Hi, I’ve been looking over different threads and the answer has been “switch to an s4 turbo ii diff”.
its 2021, and I live in Florida.
I don’t think many turbo II diffs are left, and I need other options as I’m almost done with my 1j swap.

Is there any way to make the n/a diff stronger by dropping an lsd, like a kaaz(or other) diff?
or should I go with the ford 8.8 route?

(edit: I forgot to mention that I’m pushing about 500whp.)

Any comments would be very much appreciated.
And if anyone is selling a complete s4 turbo ii diff pm me.

 

there are diffs for the NA, Kaaz, OS Geiken, i'm not sure they make things much stronger though. also the 6 cylinder might be more gentle than the rotary, so you're probably still making too much power, but it'll hang in longer than it is was a hig power rotary

 

. I heard the TII stuff is good to about 500whp so it may be best to go with the Ronin Speedworks 8.8 swap.

 

I had a buddy running a kaaz n/a diff with a stock 1jz with 3” exhaust and it survived. Iirc, it’s not the differential that blows up, it’s the stub shafts which shear.

fwiw, I’d recommend going with a t2 drivetrain. You can run Mazda 929 axles, and t2 stuff is way more beefy than N/A.

Ive ran a s4 t2 clutch diff which I shimmed with mazdaspeed oversized thrust washers and added coke can shims and it worked great. Moved to a welded s5 t2 diff, and now on a s4 t2 with an ATS Deftforce 2 way and it’s money. Dedicated Drift build.

 

And just an additional logical thought, if you spend the $1000 for an aftermarket N/A diff, then it doesn’t hold up to your power, then what? Buy a t2 diff and buy another $1000 diff? Just saying.

 

What is your budget? If budget allows go for the Ford 8.8. Then you can use an LSD for a Mustang, which gives you more options. Not just in LSD's but in gearing choices as well since your no longer tied to the long pinon setup of the FC. You then could buy gearsets from Summit or Jegs. It's the route I would've went if I had the money at the time I did my rear end swap. If not TII rears still pop up from time to time.

 

Even Ronin lets you use a Ford Explorer rear as well as an IRS.

Granny's Speedshop has options for a straight axle 8.8.

You can change the ratios super easily as well, depending on your power levels, you may need it .

 

I sheared a stub shaft on a stock N/A S4 with 170k miles on the clock. One clutch dump in 1st gear at 6k RPM on textured concrete and it was new rear diff time. I was young and dumb.

I'd shy away from trying to bullet-proof the stock rear diff.

 

I wasn't clear in my second post. I was still talking about the Ronin swap that uses the Explorer rear. Summit has a few different LSD options for the Explorer rear end. Also has probably any gear ration one would ever want for 1/3 of the price of what the only other ratio for a TII rear end would cost as well.
https://www.summitracing.com/search/...model/explorer