E46 M3 Best Subframe Reinforcement Kit?

[Cephyr13]

2002 E46 M3

My subframe reinforcement kit ripped out if my subframe.

Whats the best, strongest kit out there to replace it with?

Thanks.

- Brian C.

[9kracing]

Reddish V3 if I'm not mistaken.

I actually brought my shop the Reddish plates to install, and they told me they didn't want to drop my fuel tank, and that there was no reason to go with those, the Turner plates would be fine. So I let them install the turner plates on my car. I regret it every time I read one of these posts.

[WoGGo]

CMP Auto Engineering

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/183365-something-new-from-cmp-auto-engineering

[WestBankM4]

Reddish V3 if I'm not mistaken.

I actually brought my shop the Reddish plates to install, and they told me they didn't want to drop my fuel tank, and that there was no reason to go with those, the Turner plates would be fine. So I let them install the turner plates on my car. I regret it every time I read one of these posts.

It's all good bro, my shop did the same thing when doing my Vincebar. I know those feels.

Sent from my Pixel 7 Pro using Tapatalk

[01SG]

Turner instructions state to remove the fuel tank too. Between the space and fire risk, I do not know why anyone would not drop the fuel tank for this job. Those shops were part of the problem.

It seems what plates you have is far less important than whether or not the full plates-brace reinforcement is done. The quality of the work also comes into play.

[Tbonem3]

It seems what plates you have is far less important than whether or not the full plates-brace reinforcement is done. The quality of the work also comes into play.

Probably the most salient point made in any of these threads.

I'd rather have NO plates with TOPSIDE reinforcement than just plates and no topside. Assuming the RACP is in good shape.

Or, another way, I prefer my TMS plates and topside GTR brace against just having bigger plates like CMP or reddish or whoever, and no topside.

[Cephyr13]

Probably the most salient point made in any of these threads.

I'd rather have NO plates with TOPSIDE reinforcement than just plates and no topside. Assuming the RACP is in good shape.

Or, another way, I prefer my TMS plates and topside GTR brace against just having bigger plates like CMP or reddish or whoever, and no topside.

Explain what part you mean by topside. I've seen one setup that had topside but it was overkill. What product do you recommend and do you have a link to it so I can see it?

Thanks.

[Cephyr13]

Is there an option to have the forum email me whenever someone replies to my post? Helps me respond quicker and not forget about it.

[Tbonem3]

You can look at my journal. You can also search "topside." There are solutions from Vince, CMP, DMG, puretech, SME, yurkan, Mason, more I'm sure.

[bigjae46]

I think what we all have discovered is putting plates under the car is a half fix. You have to tie in the subframe mounting points to the frame rails which is what the vincebar does. Really can't do that underneath the car - the suspension, diff, driveshaft and fuel tank are in the way among other things.

The vincebar does the tie in with the frame rails on the inside or topside.

If its a daily driver and want to keep your backseat then the new CMP version seems like a good option.

FYI, my car had more cracks on the top or interior of the car than underneath.

[VinceSE2]

Explain what part you mean by topside. I've seen one setup that had topside but it was overkill. What product do you recommend and do you have a link to it so I can see it?

Thanks.

It’s a matter of unloading the RACP from the loads (or more correctly reliving the RACP from most of the loads) that are flexing it.

It’s the cyclical loads that break the RACP.

So the top side unloading addresses the underlying design flaw/issue rather than, like with underside plating, just adding band aids to the symptoms (the cracks forming on the underside).

Having a look at these videos is well invested time https://youtube.com/playlist?list=PL...1SznnEw9N81cN7


Sent from my iPhone using Tapatalk

[Z3 Coupe]

It’s a matter of unloading the RACP from the loads (or more correctly reliving the RACP from most of the loads) that are flexing it.

It’s the cyclical loads that break the RACP.

So the top side unloading addresses the underlying design flaw/issue rather than, like with underside plating, just adding band aids to the symptoms (the cracks forming on the underside).

Having a look at these videos is well invested time https://youtube.com/playlist?list=PL...1SznnEw9N81cN7


Sent from my iPhone using Tapatalk

So is it better to do the top side first?


Sent from my iPhone using Tapatalk Pro

[AussieE46M3]

So is it better to do the top side first?


Sent from my iPhone using Tapatalk Pro

I would say no as a lot of the fatigue related failure happens on the underside that needs to be repaired and compensated for with underside plates.

If you had a brand new, 0 mileage carrier panel and didn't install factory subframe bushings you could likely do what TboneM3 suggested and fit topside reinforcements and no underside plates however, the front two subframe mounts are prone to crack under/around the stud so I personally feel underside plates would still be an inevitability for just the front two, rear cradle mounts.

If your car hasn't got a brand new panel in it I'd do underside first. If you're on a budget and want to reduce the initial cost, you can buy chassis rail plates to close the gap between the top of the RACP & chassis rail when putting underside plates in and then add further topside reinforcements at a later date.

[tlow98]

Yep. Another decade on the real discovery is happening… err, we’ll, again!

[Pklauser]

It's really fascinating to see how the community thoughts on this have evolved over time. I'm personally 100% on board with topside reinforcement. The evidence is there and the engineering makes sense: tie the subframe to something structural, not the floor. A thicker floor is still not structural.

Run from any shop that tries to tell you it's not necessary.