Shock mount mushrooming

[DMC63]

I'm about to replace my shocks (Bilstein B12 pro kit) and I want to fit reinforcement plates to both the front and rear shock mounts (Z4 2.5i 2003).
I can't find any reinforcement plates online for the Z4 only Z3. Are the mounting turrets different? Would the Z3 plates fit a Z4?
I've tried Ocean BMW and they've nothing listed as an OEM part.
Can anyone point me in the direction to buy these please?

 

[adam1985]

Not sure about the front buts the rears IIRC are the same as z3

I went for the powerflex rear kit shown here is includes a strengthening plate http://www.powerflex.co.uk/i/product_images/4-5-5630-12 FI.pdf

 

[DMC63]

Thanks Adam for the reply. They look good to me. How are people reinforcing the front shock mount turrets to protect against mushrooming?
This video shows the guy saying he's fitting BMW reinforcement plates. https://www.youtube.com/watch?v=DZLgRNgdznU Really want to fit these along with the pro 12 kit.

 

[hopz121]

Thanks Adam for the reply. They look good to me. How are people reinforcing the front shock mount turrets to protect against mushrooming?
This video shows the guy saying he's fitting BMW reinforcement plates. https://www.youtube.com/watch?v=DZLgRNgdznU Really want to fit these along with the pro 12 kit.

You really don't need to, I have never heard of a z4 mushrooming and the B12 kit isn't a hardcore suspension set up at all so I can't see it ever deforming the front turret.

They sell the kit for the E46 M3 so if your desperate to fit some they may work

 

[DMC63]

Thanks for the reply. My car already has very slight mushrooming. The top fixing bolts of the front shocks should all be perfectly vertical. When they start to point out mushrooming has already begun. Are the shock turrets the same on the E46 M3? London is full of speed humps and pot holes, so I'd prefer to have some extra reinforcement just for peace of mind.

 

[DMC63]

Thanks Adam for the reply. They look good to me. How are people reinforcing the front shock mount turrets to protect against mushrooming?
This video shows the guy saying he's fitting BMW reinforcement plates. https://www.youtube.com/watch?v=DZLgRNgdznU Really want to fit these along with the pro 12 kit.

You really don't need to, I have never heard of a z4 mushrooming and the B12 kit isn't a hardcore suspension set up at all so I can't see it ever deforming the front turret.

They sell the kit for the E46 M3 so if your desperate to fit some they may work

Do you know if the front reinforcement plates for the E46 will fit the Z4? I can't find any answers to this question, and none of the dealerships are any help with advising on cross model use of parts.

 

[hopz121]

Thanks Adam for the reply. They look good to me. How are people reinforcing the front shock mount turrets to protect against mushrooming?
This video shows the guy saying he's fitting BMW reinforcement plates. https://www.youtube.com/watch?v=DZLgRNgdznU Really want to fit these along with the pro 12 kit.

You really don't need to, I have never heard of a z4 mushrooming and the B12 kit isn't a hardcore suspension set up at all so I can't see it ever deforming the front turret.

They sell the kit for the E46 M3 so if your desperate to fit some they may work

Do you know if the front reinforcement plates for the E46 will fit the Z4? I can't find any answers to this question, and none of the dealerships are any help with advising on cross model use of parts.

Don't have a clue, but they are not expensive if you fancy buying one to find out

 

[DMC63]

Ok thanks.

 

[Gregory_tolson]

Sorry to revive an old thread but i went forward and purchased the e46 reinforcement plates for the front and drilled a hole for the locating pin since the z4 is in a different location. I mounted them up and they seemed to fit yet i noticed my front end was sitting high. So i took them out (per FCP Euro's direction since they said they weren't meant for the z4) and then drove 20 miles, it seems the front end has settled. Im driving with brand new M sport springs and B6 Bilsteins. I think the springs needed time to settle since ive read new springs need to be driven a bit to settle. Im pretty sure the plates seated fine in the strut tower and i wasnt getting funky noises when i had them in there.

Has anyone gone about putting these in? How have they fared over a long time?

 

[Southwestz4]

I recently fitted the E46 plates in my 3.0 e85 while I was doing a suspension refresh, mine does sit a bit higher but I have changed it to se dampers and springs so it will sit higher than an m-sport setup.
Plates fitted fine and as I was using non oem top mounts with no locating pin , did not need to drill them

 

[plenty]

Anyone know the difference between the E36 plates 31312489795 versus the E46 plates 51717036781? From the pics it seems they are the same except the E36 items don't have the hole for the locating pin?

Answering my own question for anyone searching in the future. 31312489795 do *not* fit the E85. There is a raised lip around the inner edge which does not match the E85 shock tower. 51717036781 has no lip and sits flush as it should.

 

[beavtm]

You really don't need to, I have never heard of a z4 mushrooming and the B12 kit isn't a hardcore suspension set up at all so I can't see it ever deforming the front turret.

My new to me Z4 has the right front tower mushroomed. May have been the case since my dad owned it but it's pretty clear the tower is pushed up. It's in the shop right now getting all four corners addressed.

 

[grannyknot]

There also theses from Garagistic, https://www.garagistic.com/products/e46-upper-strut-mount-reinforcement-plate-51717036781?_pos=7&_sid=18b831e6d&_ss=r
I think these would be easier to fit a Z4 because they are narrower, I'm just about to place an order for these.

 

[Ed Doe]

Those will do bugger all though, the reinforcement plate is not profiled to the inside of the strut tower so isn't distributing the load better, it's creating point loading around the edge of the laser cutting no?

I seriously struggle to understand how people are getting mushrooming, anyone prepared to upload pics? I've had a problem with my intrax suspension whereby one ofy dampers was actually siezed solid. I've done maybe 6k miles and a couple of trackdays with effectively no damper travel... To add to that, previously the car has had rear true coilover suspension fitted in the past and is about to have it fitted again. No issues at all with mushrooming etc. I struggle to understand a normal road driven car on oe or even bilstein suspension getting strut tower deformation?!

 

[grannyknot]

Those will do bugger all though, the reinforcement plate is not profiled to the inside of the strut tower so isn't distributing the load better, it's creating point loading around the edge of the laser cutting no?

I'm not planning on using them as is, they are not designed for the Z4. I'll modify the outer edge with a few relief cuts and curve it to match the strut tower, once they're welded in they will work exactly the way their suppose to.
It will prevent any further stress cracks or mushrooming by adding 11 gauge plate to the thin 17ga the tower is made of.
BMW recognized this problem back with the e36 but didn't come up with their own reinforcing plate until long after the e46 were released.
I don't know how you could be struggling to understand this design flaw, the 17ga sheet metal on Z4 strut towers aren't any stronger than the 17ga on e36 or e46 towers.
The mushrooming usually starts with stress cracks around the 6 strut tower holes for the studs, these pics are of a few cracks starting on my car.
It seems most of the aftermarket top strut mounts have a smaller dia. that the stock unit and so concentrate the pressure on a smaller area instead of it being spread out.

 

[x-driver]

I'm about to refresh the suspension on my E85 and was thinking about reinforcement plates. So far I thought they were only needed at the rear but reading the posts above, the front is also at risk?

Anyway, can anyone tell if those ebay rear plates which are supposed to be meant for e36, e46, Z3 and some of them for Z4 coupe only, do they fit the E85 Z4 roadster or not?
Which ones do fit at the front? E46?

 

[BMWZ4MC]

I have stiffer Rogue Engineering rear shock mounts, which have the advantage of being under mount allowing the dampers to be changed without removing the boot carpet.
At the front I have E36 shock tower reinforcement plates (purchased directly from BMW), KW camber plates and an OEM strut brace. My car has been driven over countless kerbs on track for over a decade with this set up and it seems to be up to the task (in the same time, I’ve changed all four wheel bearings, a leaking rear damper and a broken spring (both KW)).
I presume all of the above fits both roadster and coupe, ///M and non-///M.

 

[Ed Doe]

I have stiffer Rogue Engineering rear shock mounts, which have the advantage of being under mount allowing the dampers to be changed without removing the boot carpet.
At the front I have E36 shock tower reinforcement plates (purchased directly from BMW), KW camber plates and an OEM strut brace. My car has been driven over countless kerbs on track for over a decade with this set up and it seems to be up to the task (in the same time, I’ve changed all four wheel bearings, a leaking rear damper and a broken spring (both KW)).
I presume all of the above fits both roadster and coupe, ///M and non-///M.

Off topic but do you run true coilovers at the rear?

 

[x-driver]

Where are the front reinforcement plates installed, from the top or from the wheel arch? I know that rear RP are installed on top, but I'm not sure for the fronts as some have mentioned their car sits higher with RP installed.

 

[BMWZ4MC]

I have stiffer Rogue Engineering rear shock mounts, which have the advantage of being under mount allowing the dampers to be changed without removing the boot carpet.
At the front I have E36 shock tower reinforcement plates (purchased directly from BMW), KW camber plates and an OEM strut brace. My car has been driven over countless kerbs on track for over a decade with this set up and it seems to be up to the task (in the same time, I’ve changed all four wheel bearings, a leaking rear damper and a broken spring (both KW)).
I presume all of the above fits both roadster and coupe, ///M and non-///M.

Off topic but do you run true coilovers at the rear?

No, my rear springs sit in the same position as the OEM springs. Have you changed back to a true coil over now (I think I recall your car had them but you changed them for OEM-like shocks and springs)?