the standard gtv 2ltr, the gtv6 and the 75 gearboxes?

Stronger?, differnt ratios? any advantages and will they bolt straight into my gtv 2ltr

cheers brad

[Storm_X]

116 boxes are open wheel.
good luck finding agtv6 box
alfa 75 2.0ts box will fit stronger and has lsd
      75 v6 wont fit i think but should b stronger

and more of the ratios are pretty close i think

[Sheldon McIntosh]

Here's a list of some of the ratios...  http://img136.imageshack.us/img136/5782/alfaromeotransaxlegearr.jpg

Thanks to alfabb, original link here....http://www.alfabb.com/bb/forums/milano-75-1987-1989/150794-all-you-wanted-know-about-transaxle-ratios.html

Storm_X did you check the ratios on those gearboxes you had out of your Giulietta's?  Look like they need a hand to fill in the blanks in the data. 

[deano]

can somebody tell me if there is a difference between an alfa 90 and an alfa 90 super gearbox? isnt the super open 4.1:1?

[Sheldon McIntosh]

isnt the super open 4.1:1?

Yes it is.  Same gearbox as the 75 2.5

[jimnielsen]

The gearbox to go for is the one from the twinspark 75 - as it has an LSD. Typically, people buy one of these gearboxes and have the LSD clutch packs modified so that they provide 50% lockup and also they take the first and second gears from a traditional (say giulietta gearbox with a 4.1:1 diff) and use them in their new twinspark gearbox, as it put the 2nd - 3rd gear ratios nice and close. The actual gears are too strong, if anything - I have had ones made into swiss cheese with milling and drilling to make them lighter - and never broken one. The diff ratio to use is 4.3:1.  I have used the 4.556:1 diff as well, but they are rare, expensive and fragile.

All this can be expensive - say $1200 for a 2nd hand 75 LSD gearbox, $2000-3000 to get it setup for the track.

Vin Sharp at PACE engineering is very experienced at this process.

[deano]

would you do the same sort of thing for a v6?

what i'm planning to do next year is build a 4.1.1 lsd box out of 2 gearboxes. at the moment, i have a rebuilt 3.73 LSD in the car. i have the 3.54 LSD that came out of the car (cause i broke it...) still in pieces. my mate is just starting to wreck one of his cars so i'm going to end up with an alfa 90 super box in the next few weeks.

at first the plan was to use a rebuilt ts box but i've heard that the v6 boxes are stonger but im not sure how. the plan now is to mate the 3.54 lsd with the 4.1.1 crownwheel and pinion in the 90 super box and rebuild that box also with the lightened gears and locked up diff. has anyone else done this? what do most v6 cars run? i'm guessing the hot 24s and 12s use the 3.54 box.

[jimnielsen]

Many 2L alfa's make more power than the V6 ones - either way all the gearbox internals are strong.  The final drive is important because it determines what size tyre diameter / wheel size  you can effectively use. There is a much better selection of modern rubber available, especially in slicks, as wheel size gets bigger. However, even with a 4.3:1 diff, 600mm tyre diameter is probably the max that you want for good acceleration.  With the 4.1 diff 600mm is still ok if you have enough power. Anything taller in ratio would be great for fuel economy though

[Storm_X]

Here's a list of some of the ratios...  http://img136.imageshack.us/img136/5782/alfaromeotransaxlegearr.jpg

Thanks to alfabb, original link here....http://www.alfabb.com/bb/forums/milano-75-1987-1989/150794-all-you-wanted-know-about-transaxle-ratios.html

Storm_X did you check the ratios on those gearboxes you had out of your Giulietta's?  Look like they need a hand to fill in the blanks in the data. 

i think its 41/10. took the diff apart the other week and sure it was 41/10