Mixing E36 and E46 RSMs?

[paul e]

I think I only have 1 bad rsm at the moment...I plan on having that one replaced, and I was going to use another E36 rsm...But, I was wondering, would it be ok to replace it with an E46 rsm, and then when the other side goes, do that one with E46 also? The question really is, is there a difference in flexibility or performance between the E46 and the E36 that I would notice, and which would compromise rear suspension performance, if one side were E36 and the other, E46?

[eeeks]

I dont know if this would help you, but I just had both of my e36 (non-m) shock mounts replaced with e46 M3 shock mounts. Perfect fit.

Ride Quality: no harsher than stock really, but since my old mounts were kind of shot, its kind of hard to directly compare.

[jblack]

It's a pain to move the carpet.....why not do it once, and don't foget that the other one is not far behind! Ground Control sells ones with a lifetime warranty that work very well with adjustable shocks, if you ever go that way.

If you go with the factory route, just swap them both!

[Bernman]

There will be no noticeable effect between the E36 and the E46 side.

[frayed]

They are cheap, and the extra labor to replace the other side is nominal. I'd do both.

Besides, if one died, the other is soon to follow.

[paul e]

Here's the reason I dont plan on doing them together...In January, my bmw - dinan dealer installed a new Dinan suspension, and at that time, they charged me for new RSMs...I was charged, by the way, for what they called on the invoice 'Guide Support', part number 33-52-1-137-972, a whopping 2 x $39.35 = $78.70!

I have no idea where they got those prices, but theyre almost twice what Ive seen them on line for.

Anyway, the driver side one has been clunking, grinding, squeeking, thunking, etc, almost since then. The srvc vP heard it and doesnt think its the mount, and doesnt think its serious...I disagree..I have an appt next monday, and Im going to make a stink unless they agree to go in there remove the rsm, and replace it with a new one.....

In case they dont, and want to charge me...at least I want to have one on hand, purchased on line for like 15 bucks, to give them...Or, if we disagree on the spot, I want to have one to either take elsewhere to install, or, to do it myself.

From what I have read, it seems like a very simple procedure...In my case, I have the JL Audio Stealthboxes, so, that makes it more complicated. But still, I think its a pretty easy 1 person job...I do my brake pads all the time, and I dont see this as being any more complicated. Right?

So, I was thinking, I could by 1 E46 now to replace this one...Then, when the other side goes, I'll buy another to replace that one at that time.

But I only want to do this if the E36 and E46 can co-exist at the same time.

thanks.

[frayed]

Yes, it's no harder than brake pads, though it'll take a longer. It took me 30 mins. to drop my Stealthboxes and remove the trunk interior pieces needed to access the RSMs. From there, it was quite simple, unbolt the RSM's, then remove the bottom bolts of the shocks. It took me about an hour start to finish, a first timer maybe 2 hours.

I would consider doing RSM's myself to be less of a hassle than having to deal with the dealer. But, I understand the point of wanting the shop that did the original install to 'get it right'.

Also, another issue you should be aware of. . . my local dealer will not install an non-OE parts, or any parts from a different application (eg, E46 mounts in an E36). You may want to check with them that they'd even do such a thing for you.

[monterey]

Originally posted by paul e
I think I only have 1 bad rsm at the moment...I plan on having that one replaced, and I was going to use another E36 rsm...But, I was wondering, would it be ok to replace it with an E46 rsm, and then when the other side goes, do that one with E46 also? The question really is, is there a difference in flexibility or performance between the E46 and the E36 that I would notice, and which would compromise rear suspension performance, if one side were E36 and the other, E46?

Although, i doubt it will do any harm. I don't think u can get a dealer to install the wrong part on your car. They will be liable if anything happens..

[CKim]

This is slightly off topic, but has anyone used the E30 convertible RSMs instead of the E46 ones? I e-mailed TMS and they seem to believe that the E30 ones are more durable than the E46 ones. Are they stiffer?

Also, to the Z3 reinforcements create any additional NVH (what exactly does that stand for, btw?), and are they difficult to install?

[paul e]

NVH (what exactly does that stand for, btw?), and are they difficult to install?

I bet some guys have come up with something a little more creative, but, to me, it means Noise, Vibration, and Harshness.

[norman]

i'm in the process of doing new rsm and suspension, are the e46 mounts just sturdier than the e36?

[CKim]

Originally posted by norman
i'm in the process of doing new rsm and suspension, are the e46 mounts just sturdier than the e36?

This is what I'm told. And I'm told by Drew at TMS that the E30 mounts are sturdier than the E46 mounts.

From Drew's e-mail
I would recommend these mounts over the E46 M3 or E46 Convertible mounts. When the E46 M3 mounts first came out we tried them on several cars and they failed right away. We went back to the E30 Convertible mounts and they have been working as great as always.

[frayed]

Originally posted by CKim


This is what I'm told. And I'm told by Drew at TMS that the E30 mounts are sturdier than the E46 mounts.

He told me the same thing. However, I had no problems with my E46 mounts when I ran them. . . street and track with H&R c/o's.

[CKim]

Originally posted by frayed


He told me the same thing. However, I had no problems with my E46 mounts when I ran them. . . street and track with H&R c/o's.

Hey Frayed,

Are you using just the RSMs or are you using the Z3 reinforcement plates?

[Bernman]

When I put the E46 mounts in, they appeared in all manners to be *exactly* the same as the new E36 mounts that I was taking out. The only difference that I could see/feel was that the E46 number was moulded into the new one. There chould be some internal difference, but who knows. I truely beleive this is a case of "it's used on a newer, sportier car, it must be better". There is some validity to choosing a part based on this reasoning, but it could just as easily be that the engineer changed the type of paint used on the metal part, thus changing the part number.

I do not have experience with the E30 version, but that was the part that people were using before, claiming higher durability.

Guys, this part is not some rocket science thing that is going to transform your car into a vibrating hunk, or a smooth quiet machine. If it affects the handling of the car in a noticable way, I would be *very* surprised. It is a rubber mount at the top of a damping device (the shock). It needs to have some deflection in it to allow the shock to rock back, and forth slightly as the suspension moves up and down. We all want it to last, but we talk about this little thing *far* too much

Paul, I don't think that the noise you are hearing is a failed mount. I had standard E36 mounts with the Bilstein monotube M3 shocks for about 8000 miles. When they came out, they looked as good as new. It could someother part has failed back there, or maybe they assembled the washers in the wrong order. Either way, the dealer should be able to diagnose this far better than any of us on the forum.

Good luck, and I hope everything works out ok.

Bernman

[frayed]

Originally posted by CKim


Hey Frayed,

Are you using just the RSMs or are you using the Z3 reinforcement plates?

I have an AA rear brace which takes the place and mimics what the Z3 plates do.