hey ppl, bought the car (1988 s4 rx7) a few months back and found out that it was converted from auto to manual, had to mess around with gearbox mounting as the previous owners did a crap job... so far no worries but i cant seem to be able to identify exactly wat model it is (turboII or watever) which makes things hard to work out wat diff's in it! its not lsd for sure, did all the tests... got some pics up for u all to have a looksie...
my questions are:
1: wat diff is this?
2: wats needed to make it lsd?
3: if i supply more details about the car, can someone help identifying the model?

plans are for 300-350hp in the future when the engine blows so im after something decent thatll hadle that diffwise...

 

I've never seen a rear end case like that on a 2nd gen, whether it is TII, NA, LSD or open.

You'll know if your car is a TII because there will be a turbo and intercooler under the hood, a boost gauge on the dash, etc.

 

The S5 NA case design was different from S4 NAs. Comparison in this thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/difference-na-diff-housings-421148/. If I had to guess, I'd say it's an NA open diff, but that's just from the lack of an LSD tag. The tag would normally be sandwiched between the drain bolt and the case. They're made of metal, so the only reason for one to go missing is if someone intentionally removed it. You can rule out a TII rear end just from the case design. The NA diffs are still fairly stout, but as I know Aaron can tell you, an LSD is going to put the power down much better.

 

thx aaron, there is a turbo and intercooler under the hood and boost gauge inside, but it could have been converted so not necessaryly a TII... does the FC even come in automatic turbo? anyways, the reason i wanna know the model is to work out wat diff housing to put in to make it lsd! will any housing bolt up to any chassis? i know i gotta match the tailshaft pcd to the diff's pcd and the half shafts might not match, but other than that, is there any other mods needed to swap housings?

 

Automatic turbos were available in Japan, and probably elsewhere close by. Not in North America though. All FCs in Japan were turbo.

Any diff will bolt up to any chassis as long as you stay within your model. So if you have a TII, then you need a TII diff. Ditto for NA. Do you have a TII transmission? The TII transmission has a large inspection plate on the bottom while the NA transmission does not.

Actually, this page will help and save me some typing:
http://www.rotaryresurrection.com/2n...in_differ.html