E34 Subframe Reinforcement Plates - Review

[Mr Project]

Well, last week I installed Bruno's Subframe Reinforcement plates. Color me satisfied!

First my setup:
1991 535i 5-speed, 180,000 miles
Stock suspension of unknown age, stock swaybars
Recent thrust arms, pittman arms (dog bones) are pretty worn, subframe bushings have very minor cracking (probably still ok).
Tires: Goodyear Eagle HP 215/60/15 in front, 225/60/15 in rear

Installation:
I was removing my A/C for conversion and thought I'd throw these in. Not counting 15 minutes of jacking the car up and setting it down, this took maybe 15 minutes to install. I had the car on jack stands, supported the rear suspension with the jack, and used my impact wrench to pop the 22mm and 13mm nuts off. Then, wipe the dirt off the steel parts, slap Bruno's plate in, and bolt it back up. Easy as pie. I didn't have a torque wrench at that moment, so I tightened them to around 100 foot-pounds with my calibrated elbow and cheater bar. :) Also, he calls these 'plates', but they are some kind of urethane, not steel or aluminum. Have no fear. :)

Driving impressions: (100 miles of highway, 50 miles of city, about a week so far)
The first thing I noticed, and probably the biggest difference, is the 'mushy' and 'squatty' feel is VERY much reduced in certain situations. When I pull out of my neighborhood, I often have to accelerate pretty hard through 1st and 2nd gear while turning left. That 1-2 shift under power while turning used to create a big 'squat and squirm' movement in the rear suspension. Not anymore! Power delivery is more controlled and less dramatic, with a much greater sense of firm body and rear suspension connection.

This effect is rather noticeable in applying power in corners. There is a much reduced tendency to 'squat and squirm' at all times when applying power in a corner, with a much more satisfying and controlled 'feel'. Color me impressed!

I don't know yet if this has any effect on wheel hop. (haven't tried any shenanigans)

NVH: I am getting to be a big wuss in my old age, so I was concerned that this modification might increase my NVH levels unacceptably. Those fears were unwarranted. No significant NVH increase at all. There might be a slight increase in audible impact harshness in the rear suspension, but it is so slight as to be totally undetectable with any type of other noise...radio, sunroof, fan motor, etc. Around town with our horrible roads, there is no significant ride difference I can detect.

So, for the price, I highly recommend these. I think they will be sufficient for me to delay my plan to replace all of my rear suspension bushings for a while. I'll do my dogbones sometime and that will probably be good for me for a while.

Armen - no affiation with Bruno or racingking.ca

http://www.racingking.ca/Canada/Scripts/prodView.asp?idproduct=693

[George M]

Nice write up Mr. P...you tap all the bases. Kudo's to Bruno for introducing this new product!
George

[Bruno]

For storing my tire for so long ahhahaha.
I am still hopping to see you the 27th July in the evening if that is ok with you.

[George M]

You don't have to bring a set Bruno...just come on over.
I would really like to install fresh sub frame bushings but don't feel like renting the fancy BMW tool from Brett. If you have the BMW subframe extractor/installation tool...bring that, and when I am done, I will ship it back to you.
George

[Bruno]

developping parts for the E34/E32...

I am picking up the thrust arms bushing inserts this afternoon.
I have 8 sets available, and I will probably put them on the website tomorrow or monday.

[Scott H]

I'll be halfway to Detroit next weekend near Kalamazoo.....I could meet you guys and hand you cash for a set Bruno. Install them, and drive them back home to Chicago......hmmmmm

and......I have a few things to talk to Bruno about......G-mann you know what is up so far

[Mr Project]

I do want to thank you, Bruno... this is a great product at a great price, and nobody else is committed to our community like this!

[Bruno]

I'll be halfway to Detroit next weekend near Kalamazoo.....I could meet you guys and hand you cash for a set Bruno. Install them, and drive them back home to Chicago......hmmmmm

and......I have a few things to talk to Bruno about......G-mann you know what is up so far

I will be in Michigan the 27th in the evening until the 29th of July, then I am going back to Canada with 2 racing seats, 2 harness, 1 tire, 3 sets of rims, a trailer hitch...

[George M]

...a compressed air tank pressure gauge and misc. MAF stuff...
:D
George

[jplacson]

Are these reinforcements needed? I mean, is the E34 suject to the same subframe failure as the E36 and E46, which is why these plates are needed?

[Mr Project]

Are these reinforcements needed? I mean, is the E34 suject to the same subframe failure as the E36 and E46, which is why these plates are needed?

The name is kinda misleading, I think. These aren't metal plates, and they don't reinforce the body structure like is needed on an E36. If you look at the picture on the website, you can see that they are big blue urethane donuts that take up the space between the rubber subframe mount and the lower brace that holds the subframe mount in place.

They don't prevent the body from tearing (E34s don't have this issue AFAIK), they just take up 'slop' in the rear suspension.

[jplacson]

whew! ok... I thought this thread was discussing something else, other than the urethane bushings... ok, ok... just freaked... thought the E34 had the same subframe problem as the E36/E46

[Anton CH.]

I have noticed myself that the car squints and the rear has a wider radius when applying lots of gas on a corner (wheels not slipping). So what does your car do now on corners?

[Mr Project]

Well, quite a bit less of that 'squatting' basically. That effect is greatly reduced. Not gone completely, but it makes the car feel much more responsive and controlled because the rear end is just 'tighter' in the corner.

So far, it doesn't seem to have made a big difference in wandering on the highway (there was some initial thought about that), but my car didn't wander too bad anyway.

[Russell]

Seems about the same results on my 95. I also think my wandering has been reduced a bit, but not completely. Now for Bruno's front thrust arm inserts. I will order as soon as available. I also plan to replace the dogbones.


Well, last week I installed Bruno's Subframe Reinforcement plates. Color me satisfied!

First my setup:
1991 535i 5-speed, 180,000 miles
Stock suspension of unknown age, stock swaybars
Recent thrust arms, pittman arms (dog bones) are pretty worn, subframe bushings have very minor cracking (probably still ok).
Tires: Goodyear Eagle HP 215/60/15 in front, 225/60/15 in rear

Installation:
I was removing my A/C for conversion and thought I'd throw these in. Not counting 15 minutes of jacking the car up and setting it down, this took maybe 15 minutes to install. I had the car on jack stands, supported the rear suspension with the jack, and used my impact wrench to pop the 22mm and 13mm nuts off. Then, wipe the dirt off the steel parts, slap Bruno's plate in, and bolt it back up. Easy as pie. I didn't have a torque wrench at that moment, so I tightened them to around 100 foot-pounds with my calibrated elbow and cheater bar. :) Also, he calls these 'plates', but they are some kind of urethane, not steel or aluminum. Have no fear. :)

Driving impressions: (100 miles of highway, 50 miles of city, about a week so far)
The first thing I noticed, and probably the biggest difference, is the 'mushy' and 'squatty' feel is VERY much reduced in certain situations. When I pull out of my neighborhood, I often have to accelerate pretty hard through 1st and 2nd gear while turning left. That 1-2 shift under power while turning used to create a big 'squat and squirm' movement in the rear suspension. Not anymore! Power delivery is more controlled and less dramatic, with a much greater sense of firm body and rear suspension connection.

This effect is rather noticeable in applying power in corners. There is a much reduced tendency to 'squat and squirm' at all times when applying power in a corner, with a much more satisfying and controlled 'feel'. Color me impressed!

I don't know yet if this has any effect on wheel hop. (haven't tried any shenanigans)

NVH: I am getting to be a big wuss in my old age, so I was concerned that this modification might increase my NVH levels unacceptably. Those fears were unwarranted. No significant NVH increase at all. There might be a slight increase in audible impact harshness in the rear suspension, but it is so slight as to be totally undetectable with any type of other noise...radio, sunroof, fan motor, etc. Around town with our horrible roads, there is no significant ride difference I can detect.

So, for the price, I highly recommend these. I think they will be sufficient for me to delay my plan to replace all of my rear suspension bushings for a while. I'll do my dogbones sometime and that will probably be good for me for a while.

Armen - no affiation with Bruno or racingking.ca

http://www.racingking.ca/Canada/Scripts/prodView.asp?idproduct=693

[Marshy]

Received mine in the UK about seven days after ordering - good stuff! They'll be fitted on Wednesday, so will report back then.

[mholbrook]

Installed mine yesterday. Noticeably less squat on takeoff. Noticed second gear rubber right away. So it's hooking up more positively. Round corners, the rear is glued in tighter. Have to see how it goes on next autocross. Missed Saturday since I just came back from a train ride to Colorado and back (note to self: Don't do that again!).

Ez install. Jack the car up and pull the 3 bolts (1 22 and 2 15's as I recall). Nothing really moved on my car so no other support was necessary. Took only about 15 minutes or so. Real ez. Only gets about 1/2 a wrench. If you can remove a tire, you can do this.

Price was terrific and shipping extremely fast. Thanks, Bruno. Come up with more of these little "fixes".

[Jon K]

Bruno,

Just ordered these, can't wait to get them.

I am doing upper and lower control arms also soon, when do you suspect the thrust arm inserts to be available?

[bimmerd00d]

I just ordered a set too. If you have any sort of instructions, could you post them? How are the thrust arm inserts? Do they cure the shimmy at all?

[Jon K]

I just ordered a set too. If you have any sort of instructions, could you post them? How are the thrust arm inserts? Do they cure the shimmy at all?


I plan on doing a photo-guided install... even though it's easy, I am sure people will appreciate the step by step.

[Russell]

They stopped my mild shimmy/vibration. It is gone! Also, the car seems stiifer and handles a bit vetter However, I think there is an increase in harshness when I hit sharp edged bumps such as tar srips or manholes.. However, my front struts need replacing. Hope to do so in a few days.


I just ordered a set too. If you have any sort of instructions, could you post them? How are the thrust arm inserts? Do they cure the shimmy at all?

[Marshy]

Shoulda replied to this aaaaages back when I had the plates fitted, at the same time as new subframe bushes. The net effects are (modulo the fact that I clearly can't tell you what's due to new bushes, and what's due to inserts):-

1) Much, much, MUCH sharper turn-in. Felt very odd initially, but I'd clearly got used to how baggy the car was with a wandering rear end. I'm now completely in tune with the sharper turn in.
2) Rear end doesn't steer itself in corners any more (yay)
3) Feels like it's cornering flatter, although I have a distinct impression that the front is more baggy than the rear now. Need to get the front end looked at, clearly.
4) No noticeable increase in rear-end noise. What increase there may be is drowned out by what sounds like a busted shock mount. (One day, one day)
5) Tyre's squeal more easily in corners, or so it seems. Couldn't care less about that :)

Happy customer.

[bimmerd00d]

bruno man! when are you going to get some of the thrust arm ones ready so i can order them and say goodbye to my horrid shimmy!?

[califblue]

Received my package on Tuesday via U.S. mail...installed them in about 15 minutes :p ...noticeable less squat and I have a new SACHS kit and M-tech sways (have less than 5K on it)
the back end handles way better than before and I honestly did not notice any more road noise.
BRUNO ...you are the MAN :D
Thanks

[[1990]525]

Is there really this big of a difference? How difficult are they to install? I guess I just don't see what these things do.

[willobmw]

Yes and easy to install. For the price, an absolute deal or shall I say steal. I go around corners now like JP Montoya.
Willo

[hakwuzhere]

Anyone ever do a photo install of this? I know BMWE34.net has the recomendation of them... but I still dont have a clear idea as to where these go...

Ive got them sitting in my bag of goodies to install this weekend and Ive been searching for a good pic of where to remove the bolts (and Ive read horror stories of people snapping the bolts)...

Mods to go in this weekend:

Hella Smoked Tails
Hella Smoked Turnsignals
Depo Projector34's
Lamin-X Smoked Headlight Covers
Lamin-X Yellow Foglight Covers
Euro Trim
EAT Chip (I HOPE! Mark! Wheres my chip!)

Sorry for bumping a dead thread... but it seemed the most related that ive read in the past hour.

(Edit: No one can accuse me of not using search! I just realized that I bumped a two year old thread! :p)

[MBXB]

I'm glad I keep every pic I download...500gb later...

Thanks to whoever took this pic and labelled it.

[hakwuzhere]

Eureeka! Perfect!....

And rehosted on my site JIC anyone needs to link it.

http://www.veeshanvault.org/gallery/albums/album33/subframe_bushing.jpg

[genphreak]

Peeps,

I know these seem like a great idea and all the info on them suggests they stiffen things up somewhat. However I am surprised if that gap they fill in the subframe suspension is not actually deliberate. I mean, its not a wear or manufactuing problem, design fault or other oversight (surely) or they would have fixed it in the 8 years they made the car, (let alone considering the e32).

wouldn't it be great to find out from BMW why that gap is there... i mean perhaps the gap is there to allow the dogbones to do their thing with controlling camber, or it could be something else entirely...

Anyway, it's just a thought... I'm pretty close to getting a set as everyone likes major stiffness :)

[Jon K]

Its not that noticeable now to me. I think the gap is there just to allow some extra rear end squat. Very few people buying $50,000 cars in '90 wanted something firm.

[Anthony (M5 in Calgary)]

Its not that noticeable now to me. I think the gap is there just to allow some extra rear end squat. Very few people buying $50,000 cars in '90 wanted something firm.

The air gaps are there to allow the rear subframe to deflect fore-and-aft during harsh impacts from potholes and the like. The webs of the bushing are oriented side-to-side allowing the subframe to resist movement during lateral thrust from cornering.

Filling the gaps will make impact shocks more harsh and, IMO, add little to the handling of the car. That said, bushings do get soft with age so that's why the urethane fillers would seem to "stiffen up" the rear end. I'd just pop a new pair of bushings in and be done.

[BigKriss]

Filling the gaps will make impact shocks more harsh and, IMO, add little to the handling of the car. That said, bushings do get soft with age so that's why the urethane fillers would seem to "stiffen up" the rear end. I'd just pop a new pair of bushings in and be done.
I would say they tighten up the rear, significantly reducing oversteer. I tracked my car with and without them, and existing corners with the delrin inserts made the car a lot more stable, is was noticably improved. The extra noise vechile harshness was minimal.

[Anthony (M5 in Calgary)]

I would say they tighten up the rear, significantly reducing oversteer. I tracked my car with and without them, and existing corners with the delrin inserts made the car a lot more stable, is was noticably improved. The extra noise vechile harshness was minimal.

How old are your subframe bushings?

[BigKriss]

How old are your subframe bushings?
the car is 17 years old, 225,000 kms and never have been replaced. I will replace them with solid polyurethane bushes, i'm just waiting for them to be made. I'm unsure though what polyurethane bushes would be like for the e34, as I've never heard of members on here running with them before.

[Anthony (M5 in Calgary)]

the car is 17 years old, 225,000 kms and never have been replaced. I will replace them with solid polyurethane bushes, i'm just waiting for them to be made. I'm unsure though what polyurethane bushes would be like for the e34, as I've never heard of members on here running with them before.

Back in '98 I purchased a '90 535 with ~160,000km. The rear subframe bushings were so bad the subframe would bang upwards at launch then thump down at coast, not to mention awful handling. I temporarily shored them up by using a couple of muffler hanger donuts from some other car (~2"ID,~3/4" cross section) on each side, 1 above and 1 below on each side mounted co-axially with the chassis bolt. That firmed the thing up so much that I almost forgot about them. When I had new bushings installed a couple of months later the handling difference was night and day - much firmer and more exact. I suspect you would find the same thing with just a new pair of OE mounts.

Everybody is entitled to try upgrades to their cars - we all do it. So go ahead and try the urethane bushings and report back. BMW had some pretty savvy people designing these things originally though. FWIW, the M5 uses the same subframe bushing as a 535 so I doubt it is a weak link for handling or BMW would have upgraded it for the M5.

Jacking up or supporting E34s by the rear subframe will tear bushings up pretty quick too. I always jack using a floor jack at the factory jack point then support the rear with a jackstand under the subframe mount.

[puppypilgrim]

I just got my shipment of Delrin insert plates today and will try to install them on the weekend. As Anthony (M5 in Calgary) pointed out, replacing worn rubber subframe mounts with new ones will tighten up the rear considerably. However, removing the old subframe mounts is not an easy task for DIYer without a car lift, a torch or a sawzall. The other option is to take it to the stealer so they can use their special BMW puller to pull it out.

For the price of Bruno's inserts, I figured it was well worth the try.

[Qube]

Here we go: http://www.bimmer.info/forum/showthread.php?t=24256&highlight=subframe

[puppypilgrim]

Best write up on the planet for these inserts - and I've looked everywhere! Great job Qube.

[Fetch]

Hmmm cool!

....putting this on the ol' wish list
:)

[puppypilgrim]

I tried all weekend to put the Delrin insert plates in but couldn't get past the 22mm nut. The 13mm nuts were not big problem. But the 22mm wouldn't budge even after spraying liquid wrench and WD40. I tried attaching a long pipe to increase the leverage. I tried hammering the long lever to loosen the nut. No dice.

I tried heating the nut with heat. Loosen it barely. Enough to rotate the bracket but not enough to turn the nut any more. Finally snapped the socket extension right off the the wrench.

Very frustrating. I know what to do but the nut won't budge.

[bayviewsbb]

I would say they tighten up the rear, significantly reducing oversteer. I tracked my car with and without them, and existing corners with the delrin inserts made the car a lot more stable, is was noticably improved. The extra noise vechile harshness was minimal.

G'day BigKriss,
Thinking of getting a pair for my old bus...I'm a cuppla hours north of you, and need to know what to add for air exp post to NSW...
Cheers,
bayviewsbb

[BigKriss]

I did this exact same thing, I snapped the subframe bolt and had to purchase new items (bolt and nut). I used a braker bar and a long pipe. The other side was fine though.


I tried all weekend to put the Delrin insert plates in but couldn't get past the 22mm nut. The 13mm nuts were not big problem. But the 22mm wouldn't budge even after spraying liquid wrench and WD40. I tried attaching a long pipe to increase the leverage. I tried hammering the long lever to loosen the nut. No dice.

I tried heating the nut with heat. Loosen it barely. Enough to rotate the bracket but not enough to turn the nut any more. Finally snapped the socket extension right off the the wrench.

Very frustrating. I know what to do but the nut won't budge.

[puppypilgrim]

I did this exact same thing, I snapped the subframe bolt and had to purchase new items (bolt and nut). I used a braker bar and a long pipe. The other side was fine though.

OK, so I took it to my indie specialist in Vancouver this morning and he was kind enough to put me on the lift right away. One hit with the air pressured impact gun and the 22mm came off. Both Delrin inserts were mounted in about 8 minutes. I also had them replace the front and rear sway bar bushing while they were at it (I had purchased them and had them with me). 35 minutes later we took the car for a test drive. By the time we wrote up the paperwork, he asked permission to bill me for 45 minutes of time = $60 plus taxes. I felt it was fair.

Front sway bushings at 203,500 km were toast, gone, ovalized, cracked and finito. Don't know if the one previous owner had ever changed it. Rear sway bushings did not look visibly deformed, but looked aged. Still for the cheap price of the OEM rubber bushings, I thought it was worth it.


DRIVING IMPRESSIONS
This is just the initial drive from the service shop to the office (yes I got to work late as a result of going to the service shop first thing in the morning). Everything feels more planted and tight. Noticeably better hookup on acceleration although with the wet weather here and 245/45/17 winter tires, I can engage ASC in the first three gears so all out acceleration tests are not going to happen yet. Over washboard surfaces where the imperfections are one after another, there is more harshness felt in the car. If I had to put a number to this, I would say 5% not more than 8% greater harshness felt.

On normal roads, one would not be able to tell that the Delrin inserts have been installed. The car just feels more connected to the road. No highway driving yet so don't know about that yet. High speed cornering should feel a lot better.


NEXT THING ON THE LIST

Change to Valvoline synthetic 5W-50 at 205,000 km.

Am taking delivery of front and rear sway bar end links and will order the rear dogbones as well.

Install short shifter from BMW Z3 1.9M

[puppypilgrim]

I posted my installation of the Delrin inserts on the Alpina forum and received this post from someone called Stevie.

"Sigh.

If you would take out a subframebushing you would see that the center of the subframe bushing is a hollow aluminium tube that fits snugly into a 1/4 deep recess in the shell. The subframe bushing is about 4 inches long to make sure that all forces applied to that aluminium core are distributed so it doesn't BREAK. The delrin shim you just put in does exactly that, as it allows the subframe to move on the worn bush, the 1/4 inch edge of the shell to become a pivot, and the delrin shim to form a lever. Can you say S N A P ?

Exactly this happened on Nynkes e30 because some ignorant fool inserted a shim just like yours as a bodge instead of a proper replacement, and left me and my Dremel tool to get the remainder om the alloy core out of the shell. This is not a job you'll like..... If you want to tighten it up, use a harder material as supplied by Powerflex, Turner, and many others. Don't change the concept. That bush is 4 inches high, and PF even changes the inner core to steel FOR A REASON!"

This was my reply:

"nteresting. I will share your knowledge with others who have installed the insert and sample their feedback on the failure of insert.

"However, it should be noted that the insert is shaped like an O-ring and not a solid plate through the middle and does not transmit any direct force to the core bolt. It simply limits the amount of vertical compression on the rubber bushing by filling in the gap."

For those of you who have installed the Delrin inserts, have you experienced a failure of the aluminum core or the bolt yet? Am I correct in saying that since it is an O-ring, the insert will not snap the bolt?

[BigKriss]

Right, there have been no failures on here yet. The delrin insert will make the bushing last longer because there is less flex.



This was my reply:

"nteresting. I will share your knowledge with others who have installed the insert and sample their feedback on the failure of insert.

"However, it should be noted that the insert is shaped like an O-ring and not a solid plate through the middle and does not transmit any direct force to the core bolt. It simply limits the amount of vertical compression on the rubber bushing by filling in the gap."

For those of you who have installed the Delrin inserts, have you experienced a failure of the aluminum core or the bolt yet? Am I correct in saying that since it is an O-ring, the insert will not snap the bolt?

[Russell]

No failure on the rear inserts. My have been in two years. However, Bruno's red colored inserts for the thrust arms have failled on one side. I replace with new Lemforder arms and 750i bushings

[OneBeLow]

just ordered mine

[Bruno]

just ordered mine

I have been swamped at work (still working as I type) but I will ship tomorrow.

[OneBeLow]

I have been swamped at work (still working as I type) but I will ship tomorrow.

thanks man!

[puppypilgrim]

OK did about an hour of highway driving in the rain this morning with speeds up to 140 km/h and cruising. What can I say? Beautiful, beautiful, beautiful! The car just feels so so planted even in the rain. No highway driftiness or wandering or rear looseness anymore.

No squat and funny noiseness when accelerating hard from 1st and 2nd. The car just hooks up and goes (bear in mind I push about 384 ft.lbs torque and 360 HP under wide open throttle). I can heartily recommend Bruno's Delrin inserts.

[califblue]

discussed here:
http://www.bimmer.info/forum/showthread.php?t=5323

And

http://www.bimmer.info/forum/showthread.php?t=9232

[OneBeLow]

installed mine last night, took all of 15min (Az/Ca car), I felt kinda shafted on the install, I felt a urning to do more. Gonna take a drive today.