Done: 3.46 Torsen Install in '83 533i

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Joey28
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Done: 3.46 Torsen Install in '83 533i

Post by Joey28 »

I just wanted to share my recent experience on this in case anyone else is still thinking of doing it.

I installed a 3.46:1 Torsen rear out of a 9/00 Z3 3.0 Auto into my bone stock '83 533i 5MT. The original 3.25 open rear was toast and whining so it had to go.

I got the replacement for $200 + $150 freight from Beltzville Salvage in Maryland. They packed it well on a skid and shipped next day.

Swapped my OE cover on with a new gasket. Install went exactly as some others have already detailed. Did it with exhaust still installed- no issues. I took my time and was careful about threading all 4 of the carrier bolts on top. I rounded the internal hex on an axle flange bolt and so had to weld a tool to it and replace it, but that was the only hiccup. Filled it with Valvoline 75w-140 synthetic and so far so good. Very quiet, maybe a little more pickup w the shorter ratio but I wasn't going for speed; just traction and quiet lol:). I did have to swap in the Z3 speedo sensor and fab a new pigtail, but speedo works fine so far.

Definitely a worthwhile swap for these older cars, especially if you're like me and are used to driving AWD or at least RWD with LSD. Car doesn't slip anymore. I don't ram around in it, though I do a little spirited backroad driving sometimes, and this setup seems well suited to the car's OE character. This really does seem like what ALL 533/535i 5MT cars should have come with when new.
Shawn D.
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Beamter
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Re: Done: 3.46 Torsen Install in '83 533i

Post by Shawn D. »

Thanks for the post! 3.46s go for $$$ these days, so I'm sure folks will be glad to know they can go this route.
ThirdPedalNirvana
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Re: Done: 3.46 Torsen Install in '83 533i

Post by ThirdPedalNirvana »

About a year ago I did the 3.64 Z3 torsen install in my '84 533i. Bought the diff with my stimulus money :laugh: . Absolutely thrilled with the ratio, perfect for street and canyon driving. Its absolutely acceptable on the freeway too, at about 2500 rpm at 65, but I would say if you mostly drive on freeways you probably want the 3.46.

I wasn't able to do it with the exhaust attached but disconnecting at the cat wasn't too bad.

At this point, I don't know why anyone with a medium case diff gets a clutch pack LSD anymore. The Z3 LSD's are easy to find, and if you get a used differential you're going to take off the rear cover anyway to inspect it and replace the gear oil.

One thing to note: You need to use the speed sensor that came with the Z3 diff. The Z3's speed sensor ring is slightly smaller in diameter than the OE one, and original sensor can't reliably pick up the signal. This means you either have to splice/soldier the OE wiring harness to the sensor, or go to pick'n'pull, find any 1989-2005 BMW, and snip the wire a few inches back from the plug that goes to the the speed sensor, and use it to retrofit your harness. It's just 2 wires and there is no polarity, if you can't solder you can use heat shrink tubing over a crimp connector (but maybe resolve to learn how to solder, its a good skill to have and not that hard).
cek
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Re: Done: 3.46 Torsen Install in '83 533i

Post by cek »

I'm replying simply to sub to this thread.

PO put a z3 S3.26 (?) in Vlad. It no longer LSDs.

I've assumed it was NOT a torsion unit.

I have a known good S3.25 I'm going to put on, probably tomorrow.
Yojedi
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Re: Done: 3.46 Torsen Install in '83 533i

Post by Yojedi »

Interesting read so far. Very helpful as I may eventually commit to a 3.46 upgrade.

So the rear cover from your '84 533 is directly transferrable to the Z3 3.64 and the new differential's mounting pattern is compatible with your 533 without modifications?
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