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-   -   E30/36 LSD into E46 Swap (http://forum.e46fanatics.com/showthread.php?t=908171)

aggieE46 03-08-2012 01:19 PM

E30/36 LSD into E46 Swap
Good morning fellow Fanatics. I'm hoping that this thread will go exactly as I have planned it. This is a continuation of where Raj left of here:


While brainstorming with Raj on how to do this correctly, I made contact with a differential guru that assured me that it can be done. He gave me fairly complete instructions which I will be sharing along the way. I don't have exact measurements, but I'll do my best to provide them as I go.

Disclaimer: I am NOT a differential expert. Contrary to popular belief, I'm not an expert on much of anything. I read a LOT. I generally only post when I'm fairly certain that I'm correct. That's why I'm generally right, hah. So, follow this thread with that in mind. My source is a busy man and I will do my best to not bother him during the course of this project. He has given me his blessing to share this hard earned information but as asked me to remain anonymous. We will refer to him as Mr. Wizard for the remainder of this thread.

So, let's start with what I know. The E46 non-M suffers from a serious case of one-wheel-peel. We'd all like to fix this, but our options are limited.

1. E46 M3 differential swap: This is possibly one of the least expensive options currently available. They are fairly easy to source. You'll need the entire M subframe, control arms, swaybar, halfshafts, and differential. Your stumbling blocks are going to be a) limited gear ratios (3.62 or 4.10) and b) connecting your existing transmission to the differential.

2. Kaaz: This is probably the next budget option available right now. I think the unit runs around $1000-1200 (last I checked). On top of that, you'll have to have it installed. This isn't the job for the average DIYer. If you have a friend or a hookup, this is probably good for you. The downside to this would be limited gearing options. My last search showed that the unit would only work in the 3.38 or 3.46.

3. Performance Gearing (Or whichever shop you prefer): Having Jim Blanton setup a differential perfectly matched to your needs is probably the way to go. You can choose from any ratio you like. I don't even think he charges a core charge. That means you have a spare unit in your garage just in case of any issues. Warranty. Very nice. The only downside to this unit - price. I'd love to have one, but $3000 is too steep for my budget right now.

4. That brings us to this option. Using an E36/E30 limited slip unit in the E46 housing. If all goes well, I see this as the cheapest option. Will it be the highest performing option? Probably not. This is a mass produced LS unit designed for spirited daily driving. You may be digging through salvage yards or fighting over these on bimmer forums. If this thread goes well, you may really be fighting. If the pursuit of a great performing daily driver with a budget LSD solution is what you want, this thread may help.

So, let's begin. Here's where you need to be to catch up.

Use SoloII///M's DIY to tear down your unit:


You do NOT need to remove your input shaft/pinion gear at this point. Pop out the output stubs, remove the seals, bla bla bla. He did the work, use his guide. Make sure you pay attention to which giant circlip goes on which side. I did NOT do this on my 2.93 that I will be testing this all on. I WILL do this on the 3.46 that will eventually get the transplant.

So here is what you should have handy:


On the left is the limited slip unit. On the right is the open unit from my 2.93. In the center is an output stub. We'll need all three of these to get going. Make sure the E46 bearings are in good shape. Mr. Wizard told me that E46 are not available for purchase. I'm going to double-check this with my local bearing supply, but I'd assume he knows what he's talking about. If yours are destroyed (either before beginning this project or during the next steps) this project can be tackled using E30 bearings. Your measurements will just be different to account for the difference in bearing height.

So, I'm going to leave you here. When we next meet, I'm hoping to have the bearings off of the units.

tinkwithanr 03-08-2012 01:37 PM

Niice, good luck with this.

aggieE46 03-08-2012 01:49 PM

Thanks. Units are at the machine shop now having the bearings pulled. I gave them the go-ahead to destroy the E36 bearings. He knows he can pull one of the E46 bearings without issue. The other might give him some trouble. If so, I'll be at Harbor Freight later getting a separator to do the job.

Got some quotes on the work needed, too. If they are able to do everything, this should be a cheap project. I have a rough estimate together for the total cost of the project. Including what I paid for the LSD unit, machining, a few internal parts, and fluid, I'm guessing that this will run about $540. That's a rough number. I have some options on my spacer plate. This number is with a fully cut unit. It's possible for them to make me one and me do some grinding to cut the costs. With budget in mind, I'll probably do that. If this is going into a 2.93 or 3.07, the cost will be even cheaper. I'll go over details on costs as the are incurred.


Originally Posted by tinkwithanr (Post 14163180)
Niice, good luck with this.

darksideracer69 03-08-2012 03:10 PM

:excited: i need this!

DarkJoker 03-08-2012 05:02 PM

keeping an eye on this thread as well

aikmanson 03-08-2012 05:34 PM

Interesting... subscribed.

Snik 03-08-2012 05:43 PM

woah! i was wondering about this the other day when i read the 318Ti had a LSD, now here u are. so awesome.

Thanks. subscribed.

aggieE46 03-08-2012 06:17 PM

Back from the machine shop. No luck. There were a few things that they weren't going to be able to tackle. The output stubs are hardened and would need carbide tooling to cut them. They couldn't do it. They pointed me to someone on the other side of town that was more into automotive projects. I'll head over there on Monday.

Also, upon some rational thinking and a tip from Mr. Wizard, I may switch things up and use the E30/E36 bearings. They are easy to find and are pretty cheap. If I burn up a set, I can replace them easily. If I burn up the E46 bearings, I have to pull them off another E46! This won't chance much, I'll go into detail when I get the bearings off and can provide visuals.

darksideracer69 03-09-2012 10:12 AM

What about a torsen style LSD from a z3. Would that be better?

Sent from my SGH-T959V using Bimmer App

TiAg2247 03-09-2012 10:23 AM

Awesome idea. Don't mean to threadjack, but if you want to go with the E46 M2 setup my custom driveshaft for a 5spd car + M3 diff will be for sale in late April.

Sub'd for updates!

SL Blak Soldier 03-10-2012 02:53 AM

LOL. I didn't know you already made a thread.

I'm glad you decided to take over this project. You've already done more in two days than I have in the past few years. :rofl:

I'm definitely sub'd to see more. :craig:

*edit* just found this in the other thread....


Originally Posted by aggieE46 (Post 11234082)
I'm not planning on letting you forget about this.

^I guess you kept your promise 2 years later. :rofl:

jared_wiesner 03-10-2012 07:51 AM

Very interested to see how this goes!

JDUTHIE 03-12-2012 08:18 PM

This is soo awesome, PLZ don't give up, if you can figure out how to get the 3.46 Lsd into the stock pumpkin you will be saving Xi owners a lot of money and time:woot::woot::woot::woot::woot::woot:

aggieE46 03-12-2012 09:11 PM

Not giving up. I'm just changing the plan a little. I'll be going by to get a bearing separator this week. Since I don't have to save the E46 bearings, I'm just going to buy the tool and DIY. I'd rather spend $40 and have a tool when I'm finished than... well, not.

darksideracer69 03-12-2012 09:16 PM

More tools the better.

Sent from my SGH-T959V using Bimmer App

TerraPhantm 03-12-2012 10:18 PM

Sub'd.. and I don't even have a non-M anymore.

aggieE46 03-13-2012 02:02 PM

Tried using a puller at noon to get a bearing off. No dice, lol. I may have to give in and buy the tool or have them pulled. Just seeing if I could do it :)

SoloII///M 03-13-2012 03:27 PM

If you need E46 bearings, talk to Dan@Diffsonline. He has a solution for them. So does Metric Mechanic.

I haven't had any luck pulling bearings off of those diffs without destroying them.

aggieE46 03-13-2012 03:39 PM

Email away. That will save me some head scratching.

aggieE46 03-15-2012 11:53 AM

Snore. Sorry for the delays. Had some financial things come up. Should be back on track next week for a decent update.

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