E30/36 LSD into E46 Swap

mmm there looks to be some wear on that keyed shim/spacer. I wonder if that would effect performance.

Already got with Mr. Wizard with the picture. He said the clutches looked to be a bit glazed. I'm going to replace those. He said to flip the dog-eared plates and use the unworn side.

Any chance that you can add more clutches to increase lock-up?

Yep. That'll come down the line after I figure out how much the unit is shifting.

Originally Posted by Hornung418

Since this is an active thread with some knowledgeable people posting in it, I'm curious as to how much lock-up you can modify to a stock M3 LSD. I've found 210mm 3.15 R+P for e39 M5s on eBay for $125, and it's a direct swap to the M3 case. But the OEM lock-up is pretty tame at 25%. So is it possible to add some extra clutch plates with out having to modify the shims?

The e46 M3 diff can get to 100% lock in extreme enough conditions - it's variable. It's not the same as the e36 diff.

Guys i have a 330d and would love to fit an LSD from a e36 but can someone clarify what determnes the ratio?? is it the pinion and case ring like in the pic below? and if so could it be used off the open diff?

Originally Posted by jassi uk

Guys i have a 330d and would love to fit an LSD from a e36 but can someone clarify what determnes the ratio?? is it the pinion and case ring like in the pic below? and if so could it be used off the open diff?

Ratio : Turns of the Pinon that makes 1 Complete revolution of the Ring.

Ring and Pinon: Yes it looks like the picture you attached.

Can be used in Open Diff? Depends, if its the right Ring and Pinion and etc...

-Trip

For the e36 it can either be a 168mm (small casing), a 188mm (medium casing) or a 210mm (large casing) ring diameter, the e46 LSD has a 210mm ring diameter.

Thanks for the information, Terra. I think I'm going to hold out and get the M3 rear and swap the 210mm 3.15;1 R+P.

Still looking forward to the results of this. Keep up the great work, Brady!

Edit: Is "Mr. Wizard" Wanganstyle?

So to do my swap I will require the LSD from a e46 m3 and use my pinion and ring to keep the correct ratio? Or even a e36 m3 Evo LSD as it carries a 210mm?

Your R+P is not compatible with the E46 M3 differential. The most cost-effective route to go is to buy an LSD (like the OSG that Turner sells) and install that in your case with your R+P (the one from your open diff).

Brady,

I've already gone down this road and luckily came across a 4-clutch LSD from turner for a great price, but here's my two cents regarding retrofitting the older unit as you are attempting. Instead of doing all the machining and spacer for the top hat, which by the way will require you to make a spacer for the inside of the unit to keep the clutch pack stack preloaded as original (you could add additional clutch stacks if you measure it out right); just machine a spacer for the ring gear so that it lines up with the e46 pinion.

Looking at your photo below; measure the offset between the open and LSD unit where the ring gear sits and machine a spacer of that thickness. Then you can mess with the order of the clutch pack stack inside the LSD to center the spider gears so that they match the open unit or do some machining to perform the offset and add additional clutches. I'm pretty sure the measurement you come up with for the ring gear spacer will also be how much the spider gears need to move.

But not to be a bummer, the wangan dude is right when he says you have to do a lot of grinding in the diff case to be able to make this unit fit. And with all that grinding, you'd better make sure not a single piece of trash makes to to the pinion gear bearings otherwise goodbye diff. When I got the turner diff I still had to remove material inside the case
to make it work, but it was a very small amount and I used a file and packed a ton a grease around the pinion to keep shavings out of the front of the case.


Anyhow, goodluck buddy. Pm me with any questions; and if you ever sell those schrick cams I expect to be the first one you contact.

Originally Posted by aggieE46

So, here's where we are:



As you can see from the picture, the units themselves seem to be the same height. I haven't measured, but they're pretty darn close. So to add to my excellent illustrations, here's what I'm supposed to do next. The LSD must be modified so that the ring gear is in the same position as it is on the open differential. As you can see, it's too long. I will need to have the bearing seat and shoulder milled down so that it matches. That's the next step.

I'll get ahead of myself and say that after that, the unit itself will be too short. I will then have to have a spacer made to space the bolt-on cover out towards the driver's side. That will make the LSD unit the exact length of the open unit and put the ring gear in the same position as it is on the open unit.

Enjoy the update!

Nice idea. Am I wrong in thinking that the overall length of the two pumpkins (open e46 and lsd e36) is slightly different. By this I mean the distance between the edges of the outer bearing races. Then, by machining the way Brady was planning, you would line up the ring gear as well as the overall width of the unit.

Im not a master mind at LSD's but how would adding a spacer or milling before the ring mess up the clutch pack stack I thought that would ensure that the ring and pinion engage properly. Doesn't the mechanism within the LSD determines the lock up and the ring and pinion for the ratio.

Originally Posted by jassi uk

Im not a master mind at LSD's but how would adding a spacer or milling before the ring mess up the clutch pack stack I thought that would ensure that the ring and pinion engage properly. Doesn't the mechanism within the LSD determines the lock up and the ring and pinion for the ratio.

Adding a shim under the ring gear wouldn't affect the clutches at all, but that's not what the OP was talking about doing.

So how does the milling of the length??

Originally Posted by jassi uk

So how does the milling of the length??

Give it the right amount of engagment between the 2 parts. Then u use shims to fine tune it....

-Trip

Also, the clutch/dog ear assembly needs to stay in the same position relative to the outer parts so that the axle hubs will properly engage them.

I like all the discussion. I wish I had more answers. I'll update more when I know more.

Mr. Wizard confirmed that there may be some grinding necessary. Depends on how much I have to take off.

Payday is today.... Hmmm, do I go to the machine shop or refinish my Wilwoods?

Originally Posted by Hornung418

Since this is an active thread with some knowledgeable people posting in it, I'm curious as to how much lock-up you can modify to a stock M3 LSD. I've found 210mm 3.15 R+P for e39 M5s on eBay for $125, and it's a direct swap to the M3 case. But the OEM lock-up is pretty tame at 25%. So is it possible to add some extra clutch plates with out having to modify the shims?

the E46M LSD unit is a M-variable LSD. this is a Viscous AND clutch LSD, the Viscous coupler engages the multi clutch pack stack. GKN makes this unit, it is NON-servicable.

the e36/30 M cars use a conventional Clutch LSD with 2 disc pairs. They can be and are commonly modified for more discs and more lockup.

Originally Posted by Hornung418

For the e36 it can either be a 168mm (small casing), a 188mm (medium casing) or a 210mm (large casing) ring diameter, the e46 LSD has a 210mm ring diameter.

I think I'm going to hold out and get the M3 rear and swap the 210mm 3.15;1 R+P.


Edit: Is "Mr. Wizard" Wanganstyle?

Nope. No wizard or magic here!

Just a lot of diff building for my own cars over the last decade. I started in Rally cars (AWD) - lots of LSD setup there.

I have built up with my own hands here in northern california:

e46M diff with 3.15 and 3.23 and 3.73 and 3.91. Using all OEM bmw parts; all 210mm and no wizardry needed. Fit is = BMW OEM designed fit.
e46 non-M diff with custom ratio and OS-Giken LSD (aftermarket). Fit = almost as good as BMW OEM fit (but case grinding is required to fit the OSG)

BMW OEM 210mm and 188mm gearsets have different mounting hardware standards. Some use M14 hardware/holes/threads and some use M12. Not easily mix and matched, not cheap to play with either. Everything is hardened, surface treated. Don't assume you can drill/tap anything.

the 188mm e30/36 ring and pinion with high locking setup has been proven to take over 1krwhp by a bay area local I setup. They are very strong if setup correctly. 210mm is for durability, long term wear.

e39/46 use compact nose pinion gears; not compatible with older cars.

I have played with the 188mm compact e39/e46 diff shell and decided it was not worth my time to stuff in an older e30 lsd unit - it doesn't really fit. I have both e46 non-m housings and e30 LSD units of various flavours here.... I have tried yes.

I have built OSG+ 330i e46 units for race cars in custom ratios, that was worth my time (and the customers time). Even installing the E46 non-m special OSG LSD into the Non-M case was a PITA and required grinding the case.

If this is milled and the top cap is spaced out to make up the milling distance:

you loose the cavity that the oil washer ring sits on; the would be loose- this item lubricates the spider gear (your axel is mated to the spider gear via internal splines)
+
the driver side spider gear will have no seat and there will be a giant space there. A full billet custom top hat would solve this but not be very cost effective.

Originally Posted by SoloII///M

Adding a shim under the ring gear wouldn't affect the clutches at all, but that's not what the OP was talking about doing.

this would be harder to fit the diff in the case housing, but would be more reliable as no internal relationships have been altered. I hate to see what kind of carnage a loose spider could cause.

.......messing with the internals and making custom parts for the diff (crazy IMO). I suppose if one had a machine shop that could do anything at $0... Thumbs up for the guts to play the game!