E34 Subframe Reinforcement Plates - Review

[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/Scri...?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.