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

[robox]

Yup... I like what you are doing but $500 for the stubbies from Wolf Creek is the hardest part of the upgrade in my opinion. There may be a less expensive solution. The Yoke solution arose from your trouble getting those short faced D cut bolts. A Yoke with 27 splined shaft would be a nice keystone.

To revisit an earlier part of this thread....

Couldn't the $500 for the Wolf Creek flange-shafts be saved by either A) installing splined yokes, as Blue mentions here, and then replacing U-joints to mount up the rest of the 240 half-shafts, or for that matter just re-using the flange-shafts from the original R180 that is being replaced? Even if opening the diffs were required to swap in the threaded buttons, it seems like a good way to save a bundle of $$.

Am I missing something here? That seems like the obvious and cheap solution.

EDIT: Never mind... I just figured it out. Datsun spines are 25 tooth, Subaru are 27. Bummer.

Edited January 13, 2014 by robox

[tlorber]

Stephen, I rebuilt an '82 5 speed before putting it into my '73. You definitely do NOT need to pull the motor. However, you should 1) remove the fan, 2) loosen the motor mounts and 3) lower the rear (or raise the front) end of the motor to a bit more extreme angle in order to permit the tranny to slide in. The purpose of removing the fan is so that it does not hit the radiator while the motor is at a cocked angle. I had no issues whatsoever.

By the way, if you have not already done so, don't forget to get the speedo pinion gear that matches your diff.

[malibud]

Questions ...

1. Why did you remove the half shafts ? when I replace my diff with one from a 720 I just laid the m to the side. Now i want an LSD. Is this required with a STI diff?

Also I working on getting a STI diff with a stripped drain bolt are the covers interchangeable

Thanks

Dan

[Zedyone_kenobi]

The cover for the Datsun cover will definitely fit the STI diff cover. I can tell you that for certain.

I forgot why I removed the half shafts, probably just to get them off and clean them. But also they may have been in the way to my exhaust. I wanted to install new high strength steel bolts and nuts in there that were clean and freshly cad plated as well.

[malibud]

Thanks ! thats why I got it so cheap, the stripped bolt. well that and it was low on fluid but for the price I figure i could give it a shot. it has 110k miles on it the engine spun a bearing so I wonder about the condition of the diff.

thanks

[malibud]

After installing a STI diff in I figured I would share my experience. Ok the folks at Wolf Creek say to hit the stub axles in with a hammer. Mine did not go in so easy so i put it on a press . Don't do what I did~! You must center the C-clip that lies in the diff between the shims of the LSD. I being a newbie did not know and broke the C-clip. Luckily it fell into the spider gear and locked the diff so when I turned in a parking lot it was like having a welded diff. After taking back out again and taking it to local diff guy he re-stacked the plates and replaced the C-clip all is good now. Much better handling ...

[Oiluj]

I think I remember John Coffey stating that the LSD is the single best improvement you can do for handling. With the STI set up it is one of the easiest also. The LSD is not that exotic for an OEM , just a very nice option.

Does the LSD make the steering wheel force harder on the corners? That concern is what's kept me from doing it, in case my bride drives the car...

[John Coffey]

No...

[malibud]

No, Highly recommended I have a r200 LSD in my turbo car. I like the sti diff a little better maybe because I had the shims re stacked in the sti. I found my STI diff on the WRX forums pretty cheap.

[rossiz]

for those of us who haven't experienced an LSD, can you illuminate? what makes it better? is this something noticed on the track only, or is there some quality to it that is somehow noticeable on the street? i've never noticed anything particularly odd or bad about the stock diff in my '78... what am i missing?

[John Coffey]

There's nothing bad of odd about a stock open diff. If you've never spun the rear tires on your Z in a corner, then you'll never know the benefits of a LSD. If you want the car to be more stable in a corner and allow earlier and more throttle exiting, then a LSD is of great benefit. Its the single best thing you can do for the handling of a S30.

If you're not a cornering kind of guy, no need to spend the money on the diff.

[Travel'n Man]

Alright guys, you've talked me into it - I'm joining the LSD Club!