6speed

Hey guys, just did a form search with no related results; has anyone though about doin a carbon-fiber roof for the RX-8? how much would such a kit cost? not only would this lower the weight of the car, it would also lower the center of gravity (big plus in autoX). Also, does any light pass through carbon fiber? because if so, replacing the sunroof with a sheet of carbon fiber coould be a more cost effective way with the same significance. after all, the glass is the heaviest part of the car and looking up at a sheet of carbon would be sweeeet. let me know what you guys think, a carbon fiber roof would be SICK

pdxhak

iTrader: (2)

never ever going to happen

6speed

Why not? Nobody wants to take the time to engineer it? That's one mod i would do in a heartbeat.

N rider89

so sunroof <----> CF replacement?

that sounds a little excessive and probably way to expensive.

there really isnt a market for this either. if people who are more centered towards performance would have gotten an rx-8 with out a sun roof

6speed

BMW did, any speculation as to what this would cost? yes i agree about the sunroof, but driving the 8 with wind shooting every which way is an experience unlike rolling down the windows

XDEEDUBBX

there are kits for the 350z that do an overlay for it..hehe

WreakLoosE

I know a guy that used to work with team Prototype that can make the CF roof.... They made one for my friends Matrix.. Came out NICE you can probably check them out at Team Prototype.com I think they work with http://www.cftype.com/carbon_fiber/ It will cost lots of $$$$ I think.. so if you want it done your gonna have to just bend over and take it.. with no vassoline.... just a match and a little bit of gasoline.... YEA! (Ice Cube Preditor Album)

gr8rx

..........an overlay would add weight........but you know that........it'd look cool if you could convince performance peeps it was real.........and not rice ....

6speed

Hmm...well maybe after a year or two more of college ill be able to make one myself, few ideas already shooting through my head...im double degree'n with business and mechanical engineering, so who knows maybe i'll be producing some stuff for the 8 in years to come at the lowest costs i can configure. It just seems like a sheet of the fiber (ie, a oem CF hood is like $450) finding some way to reinforce it at minimal cost...easier said than done. Im guessing the people you mentioned charge in the 4 to 5 figure range for such a project?

P.S. I just finished an autocad sketch with actual rx-8 roof dimensions...anyone know how much, say...4ftX5ft of the fiber is? what is best carbon fibers for this kind of application? what is the gel you apply to it so it hardens and shines? and how strenuous the process of taking a mold is?

kwescott

Isn't their structural considerations to be made here? I would assume the the frame/roof of the 8 needs to be very rigid given the clamshell door configuration.

I've seen the carbon fiber overlays..heck, isn't their even an overlay available for our trunk lids...., but the question would be.....why?

Carbon Fiber for Autox? Sure, but you'd be in BP...and why spend all that money on a car that has been shown to be more competitive in the the stock class than in prepared classes.

6speed

I have a rigorous triangular configuration already laid out, question is carbon tubing or aluminium? as to being in BP, so what to me autoX is about fun and ive never seen anything of this nature done to the 8, also i finished in the top 10 last month (and yes, it was my first time driving the 8 out there). what ive learned is if you wanna go fast, lose weight, then get HP. if i could design this to be just as rigorous as the current (aluminium?) roof while loosing upwards of 50 lbs (?), the oem CF hoods and trunks already on the market would go great with what it looks like...if i have all the figures to what i expect, this could be a $600-$800 material cost, then instalation...which i plan on doing all this myself when i have time.

kwescott

Good luck. I don't see a market for this.

6speed

Aipex8

iTrader: (1)

I was looking at the BMW M6 at the Portland Auto Show over the weekend and I think the CF roof is very nice looking on that. Seems a little more classy than a CF hood for some reason. I think a CF roof on the RX-8 would look great. Looking at cut away pics of the chassis, it does seem to be a separate panel with cross members under it to take care of the rigidity. Anyone ever had any experience with removing the roof? I wonder how hard it would be. Is it bolted on under the side panels? If so I can see how it would be almost impossible to swap the panel without taking the whole car apart.

Aipex8

iTrader: (1)

Another view:

6speed

THANK YOU, thats the kina response i was looking for, that image is PERFECT for furthermore engineering of this...well currently hair-brained idea being defined. I'm currently searching the rest of the internet as to how to lay the carbon fiber, hopefully i will be able to do this over my spring break. it seems like, however i may get to it, the sheet of roof can be easily replaced with cf, however for significant weight savings i may want to replace other structural items...that center brace shows that it may not need as much bracing as i expected. hopefully i wont have to take the whole car apart...because shes my baby and i'd hate to slaughter her. This image is REALLY useful and thanks for your input.

PS what is the general weight difference in replacing aluminium with carbon fiber; ie, what does an OEM hood weigh in relation to an oem-style CF hood?

Aipex8

iTrader: (1)

No problem. Here are links to a few more real photographs of cut-away RX-8's. These pics are rather large so I'm just going to link them, but in these it looks more like the crossmembers are part of the roof, so those CAD pics may have been a little misleading.

http://media.mazda.ch/dossiers/RX-8/...h/img_2810.jpg

http://media.mazda.ch/dossiers/RX-8/...h/img_2801.jpg

http://media.mazda.ch/dossiers/RX-8/...h/img_2798.jpg

XDEEDUBBX

molding is another whole process itself. I suggest you learn from a veteran so they can show you the ins and outs of it.

6speed

i agree, i'll probably inquiry at an auto-body shop...it seems that stacking and laying the fiber is best for rigidity, but with the brace underneath i may only need 2-4 sheets thick, as upposed to say...8. this is something i REALLY want to develope. i do have access to the mechanical engineering shop where we have big machines, etc.

TeamRX8

iTrader: (25)

it's an integral structural member, you'll probably be better served just doing an applique to make it look like one, I think that's how they did it for the pics in this thread:

https://www.rx8club.com/series-i-exterior-appearance-body-kits-27/anyone-know-who-makes-rear-bumper-77911/

.

XDEEDUBBX

i say do it, forget the naysayers, even if you do make it and are unable to sell it atleast you did it and made the weight savings (provided you did it the right way).It's always good to be different and one off (to an extent)

6speed

well, we'll see. im not sure when ill have a chance to pull the fabric off the interiors roof, but from the pics above it seems like it already has plenty of bracing; i could do some triangular aluminum bracing infront of the big cross pilar on the roof. i do plan on keeping all the interior stock, i want it to look completely normal on the inside...just replace the whole roof...no clip on/stick on parts

thanks X, maybe after all is said and done and i get some total costs of reproducing it some of you CF hood guys will change you minds

jmerc

It is possible to do, the easiest way would probably be to get a roof panel from a parts site instead of hacking up your 8 as you will lose the panel to mold making. As an one off peice the mold could be a simple male female mold although for production it would need to be an engineered mold. I have been considering a similar project for my FX and the 8 when I get it. If properly constructed the panel should only need the same reinforcement as the stock panel, this can also be made from cf or kevlar. Wet cf work is cheaper than dry because of handling and processes above wet cf, but dry is better. This link may be useful for procurement of materials. Good luck, and I am sure there are others here that are far more knowledgeable about this seeing as there are several guys that do this for a living around here.

http://www.shopmaninc.com/

6speed

great advice, did not know i would lose my roof to the mold; plus mine has a sunroof and thats just more work...any idea where i could find a roof panel? doesnt seem like anyone would feel the need to remove theres besides us a salvage yard? seems like an rx8 would be a rare find. any more direction would be greatly appreciated

Aipex8

iTrader: (1)

There are more than 200 scrapped RX-8's from the Cougar Ace (boat wreck) that could possibly end up in scrap yards in my area depending on what Mazda decides to do with them. They are sitting at the docks here in Portland still.

The more that I look at those photos that I linked to, the less I think this would be doable unless it was built like that from the factory... Maybe that Mazdaspeed RX-8 will have a CF roof when it comes out (in our dreams)