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My suspension bushings were last done about 8 years / 100k miles ago, didn't want to do it ever again, AND I had a friend send me a set of delrin FCA bushings from his race car when he switched to E46 arms / bushings.
Also, I couldn't quite get to zero toe in back on one side, a problem that gets worse when the car is lowered. I found some offset delrin rear bushings from Garagistic that let me get to (and even PAST zero toe) and was finally able to get the rear set to zero.
The install was a massive pain and doesn't lend itself to any sexy pictures, but wasn't overly complex. However, it did require a lot of drilling and grinding - both to get the old bushings out and to get the poly ones in. Removal has been covered ad-naseum, but install of the delrin bushings as a little different. The fronts went in easily with a little tapping with the deadblow, but the rear Garagistic offset bushings were crazy tight to get into the rear arms, as well as being crazy tight to get back into the RTAB plate
Especially with the limiters still in place (which were still recommended by Garagistic despite their seeming redundancy now), whose necessity was debatable after switching away from the factory rubber, the whole process took a lot of effort and some light grinding of the edges to get things started / pulling on the mounting plates to make them just a little wider.
It took me two very late nights to get everything swapped (wife's out of town - needed to keep the car drivable), but the end result is significantly better than I expected.
My only reservation was about additional NVH. The websites that sell polyurethane and delrin parts like this will usually have a soft and hard poly and the delrin, and tell you the delrin should only be used on a race car. My Vorshlag poly motor and tranny mounts are extremely sensitive to how tight they are cinched down as far as transmitting NVH into the cabin, and these suspension parts don't exactly have an option to not be cinched down tight. But the only thing I've noticed so far is a little more booming over big imperfections like expansion joints, which are pretty rare where I live.
The car was previously very drifty in first and second gear. Wasn't a bad thing - I quite enjoyed it. But even just taking off from a standstill, I could never put the power down in first. I didn't feel like I was making enough power to justify getting loose in first gear in ideal conditions (I do have a 3.38, LTW flywheel, and much lighter than stock Arc-8s, but still - I don't think that should have been enough to make the rear end loose). I've only driven a little last night and this morning, but this seems to have completely erased that.
Secondly, I thought the car handled well before I did this, but I didn't have much to compare it to. All my friends have fully prepped race cars, so I've never really driven another street car - massaged or not. But I have friend from work who has a '97 sedan in SF, and he drove it when he was out here a few weeks ago. He has a Dinan suspension on his car, and commented that while it has more outright grip than his car (my wider / lower offset wheels to credit there), it didn't turn in quite as precisely as his car.
So I may not have realized how loose it was before hand, but the before / after difference is tremendous. This thing is just laser precise now. I did a ZHP rack swap / E34 steering joint last year, but I am probably only just now seeing the full benefit of all of that work.
I'm thoroughly impressed and happy about the near complete lack of tradeoffs and the improvement to the car.
And I'm hoping this is enough to keep me from trying to add the outstanding bolt-ons (cams, injectors, RHD ITBs) for at least the next couple years.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
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There was a guy here years ago, Brent930, who had delrin rtabs made. He said they were miserable and took them out. It seems to me you want some compliance there or articulation through a bearing in a holder like some companies sell. Are you saying there is no drawback in terms of NVH?
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Just driving around the neighborhood last night after the install and going to the store this morning, there was no difference at all except one place where they cut the curb down to make a through street. About a 1" lip like there is pulling into a driveway. That spot made a little more of a "boom" than it used to. But it was already making a decent "thud" so very little worse, if really at all.
I have poly motor / tranny mounts and a LTW flywheel, so I've already got a decent amount of cain noise / vibration. This is less difference than the motor mounts / tranny mounts made, and way WAY less than the flywheel.
I was honestly surprised. Especially given how tight it was going in - I was a bit concerned I'd be reversing it as I put it back together last night. But the friend with the race car said he didn't notice much difference either, way back when he went to delrin, so I went ahead.
As always, your mileage may vary, but I probably wouldn't have done the flywheel if I could do it again, and I'd easily do this again.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
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I don't use delrin, but I've found with the stiff poly that in the big scheme of things the FCAB/subframe/diff bushings don't really add much in the way of NVH, with the exception of some mild diff whine at certain speeds. The vast majority of my added NVH is from the poly motor and trans mounts, which are the same ones you have. I've never had a desire to do a lightweight flywheel based on the feedback I've seen.
Any reason you went with delrin FCAB/RTAB's instead of one of the monoball bushings out there? I'd think the NVH would be somewhat similar, but the monoball would allow more optimal articulation, especially for the RTAB.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
Member
Love the precise feel of tight, solid suspension pivot points...
But I don't understand using delrin or poly for RTABs. That joint has to articulate in multiple axes as the trailing arm cycles up & down. Delrin will bind and transfer twisting motion directly to the RTAB console brackets. I use Ground Control spherical RTABs. Sphericals are the same concept (dead solid toe adjustment with zero flex) but they allow free movement in all axes. I'd run spherical/monoball RTABs on a street car with no complaints. They don't seem to add a ton of noise. Actually something like the Bimmerworld sphericals look super appealing. The sealed design is good for a car that gets daily driven in different weather conditions.
Up front I use delrin FCABs (front control arms only rotate in one axis). I feel like those don't add a ton of NVH either. They're complete overkill for the street but I found they helped in braking for track use. Delrin FCABs are something I'd consider for a dual duty car.
^ Totally agree with that observation. In my experience transmission mounts and lightweight flywheel have the biggest effect on noise. Engine mounts less so. Diff mounts about the same as engine mounts. Subframe mounts make less difference than any of the above.Originally Posted by blckstrm
^ You prefer zero toe in the rear? I can't deal with it. Way too squirrely under acceleration for my taste. Can't get the rear end to stay planted!
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You risk tearing the body bracket nutserts out of the body running solid Derlin RTABs.
RTABs need to oscillate in several planes as the suspension compresses/rebound.
Use a rose joint or mono ball if you must be solid.
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Last edited by bluptgm3; 06-20-2018 at 11:29 PM.
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I just installed these. Car feels really good now i didnt notice any NVH but i only drove it a few miles before adding umhw solid motor/trans mounts now i cant hear/feel anything.
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I'd have honestly preferred some poly mounts, but the only offset RTABs were the delrin ones. I may dial it back a bit now that I can fine tune it, but I was only able to get to zero on one side before I did this, and not the other. Now that I can get them both to zero, I may dial them back a bit. But I do like the rear end being a little loose, so I'd probably wait to dial it back until I start spending more time on track again. I have several little kids, so just not the right time for that right now.
Having said all of that, the rear end is more planted that it's been the whole time I've had it at zero with the rubber RTABs. It actually feels like it doesn't want to get sideways anymore, and never breaks traction in a straight line like it used to (obviously because at least one of my rears was in pretty bad shape).
I reinforced the RTAB pockets a couple years ago, so I'm not concerned about having trouble back there.
Hopefully this merges the double post - I never know when it'll do it automatically or when it'll just leave a double-posty mess.
I did reinforce the RTAB pockets a couple years ago, so I don't think I'll have any problems. But definitely something to keep an eye on.
I should also probably figure out why the two sides are so different that I need offset bushings on one side to match the other side. I've loosened the subframe in the past to see if it will shift a little to even things out, and it doesn't move at all. This feels kind of like treating a symptom rather than the real problem, but I've checked everything I can think of and can't find a reason the two sides are different.
Any thoughts on that?
Last edited by blckstrm; 06-21-2018 at 11:38 AM. Reason: Merged double post manually
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
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I would think 0 rear toe would make the car squirrelly under braking.
Member
Rear should have some toe for stability.
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Yeah even for track/race use people generally still have rear toe-in, often the factory recommended 1/8" inch or so. Without it you lose a lot of rear-end stability, and when the rear gets loose it will be more prone to spin you around rather than being controllable/recoverable.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
Wait, what?
100% agree with Poly and Delrin not being a good option for street. I have run nearly every combination on multiple BMW's over the years, and the only place I ever use Poly for, is the rear sub-frame. Every other application on a street car is horrendous, and makes the car drive like crap. It is not a pleasant experience unless you have glass smooth road, which if you live in the United States does not exist.
RTAB's should be rubber with limiters, anything else is ludicrous when going over expansion joints. Small imperfections on the road become magnified 10x by poly RTAB's. I've had the UUC RTAB's, Powerflex street, and AKG. Never. Ever. Again.
Poly motor mounts may seem like a great upgrade coming from mounts with 100k+miles and 20 years of heat cycles, but if you replaced them with OE mounts, I promise you would enjoy them MUCH more than any aftermarket mount. They feel amazing.
Transmission mounts are my biggest complaint, and anyone who runs poly transmission mounts is a brave sole. What everybody should be running is the E21 mounts. Part number: 23711175939 They require a bit bigger hole to be drilled, but my god it is the best street mount available. I believe they cost around $3 each. The other alternative I've enjoyed is the Rouge Engineering mounts, and those are a direct bolt on. Very firm, and no crazy vibrations or noise.
FCAB's are way too rough with poly or delrin for normal roads. If you're going to do delrin go ahead and just do the treehouse racing model control arm mounts, it's going to feel the same and at least it looks pretty. For a street car go with the upgraded solid rubber control arm bushings. They will last twice as long, have amazing steering input, and don't feel like you're about to lose a wheel when you go over a pothole or a uneven pavement.
For a street car keep fresh rubber mounts. They are 100% the best option.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
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I've had delrin fcabs and while they made my car steer like a go cart they were so harsh for street driving (oh! that's what you mean by race part?!). I replaced them with stock rubber/metal ones. I have delrin at the center diff bushing. There is some increased vibration/humming from the diff but it's not so bad. Rtabs are stock rubber/metal with delrin limiters is the only other location where I have delrin for a street car. All other bushings/ball joints are rubber/metal.
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Yep. Poly can be ok for non-moving bushings like subframe, diff mounts, etc. if you have a tolerance for the added NVH. But the binding and high friction of poly makes it a terrible option for suspension pivots that need to articulate... especially for something like E36 rear trailing arms that have to rotate and twist as the suspension cycles up & down. I learned my lesson after installing poly control arm bushings in a Miata. It felt good for a couple hundred miles until the grease got squished out. Then friction went through the roof and the suspension literally stopped working. After a short time the control arms couldn't be be moved by hand. The ride was uncomfortable. Cornering became wildly unpredictable because the suspension didn't react at all except for the largest bumps. I yanked the poly crap out, went back to stock rubber bushings and good handling returned. I can't imagine using poly pivot bushings any more, in any car... they're awful.
This is the best advice. I think most people go with poly because it's easier to install. And then after doing the work nobody wants to admit they made things worse than stock. These cars with good condition rubber mounts are pretty friggin' awesome on the street.
Stubborn Approach Racing
0 toe is perfectly fine. It has never been an issue for me, at any track, at any speed.
OP, I found that the Garagistic delrin took about 1k miles to calm down on the NVH. YMMV of course.
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I have Poly/Delrin on every single bushing except adjustable lca and diff. I used to have solid aluminum on my diff but i cracked the diff cover and it was replaced with rubber. Maybe its because I am young, but i do not really notice any NVH. I also have a Ltw flywheel and that chattering is the only real noise i hear as i do not have a radio. The car is 90% set up for DE and track days, but I drive it to events (cars and coffee) and the track. I want a car that sounds and feels raw. I have that and couldn't be bothered to go back to rubber, I have a dd for that.
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I just signed up for the synchro design works spherical bearing group buy. It’s a sealed bearing bushing/balljoint/monoball in an aluminum housing. Basically like a rear control arm bushing in a larger housing to make it the size of the rtab. Dinan, Bimmerworld, AKG, VAC, Ground Control, Turner, TCK, Gorham, Nerp and others sell similar rtabs.
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I'm with you - I love having zero toe. The car turns in better, is quick to change direction, but has never been unstable under braking or at speed, and no longer breaks traction in 1 and 2 now that I've done this.
They were so tight going into the plate (with the shims in place) that they scraped all the grease off - they were squeaking terribly by day 2. I pulled them, greased them again, put them back in, and it's great now.
So I have no NVH complaints already. The little bit of booming I noticed seems to have quieted down already (that or I'm used to it already. And that could have been the grease issue, too). Either way, it's no trade-off in my mind.
The car just feels sharper; no downside.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
Member
In the rear? Whats the benefit? Im at 0 front and .1 per side toe in rear.
Member
Yeah I don't understand zero toe in the rear. It shouldn't have any effect on turn-in; that's front toe. Dialing out rear toe or running toe-out in the rear will make the rear end easier to break loose. I guess that might make it easier to throttle-steer and slide the rear end around a corner, but that's a delicate balance unless you're wanting to drift or you have a RWD car without much power like a Miata or something. My understanding is as power goes up a RWD car will want progressively more rear toe-in in order to keep the rear-end stable and facing the same direction as the front wheels.
Also, all this talk is basically for race car setup. I don't think it's a good idea to do something like take out rear toe on a car which is driven in traffic on the street. The car will be less stable and easier to spin in adverse conditions like rain or during an evasive maneuver.
Last edited by TostitoBandito; 06-24-2018 at 03:21 PM.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
Apprentice w/#yrs. exp.
I feel that on most e36-e46 type of suspensions on BMWs,
toe settings for DD street vehicles, should be about :
1/16" Total toe-Front
1/8" Total toe-Rear
Camber about -1° Front and rear
Member
Anyone who has questions and hasn't read this should start here.
https://www.bimmerforums.com/forum/s...or-your-E36-M3
Even if you've read it, he's added some comments over the years, including another edit last week.
Joe said:
"Since 2013 I've been running 0 toe all around.
I use rear toe as a bit of a tuning tool, if the car is loose I'd run as much as 0.20 total toe in. If the car could use more rotation, I'd run 0 rear toe."
Also germane to the discussion are the Delrin bushings. Without the flex expected of rubber bushings, you can run less static toe and still have the same dynamic toe (not that you could ever measure dynamic toe).
YMMV. Your car might need some toe in. Mine does not. You might prefer it better with some toe in. I do not.
My car is stable at high speed (we have an 85mph toll road down here, so near 100mph runs are fairly common), while braking, turns in nicely, and will rotate a little more with some gas - it's perfect for me, exactly how I like it.
Member
Those with zero toe in the rear for street cars, have you considered when driving in the rain? or making C turns in obstacle avoidance?
Apprentice w/#yrs. exp.
Exactly,
there are street settings,
AND there are track settings,
unless you like spinning into objects!
Member
I haven't noticed any difference. My car isn't darty or unstable in the dry or in the rain. It's just more responsive to inputs.
And for the guys who keep saying it's a street vs track thing: why? If it's responsive but stable on track, why is that a bad thing on the street? I'll admit it slides easier at zero toe, but it still takes a conscious (throttle) decision - it's not like the rear is just on casters all the time. It's a completely neutral setup.
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