Convertible top mount subframe bar?

[macaroni86]

I know all the normal manufacturers (CMP, Vincebar, Mason, etc.) of these top mount reinforcement bars do not make a version compatible with convertibles. Has anyone cobbled together something to accomplish the same result they can share or is this something you just get a welder to fabricate when doing subframe reinforcements?

[dilmorecg]

I have been looking for one for a while but I haven't found anyone that makes one. I did have my trunk completely pulled apart just recently and it looks like it is possible since the top mounts have some clearance...not much though. The bracket would have to go down first instead of just straight across like a coupe to clear the area where the soft top goes.

[macaroni86]

Yeah, the strut tower bars would be difficult. I was hoping something across the floor though for subframe reinforcement. I imagine a welder could fabricate something with a boxed section and plates á la vincebar style but I don't know.

Sidebar: LSB and Kiwi sounds wild, I bet you get some looks with that combo. LSB/Cinnamon here

[ATB88]

Probably about 2 years ago now, I was chatting with Vince about the compatability of his bar with convertibles. I can't remember the details, but my impression was that it is installable, just not entirely. But mostly? Something about front gussett cups.

I think it's worth reaching out to Vince directly and asking him about it. He was very helpful and I think was basically saying it's no problem to install his bar on a convertible, it just won't provide *all* of the reinforcement it would on a coupe. Things/design may have changed since then, though.

[macaroni86]

Good to hear. I actually did email him today about it. He could corner the market too. There's dozens of us! I figured it wouldn't be worth the R&D effort from scratch but with the work he's already done, it's got to be nearly 3/4 the way there. Guess I'll see what he replies back with.

[dilmorecg]

Probably about 2 years ago now, I was chatting with Vince about the compatability of his bar with convertibles. I can't remember the details, but my impression was that it is installable, just not entirely. But mostly? Something about front gussett cups.

I think it's worth reaching out to Vince directly and asking him about it. He was very helpful and I think was basically saying it's no problem to install his bar on a convertible, it just won't provide *all* of the reinforcement it would on a coupe. Things/design may have changed since then, though.

From what ive found the Vincebar set up will work on the rear 2 mounts but the gusset caps wont work on the fronts. You could definitely do just the rear part. I was reading on the last forum since someone was selling a vincebar set for a good price and he was supposed to be working on something for the convertible front mounts but nothing yet.

macaroni86 - I really like LSB/Cinnamon and was going to do that but found a Kiwi interior in Canada close to me so I thought id give it a shot. Definitely different. Probably not another one like it. Im just finishing up a re-dye and refresh of my interior and was planning on posting up some pics when im done.

[heinzboehmer]

Im just finishing up a re-dye and refresh of my interior and was planning on posting up some pics when im done.

You should!

[poss]

From what ive found the Vincebar set up will work on the rear 2 mounts but the gusset caps wont work on the fronts. You could definitely do just the rear part.

Yes, I believe this is correct.

CMP advised me that the convertibles don't need a front reinforcement bar due to the fixed rear seats (but you can still get popped gusset welds there). I had a DIY stealth bar made up out of 1" box section steel. This size required an extension strip to be added to the floor panel cutout so it could be welded back on (but that's probably unavoidable anyway). I had the cutout re-welded and boot floor repainted by a body shop - looked OEM when done. Noticeably stiffened up the backend (had poly subframe mount bushes put in too)

The stealth bar combined with a good front strut brace really stiffens up the 'vert nicely.

The CMP is an H bar config adds another directly between the chassis rails - but this intrudes into the boot

From what I learned this kind of bar is essential to stop cracking. Putting reinforcement plates on the underside to repair cracks is treating the symptom not the cause. The bar directly couples the rear mounts to the chassis rails, thereby solving the chassis design flaw that relies solely on sheet metal to do the job (which flexes and eventually fails due to fatigue)

[Egone]

I read on m3cutter apparently this bar will work with verts. https://www.s-m-eng.com/product-page/e46-racp-brace

[maw1124]

I’m told that the rear subframe issue isn’t really a problem on convertibles, as the chassis is already beefed up to handle the lack of a top... this from a source who’s way more knowledgeable and into these BMW M cars than I ever will be... are there any confirmed vert owners with rear subframe issues? that might feed into why you can’t find reinforcement bars for convertibles.

maw

[macaroni86]

I'd heard the same thing but just had my subframe reinforcement completed a couple weeks ago anyway. 164k miles and here's a couple example pics of my floor pan cracks. It doesn't seem to matter vert or not, all E46 have subframe problems.

[mrgizmo04]

For the last few posts on verts being beefier and not needing a reinforcement, article 2 from CMP outlines the different failure modes, which includes verts.

https://cmpautoengineering.com/pages/technical

Sent from my SM-G950U using Tapatalk

[poss]

I’m told that the rear subframe issue isn’t really a problem on convertibles, as the chassis is already beefed up to handle the lack of a top... this from a source who’s way more knowledgeable and into these BMW M cars than I ever will be... are there any confirmed vert owners with rear subframe issues? that might feed into why you can’t find reinforcement bars for convertibles.

maw

I have a vert - bought second-hand from a BMW dealer with only 67,000 Kms (well under 50,000 miles) on the clock last year. It had cracking around left rear sub-frame mount. Threatened to sue them, got partial refund and put in custom 'stealth bar' solution' (see my previous post on this thread).

As CMP says, all E46s will eventually fail (except for the compact)

[Andrew 06M3Cab]

I read on m3cutter apparently this bar will work with verts. https://www.s-m-eng.com/product-page/e46-racp-brace

Does anyone here have experience with this? I have been looking for a solution for a while. I had the RACP reinforcement done this year, and would like to beef up the bracing. And yes, convertibles ARE subject to cracking.

[ZHPizza]

Does anyone here have experience with this? I have been looking for a solution for a while. I had the RACP reinforcement done this year, and would like to beef up the bracing. And yes, convertibles ARE subject to cracking.

I just got mine today. Amazing fit. Trying to talk a friend into installing one on his vert since it's one of the few options that fit:

https://www.instagram.com/p/CECNVkRqDBb/?igshid=yool1ptj6s5f