I'm about to start my build of my fd and I was wondering if I need to include an upgrade differential. I already will have solid diff mounts and a reinforcement brace but will the differential itself withstand the power. My set goal for the build was around 500 rwhp.

 

Clutch type LSD and a diff girdle is a must, there are a few guys using that combo on the forum.... I blew my stock LSD already...

 

You'll absolutely have to upgrade the differential. A lot of people stick with the S4 TII diffs. I went with a 1.5 way KAAZ LSD and the HPP 2in1 diff brace.

https://www.rx7club.com/group-buy-ce...brace-1002000/

 

Thanks for the reply guys, I'll factor it into the budget. Are you finding the kaaz 1.5 to be loud or near stock in regards to sound?

 

I have about 400 hp and trq. In my fd with solid delrin mounts. No braces but i welded the diff since i drift and mineha been great so far.

 

My KAAZ unit is set at 100% lock, and it is EXTREMELY loud. I'm going to adjust the clutch plates to 66% and add a friction modifier to quiet it down. A lot of people rave about the slightly more expensive Carbonetic unit.

 

+1 for carbonetic carbon diff. Mine is silent.

 

Tii Diff for the win.. got mine for 250 =-)

 

In addition to being quieter, are the 1.5 way Carbonetics with the actual Carbon plates much stronger than comparable metal units? I'm wondering what the approximate HP figures would be that the carbon version can handle.

 

Idk if the carbon unit is stronger than the metal one, but the rx7.com group down in Texas uses them on their high-HP race cars and have never had an issue. I think a KAAZ or Carbonetic unit would be more than enough for 99% of FD owners out there.

The TII may be an inexpensive solution, but you have to look at the big picture. You're buying a used unit that *could* potentially fail at any moment, all while not offering the performance benefit of a locking unit that suits your particular needs(1 way, 1.5 way, 2way). If you absolutely cannot afford the aftermarket unit, then maybe a TII is for you. I prefer the peace of mind that comes with having a brand new unit with a lock that suits my needs.

 

Maddslow, i dont suppose you will be doing the change in the next 2 months? I would be highly interested in the difference in noise levels.

 

Yes I am, just waiting for Driveshaft Shop to finish my axles. Ihor at IRP will be performing the actual work.