To LSD or not?

[d k]

Hi

Im looking for some advice on lsd options for my n54 135

Im not interested in the helical stuff, so only choices would be either mfactory plate diff or the 1M diff (which Inbelieve is the e93 m3 diff)

In the latter, I would need to tie it in with the dms to adjust the lock.

Is this even doable?

Looking for street and heavy track use (red group hpde, maybe some time attack down the road) on R comp type of grip.
Id be happy with a 1:55 at BW 13 for instance.

Something along those lines anyway.

Whats my best option for lsd (not mushrooms)?

[Ginger_Extract]

Originally Posted by d k

Hi

Im looking for some advice on lsd options for my n54 135

Im not interested in the helical stuff, so only choices would be either mfactory plate diff or the 1M diff (which Inbelieve is the e93 m3 diff)

In the latter, I would need to tie it in with the dms to adjust the lock.

Is this even doable?

Looking for street and heavy track use (red group hpde, maybe some time attack down the road) on R comp type of grip.
Id be happy with a 1:55 at BW 13 for instance.

Something along those lines anyway.

Whats my best option for lsd (not mushrooms)?

Just do the complete 1M/M3 rear end swap: diff, subframe, suspension, etc. I know plenty of locals with E90M3 doing mid-1:50's at Buttonwillow with stock rear ends and just coilovers and tires.
I wish I went that direction instead of going helical LSD and piecemeal suspension stuff. FWIW, I did a 2:01 on 255 RS3, helical LSD and coils with my 400HP 135i. Guessing with NT01 or similar I would be doing 1:56-57.

[d k]

Thanks for the info.

Ughhhh I hate helical lsds. I think they are worthless if you are pushing more than 40%

Isnt the me subframe a huge swap? I mean money wise?
Does the lsd need to be tied in to the dms?
Or is it not electrical?

Originally Posted by Ginger_Extract

Just do the complete 1M/M3 rear end swap: diff, subframe, suspension, etc. I know plenty of locals with E90M3 doing mid-1:50's at Buttonwillow with stock rear ends and just coilovers and tires.
I wish I went that direction instead of going helical LSD and piecemeal suspension stuff. FWIW, I did a 2:01 on 255 RS3, helical LSD and coils with my 400HP 135i. Guessing with NT01 or similar I would be doing 1:56-57.

[ShocknAwe]

Biggest issue is cutting and mating the drive shaft. Curious about more info on the rest of the job though.

[d k]

Originally Posted by ShocknAwe

Biggest issue is cutting and mating the drive shaft. Curious about more info on the rest of the job though.

To me the driveshaft is the easiest part.

Ive had custom ds made on many cars.

My biggest concern is whether to use the m3 subframe or not because thats the only way you can use the m3 diff right?

Does the subframe change the geometry at all?
Is it bolt in?
Lighter?
Stronger?

Or is it better to drop in an lsd into our existing diff?

David

[ShocknAwe]

Originally Posted by d k

To me the driveshaft is the easiest part.

Ive had custom ds made on many cars.

My biggest concern is whether to use the m3 subframe or not because thats the only way you can use the m3 diff right?

Does the subframe change the geometry at all?
Is it bolt in?
Lighter?
Stronger?

Or is it better to drop in an lsd into our existing diff?

David

Geometry is different, yes. Requires different lower camber arm, toe arm.

[d k]

Originally Posted by ShocknAwe

Geometry is different, yes. Requires different lower camber arm, toe arm.

Is there any data on what is different in the geometry?

Is it a bolt on conversion?

[ShocknAwe]

Originally Posted by d k

Is there any data on what is different in the geometry?

Is it a bolt on conversion?

I believe fe1rx covers it in one of his suspension threads

[drwillb]

I'm in middle of an M3 rear end swap. I can tell you that the M subframe looks more substantial and is made of all tubular pieces instead of box sections like the stock e82 subframe.

As for driveshaft, I wound up ordering a 1M driveshaft since finding a local driveline shop that was willing to take on the friction welded BMW shaft proved to be impossible.

If you add the cost of a used M3 shaft, new CV joint, and the cost of the work, you are not far from the cost of a new piece.

Another bonus from the rear end swap is getting the M3 brakes on the rear axles. Speaking of which, the M3 axles are much better than the 135i brings and built for much more power.

And yes, bring your $$$ to this project.

One last perk: tons of used M3 parts out there-- wheels, shocks, springs, rotors, BBK, pads

Lastly, if you do the rear end you will need to do the front end

$$$ + $$$

[vtl]

I've installed an M3 LSD into the stock non M subframe.

Info here
http://www.1addicts.com/forums/showthread.php?t=1148814

[d k]

I m still not sure Im getting the answers Im looking for....

What are the geometry differences and is there any substantuated difference n stiffness or weight?
Just because one looks 'boxy' and the other looks (totally) 'tubular' doesnt really mean anything to me.

Its been proven and tested that the 135 arms are every bit as strong as the M3 arms with the difference being in some of the bushings.
Straight, stamped steel can be very strong when comparing to curved aluminum...

What Id like to know is what are the benefits of doing the entire subframe vs replacing a diff?

Getting a wider selection of brake parts and coilovers is a very valid point and something that I can use in my calculation.

Are there any geometry differences!
If so, what are they!

D

[bNks334]

Originally Posted by d k

Is there any data on what is different in the geometry?

Is it a bolt on conversion?

M3 sub-frame produces more anti-squat. Can't speak for anything else. 1m/m3 rear-end swap from a wrecked car seems like the better way to go then upgrading everything. Especially if you can do the owrk yourself. Custom drive-shaft is the biggest expense and hindrance to me doing it though.

Beefier axels would also be a benefit, no? Would the M3 hubs be different? Beefier wheel bearings? Superior u-joints in the driveshaft? Possible superior linkage points of the rear arms producing a more performance oriented roll couple and COG?

I am sure there are a few benefits to the 1M/M3 rear end swap over just putting an LSD into a 135i...

Here is a relevant thread:
http://www.1addicts.com/forums/showthread.php?t=1380384

I'd say the M3 benefits from many more things than just the rear subframe that makes it faster on a track. Swapping in the M3 rear-end still doesnt get you the other half of the equation... the front end lol... Better steering, wider front wheelbase, more front tire clearance... there is plenty to note that would still put a M3 over a 135i on the track...

[d k]

I will be following your build thread in hopes of soing the same.

Let me know ifyou see relevant parts somewhere for sale

Originally Posted by drwillb

I'm in middle of an M3 rear end swap. I can tell you that the M subframe looks more substantial and is made of all tubular pieces instead of box sections like the stock e82 subframe.

As for driveshaft, I wound up ordering a 1M driveshaft since finding a local driveline shop that was willing to take on the friction welded BMW shaft proved to be impossible.

If you add the cost of a used M3 shaft, new CV joint, and the cost of the work, you are not far from the cost of a new piece.

Another bonus from the rear end swap is getting the M3 brakes on the rear axles. Speaking of which, the M3 axles are much better than the 135i brings and built for much more power.

And yes, bring your $$$ to this project.

One last perk: tons of used M3 parts out there-- wheels, shocks, springs, rotors, BBK, pads

Lastly, if you do the rear end you will need to do the front end

$$$ + $$$

[Griff500]

I installed all 1M parts from, most came from 2 donor cars with less than 5000miles on them. Front and rear of the car (including steering rack) was less than $1500, making the work quite cost effective

A few pictures here
http://s240.photobucket.com/user/Griff50078/story


I love the way the car drives now

[d k]

Your donor cars were 1M's? Or E9x?

Originally Posted by Griff500

I installed all 1M parts from, most came from 2 donor cars with less than 5000miles on them. Front and rear of the car (including steering rack) was less than $1500, making the work quite cost effective

A few pictures here
http://s240.photobucket.com/user/Griff50078/story


I love the way the car drives now