im putting a turbo 2 motor into my 85 gs. i was wondering if i switch in a gsl se rearend can i use the gsl se drive shaft as well? also if anyone knows if the gearing on the gsl se is any stronger or faster then the gs, and what bolt pattern they have and how hard itll be to swap over. as always, thanks for any and all help and advice

The rear end should be ok fitted with a lsd. Ive seen them handle 450 rwhp. You probably want to use the s4 gearbox, and have a driveshaft made up to suit. By fitting 12a turbo front cover and using s1 13b sump it should be an easy setup. I converted my friends 79 rx7 to s4 turbo engine. for best results you might want a diff ratio of 3.6 or taller to compensate for smaller wheels and lighter car.

the gsl-se gears and diff are just lsd, its the same size as the 12a stuff.



drive shaft is the same between gsl-se and everything else

A 12A differential can hold up behind a 400hp motor, as long as you don't shock it too hard (burnouts, etc).

isnt 12a diff a 6 inch and se a 7inch like na fc?

I know that the GSL-SE's had a 4.11:1 gear ratio, but I can't remember what the 12a diffs are.

The GSL-SE also has 4x114.3 bolt pattern where the 12a diffs have a 4x110 bolt pattern.

http://www.mazdatrix.com/g5.htm



If you're swapping an '85 GSL-SE rearend into an '85 GS your big decision is which brakes you want. A lot of road racers actually prefer the drum brakes. If you want to keep them, just swap out your open diff pumpkin for the SE's LSD pumpkin. If you want the disc brakes it's easiest to just swap out the whole rearend. Remember that you will have to change the proportioning valve as well. If you want to keep the 4x110 bolt pattern, use the GS axles. If you want to 'upgrade' to the more-common 4x114.3 bolt pattern, use the GSL-SE axles.

well dont the discs work and stop much better then the drums?

Personally, I prefer the discs, but I've heard a handful of racers state the drums give better bite. The one advantage drum brakes have is they dig in harder with less pedal pressure. Disc brakes require more force, thus the need for a brake booster on modern cars.