[TC Kline Racing]

OP, I would also suggest looking at the M3 front tension arms and swap those out. The subframe bushings you have now give you about an inch of vertical play, so I would definitely swap those out as well. I would not recommend anything bigger than the M3 rear sway bar. If you get too big of a rear bar the car will be 'twitchy' on corner entry (on the track)and fundamentally will be slower.

[vasillalov]

I already have full M3 front conversion. I am now addressing the rear and the LSD.

So Delrin diff bushings and M3 subframe bushings --> Check!

What's the consensus on the RSB? Change it now, or change it when coilovers are ordered?

[MikeR1994]

Originally Posted by vasillalov

I already have full M3 front conversion. I am now addressing the rear and the LSD.

So Delrin diff bushings and M3 subframe bushings --> Check!

What's the consensus on the RSB? Change it now, or change it when coilovers are ordered?

I'd change over to an M3 rear sway bar because the amount of labor involved in getting to it would just not be worth it if that were all you were trying to install. It's not a fun job at all. The M3 bar definitely isn't going to be too stiff, and I doubt many people find it too soft. Probably why it was put on the M3 in the first place.

[cvc 22349a]

Originally Posted by vasillalov

I already have full M3 front conversion. I am now addressing the rear and the LSD.

So Delrin diff bushings and M3 subframe bushings --> Check!

What's the consensus on the RSB? Change it now, or change it when coilovers are ordered?

Some track drivers have taken that rear M3 bar off of non-m cars. Lot's of threads here on the rear anti roll bar going back 6 yrs. I went with the bmw e91 14mm rear roll bar since the subframe was coming down for the bushings. To do it again, I would have installed the e93 15mm rear bar but not the m3 rear bar. Ask Berk racing, HPA or 'CJ421'. There are others who r/r the oe rear bar.

[CALWATERBOY]

Originally Posted by vasillalov

...But I will be installing an LSD. That's the reason why I am taking all the trouble.

My first mech mod; still tops the list.

[CALWATERBOY]

Originally Posted by vasillalov

So question: If I am dropping the subframe to install M3 bushings, wouldn't it make sense to upgrade to M3 sway bar since the subframe is already coming off?

Yes.

But bear in mind: First subframe drop's a meticulous job. Thereafter, nothin' to it.

M3 sway an easy job w/3-4" drop. How are you getting the 2 part bushings together on the bar?

[serotoninsteve]

Originally Posted by CALWATERBOY

Yes.

But bear in mind: First subframe drop's a meticulous job. Thereafter, nothin' to it.

M3 sway an easy job w/3-4" drop. How are you getting the 2 part bushings together on the bar?

I did my rear m3 bar about a year ago, make sure to also get the m3 stabilizer support brackets as they are different from the non M's.

Put the 2 piece hardrubber bushings on the bar (take care on the orientation and don't grease the exterior) and press them together with the stabilizer support using a vice.
They'll snap together and stay on the bar while installing. Put a bit of silicone grease between the rubber and the bar to easily adjust to the threaded holes in the subframe when the bar is in place.

[vasillalov]

Originally Posted by CALWATERBOY

Yes.

But bear in mind: First subframe drop's a meticulous job. Thereafter, nothin' to it.

M3 sway an easy job w/3-4" drop. How are you getting the 2 part bushings together on the bar?

I do not know. All the work will be done in a shop, not by me.

[materialdistractions]

Originally Posted by vasillalov

I do not know. All the work will be done in a shop, not by me.

If you don't mind sharing, what shop are you using to install the LSD? I'm in the Chicagoland area an was toying with getting an LSD also.

[MilehighM3]

Originally Posted by crypticc

Won't upgrading the front arb without doing the rear just induce large amounts of under steer?

Yes. Having done the M3 mods a step at a time I can attest to this. Loads of understeer without upgrading the rear sway bar. Night and day difference with an upgraded rear sway bar. Just don't over do it like TCK says. Otherwise you have some serious oversteer issues on turn in. If you're running a well setup coilover, you may not need to upgrade the rear bar. Talk to the TCK guys, they have great advise on this.

How has no one mentioned that you don't drop the rear subframe to install an LSD? You sure don't need to, and it is not even suggested.
Overall for a track day/DD setup you're on the right track. LSD, subframe bushings and toe arms from Rogue or HPA. Rear sway bar if you're not running coilovers to avoid overlapping labor to install one down the road. Have you considered the Powerflex inserts for factory bushings? A lot easier to install then again, just do it right the first time!

[ashmostro]

Not to dissuade you from doing subframe bushings because it's almost a must-do mod for our cars..... but you do know that you don't need to drop the subframe to replace a diff right?

[vasillalov]

Originally Posted by ccbad

If you don't mind sharing, what shop are you using to install the LSD? I'm in the Chicagoland area an was toying with getting an LSD also.

I have a good friend who has been master mechanic for Loeber for over 20 years. I am taking my car to his indy shop. Touch base with me in 10 days and I'll let you know about costs and results.

[vasillalov]

Originally Posted by Bmw135er

How has no one mentioned that you don't drop the rear subframe to install an LSD? You sure don't need to, and it is not even suggested.

I am aware of that. I am also installing the M3 subframe bushings (for which you need to drop the subframe). In addition, I am getting the Grand AM delrin differential bushings.

[dblrguy]

I know it’s not my thread but thank you to all who are offering advice. I appreciate the shared knowledge.

[neilvosko]

Hey Vasil,
any update on the Delrin bushings.....i am hearing the thump now from diff and getting the weeping fluid so changing all the seals and thinking between the lockdown kit or delrin.

[ashmostro]

Just get polyflex. I did and no clunk with minimal nvh.

[vasillalov]

The delrin bushings are great. I would advise against the polyflex because either they will get softer with time or they will crack and shear.

I do get a bit of a whine with mine and the thump is almost always there, but I've gotten used to this and it is now part of my experience driving the car. I sort of enjoy and expect the thump as its a mechanical representation of the car actually working.

[Casca]

Don't have my Bentley manual with me, but really want to know. What is the most difficult part for completely removing a rear subframe?

Its just basically remove tires, calipers/brake lines, exhaust, abs/brake sensor, drive shaft connection to differential, top strut mounting, hardware holding the subframe....and what else?

[ashmostro]

...and don't drop it!



Also, safely release compression on the rear springs before unbolting the subframe, while you are removing the shocks

[Casca]

And parking cables, almost forgot. My springs are aftermarket, with weight off wheels, I don't think there is much if any compression on them. But I'll be sure to address that during the removal.

Anything else?

[Gugs]

Since when does installing an lsd involve lowering subframe?

-It doesnt

End thread

[vasillalov]

Originally Posted by Gugs

Since when does installing an lsd involve lowering subframe?

-It doesnt

End thread

Re-read the original post. I also had M3 bushings installed, for which you need to lower the subframe.