Best subframe reinforcement kit?

[Arith2]

Bottoms plates address what someone saw with their eyes. There's feeling secure and there's fixing the problem. Vince addressed the actual problem.

[simonnim]

I have been talking with Vince about a group buy, so stay tuned

Bring it up here!

[WestBankM4]

Bottoms plates address what someone saw with their eyes. There's feeling secure and there's fixing the problem. Vince addressed the actual problem.

So you're saying if your RACP is in good shape, no cracks at all seen with the eyes, installing JUST the Vincebar will solve the issue?

My RACP is intact on my 110k mile M3, no cracks. I bought the Vincebar already but was planning on getting skins underneath, is it worth it at this point?

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[STAATS]

At a high level:

The topside kits solve the problem, well at least for the rear points they do, its hard to full solve the front points without a cage or something more elaborate like the CMP kit ... but arguable if you lock down the rear right the front solves itself... not technically true but yes

The underside kits repair damage such as a cracks and then cover the problem

Arguably if you have no cracks and you do a topside kit you are sorted... but most of the time there are hidden cracks and once cracks are there, even if you have done topside they can still propagate so its still bets to do the underside... also doing the underside is good for the front as it spreads the load, as the front cups most kits do are also only spreading the load. so with the rear locked down and the front having its load spread both above and below you should be effectively locked down at the front.

[heinzboehmer]

My RACP is intact on my 110k mile M3, no cracks. I bought the Vincebar already but was planning on getting skins underneath, is it worth it at this point?

Have you removed the subframe and undercoating to check for cracks? They're usually obscured by the subframe bushings and, if small enough, can hide beneath the undercoating too.

I would do plates even if I couldn't find any cracks. Getting the VinceBar on involves doing like 95% of the work of doing plates, so might as well.

[Slideways]

Bring it up here!

Vincebar Group Buy thread -

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/91310-vincebar-group-buy-2021

[Arith2]

So you're saying if your RACP is in good shape, no cracks at all seen with the eyes, installing JUST the Vincebar will solve the issue?

My RACP is intact on my 110k mile M3, no cracks. I bought the Vincebar already but was planning on getting skins underneath, is it worth it at this point?

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What I'm saying is someone removed the subframe, saw cracks, and that's where their problem solving ended. They assumed plates would do the job but really, it's an issue with the chassis flexing. You have to remove the subframe and clean the underside of your car to see the cracks. Looking with everything bolted in the is not good enough. The cracks will hide under dirt and grime as well. This is what I mean about seeing cracks with your eyes. Do a proper inspection. I can guarantee you there are cracks. I have not read someone not having them. There might be one or two out there but they'll be extremely low mileage cars. What I do know is my 2006 with 78k mile has cracks and just about every M3 that was inspected with lower mileage than mine also had cracks.

[old///MFanatic]

Do a proper inspection. I can guarantee you there are cracks. I have not read someone not having them. There might be one or two out there but they'll be extremely low mileage cars. What I do know is my 2006 with 78k mile has cracks and just about every M3 that was inspected with lower mileage than mine also had cracks.

We’ve inspected several Southern California M3’s with 125K-200k mileage that had no fractures. Even borescoped showed good. Just saying they are out there. Like most issues, you hear when there’s a problem but nothing when there isn’t.

[WestBankM4]

Very good points from all of you. From a visual standpoint standing underneath my rear subframe, I found no cracks. I am aware they can hide underneath the subframe once removed or under coating, paint, etc., but so far so good from my inspection and a local shop. I'm going to confirm once I pull the subframe for my suspension refresh, but lets say my car is this unicorn w/ 110k miles and no cracks.

With zero cracks after a thorough inspection, will installing JUST a Vincebar solve the issue going forward?

[heinzboehmer]

With zero cracks after a thorough inspection, will installing JUST a Vincebar solve the issue going forward?

Technically yes. But I'm not sure I would sleep well knowing that I did all that work and skipped the plates because I couldn't find any visible cracks. It's been shown that the subframe mounts cracks due to a fundamental design issue that —given enough time— will affect all cars. This is not a manufacturing issue and thus is not something that might never present itself on your car.

Yes, the VinceBar addresses the fundamental design issue that is present in the car and will divert the forces away from the thin sheet metal of the RACP and wheel well —making it so that it does not experience any more fatigue than it already has. But, the existing metal will have already experienced many stress cycles and may have lost its original structural characteristics, even with no visible cracks.

I wouldn't do just the topside reinforcement, especially considering how little extra work it is to slap some plates in if you're already doing everything else.

There's some great info here if you want to get into all the technical aspects of this:

https://cmpautoengineering.com/pages/technical

https://web.archive.org/web/20170731214304/http://www.m3forum.net/m3forum/showthread.php?t=555302

[WestBankM4]

Technically yes. But I'm not sure I would sleep well knowing that I did all that work and skipped the plates because I couldn't find any visible cracks. It's been shown that the subframe mounts cracks due to a fundamental design issue that —given enough time— will affect all cars. This is not a manufacturing issue and thus is not something that might never present itself on your car.

Yes, the VinceBar addresses the fundamental design issue that is present in the car and will divert the forces away from the thin sheet metal of the RACP and wheel well —making it so that it does not experience any more fatigue than it already has. But, the existing metal will have already experienced many stress cycles and may have lost its original structural characteristics, even with no visible cracks.

I wouldn't do just the topside reinforcement, especially considering how little extra work it is to slap some plates in if you're already doing everything else.

There's some great info here if you want to get into all the technical aspects of this:

https://cmpautoengineering.com/pages/technical

https://web.archive.org/web/20170731...d.php?t=555302

I appreciate the information, what's another couple hundred dollars for completeness sake. Like you said, everything is already out. May go with the epoxy/rivet skins that are available. I'd hate to weld knowing the cycles of fatigue and stress already presented at 110k like you said. Heating up that metal is going to weaken it no matter what.

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