Carbon Fiber Roof

[SeanC]

ok so after i finish the forced induction set-up on my car i plan on figuring out the handling and tires part of my car. of course that will include some coil-overs, all control arms/rods replaced, sway bars and so forth. now a huge part of handling is where your weight is. up top is not where you want it. now i just wieghed my full interior mostly stock s13. 2800#'s with a full tank of gas. what i am getting at is if i can shed some wieght and lower COG i would like that. a carbon roof molded into the stock pillars sounds like a great way to do this. i would of course have atleast a 6-point cage to regain the lost of rigidity. anyone do this to an s13? thanks.

[Alfador]

If you ask me, you're not going to save yourself much weight, or move the COM enough to make a difference. Any real weight in the roof comes from whatever support structure it has. Anyways, the center of mass on a 240 is already pretty low, especialy on an S13. I'd guess that replacing the roof would move it down maybe an inch, if that. If you've lowered your car with shocks and springs already, its going to be kindof pointless to do that little bit more. IF you want to reduce weight with CF take it to the hood and hatch/trunk.

[SeanC]

i would think the hood and trunk would only lower weight 25-30 lbs. i can see the roof wieghing alot w/ sunroof especially.

[nismofly]

itll be expensive as ****, just like all other REAL carbon fiber, and it wont do much

the metal panel that is your roof weighs a few pounds at most, like alfador said most of the weight would come from the structure, which youd need anyway

[nismofly]

the roof weighs maybe 15 pounds with a sunroof

[Jiggyfry]

So true, without a sunroof, the roof weighs next to nothing. A CF hatch with a plexiglass (is it plexiglass?) window would be better. Or just eat a whole bunch of EX-lax and reap the benifits of weight loss.

[nismofly]

just get fiberglass, those CF hatches you see are fake CF and weigh just as much if not more than the fiberglass

and the glass is called lexan

[teddy]

he might have more luck in just removing the sunroof and welding a piece of metal, rather than attempting to replace the whole roof with carbon fiber. The carbon fiber hoods and trunks are fiberglass resin anyway, with some carbon fiber weave layered over it. And the weight that he would lose from removing the roof he would regain with using a 6 point roll cage.

[SeanC]

i have a 93 coupe so no hatch. the trunk already seems light enough. maybe i will just get the doors for some serious weight loss.

[nismofly]

the doors are light too, changing them does almost nothing, and theyre a serious safety hazard if you do change them

if anything, get a fiberglass hood, thats about it

and theres a lot of other stuff to do that will help more

[Alfador]

From my experience the hood is the only body panel on the car that could really be considered heavy. The hatch if you include the window would count too. There was a spirited discussion in which I made an *** out of myself insisting that fenders are heavy. They aint, and accordingly, neither are other bodypanels.

[ken240sx]

maybe instead of just doing the roof in CF, since it attatches to your pillars and rear quarter panels just get the whole section(roof, pillars, and quarter panels) redone in CF, that should reduce prob about 10-20 lbs or so...really not much weight, but it's all about what you want out of it...go to http://www.kognitiondesign.com and contact them about it. they are gonna make a pair of CF front fenders for my s13 that only weigh about 1.5lbs each. they are good at making molds and will do custom work for good prices. they have to make a new mold for the s13 fenders because they havent made them before...the fenders are 700 shipped which is a good price if you ask me because they are dry carbon fiber and they didnt have a previous mold.

I thought that most cars had a pretty low COG considering there isnt much weight too them from the pillars up. but if you want to lower your COG, lower the car...and if your gonna worry about 10 lbs on the top of the car, just roll down your windows, that should give you the same change in COG i would think. hey i guess if your hardcore about it, sit lower and lean back in your seat like dem boyz in da hood yo lol. make sure you sit low enough that you can just barely see over the dash, or else you wont be gangsta enough. jp

[ken240sx]

not to mention the fact that when you add the roll cage, you'll be adding the weight right back up there where you took it off so it in essance just did nothing for your COG.

[fullthrtl_tech]

sorry dude but it sounds like a big hassel for such a little impact on the COM. Onec its lowered your pretty much set. Like they said a fiberglass or a carbon fiber hood is a good chunk of weight gone otherwise u r wasting money IMO. Also like they said the hatch glass is hwavy as hell. But then that adds diferent set of problems because lexan clouds after a while and there is also a heavy glare. thats just my .02

[HashiriyaS14]

While the aluminum roof of the Evo VIII MR has been shown to provide a meaningful difference in performance, it was not particularly easy for them to do OEM, and thus a strucuturally sound CARBON roof on a steel moncoque would be essentially impossible for you to do aftermarket.

My advice is not to touch it, It does make a difference, but it's not something you can feasibly accomplish. Shed weight elsewhere.

[McRussellPants]

WTF?

A) Its an S13.B) Your car is curbing 2800lbs and your worried about your roof? UHHHHHHHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhh. Prioritizing must have taken a back seat to dreaming

base model S13s will curb under 2500lbs all day long just by gutting them.

10lbs doesnt matter enough to spend 1000$s (don't kid yourself, it will be thousands) unless its on a rigid pole 50ft above your car.

Get a CF hood, gut your car, remove the AC and Hicas if you have it, get an exhaust and crap and your car will curb somewhere between 2500-2400lbs. Enjuku got their car down to 2100lbs by replacing the glass and otherwise stripping the **** out of it.

[Florida240sx]

After hood and trunk your only next big weight differences is switching out all your glass to lexan. Which I'll be doing soon. Even this is big but not only is it a slight weight reduction, it's safer then anything else you can do. Anything else will reduce the strength of your car.

[nismofly]

lexan is also a pain in the *** on a street car, i hope thats going to be a dedicated track car

[kognition]

Thats a grand idea Sean, unfortunately it isn't a realistic goal. Properly done, you would use fiberglass and alluminum honeycomb. Structural CF is shooting upwith the price of gold if you can even find it. I have seen 5 harness weave CF going for $80 to $100 per yard this month. There is a major shortage expected to last into 07'. Your money is better spent on the motor, susp, tires etc. There is an exact science involved in bonding disimilar materials to eachother. If that is something you are interested in, start with small projects first. Good luck.

ok so after i finish the forced induction set-up on my car i plan on figuring out the handling and tires part of my car. of course that will include some coil-overs, all control arms/rods replaced, sway bars and so forth. now a huge part of handling is where your weight is. up top is not where you want it. now i just wieghed my full interior mostly stock s13. 2800#'s with a full tank of gas. what i am getting at is if i can shed some wieght and lower COG i would like that. a carbon roof molded into the stock pillars sounds like a great way to do this. i would of course have atleast a 6-point cage to regain the lost of rigidity. anyone do this to an s13? thanks.

[penpen-commander]

wouldn't removing the roof and then welding, or whatever you're going to do, a new one back on just mess up the rigidy (stiffness) and the crush zones of the car?really, i want to know.

would it?

[Alfador]

horray for month old threads

[Veriest1]

There is a company that does this on E46 BMW's for Americans who want to create a somewhat true to form CSL M3 since we didn't get the E46 model of it IIRC. I don't feel like trying to find it on bimmerforums.com so I'll recap it as best as I can remember it.

They cut the roof out and then added a cross brace or two before glueing in the carbon fiber.

It was a couple of thousand for the parts and then about 48 hrs of labor or some stupid amount of time like that from a reputable shop. You've got to find someone who you trust to do it right because IIRC you only got one shot at glueing it in correctly without it leaking other wise you'd need a new piece of carbon.

He did say that it helped a lot on the Bimmer but they have thicker body panels than the 240.

I second lexan rear glass and a fiberglass hood... fenders maybe but a good set of 15 or 16 inch forged wheels should make more of a differance than all of those.

[180fan]

the point has been made. Locking down.