[Bayliss21]

After my installer damaged the piston rod on my front left strut leading it to leak I opted for a full coilover conversion with EDC delete. I landed on AST's 5100 Competition Kit which includes new top mounts as well as adjustable sway bar end links and linear rate springs. This kit has a true rear coilover meaning the spring perch on the lower contol arm that typically distributes the suspension forces to the subframe is no longer utilized. As a function, the suspension load will be transmitted directly to the damper tower which I doubt is designed for this load increase.

What are my options to strengthen this component of the chassis? Does anyone manufacture a rear strut tower brace yet for the g87? I haven't even poked around in the trunk yet. I'm curious to hear if any previous f87 owners or G8X m3/m4 owners have any thoughts who have had true coilovers in the rear. I reached out to AST to hear their reccomendations and advice from testing. This is my track day car.

Link to kit:
https://www.bmptuning.com/products/a...-g80-g82-m3-m4

[ZPD]

I haven't seen a strut tower brace. Is there one for the G80/82? The reason that I ask is since it has been out longer there is more time with a true rear coilover on those platforms. Maybe it's not needed?
I will be at COTA June 8-9 with the Chin event. If you are there then you are welcome to have a look at my rear suspension and see if there is any damage. I have about 6 track days on my MCS 3-way coilovers.

[Bayliss21]

Originally Posted by ZPD

I haven't seen a strut tower brace. Is there one for the G80/82? The reason that I ask is since it has been out longer there is more time with a true rear coilover on those platforms. Maybe it's not needed?
I will be at COTA June 8-9 with the Chin event. If you are there then you are welcome to have a look at my rear suspension and see if there is any damage. I have about 6 track days on my MCS 3-way coilovers.

Nice, I'll be there too. First time tracking this car! I have a black M2 with Anthracite Apex Wheels. I haven't seen anything for the aftermarket on the M3/M4 for the rear strut towers. I think the answer AST will give me is that the top mounts they designed for the rear effectivley distribute the load to the chassis. I'll keep you posted on their response and see you at COTA!

[Bayliss21]

Just found this on MCS website:

"Should the rear be a coil over on G8X? No one has done independent lab testing of the loads the rear shock towers can take. However, in our experience the rear shock towers are sufficiently reinforced from the factory that no additional reinforcement is needed. Especially if running softer springs and street tires. However, for any regular track use we would like to see a cage or half-cage in the car anyway. These usually tie into the shock towers and add thickness and rigidity."

https://www.bimmerworld.com/Suspensi...G8X-M3-M4.html

[ZPD]

Originally Posted by Bayliss21

Nice, I'll be there too. First time tracking this car! I have a black M2 with Anthracite Apex Wheels. I haven't seen anything for the aftermarket on the M3/M4 for the rear strut towers. I think the answer AST will give me is that the top mounts they designed for the rear effectivley distribute the load to the chassis. I'll keep you posted on their response and see you at COTA!

I will be #43

[Bayliss21]

I also found this for what its worth. MCS seems to think that the rear towers are perfectly capable of handling the increased suspension load.

"Note: We typically sell every MCS damper system as a coilover rear. The same dampers can be used as a divorced setup if desired, just pick this option in the drop down. Contrary to what you may have read on the forums, you do not need to tie a cage into the rear shock towers to safely run this set up on E9X, F8X and G8X chassis. Reinforcement load plates for the E36/E46's to assist them are required. Of the thousands of MCS's we have assembled, we have never had an issue with any C/O rear, including all of our race cars running very high spring rates, slick tires, massive cornering and acceleration loads, aero or any other factor that could contribute to an issue."

https://www.racewerkz.com/products/m...rive-coilovers

[HP Autosport]

Originally Posted by Bayliss21

After my installer damaged the piston rod on my front left strut leading it to leak I opted for a full coilover conversion with EDC delete. I landed on AST's 5100 Competition Kit which includes new top mounts as well as adjustable sway bar end links and linear rate springs. This kit has a true rear coilover meaning the spring perch on the lower contol arm that typically distributes the suspension forces to the subframe is no longer utilized. As a function, the suspension load will be transmitted directly to the damper tower which I doubt is designed for this load increase.

What are my options to strengthen this component of the chassis? Does anyone manufacture a rear strut tower brace yet for the g87? I haven't even poked around in the trunk yet. I'm curious to hear if any previous f87 owners or G8X m3/m4 owners have any thoughts who have had true coilovers in the rear. I reached out to AST to hear their reccomendations and advice from testing. This is my track day car.

Link to kit:
https://www.bmptuning.com/products/a...-g80-g82-m3-m4

No need. That part of the tower has already been reinforced since the F chassis.

Here is a true coilover rear Nitron elec-TRON R3 for our customer's G82 M4.

[HP Autosport]

MCS 2Way for F8X M with a true coilover rear.