WTB: 3:64 LSD from E32 for 8 series swap

[Black88GTA]

**EDIT 11/07: Looking for open or LS at this point...***

Hi all, this might be a long shot, but here goes anyway. I'm looking for a 3:64 limited slip "large case" differential to swap into my 1994 840. I had found one a few months back, and was making arrangements to get it - and then the person inexplicably stopped responding to my emails. :( So I'm back looking.

If you have one for sale, please let me know what you would like for it, and where you are located. Or if you know where one is located, I'd be most appreciative if you could pass the information along. Local to Long Island, NY would be great (although I know beggars can't be choosers) so really anything in the continental US or Canada would work.

Send me a PM here, or email me at eharding at gmail.com

One last thing - as more of a favor / common courtesy - all I ask is please be serious about selling it! I was making plans on installing the one I had lined up before it got cold out, and it was somewhat disappointing (to say the least) when the seller broke off contact.

Thanks in advance...

-Evan

[Auraraptor]

You realize with a 3.64 your highway rpm at 80 would be over 3000 right?

3.15s can be had cheap and are plentiful, and still provide a 12% increase.

[Black88GTA]

You realize with a 3.64 your highway rpm at 80 would be over 3000 right?

3.15s can be had cheap and are plentiful, and still provide a 12% increase.

Yes, I know...from what I am reading, other owners who have swapped to a 3:64 report that the cruising RPM increase isn't a problem for normal highway speeds, although fuel mileage suffers a bit. My goal is to greatly improve the off the line performance - I think that the 3:15 might be a bit too mild for what I am looking for. I don't want to go through all of the work swapping the diff only to be disappointed with it. Most of my driving is around town anyway.

[Auraraptor]

Fair enough. I am happy with my 3.23, though I might have made a 3.45, so I understand where your coming from.

Anyway, The second question becomes:

Do you need an LSD? I ask as the 3.64 open was factory on the early 4spd autos. Many upgrade to a 3.91, so it should be able to be had cheap. In fact I was condering doing just that just to 'try out' the 3.64 myself before I spend the extra $$$ for an LSD varient or go hunting for the very rare 3.45 gear set.

[rcrad6653]

To the OP: +1 to what Aura said about LS... I will be swapping my rear out as I've found a 3:91 early M5 unit, and my 3:64 open diff will be available (45k), and there's also one in the '93 parts car (90k).
To Aura: The german M-sport gears can still be gotten in the 3:45 ratio if you're still looking.

[Auraraptor]

Randy is local too and a nice guy to boot. The factory Sal LSD pre VarMtech (which what your looking for would be) is a rather dinky 25% static unit (think about that...that's less then 80hp shunted) and not worth the extra cost. If you want a proper LSD it will set you back $$$$$. Case in point, my custom 3.23Q and 3.38Q cost well over $2000 EACH (not to mention time spent sourcing)

Note no affiliation/he isn't paying me/etc blah blah, if anything I want to buy it! (but I am trying to get a car right now...)

Edit: you can closely mimic the cruising rpms of a 3.64 by dropping down to 4th on the highway and driving for a while...just an FYI.

[Black88GTA]

Thanks for the replies guys.

Well, I guess the LSD isn't really necessary...I don't plan any serious engine mods or anything. I have a Wokke chip, but that's about it. I just figured that as long as I was doing the work, might as well toss an LS unit in there. It seems that the 3:64 open may be what I end up doing, due to availability. And you are right, I just can't justify the high costs of an aftermarket LSD unit (I had briefly looked into it).

I had considered acquiring two differentials - one 3:64 and one common ratio LSD, and combining the 3:64 gearset with the LSD carrier, but I don't have a clue how to do that and don't want to have to tear it apart again if I mess it up somehow. :embarrasm

My only concern with going to an open diff is that with all the extra torque going to the rear wheels (as a result of the gear ratio change) I might run into wheelspin problems in the wet. Does anyone run into traction problems with an open 3:64 mated to a mostly stock M60 motor?

Randy, I will be PMing you shortly...

[Auraraptor]

You can't just add an LSD, it requires proper shims and blacklash adjustments to prevent well, implossion for one, and excessive Noise for another. The tools are rather specific to the point your average well equipped garage doesn't have it and it's a bit of an art to make it right. It is part of the cost of my custom diffs: Assembly of an LSD and gearset into a case (realize the gear ring comes out, the LSD replaces the open unit, and then it is replaced in the case - it's not just openning and adding) by a skilled hand costs $1200-$1500 alone....and that's with me providing all the parts! (case, gear ring, LSD)

If you want to go that route, I can provide the contact info of my builder, Jim Balton. He is the best in the country and does most of BMW race teams diff work in NA, and was originally recommeded to me by THE E31 guru Mwrench (Ed) himself. (again no affiliation/$$ kick back to Jim other then a now repeat customer!)

Edit: also I can provide you with a list of sources for the proper filament LSD which can matte to the gear set in a large case.

[Black88GTA]

You can't just add an LSD, it requires proper shims and blacklash adjustments to prevent well, implossion for one, and excessive Noise for another. The tools are rather specific to the point your average well equipped garage doesn't have it and it's a bit of an art to make it right.

Heh, this kind of goes along with what I had been reading when I was researching this. That's what scared me away from it. I have already ruled out the possibility of me doing this myself, and the cost to have it done by a pro is far more than I can justify spending on it.

Maybe in the future, if I ever decide to S/C the 8 or something...but that's a long way off, if it is ever to happen at all.

[Black88GTA]

Bump to the top. Looking for a 3.64 open or LS now...

[Auraraptor]

Talk to Randy (again) for an open....

[kalevera]

Have a 3.64 large case available, but it's open. Actually have multiples, have taken down a lot of late E32 750s recently. Also have an extra M variable LS on the shelf that could go in it, but I'd need a large case LS core for it. It'd have new seals and a proper shim/stub axle setup in that case, and if you want to send in your pinion flange for setup, I can do that, too. PM me if you want to discuss.

[Black88GTA]

Talk to Randy (again) for an open....

I was in contact with Randy, we spoke a bit on the phone. Really nice guy. He did have one, which I was going to pick up, but someone else beat me to it. :( No sour grapes or anything, but it does leave me still looking. To my knowledge (at least, last time we spoke), he doesn't have another available right now.


Have a 3.64 large case available, but it's open. Actually have multiples, have taken down a lot of late E32 750s recently. Also have an extra M variable LS on the shelf that could go in it, but I'd need a large case LS core for it. It'd have new seals and a proper shim/stub axle setup in that case, and if you want to send in your pinion flange for setup, I can do that, too. PM me if you want to discuss.

PM sent...

[Bryson]

Aura, I believe the name you were searching for is Jim Blanton? Very famous diff builder indeed

[Auraraptor]

Yes, my spelling is awful. Thank you for the correction. Jim Blanton was the fellow who made 2 of my diffs thus far (and eventually will be making me a third).

[rcrad6653]

Evan, I'm not sure what Aura's reference was about a diff, because afaik it is spoken and paid for, unless there's something I'm unaware of at this point. Depending on your time frame my 45k diff will be available when I go to a 3:45 LSD.

[nukeduster]

3.64 + auto or manual both has managable highway RPM. I haven't been able to break 18mpg though ever since swapping in the 3.64 + 6 speed. You're cruising at 2800 @ 65mph pretty much. I seem to average about 17mpg every fill up these days, after about 10 fill ups since swapping mine in.

[Black88GTA]

Evan, I'm not sure what Aura's reference was about a diff, because afaik it is spoken and paid for, unless there's something I'm unaware of at this point. Depending on your time frame my 45k diff will be available when I go to a 3:45 LSD.

Don't worry about it, it's no problem. I managed to snag a 3.64 open out of an E32 from another member, which arrived yesterday. Now I just need to find the time to install it!


3.64 + auto or manual both has managable highway RPM. I haven't been able to break 18mpg though ever since swapping in the 3.64 + 6 speed. You're cruising at 2800 @ 65mph pretty much. I seem to average about 17mpg every fill up these days, after about 10 fill ups since swapping mine in.

Thanks for the input, this seems to go along with what I've been reading. My gas mileage is awful around town anyway, which is where I do most of my driving. I usually get between 12 - 14 mpg. Although, I consistently get 22 - 23 mpg on long highway trips. Probably can say goodbye to that once this goes in, but I'm prepared to live with that :cool