Hey guys, I think this is possibly my second post I've written on Hybrid. Although I am often on this forum looking to you guys for answers. I've been paying close attention to this thread because around the time that this thread started I too purchased a 2004 Subaru STI differential. In addition to the diff, I also pick up two STI axles.
Before spending any money I made sure that this setup was even remotely possible. Because I planned on using the STI axles with the STI Diff, I knew there were no issues on the axles-to-Diff side, with splines and what not. I also noticed that the input flange on the differential was a different bolt pattern. But that problem was easily resolved by simpley swapping the r200/r180 (from the datsun's) with that of the Subi.
Now there were two big issues that I came across. One: Is that the subaru axles are about 4-6 inches to long. Two: Is that the hub side of the subi axle has splines that go into the STI's wheel hub assembly. And I needed to somehow modify it to a flange.
So...
For the length issue, I thought, there had to be a place that made a shorter center shaft for an STI. Sure enough, the Driveshaft shop make a shorter center shaft for the STI. The stock shafts are 20 1/2". And after measuring and calculating I determined that the ideal length would be 15 1/4" to 15 1/2". As a bonus the shorter center shafts I ordered were made to handle 400 Hp +. Now I'm just running a L30 stroker, so there is no chance I will break them. Oh I should mention the two stronger shorter shafts were about $400. That also includes: 4 New CV boots, 4 Tubes of CV grease, and 12 clamps. (6 small, 6 large).
Here the stock shaft and new shaft are side by side:
For the other issue, the problem with not having a flange. I took the outside axle case and the 280z stub axle flange to a machinist. I told him that I wanted the spline section removed and a flange welded on to match the 280z flange. This was a little difficult because I also wanted a center circle sticking out from the flange to match the inboard circle of the stub axle. It's hard to describe. But to your luck I have photos.
This is the planning:
And this is the outcome, all painted and looking good:
These are the axles in pieces and ready to be assembled:
Well, thats my setup. I'm kicking myself that i didn't take any pictures of it in the car after install. But I just took a picture of them now. It's a little dirty because I've done about 2000 miles on the setup.
Works flawlessly though. The axles fit perfectly so it isn't a pain in the ass to take out, like it was with the z31 axles. But best thing about this setup is that I got Limited Slip, the 3.90:1 gears that I wanted, and both my axles and Differential have less then 20,000 miles on them.
Price wise:
-The 2004 STI LSD differential with 3.90 gears. (16,000 miles) cost me about $400.
-Both the axles (18,000 miles) cost about $250.
-The new center shafts, and boots. etc. cost $400
-Welding/machining on outer CV case cost about $100
-Some POR paint and Redline gear oil. Under $100
Well, I think I marked new territory here. While it cost a little over $1,200. Spending $700-$900 on z31 r200 LSD is sort of ridicules. Considering how many miles there are on a 1987-1989 differential. Maybe a couple of years ago the r200's ran for a lot less than that. But I am very please with my setup. And I would recommend it.
