I got a RX7 FC Cab USDM N/A rebuilt to Turbo with gearbox (and I guess everything behind that too).

I want to know what diff is in this car, what diff is the best to use for winter, summer, drifting in both and regular driving, and what fits?

 

an aggressive 2 way and welded diffs are scary in the rain esp if you have to hit the highway/freeway, but alot daily drive with them with teh intended use of occasional drift events.

But since you want it for all around, a 1.5 or stock LSD might do. Since your car has NA drivetrain you could source a NA S4 LSD, which is clutch type *rebuildable*,,, if you go with a turbo diff, you will need to swap out the drive axles and driveshaft as well since they are beefier than the NA. You can go with S5 diffs as well, but the LSD is viscous and not rebuildable. The S4 diffs are more commonly desired.

 

It depends on how the conversion was performed. Here are the most common methods:
A. Mazdatrix or other brand of altered driveshaft (propeller shaft) that allows the Turbo II transmission to mate to the original N/A differential.
B. Full Turbo II drivetrain swap, including a 4.10 Turbo II differential.

If you have B, then it is either a 87-88 clutch-type LSD, or a 89-92 viscous LSD (VLSD). The clutch type is better for performance, but the clutches need to be replaced periodically, which costs about $800 USD. The stock VLSD is the worst performing type, but it lasts a very long time before it fails.

In general, anything that is good for drifting is bad for regular driving. Drifters usually prefer a 2-way LSD due to its consistently harsh lock-up, while road racers usually prefer a 1.5-way LSD to maintain traction around corners, and a 1-way LSD is safest for every day driving.

Kaaz and Quaife LSDs are common performance upgrades, as well as other brands like Cusco and OS Giken.

 

I wondered. What about a FD torque sensing one? Will they fit over?

I know viscous diffs from Mazda need to be replaced (or the main part of it) after 60k mi or so?

 

Really, I am sceptical to the clutch diffs, because of the Haldex 4x4 system with clutches. They tend to suddenly lock, and whoosh there goes the *** out. Seen it on a Volvo V70 AWD.

Thats why a torsen could work. Or? I guess the torsen-style diff on FD are working liek it should locking when it is supposed, and open when it it should?

 

Find a miata/mx5 in a breakers it needs to be a 98+ (mk2 or 2.5) is edition you can tell its an is as it will have abs, aircon & a 3 spoke steering wheel ... these all come with a torsen lsd (perfect for what you want & they dont need to be rebuilt) which will drop into a n/a housing no probs.

 

Guess this is the one. The top is a crap diff.
But the torque sensing, how much do they regulate/lock up?

 

i recall hearing the miata diff isnt suitable for higher hp? esp hes looking at turbo

 

I didn't bother reading through the thread.

I'm sure torsen was mentioned.

Screw one way diffs..... Leave those to ff cars.


Find a TURBO II S4 CLUTCH TYPE LSD and case. The TURBO II guts are larger than s4 guts and will not fit in the n/a case. I have one. I raised the break away torque via shims and it's still VERY streetable. No chatter, no dragging the tires on low speed turns and it GRIPS HARD during agressive cornering. For drifting, the lock is very predictable but i was more astonished with how hard i was able to pull through a turn than it's drifting prowess because i'm a noob drifter.

You'll be happy with it. I'm sure.

If you have the bank, get a nice kaaz/cusco 1.5 way. Either way, you'll still have to get a tII lsd.

viscous lsd's are garbage. I dont care what anyone says.

 

Any one with any opinions on the Quaife vs. the OS Giken differentials?