I have a 89 gxl and wanting to upgrade to an lsd. What are my options as far as something that will bolt right up? Basically what rear end am I looking for with keeping the tranny intact? Thanks

 

stock Series 4 non turbo lsd.

 

You could look around for a s4 with a clutch type diff if it still locks up on s4 87-88 models. Its a simple n/a on n/a swap. If its on a s4 onto a s5 its mostly likely interchangeable but don't quote me on that alot of part are and aren't.

 

^^^Get this.......from a S4 GXL

 

I was told that some sport model S4s came with LSD that had a higher break away torque than the GXLs.

 

Thanks guys s4 gxl it is.

 

Or you can get a helical type from a miata (I think it's the 1999+ 1.8L) and put that in your rear end. That's what I did. I took my rear end to corksport and had them swap it. Works great

 

The '88 GTU did come with LSD, but I'm pretty sure it's identical to the unit used in the S4 GXL.

 

If you want a friction type of limited slip it will have to be the S4 version. Luckily it was an option on the na's. If you want the viscous limited slip then you'll have to go S5. However this was only on the TII's which would be harder to find. You'd either have to use the entire TII drivetrain or use a driveshaft that bolts to the na transmission but the TII diff. Mazdatrix sells one configured specifically for this. Of course it would also work if you were to use an S4 TII diff as well.

 

the s4 gtu as well.

 

technically the GTUs had it in 89, but good luck finding a GTUs diff

 

Yeah I don't see any proof of what I was told after some researching so you may be right. However, I was told this by JunpoweR at a meet not too long ago so I will ask him about it to get to the bottom of it.

 

just get the GXL diff, but keep your hands of my 3.909 LSD's.

 

I have a GTUs diff in my 87. I love it! Also my friend found one for 50 bucks and bought it with the quickness.... so just keep your eyes open on craigslist.

 

yeah, I would highly recommend a torsen (aka gear type, aka helical type) LSD out of a miata. It'll drop right into your carrier in place of the open diff. you might need new stub shafts, but I don't think so.

any 1.8L miata (94-05) torsen LSD will work.

any S4 LSD you find is most likely already worn out and not that great to begin with

I have a torsen in a TII Diff (from an FD) waiting to go in my car. It only cost me about $100 to get it installed in the carrier.