1G 3 bolt to 4 bolt conversion?

[GSXlaunch]

I know this has most likely been discussed many times but I am at work now and really shouldn't be surfing. Can anyone tell me if I can swap the 3 bolt rear end assembly in my 90 GSX for a 4 bolt assembly out of a 92 Talon AWD Auto? Maybe someone can just point me at a discussion topic, thank you.

Also, does anyone know what size or the part number for the turbo stud used for the O2 housing to turbo mating. I know there are 3 bolts and this one stud. I am just getting around to installing my Evo III set up and the dealers did not have this stud in stock. I am trying to find one that will fit at a local bolt shop. thanks

 

[ASZRAEL1266]

i can't help you with the bolt i just got mine from the dealer when I changed my turbo.

As for the 4 bolt, the auto 4 bolt has different gearing then the 3 bolt. It wont work ,the rear will be moving at a high speed than the front. With AWD cars you need to make sure the gearing is the same or it could really messing something up like the center diff.

Hope that helped.

 

[98RedGs]

Quoted DIRECTLY From The VFaq Link I Posted


http://www.vfaq.com/mods/4bolt.html
4 bolt rear install
This is the [short version of the install, where you just replace the rear diff, axles, and axle retainer cups ("axle cups"). It is much faster than a complete suspension swap, and will save you a lot of money if you are buying your new rear from a junkyard, as they won't be selling you anywhere near as many parts. Just make SURE7 you get the axle cups, as they aren't cheap new, and shouldn't cost much used.


Tools needed:
1/4" 12mm shallow socket
1/4" ratchet and extensions
3/8" 14mm shallow socket
3/8" ratchet and extensions
1/2" ratchet
14mm combination wrench
12mm combination wrench (maybe 2)
1/2" 27mm socket
Crowbar
Tire wrench
Flat-bladed screwdrivers
Optional: "special" tool - modified flat barstock

 

[GSXlaunch]

Sure did thanks. Do you know if I can still use the rear end on my 90 and just mate it to the 4 bolt set up off the 92? Thanks again.

 

[ASZRAEL1266]

Originally posted by GSXlaunch
Sure did thanks. Do you know if I can still use the rear end on my 90 and just mate it to the 4 bolt set up off the 92? Thanks again.

I'm not sure if I understand what you're asking. The problem with an auto rear end in a mt car is the gear ratio in the rear end it self is different. The autos have a wider gear ratio. So if you are driving at say 30 mph the rear will be moving a little faster at like maybe 33 or so but as the speeds increase so will the difference. The center diff will be burn out pretty quick. If its an auto rear end I would just sell it to some one who has a 3 bolt auto and try to find a mt 4 bolt diff.

 

[GSXlaunch]

Thanks. I knew what you guys were saying about the gearing issue.

My question was can I use the 92 4 bolt assembly minus the diff and just swap the axles off the 92 diff into my 90 diff. After looking at http://www.vfaq.com/mods/4bolt.html it seems that is impossible and pretty much a stupid idea. That sucks cause this 4 bolt was gonna be given to me in exchange for my 3 bolt.

By the way, the stud size is 10x27 for the turbo stud to O2 housing. I paid $12.84 from the dealer to have it here by tomorrow. Thanks again fellas.

 

[Chapmanwired13]

I have 4 bolt axles and cups, can I use them on my 1990 Talon?

Or are the splines in the rear diff, different from 3 bolt to 4 bolt? The problem is I can't find 3 bolt axles anywhere. For some reason I can find brand new 4 bolt axles or brand new front axles for a 90-91 but can't get new rear 3 bolt axles. Not any parts store or any dealership can get them or anywhere online.

I do have a set of 4 bolt axles and cups. I also have the 4 bolt diff but was hoping to just use the axles. Or if anyone can point me to where I can buy 3 bolt axles that would be great. Thanks

 

[1990TSIAWDTALON]

4 bolt diff needs 4 bolt axles. Also different from open to VC diff.
Your cups should bolt up to your splined rear hubs ok.