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View Poll Results: Would you like to have a CF roof on our E90/E93?
No, since I only like the E92 coupe. 22 39.29%
No, a CF roof on the E90/E93 is over doing it. 13 23.21%
Yes, I have a E90/E93 and would like a CF roof. 15 26.79%
Yes, if the E90/E93 had a CF roof I'd get it instead of a E92. 6 10.71%
Voters: 56. You may not vote on this poll

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      09-10-2008, 07:28 AM   #1
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Where is the CF roof?

Although the amount of "go fast factor" it adds to the E92 is questionable, most of us got the CF roof for its looks. Awesome isn't it? But why is it exclusive to coupes? I understand, with all the mechanical parts, it will be difficult to make the hard top of the E93 CF, but what about the E90? Can't the sedan use a CF roof?

I am no engineer, but the roof on the sedan isn't much different from the coupe. I know, with four doors, the E90's roof is longer, but I've seen much larger CF structures. Is this just a matter of ///M not wanting to make it?

Even with the E93, I still think it will be possible. CF is just a fabric coated with resin. I don't see why can't a foldable roof, especially the large pieses, can't be CF.
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      09-10-2008, 08:29 AM   #2
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just speculation, but economies of scale surely play a part.
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      09-10-2008, 08:51 AM   #3
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Question.... is the entire roof (ie, the supporting structures underneath the roof's body panel) carbon fiber? I doubt they are. My assumption was that it was just a sheet of carbon-fiber replacing the sheet of steel or aluminum they would normally use. Anyone know?
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      09-10-2008, 10:16 AM   #4
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Same reason M5 doesn't have CF I guess. Just a different focus. Their market research probably tells them that the most sedan buyers will opt for the sunroof anyway. If you want the CF roof, then you probably want a more focused car and will take the lighter stiffer coupe anyway.
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      09-10-2008, 11:04 AM   #5
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my .02

Maybe the reason behind the M3 4 door not having the CF roof is because if the owner really is concerned with saving weight he/she would have went for the coupe; yes I understand some might like saving weight and having 4 doors but from BMW's standpoint, as far as their pure performance series goes..M series, the weight saving option offsets itself with the 4 door/convertible car...just my .02; maybe there is a mechanical issue but I'm just looking at it from a Marketing standpoint
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      09-10-2008, 11:29 AM   #6
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E90 is for families.
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      09-10-2008, 12:02 PM   #7
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I don't believe that saving weight is the issue, especially considering that there isn't much of a weight difference between the coupe and the sedan (..equally optioned). IMHO, the coupe received the CF roof simply based on the assumption that the sedan demographic is more understated. I do wish that BMW offerred sedan drivers the option however (..i.e...non-moonroof receives CF; moonroof equipped receives steel roof). A CF roof would make the sedan more appealing to some, including myself.


Simply put.....

.....it's marketing!
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      09-10-2008, 12:22 PM   #8
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I think that it's just a piece of CF on a metal frame.
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      09-10-2008, 12:52 PM   #9
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Quote:
Originally Posted by synclastica_86 View Post
I think that it's just a piece of CF on a metal frame.
I believe that you are correct.
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      09-10-2008, 12:58 PM   #10
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why waste CF on E90's? no matter what u do they wont look pretty
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      09-10-2008, 01:05 PM   #11
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Quote:
Originally Posted by ///Mantis View Post
why waste CF on E90's? no matter what u do they wont look pretty
That's all a matter of opinion ///Mantis, my boy.
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      09-10-2008, 01:06 PM   #12
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Quote:
Originally Posted by Sedan_Clan View Post
That's all a matter of opinion ///Mantis, my boy.
no disrespect, but every E90 vs. E92, every 6MT vs. DCT, every M vs. AMG has to have a douchebag saying something like i said. im just doing it for the sake of consistency
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      09-10-2008, 01:10 PM   #13
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in that case, why didn't you say: why waste ///M on e90 period.
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      09-10-2008, 01:14 PM   #14
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CF roof

Quote:
Originally Posted by mkoesel View Post
Same reason M5 doesn't have CF I guess. Just a different focus. Their market research probably tells them that the most sedan buyers will opt for the sunroof anyway. If you want the CF roof, then you probably want a more focused car and will take the lighter stiffer coupe anyway.
I agree.

Quote:
Originally Posted by synclastica_86 View Post
I think that it's just a piece of CF on a metal frame.
The CFRP panel has one or two steel roof bows spanning between the side members, but nothing else.
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      09-10-2008, 01:17 PM   #15
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Come on... the E90 isn't that bad...
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      09-10-2008, 01:17 PM   #16
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Quote:
Originally Posted by GregW / Oregon View Post
I agree.


The CFRP panel has one or two steel roof bows spanning between the side members, but nothing else.
The question is is the CF roof structual?
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      09-10-2008, 01:19 PM   #17
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Quote:
Originally Posted by ///Mantis View Post
no disrespect, but every E90 vs. E92, every 6MT vs. DCT, every M vs. AMG has to have a douchebag saying something like i said. im just doing it for the sake of consistency
I'm glad I held off on flaming you back then.

Either way, I'm not sure I want my next M3 to look "pretty" anyway. My current M3 looks "pretty" (I guess), and my buddies bust my chops enough for that as it is.
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      09-10-2008, 02:19 PM   #18
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Quote:
Originally Posted by GregW / Oregon View Post
I agree.


The CFRP panel has one or two steel roof bows spanning between the side members, but nothing else.
Edit: Greg you were right. There is one roof bow across.
---------------------------
I think besides the frame on four sides, which are steel, the rest of the roof os CFRP, with nothing underneath. There is a video on BMWNA web site that shows the bounding process on the roof.
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Last edited by rzm3; 09-10-2008 at 07:03 PM.
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      09-10-2008, 02:24 PM   #19
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Quote:
Originally Posted by synclastica_86 View Post
The question is is the CF roof structual?
Yes. It increases torsional rigitity.
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      09-10-2008, 02:37 PM   #20
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Quote:
Originally Posted by rldzhao View Post
Yes. It increases torsional rigitity.
No it doesnt... its a thin sheet of CF glued to the roof of the car... it provides no structural rigidity vs. a steel piece. The rigidity comes from the steel bows running across the roof.

The cf roof is simply there for lightness and looks.
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      09-10-2008, 03:16 PM   #21
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Quote:
Originally Posted by seriousm3 View Post
No it doesnt... its a thin sheet of CF glued to the roof of the car... it provides no structural rigidity vs. a steel piece. The rigidity comes from the steel bows running across the roof.

The cf roof is simply there for lightness and looks.
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      09-10-2008, 03:33 PM   #22
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Quote:
Originally Posted by synclastica_86 View Post
Come on... the E90 isn't that bad...
it's not. i like it
Quote:
Originally Posted by mkoesel View Post
I'm glad I held off on flaming you back then.

Either way, I'm not sure I want my next M3 to look "pretty" anyway. My current M3 looks "pretty" (I guess), and my buddies bust my chops enough for that as it is.
and why would u flame a bored idiot??
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