Project: 2003 BMW M3

[GTBrandon]

So other than reading through this and thinking to myself, wow I really want to get a 10 year older version of my car now (I love how insane that sounds to most non-car people), I have a question that doesn’t seem to be addressed. I’m not super familiar with the process so this might not make sense to do, but why not weld and fill with foam for double the reinforcement if you are already planning on doing the welding as it seems the foam isn’t that expensive? Planning for hopefully the future as this car has always been a dream of mine and I honestly regret going newer other than the whole broke in college and rely on warranty thing.

That said, I have epoxied plates on, enjoy the car but don't abuse it, and sleep pretty well at night.

Only issue is if I was ever to get this car then it would be destined for the track and every autocross within an hour until it wasn’t road legal anymore. Why did you end up epoxying plates rather than welding. Seems easier but not as structurally sound, no?

[Beej]

Why did you end up epoxying plates rather than welding. Seems easier but not as structurally sound, no?

Just sorta happened, ha.  I originally just planned on pulling the diff to replace the input seal...once I got that out, the job snowballed.

Beforehand, I had talked to two race shops in the area about reinforcement, neither of which wanted to take it on.  So I was on my own.  My general experience (and I know there are good ones out there), is that welds always rust.  Even if properly protected on the outside, it's thin metal and I didn't trust it to not rust inside the RACP.

So that, combined with the fact that my RACP was in good shape, the car was stuck on jack stands, and I could do epoxy myself...here we are.

I am in no way qualified to speak to whether welding or epoxy is better/stronger (particularly for this application).  I did like that epoxied plates are "glued" for 100% of the surface area as opposed to just where the perimeter of the weld is.  Where the welds do one-up epoxy is that you're instructed to drill/expose the threaded receiver in the RACP so as to (rosette, I believe is the term?) weld all 3 layers of metal together.  All I really did was strengthen the skin.  I believe the "Vince-style" support is all done from above, so the plates shouldn't interfere should I decide to go that route eventually.

[RawrImAMonster]

The vince style fix is really about the only way to actually fix the issue. Reinforcement plates, welded or epoxied, are just a bandaid and the car will eventually have problems again. Will they last for 100k+ miles? Probably? Who knows. But if you take some time to look into the issue, it's easy to see they're just bandaids.

Have you ever driven one of these? They are NOT a 10 year old version of your car. The 135i I had and this M3 are about as far apart as rwd coupes from the same manufacturer could be.

[JPolen01]

Have you ever driven one of these?  They are NOT a 10 year old version of your car.  The 135i I had and this M3 are about as far apart as rwd coupes from the same manufacturer could be.

I don't even know what he is talking about. Trying to compare a bloated 4 door/CUV thing to an m3? I am confused.

[Senor_Taylor]

Have you ever driven one of these?  They are NOT a 10 year old version of your car.  The 135i I had and this M3 are about as far apart as rwd coupes from the same manufacturer could be.

I don't even know what he is talking about. Trying to compare a bloated 4 door/CUV thing to an m3? I am confused.

Horsepower is the only thing that matters bro.

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[.RJ]

Have you ever driven one of these?  They are NOT a 10 year old version of your car.  The 135i I had and this M3 are about as far apart as rwd coupes from the same manufacturer could be.

I don't even know what he is talking about. Trying to compare a bloated 4 door/CUV thing to an m3? I am confused.

135 is a coupe.  Seriously considering keeping mine.

[RawrImAMonster]

Have you ever driven one of these?  They are NOT a 10 year old version of your car.  The 135i I had and this M3 are about as far apart as rwd coupes from the same manufacturer could be.

I don't even know what he is talking about. Trying to compare a bloated 4 door/CUV thing to an m3? I am confused.

135 is a coupe.  Seriously considering keeping mine.

He's talking about Brandon's car.  It's a 4 door grand touring 335xi.

[D_Eclipse9916]

FYI, I did the plate fix on my mom's E46, my SE46 race car, my GTS4 car, and most of the racers I know...

If it can handle that, I am sure it can handle some hoonage on a street car. Don't over think these things.

[RawrImAMonster]

The plate fix doesn't really add any protection from the whole trunk floor separating is the thing though. I'm sure it's fine in 95% of the cases, but you don't want to be one of the few that it's not.

The other thing is that this will probably be more of an age related thing. Are these welded plates going to hold up in 10 years?

Like DJ said, you'll most likely be fine with just the reinforcement plates.

[Sully]

Curious, DJ did you happen to look at your plates after the wreck? How did it fair after the stress of a trailing arm pocket ripping out over 100mph?

Another question though, can you even tell if it fails after it's covered with a plate and welds?

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[GTBrandon]

I wasn’t saying my car is simply a newer version of a e46M, just saying I wanted to go back in time to when BMW’s weren’t bloated and filled with fancy screens and fake leather. I lack the connection to my car like I feel in older BMWs and so I would love to experience that by owning an E46 either M3 or 330 to be a more practical track build one day in the future.

---

Why did you end up epoxying plates rather than welding. Seems easier but not as structurally sound, no?

Just sorta happened, ha.  I originally just planned on pulling the diff to replace the input seal...once I got that out, the job snowballed.

Beforehand, I had talked to two race shops in the area about reinforcement, neither of which wanted to take it on.  So I was on my own.  My general experience (and I know there are good ones out there), is that welds always rust.  Even if properly protected on the outside, it's thin metal and I didn't trust it to not rust inside the RACP.

So that, combined with the fact that my RACP was in good shape, the car was stuck on jack stands, and I could do epoxy myself...here we are.

I am in no way qualified to speak to whether welding or epoxy is better/stronger (particularly for this application).  I did like that epoxied plates are "glued" for 100% of the surface area as opposed to just where the perimeter of the weld is.  Where the welds do one-up epoxy is that you're instructed to drill/expose the threaded receiver in the RACP so as to (rosette, I believe is the term?) weld all 3 layers of metal together.  All I really did was strengthen the skin.  I believe the "Vince-style" support is all done from above, so the plates shouldn't interfere should I decide to go that route eventually.

Makes sense honestly, I would have done the same and sounds like you’d already done the research. I do see the Vince as being more effective based on the description of it but I guess the more the merrier if you have the time/skill/resources. DJ what style did you do, simply weld onto the outside? If that worked for you, then I’m thinking it wouldn’t be an issue considering my times will probably be closer to a EV truck if I ever turn this dream into a reality

[D_Eclipse9916]

Curious, DJ did you happen to look at your plates after the wreck? How did it fair after the stress of a trailing arm pocket ripping out over 100mph?

Another question though, can you even tell if it fails after it's covered with a plate and welds?

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My moms car had the plates for only a year, but my SE46 had the plates welded in for 4+ years as a race car before I bought it, and is still going strong today.

My GTS4 car, the plates were just fine on the subframe.  I have managed to have stress failures on these bmws more than anyone I know, to date I am still the only person I know that has ripped out the front frame rail out of an E36.  I am extremely hard on suspensions (had to switch to sphericals since the control arm ball joints were wearing out every 2-3 events).

 I am not saying you can't go above and beyond, but I would weld in the plates and never look back.  If it was a street car I would probably epoxy to reduce chances of rust and then just check them every 2-3 years.    You can tell if it fails, but only if you remove the undercoating. My mom's subframe was cracked in what I thought was a minor spot in one location. Once I pulled off the undercoating it was cracked in 3 of the 4 subframe mounts and extended its way to the trunk.  Welded it all up and just took a look last week when I gutted the car and they are good to go.

[davej]

when I gutted the car

Hold up, am I missing a new race car build thread someplace?!

[D_Eclipse9916]

when I gutted the car

Hold up, am I missing a new race car build thread someplace?!

  I don't want to post up for fear of embarrassment that someone like Taylor who knows how to build "trackworthy" cars might comment.

Yes Race Car V4.0 is currently under the knife.

[davej]

[emoji23]
Exciting to hear!! If you need help interwebbing for parts let me know, it's probably about the only value I could add.

[RawrImAMonster]

Check out the pictures in this thread of a recent failure. Reinforcement plates won't do shit to help this. These type of failures will only become more common as these cars age.

This is probably a $5k+ fix.

http://www.m3forum.net/m3forum/showthrea...925&page=5

[D_Eclipse9916]

My personal thought is that is because they never reinforced to begin with and it propagated FROM where the plates reinforce (which mirrors what I see on failures on these cars as the cracks reach out they increase the flexing of the entire floor). I won't discourage you if you really want to go that farther, just stating what I see when 99% of my race field is E46s being abused constantly, and none see that damage after the plate fix.

[Senor_Taylor]

when I gutted the car

Hold up, am I missing a new race car build thread someplace?!

  I don't want to post up for fear of embarrassment that someone like Taylor who knows how to build "trackworthy" cars might comment.

Yes Race Car V4.0 is currently under the knife.

You can stop now.

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[.RJ]

I've seen it. Although looks like a junkyard, not a 10 second car.

[RawrImAMonster]

I've said this on the chats, but I'm having a hard time deciding on whether or not I want to keep this thing at the moment. I go back and forth on this decision almost daily, but I'm getting to the point where I need to make a decision.

I'm selling the subaru either way.

Option 1: Buy a MK6 GTI (12-13K), keep M3 for now.
Option 2: Buy a MK6 Golf R (18-19K), mod it to 330whp or so (downpipe, fuel pump, tune) and sell the m3. Maybe get an e30 or something to mess with as a project car.

If I keep the M3, there's a few expensive maintenance items coming up. It may be easier just to sell it. It runs and drives very well right now, but there are a few things it really should have.

Things it NEEDS:
Rod bearings, I just hit 130k so I'm really on borrowed time. - ~$700 ish in parts including a used snap on techangle for the angle torque

Things it needs, but can wait:
RTABS - $200 for rtabs, limiters, and rtab tool
Maybe front lower control arms (haven't investigated yet, but one of the ball joints just started making a noise when you turn the steering wheel) - $535
Washer fluid reservoir - $70

Things it should have:
Shifter rebuild kit - $73
Motor/Trans mounts - $293
VANOS rebuild/bulletproofing - $470


Just not sure which direction I want to take with cars right now.