LSD in S5 NA
 

Hi, I have an S5 NA, which I believe all have open diffs. I would like to install an LSD, but I'm not sure what will fit and what won't. Are there diffs that will be a perfect fit without adapters and stuff? I vaguely recall hearing that the S4 NA LSDs will fit. Are there aftermarket diffs that will work without pulling parts from a T2?

Yes, all S5 NAs (except the GTUs) had open diffs. An S4 NA clutch-type LSD would be a direct swap, but you'll need to be sure you're getting it from the correct model. An '86 to '88 GXL would have a 4.1 LSD if manual, and a 3.9 if automatic. An '88 GTU would also have the LSD rear end.

All years of TII rear ends would also work, but it would also require matching halfshafts and a custom driveshaft (NA yoke + TII pinion flange).

Dealer Brochures here: https://www.rx7club.com/new-member-rx-7-technical-256/specifications-what-did-2nd-generation-rx-7-come-w-options-standard-features-963417/

Awesome, thanks for the information. Are there aftermarket LSDs that fit in the NA S5s (or is it possible to still buy OEM S4 LSDs)?

I think he was referring to buying and swapping an entire differential used from an 86-88 LSD model.

There are aftermarket LSDs that will fit from Kaaz and a few other companies. One difference between the S4 and S5 diffs is that S4 has a mechanical LSD and the S5 have a viscous LSD.I thought that the S5 GXLs also had a VLSD.

will the S4 differential itself fit in the S5 rear end? I have an S4 LSD rear end but the bearings seem worn. My S5 diff is just fine. Wondering if it's possible to take the S4 LSD guts and put them in the S5 case.