Hey I know this may sound like kind of a stupid question but are there any lsds that would work for both an NA and TII s5? Or are they to different to be able to do something like that?

 

As long as you match the half shafts to the diff youll be good.

 

you forgot the driveshaft

 

Completely different. Halfshafts, driveshaft and internals. TII is larger.

 

Can you not bolt a TII D Shaft to a NA rear end? I thought it was just the transmission yoke that was different?

 

I believe the spacing for the driveshaft flange bolt holes is wider on the TII diff than on the N/A diff. But presumably one could redrill the holes. Or just swap an N/A flange to the TII driveshaft.

The driveshaft has to match the transmission, the rear flange on the driveshaft has to match the differential. I think.

 

Yup

 

Man, its been a while.

 

Thats what happens when you goto the dark side, you forget things lol

 

There are aftermarket LSD's that can go into a NA diff housing.

 

Still love the rotary engine, but iv'e never got so many compliments on my **** box.

 

No factory Mazda differential is backwards compatible between NA and turbo. If you do one or the other you have to have the matching axles, drive shaft, and stub shafts.

 

I guess if one really wanted an "interchangeable" rear axle, one would use this:

FC Ford 8.8 IRS - Complete Mount Kit w/ Axles

Mount a 8.8 rear where one could interchange rear gear ratios for whatever you need, at wutever power one needs.

 

I've been really interested in the Ronin 8.8. But this got me wondering, are there any easier options? The MX5 community is pretty strong today and they have been doing all kinds of power adders to their chassis. Just thinking out loud here, they've got to have come across a plethora of rear end options. Considering the similarities between them and us, what can be learnt from them?

 

The Miata has a few different rears, one weird 6" on earlier models, but most use the Miata Type M differential which is a 7" rear end, the same in the NA 1986-1991 RX-7s.

They tend to use S4 clutch type differentials out of 86-88 NAs or Torsen differentials.

Also consider the weight of their cars. Most Miatas are typically lighter then the average second generation RX-7, it's like when I had an LS1 RX-7. 03-04 Cobra guys where jacked to use straight axle 8.8's, LS1 RX-7 owners took the the Cobra IRS and ran them in a lighter chassis with tons of success. With that being said, Miata guys may not need as much "differential" as we do with weight factored in.

I think you're over thinking this cowboy. 8.8's are great for choices and aftermarket, otherwise you have two stock choices and the TII rear end is one of the best out there for stockish/powerful car.

 

 

Kia Sportage front differential ring would fit, as well as a handful of B-series pick ups. But the thing you're going to find to be the issue is the long pinion on a FC3s. There are going to be a handful of 7" rear ends that'll "fit" in theory, but we really have the options through the aftermarket or through stock options.

You'll find the clutch type and the viscious that came with these cars are great fits for what most people would love to do. Some people like the torsion differentials as well.

I drove all 3 and honestly since I don't care or "push" my car to any limit, I couldn't tell you what the difference with driving.

I used a clutch type in my 400HP LS1 RX-7 and it seemed to work just fine.

I'd pick a flavor of what you'd like to do, swap it in, and be king for a day. What a time to be alive.

 

Gotcha. I was aware of the Kia and the Mazda B series parts as they share more than that. If my memory serves me correct (and it doesn't often) the B- series transmission is what the turbo trans is a derivative of. I think there was some conjecture on the fact that it's just an old truck tranny.

Don't get me wrong, I agree with you 100%. But perhaps its the maker in me that is thinking beyond my own needs and more into the greater idea. Not everyone wants to pay top cash for old rx7 parts (if you can even find them in your area) so maybe find more common derivatives to swap in. Hell I've even been thinking about ways in which some adaptor kit can be fabbed up that allows other aftermarket internals in the original case. I have some limited modeling, design, and fab skills along with offshore manufacturing access so just maybe?

What a time to be alive....you are 100% correct...100%