Subframe Reinforcement Status Thread

[ecwx215]

Just picked up my new (to me) 2002 M3. I brought it to my shop (VAC motorsports in Philly) for a subframe analysis. The tech mentioned that since he saw no cracks or any signs of stress to the area, he recommended the foam injection remedy that BMW offered back in the early 2000's. According to him, if the subframe mounting points are in good shape and show no signs of cracking, he stated that he did not want to drop the rear subframe, galvanize the steel and weld in the plates. Mind you this is coming from VAC motorsports, they specialize in these cars and know their stuff.

Has anyone had any experience with the foam injection process for subframe reinforcement? And what have your results like? Eventually I'll wind up reinforcing it, I just want to only have to do it once. Thanks!

Your first mistake was going to VAC. They half ass the process and will charge you an arm and a leg. Since it sounds like you're in PA, reach out to Matt @ Kassel Performance. He's the guy that you want to work on your m3.

[newton22]

Mine had 120k miles. Zero cracks even after removing subframe and grinding it down. Not even hairline cracks. Obviously I went ahead and welded in plates at that point.

My car has never seen snow/the north though.

[Silbergrau metallic]

Curious! if you have a E46 M3 or in the Market for one and you're concerned about re-sale value or looking for a Car that's had the work done as far as Subframe re-inforcement, which would you prefer, No Cracks, No Cracks, but re-inforced plates either epoxed or welded in or a brace installed either Mason Engineering or DMG Autosport.

[Titaniu//M]

Just had mine done at 54k miles. No cracks found at all, but both rear springs were cracked. Had it reinforced anyway for piece of mind since the subframe was already off. New bushings and springs as well.

[wsybert]

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!

[BigDave]

Thanks! Can you tell me what you had done and approximately how much $$$ it was?

I had my 2005 Cabrio done in 2010. It had 20K miles on it at the time. No cracks at the time.

I supplied my welder at Redline BMW in Pompano Beach FL with two sets of plates. One from HPF and one from Turner Motor Sports. The welder mixed and matched the plates and used the ones he thought were best. He did extensive welding. Opened up sections, welded and stitched them closed.

The paint shop on site did a full metal prep and a two part urethane sealer paint. Man, did it come out nice! "Only" $1,100 in 2010 for all that work. I thought it was money extremely well spent.

I just dropped the rear subframe two weeks ago to install new OEM bushings. The chassis surfaces were immaculate. Zero rust, zero cracks and still shiny paint underneath. Low mileage still, however. Only 45k miles on chassis. However, I have done many hard launches and snapped a few rear half shafts in the process. I have not babied the car. The welder said the rear was good to over 1,000 HP should I ever go Forced Induction.

[jowo]

turn3autosport did an excellent job on mine. Also Nixon and CG Motorsports are great shops as well, but don’t have first hand experience on subframe reinforcement from those two.

Thanks! Can you tell me what you had done and approximately how much $$$ it was?

[wahsm]

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

turn3autosport did an excellent job on mine. Also Nixon and CG Motorsports are great shops as well, but don’t have first hand experience on subframe reinforcement from those two.

[wahsm]

That'd be amazing if true, but send me pics of your front mounts and all those little spot welds that have tiny cracks radiating off of them before I believe it. How many miles?

I’ll see if I can find the pictures. Might have to contact the shop that did it as don’t remember if I took from my phone. I did see it with my own eyes before it was red forced. There was about 95600k miles 154k km since it is a Canadian car. The original owner I bought it from did baby the car. Although I did have a nasty shearing on some bolts when I rebuilt my vanos. May post that this weekend. One more track day could have done in the engine.

[trigtm]

I just finished with my RACP reinforcement with the turner plates installed below and the VinceBar installed above, both epoxied in. When I removed everything and cleaned the underside up, I have 0 cracks and I checked everywhere. I was absolutely amazed how clean the underside was of this car. 105k, Texas car that from what I can tell was never tracked or abused at all since everything is in nice shape.

VinceBar was easy to install and get in, the only trouble I had was all the bushings in the subframe which I did all of. I made a few tools to get them in and out copying the tools that people normally buy but that wasn't too bad. Pretty easy and straighforward install overall tbh. Great to do if you have time and the car isn't a DD. Needed two people to get the subframe back into the car but other than that, it was a 1 man job. Once I get the pics uploaded, I'll post of my before and after process.

[MrClutch55]

very interesting read, as of now, i have no visible crack. reading all the comments, i guess i will find out if there are any until i drop my subframe.

[timmo]

At this point in time, I do not have any RACP cracks, and I am wondering the same about the (full) MASON Bar....would it alone suffice????

If the bar I'm looking at is the same as yours, I'm inclined to say not exactly. The rear points are tied together nicely with a straight-through bolt design, but the front is unchanged.

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.

When I had cracks I did extensive research, and found that there were a handful of cases where cars with just plates had RACPs that were starting to pop spot welds and separate, since those are the next weakest link. CMP or Vincebar are IMO the only two options that actually fix the root of the problem by transferring some of that load to the chassis rails.

[Fresh1179]

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.

[Flat-Six]

I have a 2005 M3 ZCP and don't know if I have any Subframe cracks or not, but I'm planning on having it reinforced just to be safe. Curious of what is considered the best and strongest method of doing this. I've looked at the Mason Bar and I like the look of it in the Trunk, so I was wondering the advantages or disadvantages of it are compared to a Vincebar or CMP reinforcing kit. With the Mason Bar, does it eliminate having to have the reinforcement plates installed.

At this point in time, I do not have any RACP cracks, and I am wondering the same about the (full) MASON Bar....would it alone suffice????

[jbfrancis3]

Mine did not have any visible damage, nor any "real" damage when I ground it down to bare steel except for a single split spot weld and another spot weld starting to pull ever so slightly. This was just one corner (front, drive). Any vehicle is on the proverbial curve, its just comes down to timing and how rapidly it worsens thereafter. I used Lang Racing's plates and they were excellent, FWIW.