The carbon slicktop thread

[bavarian3]

FYI - I paid $2500 for the labor alone and he sourced the OEM glass from a local dealer which I also paid for. Carbon roof, new OEM seals, and roof bow were supplied by me.

I should have asked for the street car installation package instead of track car. lol

I may have missed it, but what do you plan to do about sourcing a slicktop headliner?

[bigjae46]

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 at the time and I'll just leave it at that.

For anyone else looking into doing this, let this be a list of items to look out for.

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 (see photo).
*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
*Parts of the front and rear windshield seal edge were folded in. As simple as it sounds, I used a trim tool to lay the edges flat against the glass
*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 sheet metal roof panel flare out (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. Owner told me to cover it up with a plug, but in my head I'm thinking why he didn't just tape over it in the interim if he knew about it.
*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, that sucks. Disappointing it is a well known shop.

Looks like the underside is a unidirectional cloth? I can see the threads woven into the carbon. I wonder if they just layup up a cosmetic layer and then built it up with a unidrectional cloth which would be cheaper and faster. But I'd be a little disappointed with a $2000 roof. You want to layup the roof with a +/- 45 degree cloth to better align with the loads.

[Epsilon]

Sorry to hear this, and it's a bummer for all of us. I assumed they were the go-to given their apparent experience with the project.

FYI - I paid $2500 for the labor alone and he sourced the OEM glass from a local dealer which I also paid for. Carbon roof, new OEM seals, and roof bow were supplied by me.

I should have asked for the street car installation package instead of track car. lol

[bavarian3]

You guys are right. I got work done at 2M.

I was lured with their euro headliner saying that they may have one available and if my car was in their shop, I could get it first before others waiting for it. Once my car was transported there, the story changed to how their mold is almost complete and it just kept dragging out since. After 2 months of waiting with no headliner, I just wanted my car back and then I posted my observations in my initial post. David was very pleasant to work with throughout the process and there was no way I thought anything could go wrong with all the carbon conversions they may have performed. I did have to press him a little to start working on my car and either he was very passive because he was very agreeable or I was just a fool. Likely, the latter.

Sorry to hear this, and it's a bummer for all of us. I assumed they were the go-to given their apparent experience with the project.

They have been stringing along production of the headliner for over a year now, even having sold one on marketplace, then going back to "still working on it". Ref: https://nam3forum.com/forums/forum/m...730#post263730

Looks like the best way to do this job is at home, like most jobs with these cars.

[Epsilon]

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.

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

You guys are right. I got work done at 2M.

I was lured with their euro headliner saying that they may have one available and if my car was in their shop, I could get it first before others waiting for it. Once my car was transported there, the story changed to how their mold is almost complete and it just kept dragging out since. After 2 months of waiting with no headliner, I just wanted my car back and then I posted my observations in my initial post. David was very pleasant to work with throughout the process and there was no way I thought anything could go wrong with all the carbon conversions they may have performed. I did have to press him a little to start working on my car and either he was very passive because he was very agreeable or I was just a fool. Likely, the latter.

[0-60motorsports]

I guess get whatever you want, karb is one of the best in the market and everything is manufactured in house.

[x Spades x]

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

Not the CSL roofs... I think at the time people were saying they were making the current BMW roofs. I got confirmation from a few sources back then, thats why I got it. My previous roof was perfect. Weave, finished, fit... it looked oem with zero issues for the 12 years I had it. Slap a ppf up there and it was good to go.

This was before Karbonius made them (they were actually still Repoman starting of their first airboxes).
Evolve started making the roofs, but they had qeave issues abd spots you can see through.

This mod has been so popular over the years and I know there have been some new players producing. So Karbonius is better the RKP now?

[Slideways]

The alignment of the roof being off, the roof rails not fitting properly and issues with the damaged spot welds reminded me of this video, which was posted in the carbon roof DIY thread:

He highlights all those issues and more with the roof he is removing.

[Slideways]

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.

The topside where the clearcoat is sprayed. After some heat cycling, the clearcoat slowly goes from perfectly smooth to being textured in the pattern of the CF weave. From what I understand , they remove the part from mold, scuff it up, spray automotive clearcoat and then sand and polish.

[Epsilon]

I think OEM windshield is NLA

Salt on wound

[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

[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

[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.

[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.

[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