Subframe Reinforcement Status Thread

[BigDave]

Just did my reinforcement this weekend. Got the underside done yesterday and waiting on new bushings. Once it is back together, I will do the trunck area. This is my second time doing this... first was a 1999 E46 328 I turned into a track car... forgot how my much of a PITA this was.
Mine is a 2003 with 55k. Not a crack or issue when looked it over... now it's good for a long time!

How do you do the trunk area? Are you talking one of those giant bars that takes up half of your trunk space?

[Syfon]

I had a thread on M3Forum with a heap of pics etc., but we all know that's gone. Here's a few pics of mine.

[wsybert]

New delrin subframe and Rtab bushings are installed. Ready for reassembly. I used seam sealer on all the welds and coated everything with POR 15. Going to do one more coat of POR and start reassembly this weekend.

[roverT]

Agreed. Anyone know of any trusted shops/mechanics in Canada (particularly west coast) that has done a CMP subframe reinforcement?

My good friend Josh did mine at his private place. I was probably one of the first, two years ago to get Vincebar and skinz epoxied to the car. We just used welding to fix the cracks in the RACP.




As you can see I had some pretty major problems on both bottom and top sides.

RACP-6018


RACP-6186

But then once we got everything fixed, it was time to install the parts...


RACP-6349


RACP-6376

Once the top parts were installed and Vinceskinz underneath was all epoxied and riveted to the RACP, everything was rust primed and rustproofed and the inside trunk was color matched painted with the plate covering the Vincebar.


RACP-6399


RACP-6408

It's been a couple years now and everything seems fine and I am loving the freedom and peace that I can launch and drift with no guilt.

[Nick_P]

I just completed this as well, went with Reddish plates and Turner solid bushings/ mounts, monoball RTABs. After reading from multiple sources about how just the reinforcement plates are not a permanent solution, anyone care to share pros and cons of Vincebar, CMP topside beam kit plus front extension and Mason X-brace? One would be that the Mason bar doesn't extend to the front mount area I guess, any other ideas?

[scubastove]

Planning for this post-COVID-19. Anyone have this done is the greater Wash DC metro area? Fellow enthusiast gave me the name of RRT out of Sterling, VA.

RRT did the subframe reinforcement for my other m3 (currently for sale) with Turner plates, done under previous ownership. It was done in 2015 and has held up so far for ~35k miles

[BlueBimmers]

Planning for this post-COVID-19. Anyone have this done is the greater Wash DC metro area? Fellow enthusiast gave me the name of RRT out of Sterling, VA.

[mrgizmo04]

Respectfully, I would like to disagree about the ability to install the topside beam and front extension without dropping the subframe. Having just installed the kit myself, you would have to be an incredibly skilled welder to be able to install these kits without causing damage to the underside of the car in the form of weld through heat blistering up the undercoating. Not to mention the welds proximity to the gas tank.

It's not easy, but I got this kit only after speaking with Cayn (owner of CMP) about my situation, which was - I already did the rear subframe rebush work a year prior to engaging with him in a conversation about his solution, and was not looking to drop it again, and, especially since I already had plates welded on the car from po. He confirmed that it could be all done from the top. His instructions were even modified for that case (rather than assuming that someone was doing everything including plates as part of the job and the subframe would be down anyway).

[Jersey_M3]

CMP topside beam and extension can be done from the top without needing to drop the subframe again. So if you had plates previously welded or epoxied, there is some time/work saved. However like I mentioned before, 80% of time is spent on prep - scraping off sound deadening, paint, etc to get a clean area to have clean welds. The amount of prep for topside portion is still non-trivial with everything that has to be cleaned up in trunk and around rear seats.

Respectfully, I would like to disagree about the ability to install the topside beam and front extension without dropping the subframe. Having just installed the kit myself, you would have to be an incredibly skilled welder to be able to install these kits without causing damage to the underside of the car in the form of weld through heat blistering up the undercoating. Not to mention the welds proximity to the gas tank.

[mrgizmo04]

CMP topside beam and extension can be done from the top without needing to drop the subframe again. So if you had plates previously welded or epoxied, there is some time/work saved. However like I mentioned before, 80% of time is spent on prep - scraping off sound deadening, paint, etc to get a clean area to have clean welds. The amount of prep for topside portion is still non-trivial with everything that has to be cleaned up in trunk and around rear seats.

[Keyser Soze]

I had this job done about a month ago on my 06' with approximately 104k. I opted for the Redish plates based off of their reputation and quality. I had a local shop perform the job (I don't weld) and replace my rod bearings while everything was off the car. I think the choice of product that you use it is less of a structural integrity issue than an insurance policy. I haven't heard of any RACP failures with a welded vehicle, although I am certain that someone will correct me if I am wrong. That being said, I considered the CMP topside solution and am still looking at it for additional insurance. IMHO ,I would discourage solid bushings, and even super hard delrin bushings when you have them replaced unless the vehicle is exclusively a track or race car, otherwise you will be absolutely punished on the road. The car is significantly tighter after a plate reinforcement and poly bushings. I don't think you can go wrong with any of the choices.

There has been instances of failure after Turner plates were welded in on some cars.

[mugm3]

Does anyone know of a good place in Indiana that does RACP repairs? I know of one place Northwest Frame and Alignment. I think they don't want to do it though cause he quoted me 2600 bucks. To me that seems pretty high for just welding in plates. I can see that with doing the cmp front and top bars plus plates which I will probably end up doing. Just seems really high to me. I am half tempted to do it myself but would have to add a 220 socket and breaker at my house then also get a welder. Or am I just overreacting?

[mrgizmo04]

Take a look at 4 articles from CMP here. https://cmpautoengineering.com/pages/technical

There are a lot of parts to the failures. To do it properly, you need to not just lower/remove the subframe to see if any cracks are hiding behind the surface of the bushing (why PPI are worthless here with their visual inspection without at least removing the subframe), but also remove the underbody weather coating (this is probably 80% of the total time of the job, cleaning that and the black cover in the trunk). You also need to cut into the metal and expose parts of the trunk and floor to see if some of the spot welds have popped and to reweld them with reinforcements. You also need to seam stitch the wheel arches, tie front and rear mounts together, etc.

I went to CMP kit because I spoke with Cayn extensively about the problems and his solutions. He is an engineer (as I used to be), so his solution seemed sound and well thought out. I got the full kit with front extension but without the strut brace part. It is definitely a huge job overall and to strip the entire rear end to clean/prep and do correctly and address all modes of failure.

[TexaZ3]

Do it the right way.

[Syfon]

As a few have already said, if cracks are no visible under the car, they will be once the subframe has been removed.

We all know its a matter of when, not if, with these cars.

If you drive your car hard or track it, I'd be doing a full underside & topside reinforcement (with a 6 point brace like mine if you so desire).

I acquired my car at 50k km (31k miles) and cleaned/checked the underside. I found no evidence of cracks, however after 40k km (some of which was pretty hard), the rear right mount pointhad a tear in the metal. I went the whole 9 yards and reinforced everything so it won't fall apart. Rear end is tight as now!