Anti-Roll Bar Bushings

[Shipkiller]

I am currently on travel and can't get to my car. I have a question and hope that someone MIGHT have the answer. I don't think anyone has this data so will have to wait until I get home to remove one of them and measure them, so this is shot in the dark....

The front anti-roll bar (inappropriately called sway bars) is a 27mm bar so I am going to assume that the two rubber bushings are also 27mm.

Has any one measured the mounting hardware dimensions for these bushings?

[MFGJR]

Hey Ship,

Thinking about upgrading those bushings? Me too, and I've been doing some research. The brackets into which go the sway bar bushings are common to the Z4M and E46 M3--same part number front and rear per RealOEM--so M3 bushings should work so long as the bar diameters for which they are intended are right.

Now, the rear bars on the Z4MC and the M3 are the same (22.5mm), but the M3's 26mm front bar is smaller than the Z4M's 27mm. (Roadster guys, note that your rear bar is 21.5mm, I believe.)

Jamie at BimmerWorld scoured the Powerflex inventory, and brought some possibilities to me at VIR this weekend. I took home a pair of M3 22.5mm rear bushings which should drop right in, and a pair of M3 26mm fronts which I'm hoping to bore out to 27mm. I have some feelers out on how to accurately do that... (Ideas, anyone?) I'll report in once I get around to working it, but that'll probably be November.

I took some pics of the m3 front bushing. Sorry I didn;t have a metric tape handy, and note that the bushings and the tape were aligned; camera angle make it look otherwise. If you need something more precise, maybe stop by the local dealer up there and buy a bracket--I think list is around $4.

-Frank

[Shipkiller]

I have had several discussions with some knowledgeable persons about suspensions in general and specifically Z4M suspensions.

I do not believe the anti-roll bars on the coupe need to be upgraded. BUT I believe I can remove the two rubber bushings and replace them with something with less give.

I can find the proper sized bushings (27mm and 22.5mm). The new bushings come with new mounting hardware but since I am out of town until Nov. and do not have access to my car, I can't pull off the mounting hardware and measure them.

I am in no hurry, I am just doing a lot of research from my hotel room.

Frank, I am heading to VIR on Nov 27-28th. There is still room to signup...

[MFGJR]

Originally Posted by Shipkiller

I can find the proper sized bushings (27mm and 22.5mm). The new bushings come with new mounting hardware but since I am out of town until Nov. and do not have access to my car, I can't pull off the mounting hardware and measure them.

I am in no hurry, I am just doing a lot of research from my hotel room.

Frank, I am heading to VIR on Nov 27-28th. There is still room to signup...

Jay,

Who's bushing are you looking at? I'd sure like to find an easier alternative to modding the Powerflexes that I have.

I'll have my car in the air this weekend, swapping back to the street brakes, and can take a look at the stock mounts then. I guess the critical dimensions are (i) the spacing between the OE bracket's two mounting bolts, (ii) the bushing's base to bore-center distance, and (iii) exterior clearance around the OE bracket on each side. Anything else?

Can't make it to VIR in November--think I'm done for 2011. Be there in February, though.

Frank

[MFGJR]

Looks like these 27mm Racing Dynamics urethane front bushings should work without new mounting hardware:

https://racingdynamics.com/eStore/in...968246100.html

Per RD, these are replacement bushings for their 27mm E46 front sway bar kit, and that kit doesn't appear to come with new brackets. So, I assume that it uses the OE brackets, and that the replacement bushings for this kit fit the OE E46 brackets:

http://www.racdyn-usa.com/Merchant2/...ry_Code=e46sus

The OE Z4M front bracket (p/n 31 35 1 094 552) looks to be common to the Z4M (and 3.0si) and all E46s:

http://bmwfans.info/parts/catalog/31351094552/

Should work, yes?

Frank

[MFGJR]

Ship,

Don't know if you're back home yet and have looked at your car...

Swapped brakes yesterday and took a couple pics on the driver's side. Couldn't accurately measure the bolt spacing without removing the bracket, but confirmed that there's plenty of vertical clearance around the bushings. Maybe these will help.

I ordered the Racing Dynamics fronts, and will use the Powerflexes on the rear. It's going to be next month before I can get to the install--gotta get past Street Survival, and then fix a couple things on on one of the E46s first. Stay in touch on what you're doing.

[MFGJR]

Ship,

Don't know if you're back home yet and have looked at your car...

Swapped brakes yesterday and took a couple pics on the driver's side. Couldn't accurately measure the bolt spacing without removing the bracket, but confirmed that there's plenty of vertical clearance around the bushings. Maybe these will help.

I ordered the Racing Dynamics fronts, and will use the Powerflexes on the rear. It's going to be next month before I can get to the install--gotta get past Street Survival, and then fix a couple things on on one of the E46s first. Stay in touch on what you're doing.

[Shipkiller]

No, still in CT.

We just powered up the Combat Systems on SSN-780. It has taken us three days just to troubleshoot all the issues with a new system. Oh the joys of being a deck-plate engineer.....

I have not driven my car since Aug. Driving a stupid Chevy Cruz.. The car is ok, the Transmission SUCKS large A$$

[Jumbosock]

Great thinking and internet research guys! Not a bad way to tighten things up for under a hundred dollars total!

[MFGJR]

Originally Posted by Jumbosock

Great thinking and internet research guys! Not a bad way to tighten things up for under a hundred dollars total!

Also dropped in a set of TMS RTAB limiters ($90), which seem to make the back end a bit more composed, and BW front camber shims ($25) for some front-end bite. And, I have GC RSMs ($98) waiting to go in, too. A few more inexpensive ways to sharpen things up. Gotta look some more at other opportunities in the rear suspension and subframe, and if Rogue will come through on the FCABs....

http://www.turnermotorsport.com/p-96...-shim-kit.aspx

http://store.bimmerworld.com/e36-fro...-kit-p610.aspx

http://store.bimmerworld.com/ground-...unts-p106.aspx

[inTgr8r]

Originally Posted by MFGJR

Also dropped in a set of TMS RTAB limiters ($90), which seem to make the back end a bit more composed, ......

Had you considered the R.Eng RTAB bushings at all?
I was thinking about using the TMS limiters as well until I came across the R.Eng. bushings

[Caddyshk]

Interesting...

[MFGJR]

Originally Posted by inTgr8r

Had you considered the R.Eng RTAB bushings at all?
I was thinking about using the TMS limiters as well until I came across the R.Eng. bushings

Yeah, definitely thought/am thinking about urethane RTABs like the REs. Tried the limiters first because it's an easier DIY as you don't need to press bushings in/out of the trailing arm to install them. Getting all the plastic bits out of the way to drop the brackets is a PITA for either task, though--about three times the number of pieces needed to get the job done, and maybe six different types/sizes of fastneres. Must've had a lot of miscellaneous leftover parts laying around Spartanburg that they wanted to use up!.

So far, I'm very happy with the limiters. No increase in NVH, and the car is noticably more composed on hard accel and braking. Now, this is a car that has a stock drivetrain and suspension, and gets tracked a few times a year on street compound rubber... your mileage may vary.

[inTgr8r]

Originally Posted by MFGJR

Yeah, definitely thought/am thinking about urethane RTABs like the REs. Tried the limiters first because it's an easier DIY as you don't need to press bushings in/out of the trailing arm to install them. Getting all the plastic bits out of the way to drop the brackets is a PITA for either task, though--about three times the number of pieces needed to get the job done, and maybe six different types/sizes of fastneres. Must've had a lot of miscellaneous leftover parts laying around Spartanburg that they wanted to use up!.

So far, I'm very happy with the limiters. No increase in NVH, and the car is noticably more composed on hard accel and braking. Now, this is a car that has a stock drivetrain and suspension, and gets tracked a few times a year on street compound rubber... your mileage may vary.

I hear ya!
I'm not looking forward to that job.
I've seen one DIY & it sure does look like a PITA.

[MFGJR]

Originally Posted by inTgr8r

I hear ya!
I'm not looking forward to that job.
I've seen one DIY & it sure does look like a PITA.

Oh yeah--careful about pre-load on the reinstall, too, whether limiters or new bushings. It might be easier to get it right with the car sitting on the ground (but who's that skinny?), or maybe on a four-post lift, when torquing the arms back into the brackets. And circling the bracket bolts with a paint marker prior to disassembly, per the TMS instructions, is a neat trick to keep the alignment right.
http://www.turnermotorsport.com/page...rm_limiter.pdf

Good luck with the install.

[inTgr8r]

Originally Posted by MFGJR

Oh yeah--careful about pre-load on the reinstall, too, whether limiters or new bushings. It might be easier to get it right with the car sitting on the ground (but who's that skinny?), or maybe on a four-post lift, when torquing the arms back into the brackets. And circling the bracket bolts with a paint marker prior to disassembly, per the TMS instructions, is a neat trick to keep the alignment right.
http://www.turnermotorsport.com/page...rm_limiter.pdf

Good luck with the install.

Good point about preload.
I have stands for things like that.

[F360C]

Originally Posted by inTgr8r

I hear ya!
I'm not looking forward to that job.
I've seen one DIY & it sure does look like a PITA.

Its not to bad. It took me about two hours to do my brothers the first time. After I knew what I was doing I was able to crack mine out in just over an hour. An extra set of hands def helps.

[Shipkiller]

RTABS were my first research component before I started into the anti-roll bar bushing mounts..

Talking with my local shop, he told me to stay away from the Turner Aluminum limiters. Not because they don't work or are faulty, because you have to grease the aluminum regularly or they will bind.

Since he was on of the mechanics on the Bimmerworld Race Team before opening up his shop, he pointed me to this: http://store.bimmerworld.com/powerfl...-rtab-p91.aspx

He says that they perform better than the original RTAB with a limiter. So far his advise has be spot on....

Just something to think about.

[inTgr8r]

^they look very much like the R.Eng bushings.

FWIW, One thing I like about the R.Eng RTABs is that they have a grease trap built in.
And "Both compounds now incorporate a silicone impregnated, polyurethane compound." (less squeaking)

[MFGJR]

Black Friday means the girls go shopping, and leave me to spend some quality time with the car. Beat the Hell out of going to the mall!

I've had the pile of urethane bushings sitting around waiting to go into the car--the Powerflex rear sway bar bushings, Ground Control rear shock mounts, and the Racing Dynamics front sway bar bushings. Already had the Turner RTAB limiters in there, and got the PowerFlexes in last weekend while the mufflers were off the car. Installed the RSMs and the front sway bushings today. Those RD bushings were a bitch to get on the bar--I'll post some info on all the installs soon. But, they do fit!

Just wanted to provide some qualitative feedback on all this... Nothing was worn out (car has 28K on it), and I swapped stuff out really just to add that extra half-ounce of stablity at the track. I didn't expect to actually feel any difference. However, after a 6/10ths or so back roads test drive, the car feels noticeably "nicer." Hard to describe, but it feels better damped, more linear in its motions, and less clunky. I'm really happy with it.

Now, if someone would come through with FCABs!

[Finnegan]

Great thread!

[MFGJR]

Hey Ship--where'd you end up on the front bushings?

Hope you and Randy are having a ball at VIR!

F