Jump to content

IGNORED

Starting a new project...Subaru STI Differential swap into my Z


Recommended Posts

Drove to Nebraska in August for the Sand Hills Open Road Challenge, 2600 miles round trip...got between 22 to 24 at highway speeds (80+). Sure wish I had cruise control!!!

And I was towing a trailer!!

Edited by ZXR616
Link to comment
Share on other sites

I am not sure buddy.

I have not finished this mod yet. I have just ordered parts.

UPDATE:

Wolf creek half shafts are ordered and on the way.

All parts should be here in about a week!

When I get them installed I will see what kind of mileage I get Ray.

But I bought this ratio with the intent on one day maybe putting in a Datsun 5 speed.

Link to comment
Share on other sites

Keep us updated - the 5 speed is the way to go if you do any traveling at all. Slipping in 5th gear a 60MPH is a beautiful thing.........and still have plenty of get up and go! My 3.90 diff is great through all the gear changes with the 5 speed. Putting in a 4 speed with the 3.90 may be a little over the top........fyi.

Link to comment
Share on other sites

Well I can start out with the 3.90 as it is, and then if it gets too bad, I can install a 5 speed. I already have the tunnel cut, and the console modified to accept the Type B. So it should be a breeze. Still I mostly just put around doing car shows locally within 20 miles. So it may not be too bad. The occasional track day as well.

Still the new diff may make my dieing tachometer a bit more of an annoyance. Time will tell. I can see mostly good coming from this.

Link to comment
Share on other sites

I like the upgrade and I understand that you are getting a modern, good condition diff, but wouldn't finding a low mileage R180 or R200 and installing an OBX LSD be a cheaper option? It's not a shot at you, I'm really asking which is better/cheaper. Here in the east, there are countless rotted out S130's with low mileage 3.90 R200 diffs. The OBX sells for about $400 and the S130 R200 can be had for nearly nothing. I paid $500 for an F54 engine, 5 speed trans, 3.90 R200, driveshaft and halfshafts all with low miles.

Link to comment
Share on other sites

With the OBX you'll have to get deep in to the guts of the differential, and the odds are high that there will be clunking or howling or the Belleville washers will fail if you don't replace them. With the STI you could not even remove the cover and probably end up okay. Kind of comes down to how much risk you want to take and how much wrench work you want to do. The OBX seems simple in concept but the details are difficult.

On the 5 speed - don't forget that the early ones have a 3.321 1st gear and .864 5th, while the later ones have a 3.062 1st, and .745 5th. The later ones, 80-83 ZX, typically came with the 3.9 rear gear, so you'll want an 80-83 ZX 5 speed.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Who's Online   1 Member, 0 Anonymous, 158 Guests (See full list)

×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.