318ti LSD or E30 LSD
 

I am debating what to get. Currently i have an open differential on my 318ti M3 swap. Whats do you guys think i should get. E30 with modified axles or 318ti LSD. I would rather go with mcoupe/roadster rear subframe but they are very rare to find.

well... if you have the source and the funds... get the M coupe.
Otherwise.... stay simple and get a 3.25 E30 LSD and E30 axels. works fine for me.

exacly what part of the E30 axle is used?

Bro. I used THE WHOLE thing. What you read on the write ups is correct to an extend. BUT the ONLY reason he used part of the stock and part of the Ti's axels (hybrid axels) is because he was not able to fint an E30 set in GOOD SHAPE.

Remember.... don't cut corners... if you are planning to get some power out of the S50 do it right. Do it ONCE.
On BMW swaps, NOTHING IS "NEW", I mean people have triyed and done it pretty much all... so trying to "come up" with a new idea is really a waste of time. (not in all cases.. I mean, talking about diffs, etc... and if you have the cash, you can do it all!)

if you source E30 axels, please let me know... I'd like to have a set for spares.

Can you send me a picture of your extra E30 axles. I might be interested. I was looking at the diffrential write up under the notebook section. If you compare the E30 to 318ti. The e30 is alitlle longer dont you think. I thought for this swap to work you only needed the inner cv joint from the E30 to make a hybrid axle (e30 inner cv and the rest 318ti). Isnt that the reason the hybrid axles was used so that it can be bolted up to the E30 differential........
Send pics to tad@dynamictransmedia.com

I just picked up an E30 diff. and was wondering if there is any reason to not just order a new set of E30 axles. From what I have read there is not reason they will not work as long as I shim the ABS sensor.

Let me know cause either the write up is outdated or just have minor flaws. To me the E30 looks a little longer. I dont know :(. If it bolts write up without any modifications, then your best bet is just to purchase a newer axles. Let me know your experience..

i'm in process of this swap right now. once completed, i can tell you exactly what i needed and what i did (compared to the write up).

here's what i've done so far:

1) get used E30 3.73 LSD
2) ordered used E30 half shafts
3) ordered a crapload of new mounting hardware, M coupe finned diff cover, speed sensor, etc
4) clean it up and paint it (see my thread that i started for covering that)
*** insert tremendous help and experience of my best friend from here down ***
5) remove half shaft flanges and seals, install new ones
6) remove old diff cover, clean up mounting surface on diff (all old gasket material, etc), spray new gasket (both sides) and all mounting bolts with high-tac, install new M coupe finned diff cover
7) remove halfshaft hub nut lock ring and nut (they were rusted in there like you wouldn't believe, my friend worked those out and then used an impact wrench to break the nuts free while i worked on the diff)

that's as far as i've gotten so far, have to drop the exhaust and then finish up the diff job today ... then install the new superspring exhaust too :)

Let me know if you just bolted up the E30 axles without modifications. If it bolts on the 318ti then im probably going this route while a complete mcoupe subframe comes my way:) someday

guys... this subject is SOOO worn out! let me brake it down

Listen, E30 axels bolt on FINE! All you need to do is SPACE OUT THE ABS SENSORS WITH 3 "O" rings. (I used Air Cond. O ring gaskets... yes! $0.25 e/a the green ones!!)

DO IT RIGHT! DO IT ONCE!

I swapped mine right after Constant did his diff. Didn't have to do any ABS sensor spacing. Just make sure you unbolt the ABS sensors before you install the e30 half-shafts.

SL

Kirasir:

Thanks for the clarification. I guesss I will be going this route until i find something better (eg. Mcoupe). So all I need to do is unbolt the abs sensor before installing the E30 axles. I probably make a trip to a local junkyard next weekend or so.
I've been busy this weekend. Finally got my 6cyl gauge cluster working properly. I made sure I wired the mpg gauge right. I took a few picture of the process. I probably make a step by step write up with pictures. The direction i got from DIY was kinda confusing. Stay tune...

Not to beat a dead horse, but I just wanted to clarify. I originally did the E30/318ti hybrid axles because the ABS pulse ring on my used E30 axles were in bad shape.

I have since switched to E30 325i axles, and they work fine. Like Serge, I didn't have to use a spacer on the ABS sensor. But I've also heard that some people did, so YMMV.

Constant

Sounds like if three people who have done this from start to finish would
get together and write up a basic checklist of what works it could be sticky
in the drive train section and folk who need it could sort out myth from legend.

I know that I've been considering the rear gear swap and it
was an item I was wondering about as well....
:)

Dave

That is exactly why I have waited to jump into this project!
When I'm sure I understand what needs to be done, then I'll get right on it.

The last thing I need is to drive to my brother's house, put it on a lift, tear it out, and then realize I don't have what I need to finish the job.
This is my only car, I can't afford any down time. :(

This is exactly what im talking about. Make it clear so that others can benefit from it. Isnt that the purpose of a forum. There should be no reason another member should charge for instructions in this community.

i have some input ... the e30 diff is a little too long, found we had to grind out semi-circular sections of the rear subframe that is part of the unibody/trunk to get it to fit properly (the part in constant's write up about the top diff cover bolt "touching" was an understatement in my situation, the subframe was RESTING on the top diff cover bolt and the diff cover bushing was still about 1/2 -3/4" below where it needed to be to bolt up). we used a grinder with grinding wheel to remove just as much metal as we needed to get it to fit. i don't know how anyone did it without doing that unless tolerances are fairly different between cars (constant's is a 4/1996 and mine is like 5/1996 so i find it hard to believe they are that much different). i used the e30 3.73 LSD and m coupe finned diff cover just like him. hated to grind, but i found it a necessity to get it to fit. we also found one of the other diff cover bolts prevented the diff cover bushing from getting where it needed to go and we had to grind off a small section of the diff cover bushing mount (most rearward one) that is also part of the unibody. we ground over to the ribbed section but not into it to retain strength, probably had to grind upwards about 1.5 - 2". UPDATE: was under there last night and noticed my friend had ground (and needed to) the edges of BOTH the mounts (there is one on either side of the diff cover mount bushing).

so it sounds like we have the following that make this swap potentially not just "bolt up":

1) clearance of diff cover bolts with rear subframe and diff cover bushing mounts attached to subframe/unibody, may require grinding
2) abs sensors may require shims (remove before installing half shafts back in hub to check)

also, things i'm looking for still:

1) proper torque settings for diff cover bolts (we torqued them to 35 since the cover is aluminum and i don't want to damage it but this was just a somewhat educated guess)
2) torque for new diff drain/fill plugs that use an imbedded o-ring (rather than the aluminum crush washer)

anyone who can send me those ASAP i would greatly appreciate!

btw, who is charging for instructions dredder? i agree, provide help/instructions where you can and you get so much in return here that it's justified, imho.

1) Diff cover: M8 bolts = 33Nm = 24.3 ft-lbs, M10 bolts = 47Nm = 34.7 ft-lbs (Good guess!)

2) Don't know about the "new" style plugs, but the old crush washer ones are 51.6 ft-lbs.

Constant

Damn! That wa good Cali... It is JUST AS IT IS IN REALITY.. NO BS. EVERYONE COPY AND PASTE THIS INFO ON YOUR OWNER:S MANUAL!

1) hmmm ... opinion on what i should do with the m8s which are currently torqued to 35 lb-ft? should i back them out and retorque them to 24? or should i leave them as they are since it's seated with the gasket? which ones are which (m8 vs m10)? there were two black ones (bottom of the cover) and the rest were a different color (too tired for brain to think of the color) - two short that go at the top and the other four that go at the four corners of the middle raised section.

2) well ... maybe i'll go with that. not sure how the rubber o-ring will deal with that, but i have spares of the old style with crush washers. doesn't that seem high for aluminum? the last thing i want to do is mess up the threads for the drain/fill plugs after all this! :p

i updated my post above with some more info re: diff cover bushing mounts attached to the unibody). both of them needed to have their edges ground down, not just the most rearward one).

well, i don't want anyone else to find out they need to do this crap once they've already removed their old diff and are trying to mount the new one. we had a hell of a time and made extra trips to the farm & fleet (20 mins away) because i didn't know we'd need a grinder (i'm not an auto shop so i don't have unlimited tools at my disposal ... although i'm getting there, lol). i want to give everyone the straight poop too so they can decide if they really want to do this on their own car. after all the work i'd done up to that point, i sure as hell didn't want to put the old whining damn diff back in, lol ... we determined that just grinding off what we needed to was the best option and proceeded. i don't think it will really affect the structural element of the subframe.

Come to think of it, I believe all the E30 bolts are M10. I think the M8's only apply to E36's (non-ti). I searched for E36, so that makes sense. You should be OK.

Yeah, it does seem high. But that's the info I got according to Bentley & Ron Stygar's site. The crush washer is supposed to distort when you tighten it down. I wouldn't do 52 ft-lbs w/ the rubber o-ring, however.

thanks constant ... i feel more at ease now re: diff cover bolts (whew!). maybe i'll do the drain/fill plugs at the same (35 lb-ft). thanks!

Cali ti,
I was wondering if you had to grind because you had a vented diff cover, or if the regular diff cover will also require subframe grinding? I have a E30 diff in the mail right now so I'm trying to get everything lined up and hopefully get the swap done in two days (since that's the most I can take off in a row).

the top of the finned diff cover isn't any thicker. be aware of it the first time you attempt to fit it up there and mark where it hits (if it's going to) both on the mount brackets and the subframe itself. then grind and attempt to remount (i actually painted with rust preventative paint once we had it right).

hey guys. just to chime in, i just installed an mcoupe diff in my stock subframe, used my stock ti axles by swapping the diff output flanges with my ti ones(takes a whole minute to do) and everything bolted back up just fine. i didn't have to grind any of the subframe away. before this i had an e30 3.73 limited slip in there, basically the same way. i switched to the 3.23 mcoupe diff cause i felt the 3.73 was just a tad short for comfort on the street, plus 1st gear broke traction way to easily. honestly though, i think any 4 cyl with an open diff would benefit from a 3.73 e30 lsd swap.. they can be found relatively easily and they are not expensive at all.

I had the clearance issue with the diff cover bolt hitting underbody of the car. I had to loosen the 4 bolts that bolt the diff to the subframe and use a pry bar to get it to clear (remember to tighten the bolts again :? ). It made it without modifications, but it does make some nice contact with the underbody.

I had to shim my sensors. They were also seized into the wheel hub, so you might need new ones if you damage them.

The e30 325i axles I used fit perfectly, aside from the above issue of shiming the sensors. The tone ring is bigger in diameter.

well hey, at least i'm not the ONLY one with clearance issues, lol :) it's in there now ... and getting a decent workout daily :biggrin:

I'm contemplating doing the same thing; using the ti flanges with the 6-cylinder diff. Have you noticed any problems? I may keep it that way, or maybe swap the flanges and inner CV joints to the E30 style afterwards.

OK I'm prepping to do this swap and am still a little unclear on the parts required. I'm up in Canada so shipping for the specialty items is a pain and I'd like to get all the bits required the first time. Really can't afford to have my daily driver waiting on a hoist for an international shipment!

Sounds like the consensus is hybrid axels are not required so long as I have e30 axles in good shape? If this is true am I correct that I only need to pick up these two new parts and skip the CV circlips?

33 41 1 124 945 (x2) drive flange collar nut securing plate
07 12 9 964 672 (x4) driveshaft self-locking nuts

On pelican the 945 is showing up as a "lock nut rear axle" is this the correct part?

Are there any other parts not mentioned in the notebook procedure that I should consider buying?

http://www.318ti.org/notebook/diff_c...ion/index.html