harder rubber subframe bushings?

[cali-ti]

while doing my diff swap (which still isn't done yet, but that's another story), i noticed my rear subframe bushings are pretty well shot (can't believe that after only 207k miles! :p). does anyone know if harder (than stock) rubber subframe bushings are available somewhere? or am i limited to either stock or urethane?

TIA

[1996 328ti]

Road Race Technology told me to stick with stock rubber bushings. They lasted almost 200K miles on my car. Ireland sell polyurethane. What I am noticing is the car steps out a little more than it used to. This is because the old worn bushings had a bit of slop in them. New bushings will give a bit. I am not sure what the desired effect you want. Part of the reason the car is stepping out for me is because I have too much toe on the left side. Now that I have the solid bushings it is more pronounced. Of course, YMMV.

[cali-ti]

mine is a daily driver so i'm looking for longevity as well as better roadholding in turns, etc. i remember reading comments on the butt strut taking the wiggle out of the rear of our cars. i was wondering if the urethane subframe bushings would have a similar effect, but what you're describing may be worse off (although perhaps with the ireland camber/toe kits you'd be able to hook up better, i don't know). you race/autocross yours so you certainly have more experience. from what you said so far, i guess i would go with what road race tech said and put in stock bushings (unless harder rubber ones are available).

[CirrusSR22]

My Irelands have been in for about 1500 miles now and I'm very happy with them. The car is a bit louder, not really road noise, but you can hear the "gear whine" (diff/tranny/whatever) sound a little bit, but it's only when my auto tranny downshifts when I'm going really slow.

Also, I have a diff. pinion bearing that's been bad since I bought it, and I can hear it a little bit more now.

As you have probably read, the rear end feels more "planted" when taking turns and I totally agree. Surprisingly, I think the car actually rides smoother now. Maybe the harder bushing allow the suspension to take the bumps, versus the worn bushings moving to absorb some bumps??

I could see that my old ones were tearing/cracking badly. When I placed a jack under the rear subframe, the subrame would rise .7" up/down on it's studs.

[AlaskaBlue]

How hard is it to replace the subfram bushings? I was planning on geting coil-overs, new control arms, tierods, control arm bushings front cambe plates, and rear camber adjusters. Would it be easier just to get subframe bushings when I put all that on?

[CirrusSR22]

I took the entire subframe out to replace the subframe bushings and RTAB. It's actually not very hard to get the subframe out, but the bushings are a different story.

I welded and made a very beefy tool that started to work well, then it started to bent and all hell broke loose :(

In hindsight I ABSOLUTELY should have heated up the subframe bushing area before I tried to press them out! I ended up hacking up the area while beating/cutting/drilling/pressing/prying those damn things out. Nothing that really matters though.

Same with the RTAB's. Heat them first, like this http://www.mydig.com/auto/articles/ta_bushings/

[1996 328ti]

Labor was $300 for my subframe bushings. $300 for the trailing arm bushings.
Figure $65/hour. So that is 10 hours right there.

[cali-ti]

Cirrus, do you have their camber/toe kits installed on your subframe as well? your opinion of the urethane bushings seems to differ fairly significantly from steven's. it's obvious i need to replace my subframe bushings and i might as well have the other stuff done at the same time (RTABs, ireland eng camber/toe kits and turner rear sway bar tab reinforcements). ****, this ain't gonna be cheap :p the other question is if i can get it all done at my usual shop before i move to denver. i'm running out of time and money quickly! aaaaaaaaaaaahhhhhhhhhh!!!!!!!!!!!

[1996 328ti]

My opinion probably has something to do with toe on the left side.
If the rear was better aligned I'm sure it would be different.
I'll be at Mid-Ohi next month and that is where I will notice the difference.

[cali-ti]

i'm sure the urethane would last longer too (added benefit). not to sound negative, but i hope the issue you've encountered since having the urethane bushings installed IS due to the toe setting (so i can get urethane installed ;) ). i'll ask my shop what they recommend too (they race prep bmws and do some racing themselves).

[CirrusSR22]

Cirrus, do you have their camber/toe kits installed on your subframe as well?

Nope, I put in new OEM RTAB's while I was in there

[cali-ti]

cirrus ... so you have irelands polyurethane subframe bushing and stock rubber RTABs, correct? steven, you have ireland's polyurethane subframe bushings too and what are you running for RTABs and how long ago were those replaced?

[CirrusSR22]

Correct, but I have some Ireland non-adjustable RTAB's waiting for install just because I'm not happy with how the OEM ones went in. They sort of deformed a bit while I pressed them in. They seem to be working just fine though.

I think it's because I moderately scratched the inner surface of the trailing arm bushing hole, while I was trying to get the old ones out. Another reason I should have heated them up first :)

[1996 328ti]

I also replace the rear trailing arm bushings with polyurethane. 200K on the original and they were probably still good.

[pdxmotorhead]

Has anyone tried Poly with holes ? Usually you can "tune" bushings, by putting holes
in them to reduce the stiffness a bit... Sort of like the stock rubber front ones...

Dave

[cali-ti]

hmmmm ... interesting ... cirrus, when were you planning on doing the urethane RTABs? be nice to see what happened with you before i get everything installed :)

[pdxmotorhead]

I know a guy who makes poly bushings, gonna talk to him about this
next chance I get....
Dave

[cali-ti]

thanks motorhead (you're not a lemmy fan by chance, are you? :p ). any input is appreciated :)

[CirrusSR22]

hmmmm ... interesting ... cirrus, when were you planning on doing the urethane RTABs? be nice to see what happened with you before i get everything installed :)


Probably won't be for a month or two. I did the IE subframe bushings and OEM RTABs 3-4 weeks ago and I'm burnt out on taking my car apart, for now :)

[cali-ti]

lol ... after this diff swap, i COMPLETELY understand what you mean. but i have to do a full brake job very soon (including the parking brake cables), can't afford the time to wait (have to finish too many things before moving). no worries mate!

[cali-ti]

ok, here's what i ordered today from ireland engineering:

1) e30 urethane trailing arm bushings
2) e36ti urethane subframe bushings
3) e36 front camber kit
4) e30 rear camber kit
5) e30 rear toe kit

going to have rauch performance install all of them at the same time. may be without my car overnight while they do all that (and the turner rear sway bar mount tab reinforcements too). not sure when i'll be able to schedule it all, but it should be set for another 200k plus after all this shizat :)

[CirrusSR22]

Sweet! I'll be interested to hear what you think of the RTAB's.

[cali-ti]

the "problem" is that i'll be doing them all at once. it would be nice to see the effect each one has independently, but as steven pointed out before, not with the labor costs that are going to be involved with this kind of work. i will certainly let you know once the work is completed. the other bad thing is that my current subframe bushings are shot. replacing them with stock rubber could have the same feel as putting in the aftermarket poly ones, i will never know. i'll just have to rest easy knowing that it's all fixed up and most likely won't go bad in that area again for the remainder of its life :biggrin:

[pdxmotorhead]

thanks motorhead (you're not a lemmy fan by chance, are you? :p ). any input is appreciated :)

Naw,the nick comes from being in a 4x4 club with 4 davids that
all tinker with race cars..... We each ended up with and e-mail
alias that had a city and what we did most....
Too many beers probubly influenced the whole thing but I'm not admitting to anything... :)

[cali-ti]

here's a pic of my current subframe bushing(s): http://www.318ti.org/gallery/showphoto.php?photo=440&cat=500&page=1

nice, huh?

[cali-ti]

got my car back after <cough> $1440 in labor for all the mods. i'll comment here on the poly subframe and RTABs. this is after picking it up today just after noon and the few drives to lunch and home that i've done so far. the back end feels DAMN GOOD AND PLANTED! the e30 LSD is definitely a helpful and potentially big factor, but there is no sloppiness that i can tell at all. it feels tight and gives you much better feel going through corners at speed. they were also able to dial in camber/toe now that the adjustable kits have been installed. i've only begun to explore the new handling capabilities and i'm sure i'll learn much. stock 15's with potenza re950s (if i remember correctly) which aren't that impressive a tire and this thing can go through corners VERY nicely. i believe i have some more road noise being transmitted, but it is not at all bad ... and i currently have the complete rear interior out of my car which should help to dampen it when i reinstall that. my rear subframe bushings were starting to break down. rauch said they really would have been bad in a year or two (around the 10 year mark).

[1996 328ti]

Well, just got back from a weekend at the track.
Not sure if I noticed an improvement with the bushings. I do notice that the rear is more twitchy with R-rated tires on the street. Didn't seem any worse with R-comps. I will say they squeak like hell after my first session.

[cali-ti]

yes, i'm starting to notice the squeak myself. they came with some lube that's not supposed to wash away, but i'm guessing it won't last either. first day, i really didn't notice much. i notice it most in the morning when i'm first pulling out and backing into the shallow valley between buildings that's used for drainage. they squeak like an old man's joints ... which seems fitting since it has 208k now :p hopefully it won't drive me insane. once underway, the road noise pretty much seems to cover it up. anyone who finds polyurethane squeaking annoying though, may want to avoid using them. steven, don't you just have the poly subframe bushings and rubber trailing arm bushings? i'm surprised the squeaking is from the subframe bushings, i figured mine was pretty much all coming from the trailing arms.

[1996 328ti]

I don't know where the squeaking is from exactly.
After braking at 115 I heard something. I thought it was the car in front of me.
That was until the next lap and I heard it again and there were no cars around.
It no longer concerns me since I know it is normal. :(
BTW-I have the TABs and subs.

[cali-ti]

ah ... that's right, there was someone else who'd done subframe and was planning to do the TABs as well. so you're all poly like me (well, i'm all poly like you since you had yours done first). my guess is most/all of it comes from the TABs since i can't imagine the subframe ones move around much at all while the trailing arms are going to be pivoting frequently. considering the additional transfer of diff noise, road noise and poly squeak, i'm going to have to learn to tune a bunch of things out ... or perhaps put in some additional sound deadening material (of which i have quite a lot from a car audio project i was going to do on a previous car i owned that i never got around to doing). i agree with you though, as long as you KNOW what the sounds are and that they aren't bad, it's easier to deal with. i was hearing additional noise from my diff and took it to my shop for a test drive with one of them. i was either becoming more attuned to the noise or it was getting louder ... i was figured the damn used diff i put in was headed south. he drove it and said it's the ring and pinion, that it's normal and nothing to worry about. there's also a little slack in the used halfshafts i got which adds its own little clunk in there on shifts. i'll swap those out with bmw reman'd once i find it too annoying.

all that considered, how'd the racing go? do you prefer the poly subs/TABs or are you still getting used to them and it's too early to say or would like to go back to stock? from what i've felt, i greatly prefer them (except for the squeak). being able to dial in the camber/toe better than before could also well be influencing what i'm feeling (and the LSD). everything combined, the back end feels awesome compared to what it used to.

[1996 328ti]

I'll start a new thread. I had an excellent instructor, 318ti owner, Brook Harmon.

[CirrusSR22]

I have IE's and new OEM RTABs. I have zero squeak.

[1996 328ti]

I had zero squeak until my first track session.
So I guess the squeak is the RTABs.

[cali-ti]

which is what i figured. good to let other people know before they install them. the feared polyurethane squeak :( i'll see if it gets any worse over time ... not going back now! :p