128i LSD Q/A

[E30ROB]

Building my 128i to have some fun, and the next step is LSD..

Instead of doing subframe swaps or sending my diff off, id like to see what other options could be had with a little work?

Looking into the Mfactory 135i LSD full pumpkin.
Does the 135i and 128i share the same pumpkin?
If so, would I just need to swap flanges?

Any insight is helpful!

My car: 2010 128i 6mt slicktop manual sport package

[gixracer]

Originally Posted by E30ROB

Building my 128i to have some fun, and the next step is LSD..

Instead of doing subframe swaps or sending my diff off, id like to see what other options could be had with a little work?

Looking into the Mfactory 135i LSD full pumpkin.
Does the 135i and 128i share the same pumpkin?
If so, would I just need to swap flanges?

Any insight is helpful!

My car: 2010 128i 6mt slicktop manual sport package

Different pumpkin on 135i manual(large). 135 auto is the small size different flange. You would be better off finding a spare 328i diff on the cheap and sending it out. Also the sub frame does not need to be dropped for a diff swap. Disconnect the half shafts and drive shaft then the three bolts with as jack underneath the pumpkin. I have yet to see anything on changing yokes

[asbrr]

I would add that for a 128i, a diff upgrade is usually one of the last few things one does as the power in question is not so much that the diff comes into play unless you have a really stiff rear swaybar and you're doing a lot of track driving.

Money into the rear subframe bushings and suspension will produce better bang for buck IMO.

Having said that, I do have an M-factory diff, as I got a great deal on a swap from a 328i. So yes, a 328i diff will fit right in.

[lowside67]

Do diff, rear subframe bushings, and rear swaybar at the same time. I have a Diffsonline built clutch LSD in my 128i and it's fantastic.

-Mark

[Suprgnat]

Originally Posted by lowside67

Do diff, rear subframe bushings, and rear swaybar at the same time. I have a Diffsonline built clutch LSD in my 128i and it's fantastic.

-Mark

I have a Diffsonline 3-clutch 3.64 with 35/60 ramps. I feel it and enjoy it every time I drive and will never have a personal car without an LSD again.

+1 on do it all at once. If I did it again, I'd go solid subframe bushings.

[chris82]

Originally Posted by Suprgnat

I have a Diffsonline 3-clutch 3.64 with 35/60 ramps. I feel it and enjoy it every time I drive and will never have a personal car without an LSD again.

+1 on do it all at once. If I did it again, I'd go solid subframe bushings.

Solid bushings won't improve anything on a 128i imho. They were designed for an M3 which has more of everything; weight, torque, power, grip, the list goes on. Just go with OE BMW

[Suprgnat]

Originally Posted by chris82

Solid bushings won't improve anything on a 128i imho. They were designed for an M3 which has more of everything; weight, torque, power, grip, the list goes on. Just go with OE BMW

I currently have M3 RSFBs and they were an improvement, but I now see no need to isolate the sub-frame from the chassis. There is only a marginal improvement in NVH with rubber bushings, stock or M3, introducing another point of undamped suspension deflection. No me, at least, it has nothing to do with the specific output of the engine. I'd do the same if I had a 120i or an S65 powered 1M clone.

[Bimmer-Bob]

Originally Posted by lowside67

Do diff, rear subframe bushings, and rear swaybar at the same time. I have a Diffsonline built clutch LSD in my 128i and it's fantastic.

-Mark

Originally Posted by Suprgnat

I have a Diffsonline 3-clutch 3.64 with 35/60 ramps. I feel it and enjoy it every time I drive and will never have a personal car without an LSD again.

+1 on do it all at once. If I did it again, I'd go solid subframe bushings.

+2. I went with a 3.73 LSD, poly RSFBs, and a beefy 20mm rear sway and the combined effect was pretty amazing. I love every drive I take in that car.

[E30ROB]

Originally Posted by Bimmer-Bob

+2. I went with a 3.73 LSD, poly RSFBs, and a beefy 20mm rear sway and the combined effect was pretty amazing. I love every drive I take in that car.

Did you have an LSD unit installed into your current diff?

I want to find an entire pumpkin ready to drop in..

[Bimmer-Bob]

Originally Posted by E30ROB

Did you have an LSD unit installed into your current diff?

I want to find an entire pumpkin ready to drop in..

No, I got a complete pumpkin with LSD and a 3.73 ring and pinion built by Jim Blanton (Performance Gearing). He didn't charge a core deposit, and didn't even want my core back (he said the 3.23s were very common, and not very desirable anyway). I had it installed right by you, at BPC, as I was living in NC at the time.

[Z3SpdDmn]

I'll be installing an LSD in my 128i in a couple weeks (Diffsonline 3.64 3-clutch by way of BimmerWorld). I understand there's a giant nut holding the driveshaft to the input shaft of the diff. What tool(s) will I need to remove this? Can anyone comment?

TIA.

[Suprgnat]

Originally Posted by Z3SpdDmn

I'll be installing an LSD in my 128i in a couple weeks (Diffsonline 3.64 3-clutch by way of BimmerWorld). I understand there's a giant nut holding the driveshaft to the input shaft of the diff. What tool(s) will I need to remove this? Can anyone comment?

TIA.

Hi, Anthony.

On the 128i there are just 4 old-school nuts and bolts.

Regards,

Paul

[gixracer]

Originally Posted by Z3SpdDmn

I'll be installing an LSD in my 128i in a couple weeks (Diffsonline 3.64 3-clutch by way of BimmerWorld). I understand there's a giant nut holding the driveshaft to the input shaft of the diff. What tool(s) will I need to remove this? Can anyone comment?

TIA.

So how are you connecting the 128 driveshaft to a 135 diff. 128’s are 4 bolts 135’s are a 50mm nut. That nut needs to be turned clockwise when you are looking backwards with your head under the driveshaft. For the 128 it’s simple by removing the 4 bolts.
If you need to get the nut off a 50mm harbor freight box works well. Shave about 1-2mm off to make it thinner.

http://www.e90post.com/forums/showthread.php?t=619618

[bionicbelly]

I am installing an LSD right now. It is really not that bad of a job.

On the bushings, go solid. I will be installing in my 128 this week, but on my Z3, solid subframe mounts, and front eyeball arms were the best thing I ever did to that car. The difference even from poly is immense. I like Condor bushings' stuff. NVH gain was negligible, and I can't even begin to explain how much more precise that car was after installing those.

[Z3SpdDmn]

Originally Posted by gixracer

So how are you connecting the 128 driveshaft to a 135 diff. 128’s are 4 bolts 135’s are a 50mm nut. That nut needs to be turned clockwise when you are looking backwards with your head under the driveshaft. For the 128 it’s simple by removing the 4 bolts.
If you need to get the nut off a 50mm harbor freight box works well. Shave about 1-2mm off to make it thinner.

http://www.e90post.com/forums/showthread.php?t=619618

I'm not. I HEARD that it had the giant nut. It sounds like that's the case on the 135i, but not the 128i. Great news! Should be a cinch.

I am planning on doing the diff bushings...
http://www.bimmerworld.com/Powerflex...-PFR5-426.html
http://www.bimmerworld.com/Powerflex...-PFR5-425.html

...and the subframe bushing INSERTS
http://www.bimmerworld.com/Powerflex...Track-Kit.html

Can anyone confirm if the subframe needs to come all the way out to change out the diff bushings? This is what I'm trying to avoid.

Thanks!

[bionicbelly]

I don't think it does. I know that a friend of mine with a 335 did it with the sf still in the car. I was not there to see it, and I think you need the bmw tool set to do it. you do have to lower it a ways to get the tool up on the back side, but you can do it.

Like I said, I haven't done it, but going a little bit further, and taking it (the sf) all the way out might make it easier on every front. It really was not that bad to do.

Also, do you still have a Z3?

[Z3SpdDmn]

Originally Posted by bionicbelly

Also, do you still have a Z3?

No, I don't. It went to my dad when I got a Z4 3.0si Coupe. It is now with my cousin when my dad got a Z435i Roadster. So, it's still in the family!

[bionicbelly]

Nice! I wrecked mine last year, but still have it. (going to rebuild for endurance) It ended up being a pretty capable car, with a couple of glaring weaknesses. I am hoping the 128 will address a couple of those.

[Z3SpdDmn]

Originally Posted by bionicbelly

Nice! I wrecked mine last year, but still have it. (going to rebuild for endurance) It ended up being a pretty capable car, with a couple of glaring weaknesses. I am hoping the 128 will address a couple of those.

My dream project, which I'm constantly on the look out for the donors for, is a Z3 Coupe with a BMW V12 with headers and straight pipes. I hope to do it in the not-to-distant future.

[Z3SpdDmn]

Originally Posted by bionicbelly

Nice! I wrecked mine last year, but still have it. (going to rebuild for endurance) It ended up being a pretty capable car, with a couple of glaring weaknesses. I am hoping the 128 will address a couple of those.

This inspired me to go look at what was out there..... and I may have just found my car. Just chatted with the owner and setting up a friend to go look at it for me!

[bionicbelly]

Nice! That would be an absolute demon wagon. The sounds...my god, the sounds...

Another question, Do you race with NASA GL then? I am mainly central, but I get to a few of their events. Going to NCM, autobahn, and at least one Mid-O this year. Thinking about gingerman also.

[Z3SpdDmn]

Originally Posted by bionicbelly

Nice! That would be an absolute demon wagon. The sounds...my god, the sounds...

Another question, Do you race with NASA GL then? I am mainly central, but I get to a few of their events. Going to NCM, autobahn, and at least one Mid-O this year. Thinking about gingerman also.

Yes, NASA GL is my home region. I didn't do any local races last year due to the PWC schedule, but I might do one this year to sort out the SpecE30 on the new coil-over kit that was just made legal. I'd probably do Mid-Ohio. Maybe GingerMan.
I do a lot of AER races, too.