128i LSD Q/A

[chris_flies]

Originally Posted by desertman123

1, 1.5 and 2 way is how the diff locks on accel/decel

1 way is lock on accel, no lock on decel
1.5 way is lock on accel, partial lock on decel
2 way is lock as much as possible, really

For a daily, I'd go max a 1.5 way. A 2 way will have you chirping tires getting into parking spots. Not that that's bad but you'd chew threw tires with it

Also look into E93 M3 front/rear sway bar - real cheap and bolts right in

Next suspension mod will likely be a 28mm (same size as E93) front sway bar, and some heavy duty end links...

[E30ROB]

Originally Posted by chris_flies

Next suspension mod will likely be a 28mm (same size as E93) front sway bar, and some heavy duty end links...

That's is on the list as well, not sure if im going to run an upgraded rear sway bar or not.

[Z3SpdDmn]

Originally Posted by E30ROB

That's is on the list as well, not sure if im going to run an upgraded rear sway bar or not.

You will. The LSD, alone, will add some understeer. When you upgrade the front bar, you'll add significantly more understeer. I'd recommend an adjustable rear bar so that you can make some adjustment to suit your preference. I'm getting the Eibach from Bimmerworld. Just waiting for it to come in. Let me know if you'd like me to get you one, as well (I'm a retailer for BW).

[E30ROB]

UPDATE: 4/28/18

Ended up having an oopsie and wrecking the car. Attempted to go through insurance and long story short, I was mislead on my policy and they made some really low offers. I also supplied $14,253 worth of parts receipts for this car, and that's with absolutely no labor..

Ended up tweaking some driver rear control arms, two front fenders, driver side skirt, both driver wheels, and front bumper.

Took this opportunity to start the 1M conversion so I went ahead and ordered everything needed to do a full 1M front conversion correctly. $2400 in parts

Car will be down for a bit while I gather parts and fix myself at home. hopefully end of may shell be back on the road..

[chris_flies]

Originally Posted by E30ROB

UPDATE: 4/28/18

Ended up having an oopsie and wrecking the car. Attempted to go through insurance and long story short, I was mislead on my policy and they made some really low offers. I also supplied $14,253 worth of parts receipts for this car, and that's with absolutely no labor..

Ended up tweaking some driver rear control arms, two front fenders, driver side skirt, both driver wheels, and front bumper.

Took this opportunity to start the 1M conversion so I went ahead and ordered everything needed to do a full 1M front conversion correctly. $2400 in parts

Car will be down for a bit while I gather parts and fix myself at home. hopefully end of may shell be back on the road..

That's too bad! You have to post pictures is your results!

EDIT: I did an upgraded rear bar first (15mm from ECS) and it made the car feel much more tossable, but it still rolls a fair deal. I just ordered an upgraded front bar, and I'm really looking forward to getting it in the car...

[Ryan13]

Following the thread, but have a slightly different version of the question. I don’t post much, but some of you may have seen my build thread on a 128i track car. My wife has been running it for 2 years now, but I can’t seem to get her to successfully learn how to heel-toe, so I’m looking for a solution.

Potential “fix” is to get a 135i. I’m looking at a 2008 with steptronic. I believe the diff case is the smaller 188mm, similar in size to the 128i size. I also understand both are bolted...I know this is a 4 bolt on the 128, not sure if the same 4-bolt is on 135.

I purchased a 3.73 LSD for the 128 when I built the car. Will that possibly fit in the 135 steptronic? Is it just a flange change?? How difficult???

I know I’m going in reverse direction to this thread. Just trying to find out if I can reuse the differential in this 135i build. I know the easy answer...more heel-toe.

[gixracer]

Originally Posted by Ryan13

Following the thread, but have a slightly different version of the question. I don’t post much, but some of you may have seen my build thread on a 128i track car. My wife has been running it for 2 years now, but I can’t seem to get her to successfully learn how to heel-toe, so I’m looking for a solution.

Potential “fix” is to get a 135i. I’m looking at a 2008 with steptronic. I believe the diff case is the smaller 188mm, similar in size to the 128i size. I also understand both are bolted...I know this is a 4 bolt on the 128, not sure if the same 4-bolt is on 135.

I purchased a 3.73 LSD for the 128 when I built the car. Will that possibly fit in the 135 steptronic? Is it just a flange change?? How difficult???

I know I’m going in reverse direction to this thread. Just trying to find out if I can reuse the differential in this 135i build. I know the easy answer...more heel-toe.

A lot of questions here. Driver mod! Keep your 128, you will not get your money out of your build.
4 bolt 128 diff does not match to the 135 drive shaft. The “4 bolt” refers to the input flange not the actual bolted diff inside the pumpkin. The small 135 auto diffs have bolted gear rings to the diff.
Hope this helps, keep the 128 and practice the heel toe. Try just a roll over when on the brakes. There are tons of videos. I do the roll because of my foot postition because broken bone in my ankle from motorcycle racing.

[chris_flies]

Originally Posted by gixracer

A lot of questions here. Driver mod! Keep your 128, you will not get your money out of your build.
4 bolt 128 diff does not match to the 135 drive shaft. The “4 bolt” refers to the input flange not the actual bolted diff inside the pumpkin. The small 135 auto diffs have bolted gear rings to the diff.
Hope this helps, keep the 128 and practice the heel toe. Try just a roll over when on the brakes. There are tons of videos. I do the roll because of my foot postition because broken bone in my ankle from motorcycle racing.

My issue with heel-toeing on the track was that after a few laps, I had to push the brake pedal well past the gas pedal to slow effectively. That was on OEM F30 335i pads, so, yeahhh...

Now I've got EBC Yellows which should fix that. I hope.

[Ryan13]

Thanks for the response. If it were driver mod for me personally, then we wouldn’t have an issue...this is my wife who does 10-15 days per year. She can’t seem to master it and yes, the break pedal does “sometimes”get a little deep. I run PF08s, so it is not a pad issue.

I track between 35-40 days a year in a Z4M, but I drive the 128 every now and then. It will keep pace with most stock E36 M3s, so it is not a slouch on the track.

I know about the 4-bolt flange on the 128, I’ve installed, uninstalled the diff about 3 times now. But I have not been under a 135 steptronic. Is the geared flange on the 135 removable/replaceable/swappable to the 128?

I’m not concerned about getting money back out if the 128, not planning to sell it. If they become the next thing in BMW club racing, then I’ll cage it and use whatever the rules allow me to use...but that’s a different time.

Will the diff fit, with work if needed, or not? I get the 3.73 is not numerically ideal for a turbo 135, but the tracks we run are never in 2nd, and 5th is a given on the front and back straight at VIR.

[gixracer]

Originally Posted by Ryan13

Thanks for the response. If it were driver mod for me personally, then we wouldn’t have an issue...this is my wife who does 10-15 days per year. She can’t seem to master it and yes, the break pedal does “sometimes”get a little deep. I run PF08s, so it is not a pad issue.

I track between 35-40 days a year in a Z4M, but I drive the 128 every now and then. It will keep pace with most stock E36 M3s, so it is not a slouch on the track.

I know about the 4-bolt flange on the 128, I’ve installed, uninstalled the diff about 3 times now. But I have not been under a 135 steptronic. Is the geared flange on the 135 removable/replaceable/swappable to the 128?

I’m not concerned about getting money back out if the 128, not planning to sell it. If they become the next thing in BMW club racing, then I’ll cage it and use whatever the rules allow me to use...but that’s a different time.

Will the diff fit, with work if needed, or not? I get the 3.73 is not numerically ideal for a turbo 135, but the tracks we run are never in 2nd, and 5th is a given on the front and back straight at VIR.

The 135 is splined. The whole pumkin drops in. Earlier in this thread one of the posters swapped a pumpkin in. If I recall the pinion swap did not work.

[E30ROB]

Originally Posted by gixracer

The 135 is splined. The whole pumkin drops in. Earlier in this thread one of the posters swapped a pumpkin in. If I recall the pinion swap did not work.

Correct, the pinion swap was unefective.

What was needed was a 135I rear driveshaft half. I reused 128i CSB as I was in a pinch and it works great. Logged over 2500 miles of hard driving no issues. I even just wrecked the car and its back on the road now. Was down last month. Need to be more careful...

[chris_flies]

I have some questions, again. I'm planning to rebuild, myself, a 3.73 diff from a 328i/128i auto with an LSD unit. Leaning towards an MFactory helical diff for the drivability and refinement advantages. However, I'm slightly concerned about snow traction and the predictability of the helical-type units. I want to be able to hang the tail out controllably and stably on a wet backroad, for fun, and get as much grip and stability on-track as possible. So, my first question is, would a clutch-type LSD (1.5-way MFactory) be a better purchase for me? I'm kinda torn; they would both be a HUGE improvement over the crap that the car came with, but, the helical sounds like it has traction and predictability issues vs. the clutch-type, and the maintenance needs of the clutch-type are also of possible concern vs. the helical.

Another question regarding the actual rebuild; what hardware needs replacing? I'd be getting a donor diff with around 100k miles (definitely try to find the youngest one possible). I know that the output flange seals and ring gear bolts need replacing, but what other internal parts (bearing parts, etc.) would need replacing at this mileage?

This is intended to be a learning experience and a summer break project for me, and the car won't be out of service since I'll be keeping the car's original diff in-place. Thanks for any info and help you can offer!

[jcrane82]

I am in the same boat as chris_flies when debating between a 1.5 way MFactory and a helical MFactory. I only do 1-2 track days a year, but regularly have tail-out antics on the street and want predictability.

My experiences with a helical (TORSEN) differential were with a RX-8 6MT and a NA Miata. I thought both of those cars had great handling predictability at the limit, and both were a blast drifting though Wisconsin winters with.

My experiences with a clutch type differential is with my E36 M3. This car is also a blast to drift with and has fantastic predictability.

Honestly I don't even think I could tell the difference between the differential types when comparing the Miata/RX-8 and the M3 by driving them. Is the difference so small that it is only really noticeable in a track setting with slicks? Would I even notice the difference in the rain on 10 mph corners? Any help is much appreciated.

Thanks,
Jesse

[chris_flies]

Originally Posted by jcrane82

I am in the same boat as chris_flies when debating between a 1.5 way MFactory and a helical MFactory. I only do 1-2 track days a year, but regularly have tail-out antics on the street and want predictability.

My experiences with a helical (TORSEN) differential were with a RX-8 6MT and a NA Miata. I thought both of those cars had great handling predictability at the limit, and both were a blast drifting though Wisconsin winters with.

My experiences with a clutch type differential is with my E36 M3. This car is also a blast to drift with and has fantastic predictability.

Honestly I don't even think I could tell the difference between the differential types when comparing the Miata/RX-8 and the M3 by driving them. Is the difference so small that it is only really noticeable in a track setting with slicks? Would I even notice the difference in the rain on 10 mph corners? Any help is much appreciated.

Thanks,
Jesse

In the end, I went with the 1.5-way diff (and a 3.73 rear-end ratio upgrade). I figured that the additional fluid changes and maintenance would at least help me keep better in-touch with how my car is doing, and, like you, I wanted maximum predictability for occasional street antics.

I'm super happy with my decision. The car is wonderfully predictable, it dances around so controllably when you pass that traction limit, and makes second-gear corners SO much fun in the rain (and in the dry, depending on the pavement). It does clunk and make some odd noises when setting-off, but it's generally pretty civilized (unless it's cold or hot).

[E30ROB]

I love the Helical, locks up great in the wet and dry. About to do my first fluid change just because I was pushing the car pretty hard and driving alot in it. about 25k miles a year at this rate...

Still very quiet, no weird noises. I am also replacing subframe bushings with billet Turner mounts, and M3/135is OEM diff bushings filled with 80A polyurethane, should be a nice smooth ride with the PSS9 and the Helical

[Mobster_Lobs3r]

Hello, I wanted to mod my car for a while now I was looking at this exhaust ( https://www.carid.com/agency-power/s...833&url=445422 ) would it fit in my little 128 stock? Thank you for your help!

[chris_flies]

Originally Posted by Mobster_Lobs3r

Hello, I wanted to mod my car for a while now I was looking at this exhaust ( https://www.carid.com/agency-power/s...#38;url=445422 ) would it fit in my little 128 stock? Thank you for your help!

LSD Q&A here.

There are numerous exhaust threads to ask that in. The website also says "135i" for fitment.

[jcrane82]

I have received my M-Factory helical LSD along with shim kit and bearing kit. Installation is planned for this weekend, and I will report back with my experiences.

[jcrane82]

Finished installation of the M-Factory helical yesterday. I bought the ECS tuning diff rebuild kit that included seals, tapered roller bearings, and new ring gear bolts. I used the new seals and new bearings, but decided not to use the ECS tuning ring gear bolts. The OEM bolts are 12.9 and have knurling under the heads of the bolts, plus they look to be cold headed. The ECS tuning bolts are CNC cut, and do not have any knurling under the heads.

Installation wasn't bad, and I got extremely lucky and the 0.364 and 0.380 thick snap rings my OEM diff came with were reused without any shims to provide 0.008" backlash, so I didn't use the M-Factory shim kit either.

Initial driving impressions: The tail steps out nicely. I only have a couple hours driving on the new helical, so I am still trying to get a feeling for it. I have not coded off any electronic nannies yet, so that is on my list of things to do (including coding off e-diff). The lame OEM open differential is no more and the 128i feels like a proper car now! The M-Factory helical is quiet......like really quiet and makes ZERO NOISE. No clunking when putting into gear (I have a 6MT 128i). The oil I am using for break-in is Lucas synthetic 75w-90.

I will come back and provide more information as I spend more time with the M-Factory helical. I am also really looking forward to some snowy roads this winter for drifting fun!

[E30ROB]

Originally Posted by jcrane82

Finished installation of the M-Factory helical yesterday. I bought the ECS tuning diff rebuild kit that included seals, tapered roller bearings, and new ring gear bolts. I used the new seals and new bearings, but decided not to use the ECS tuning ring gear bolts. The OEM bolts are 12.9 and have knurling under the heads of the bolts, plus they look to be cold headed. The ECS tuning bolts are CNC cut, and do not have any knurling under the heads.

Installation wasn't bad, and I got extremely lucky and the 0.364 and 0.380 thick snap rings my OEM diff came with were reused without any shims to provide 0.008" backlash, so I didn't use the M-Factory shim kit either.

Initial driving impressions: The tail steps out nicely. I only have a couple hours driving on the new helical, so I am still trying to get a feeling for it. I have not coded off any electronic nannies yet, so that is on my list of things to do (including coding off e-diff). The lame OEM open differential is no more and the 128i feels like a proper car now! The M-Factory helical is quiet......like really quiet and makes ZERO NOISE. No clunking when putting into gear (I have a 6MT 128i). The oil I am using for break-in is Lucas synthetic 75w-90.

I will come back and provide more information as I spend more time with the M-Factory helical. I am also really looking forward to some snowy roads this winter for drifting fun!

Great to hear you had good luck with the installation!!!! I love mine, no noise or clunks and locks up perfectly wet or dry. I did not do any coding and it reacts perfectly. When I drive in the mountains I put the TC only halfway off and it will only interfere if it senses too much rear wheel spin. I have had it kick on and correct and it did its job so I didnt bother finding someone to code it for me.

[chris82]

Originally Posted by chris_flies

LSD Q&A here.

There are numerous exhaust threads to ask that in. The website also says "135i" for fitment.

How's the 28mm sway? Is that installed yet?

I was just about to put the eibach 28mm on tomorrow but UPS delivered my package to the wrong address so that's not happening LOL

[chris_flies]

Originally Posted by chris82

How's the 28mm sway? Is that installed yet?

I was just about to put the eibach 28mm on tomorrow but UPS delivered my package to the wrong address so that's not happening LOL

Oof...

I think it's awesome, it would be more awesome if I had some stiffer springs and, but I really like. No gain in understand like some fear, just a good improvement in responsiveness and stability, especially at highway speeds.