The CF roof is a marketing gimic.

I've got extensive experience with composites and can tell you that CF roof *skin* is not going to save much weight over a metal one. The structure under the skin is still steel. Obviously, most of the weight is saved from the elimination of the sunroof assembly.

Not to say it doesn't look cool though....

 

Wrong!
First, it's not skin. Second, there's no steel anywhere on top of the car. Entire piece is call Carbon Fiber Reinforced Plastic (CFRP).

http://en.wikipedia.org/wiki/Cfrp

http://www.worldcarfans.com/News.cfm...01/country/gcf

Here are some links to read and gain more experience.

http://www.m3forum.net/m3forum/showt...hlight=CF+roof

http://www.m3forum.net/m3forum/showt...light=csl+roof

http://www.m3forum.net/m3forum/showt...bon+fiber+roof

Roof from underneath.

 

I'm sorry, I just had to laugh. Thank you enlightening me on what CFRP is.

First off, I should simply state that i've had a Composite manufacturing business in the past and worked extensively on new composite technologies. We worked *mostly* with carbon fiber. No need for me to "gain more experience" on wikipedia or "M3 Forum", which is quite a staple in the composites world...

#1- That is a skin. See those metal bars which the CF piece attaches to? Those are structural metal bars. Those are the foundation of the structure. The CF piece simply encloses the area between those bars. You are thinking of the term "overlay" where you wrap CF on top of something else, like metal. That is not what I am refering to. Most body panels are basically skins.

#2- Most of the weight coming off those CSL roof transplants is coming from the sunroof assembly. If you compare the weight between a CF roof skin and non-sunroof metal skin, I wouldn't expect a massive weight change. A few lbs, but thats is nothing in the big picture.

#3 CFRP is nothing special as you make it sound. Reinforced Plastic = Resin. Its the same way all other CF parts are made. Nothing new/special here, just another way of stating the obvious.

If you have any further links or statements, feel free to chime in...

 

Just messing with you man.

Thought skin is like the ones you see on some honda civics. They call it CF overlay/wrap or whatever.

 

Damn... just wasted 10 minutes typing that up.... i'll send you a bill in mail...

Wrapping the stock metal roof skin in CF would be a much better route IMO. Most of these guys just want the "look", so might as well save yourself $4000 (or whatever the part + install costs).

 

One last statement, you can buy those structural metal bars in CFRP. Just like in Formula 1 suspension links. Also, you said CFRP is nothing special or new. CF saves 50% of weight over steel (steel M3 roof 12lbs, CF = 6)and offer same or better regidity. If it's no special, everyone will be using it on all their cars such as Ford Focus to Hummer. There is a reason why the most exotics like F1 cars, Enzo and CGTs have those parts on. If you're still disagree, you could sent a letter to FIA and ask all the F1 teams to start using steels instead of CFRPs because Reinforced Plastic = Resin; nothing new.

You're right about few pounds but it's the few pounds where it effect the most (I'm sure you know this already). Highest point of the car is the best place to save weight. Try running around the block with motocycle helmet on. It's just a few pounds. And, go thru turns quick. I'm sure, you'll know.

I drove the car with CF roof. It's feel almost as if there are BIG sway bars on. The car has zero body roll and steering feel as if it has quicker steering rack. It work!! Trust me. Sometime smallest things can make a big difference.

 

Are we joking again? You are hard to read through the 'net.

When I stated it is nothing special, I meant, the term "CFRP" simply means carbon fiber fabric with resin. When I said, its a "CF roof" and you said, the piece is "CFRP". From my vantage, you made it sound like some new compsite process/technology. My point is, it's the same thing, basic composite structure. This is nothing new though, its like when these body kit guys use the term "FRP" (fiber reinforced plastic) for their fiberglass/polyester crap. Its technically correct, but I can't count the amount of times people say "no, its not fiberglass, its fiber reinforced plastic", thinking its something else other than a POS.

I think CF is very "special," hence why I had business based on it, and tried to push the limits of where it is applied. Believe me, i've seen/handled CF parts that would blow the minds of automotive guys who think they have seen strong/light CF parts. I'd still be in the biz if it wasn't for the massive supply shortage at the moment....

 

Okay, now I know you are joking...

 

I just learned something

....and ill still go with a sunroof and painted roof

 

this thread just off on a crazy CF tangent!

 

i like you guys....but youre crazy!

 

Sorry Spencer but I disagree. When I did the cf roof on my m3 there were no structural bars under the aluminum roof skin underneath, in fact most of the cars rigidity was in the a-pillars hence why there were no bars underneath. It saved a good amount of weight removing the sunroof glass, assembly, motor and so on, also lowers the center of gravity , IMO a great mod for someone after 100%performance out of their car!

 

You aren't disagreeing with me.

There are bars under the skin. You can see them in the links posted above. And I fully agree the pillars are the main structure (I was including these in my term "bars"). My point here is that the CF on the roof is just skin. Its not like you are replacing 50lb structural steel bars with lightweight composite replacements.

As you said, and I did too, the removal of the sunroof assembly is where the majority of the weight comes from. Not the use of CF.

You'd get the same effect by welding a non-sunroof metal roof onto a sunroof equipped car, or by just ordering a sunroof delete car from the factory.

 

Oops in that case yes I totally agree, my point was basicaly its not a gimic and depending on the person very worth it, awesome option for someone like myself , past 3cars have been sunroof-less hah

 

I work in NATM tunnels and behind TBM's and I ve seen fiberglass bolts reinforcing concrete replacing steel... Composites are strong but as Spencer said, on the car panels just there to "cover". Not to tie the car together.

The CF roof panel on a 3600 pound car reminds me of a fat chick holding a latte cutting her hair as a way to lose weight...