The carbon slicktop thread

[karter16]

Honestly, every time I've clicked on this thread over the years I expect to see photos of Carbon-black coupes with no sun-roof. No matter how many times I get caught out I keep making the same mistake 😂

[Cronenberged]

I recently had a carbon slicktop conversion at a popular Southern California shop. My car was transported over to the shop and I was unable to inspect the work in between or after until it was transported back. I also had my own carbon roof which was transported to the shop. I have my own headliner which I did not ask the shop to install. The shop owner was easy to reach and friendly and I'll just leave it at that.

Here are my observations after getting the car back:

*OEM Windshield is misaligned. This is visually obvious with how much gap there is on one side compared to the other.
*I see scratched paint in the side gutter of the windshield seal like a metal screw driver was used to pry it.
*New windshield seal has a 1-2mm rip
*Glued on roof rail on one side is misaligned. Where the rear window seal and roof rail meet, the window seal protrudes up compared to the other side.
*Inside, there are drilled holes that are not sealed or rust protected
*I see a pried metal roof panel was not bent back on the inside (see photo)
*I see multiple drilled through holes. Instead of drilling just enough to separate the roof panel, welds should not be drilled through.
*Although water tight from my own testing, there are internal areas where I am expecting to see glue but don't see any used.
*The trunk antennae hole was not covered and my trunk was soaked. This also caused condensation in my left taillight. I think this was during the water test for leaks.
*My C-pillar covers were yanked out instead of properly removed
*My rear tint was scratched up along the edges
*My roof rails were painted black, but I see dirt particles under the paint. I feel like using my nail to scratch off the dirt, but it's painted over.
*Will have more photos when I get a chance.

In short, I love the way the carbon roof looks but wish the workmanship was better.

In terms of drive, I can feel the car having less lean around street corners, but my main goal was mainly aesthetics.

spill the beans so others don’t don’t get shitty craftsmanship. We have a whole thread dedicated to speaking about bad service that’s justified. Sucks they didn’t do a good job but don’t protect them….they didn’t protect your car.

[SQ13]

I recently had a carbon slicktop conversion at a popular Southern California shop. My car was transported over to the shop and I was unable to inspect the work in between or after until it was transported back. I also had my own carbon roof which was transported to the shop. I have my own headliner which I did not ask the shop to install. The shop owner was easy to reach and friendly and I'll just leave it at that.

Here are my observations after getting the car back:

*OEM Windshield is misaligned. This is visually obvious with how much gap there is on one side compared to the other.
*I see scratched paint in the side gutter of the windshield seal like a metal screw driver was used to pry it.
*New windshield seal has a 1-2mm rip
*Glued on roof rail on one side is misaligned. Where the rear window seal and roof rail meet, the window seal protrudes up compared to the other side.
*Inside, there are drilled holes that are not sealed or rust protected
*I see a pried metal roof panel was not bent back on the inside (see photo)
*I see multiple drilled through holes. Instead of drilling just enough to separate the roof panel, welds should not be drilled through.
*Although water tight from my own testing, there are internal areas where I am expecting to see glue but don't see any used.
*The trunk antennae hole was not covered and my trunk was soaked. This also caused condensation in my left taillight. I think this was during the water test for leaks.
*My C-pillar covers were yanked out instead of properly removed
*My rear tint was scratched up along the edges
*My roof rails were painted black, but I see dirt particles under the paint. I feel like using my nail to scratch off the dirt, but it's painted over.
*Will have more photos when I get a chance.

In short, I love the way the carbon roof looks but wish the workmanship was better.

In terms of drive, I can feel the car having less lean around street corners, but my main goal was mainly aesthetics.

Damn dude, so sorry to hear about the issues. This is exactly what I was worried about and why I decided to just DIY it. Hopefully you can get everything sorted out.

For anyone thinking about DIYing, I made a DIY thread that you can check out and can rent out my one time use tools. I’m also happy to do installs for locals if my schedule allows.

[Epsilon]

Damn dude, so sorry to hear about the issues. This is exactly what I was worried about and why I decided to just DIY it. Hopefully you can get everything sorted out.

For anyone thinking about DIYing, I made a DIY thread that you can check out. I’m also happy to do installs for locals if my schedule allows.

Had I known you offer installs, I'd probably consider shipping my car out to you if the numbers add up. This project was already expensive just parts alone.

I purchased all the tools to DIY too but just couldn't find the time to do it with family and work. After seeing so many E46s and other M3s come out of this shop on IG, I thought my car would be under quality care. The owner knows his E46s in and outs, but I don't know if he works on the cars himself. The folks who's had their conversions done probably never looked inside since their headliner's installed by the shop already.

Not sure how I can work things out with the shop yet as I'm still undecided.

Even my wife noticed this:

[Nate047]

That sucks, but the only way this post would actually be helpful is if you name the shop so others can avoid it.

[bavarian3]

This is scaring me off from doing the job. It seems hard to get a perfect fit and there's no going back once you rip that og roof off. There have been others with water sealing issues as well.

Epsilon please provide or DM the shop name.

[x Spades x]

Hey Fellas

So i have another E46 M3 to modify. My previous was FBO and I got the Challenge CSL roof (2014), as I heard they made the oem roofs at the time.

Do they still make the roofs? Are there better quality ones out now?

Kareem

[0-60motorsports]

Hey Fellas

So i have another E46 M3 to modify. My previous was FBO and I got the Challenge CSL roof (2014), as I heard they made the oem roofs at the time.

Do they still make the roofs? Are there better quality ones out now?

Kareem

Karbonious bro! I highly doubt challenge made the OEM roofs. No way.

[Epsilon]

Hey guys, the only thing that can "easily" be fixed is the windshield and I want to see if I can get that repositioned locally. I'm going to let thing setting first before giving out the shop. You can drop me a shop name I will let you know if I recommend them or not or don't know.

On a side note, does this rear window seal look right? Not the crease, but how the edges fold up and the gap?

[Slideways]

Challenge definitely did not make the OEM roofs. BMW did those in-house until the tooling/mold wore out, at least that was the reasoning I remember.

I'm not sure if it was only Challenge or Karbonius who made the F80 style roof for the E46, but I have seen one example where the clearcoat had textured from the CF. I have also seen an Evolve roof that had the same issue.

Whatever resin or coating the BMW factory uses does not texture like this. Maybe bigjae46 can explain.

[Epsilon]

Hey Fellas

So i have another E46 M3 to modify. My previous was FBO and I got the Challenge CSL roof (2014), as I heard they made the oem roofs at the time.

Do they still make the roofs? Are there better quality ones out now?

Kareem

"RKP Composites has acquired every BMW aero component mold from Challenge USA."

https://www.m3post.com/forums/showthread.php?t=1542168

[SQ13]

Ignore the condition of my front windscreen moulding—my bad for not using a new seal when the glass was reinstalled. I watched my glass guy install the front and rear glass. All he did was push the glass up towards the roof until it wouldn’t slide up anymore. If that’s how your glass was installed, I think your roof was installed slightly crooked.

[bigjae46]

Challenge definitely did not make the OEM roofs. BMW did those in-house until the tooling/mold wore out, at least that was the reasoning I remember.

I'm not sure if it was only Challenge or Karbonius who made the F80 style roof for the E46, but I have seen one example where the clearcoat has textured from the CF. I have also seen an Evolve roof do the same.

Whatever resin or coating the BMW factory uses does not texture like this. Maybe bigjae46 can explain.

What do you mean by textured? The underside of the roof?

Composite parts will have a thin layer of the matrix or resin above the fabric reinforcement if the mold surface is polished smooth. For example the roofs I make, you see a clear layer of epoxy which if wet sanded and polished will look glossy. The problem is I think most clear coats are polyurethane which does not chemically bond to epoxy. So you have to get a mechanical bond but roughing up the surface. There are clear gel coats which are epoxy compatible but even those will fail after enough heat and UV exposure.

The problem is epoxy does not thermally expand, polyurethane does. So if you clear coat the roof and it gets hot enough, then you'll start to see the clear coat separate.

Duratec sunshield is the most widely used product for UV protection. It is a sprayable clear gel coat. A lot of shops will spray sunshield in the mold and then layup the part.

[Epsilon]

This is scaring me off from doing the job. It seems hard to get a perfect fit and there's no going back once you rip that og roof off. There have been others with water sealing issues as well.

Epsilon please provide or DM the shop name.

DM'ed earlier.

I reached out to the shop and long story short, he is not accepting responsibility.

I only asked for the cost of the windshield to be realigned and likely a new one if cracked during removal. He offered $140 for what he paid to his windshield installer of 10 years and claims that it's 3rd party and he is not responsible. OEM Windshield is like $500+.

Anyway, moving on. Send a DM to barvarian3 for questions. lol

[Arlen4369]

DM'ed earlier.

I reached out to the shop and long story short, he is not accepting responsibility.

I only asked for the cost of the windshield to be realigned and likely a new one if cracked during removal. He offered $140 for what he paid to his windshield installer of 10 years and claims that it's 3rd party and he is not responsible. OEM Windshield is like $500+.

Anyway, moving on. Send a DM to barvarian3 for questions. lol

I think OEM windshield is NLA