Carbon Fiber Hood/Trunk

[Levi]

I think an AS1 with dry CF hood, trunk, doors, roof, underbody panels and lexan windows all round will still be cheaper than a Cayman.


There is something that some do not understand when comparing prices of cars. Fisrt of all I only compare new cars to other new cars and used to used. Then I compare the price of the car as I want it, and not the base price. Usually there is nothing worse than buying a base german car, because it has nothing. You'll easily add 10K of options.

You may say me instead of spending 15K of modds on a BRZ better get a 370 Z. But this having the same purpose, I'll always think of adding 15K of modds, and again for this price I can get a Cayman. But then I'll again think about putting GT3 suspension and powertrain. At this price point you can get a 911 GT3 that doesn't need to be modded. But I don't have 130K and don't think I'll have them. So it is cheaper to build a racecar on the base of an AS1 than any other car. I don't like roadsters for this purpose in case you tell me about the MX-5.

[Dimman]

Originally Posted by WingsofWar

to much generalizing of what cf is across ill informed tuners

Carbon Fiber w/ Fiberglass structure (CFRP molding) = At most times heavier than Aluminium, not always, also great alternative to steel hoods or steel components = Cheap Cost

Carbon Fiber Dry Layup = Lighter than aluminium (at times stronger) = Super High Premium

Carbon Fiber Composite = Carbon poly with; Kevlar/Aluminum/CarbonTubes providing the strongest structure possible without the penalty of relative weight = VERY expensive process VERY expensive cost.

For the average tuner to take a 20-25k car and drop 10-30k on top quality dry carbon parts isn't likely. I can see shops building demo cars, and race groups put that much cash into carbon fiber for any car to save as much weight as possible, AS1 included.

But when we talk Carbon Fiber automotive parts in a general sense to the average/beginner tuner, we mostly refer to CFRP, which at most is purely show than real performance.

Going to nit-pick some of this terminology.

CFRP simply stands for Carbon Fiber Reinforced Plastic. It means there is some but also could even be all carbon in the matrix.

Dry Layup only technically means that the fiber goes into the mold 'dry' and there is no rolling or brushing of liquid resin. I've seen Vaccum Resin Transfer parts made with liquid polyester resin referred to as 'dry layup'. Also, just because the part is satin or not glossy, doesn't mean it is 'dry' carbon.

Be careful with the word 'dry' when buying CF!!!

What people are really looking for when buying 'dry' carbon, is parts made with aerospace-type Pre-Preg carbon cloth.

Composite simply means more than one material. Every fiberglass, kevlar or carbon fiber part is a composite.

What we are technically looking for in a quality carbon-fiber part is:

a) Only CF is used as the reinforcing fiber. (in some cases other high-performance fibers like kevlar may be better suited to certain areas of the part)

b) Epoxy resin instead of polyester or vinylester resins.

c) Proper resin to fiber ratio. Quality vaccum-bagged wet layups can still be very, very good.

d) Also Twill weave (2x2) is slightly mechanically stronger than plain weave.

e) Elevated temperature cure.

f) Proper engineering of the part with regards to stiffness. This can be achieved with core structures.

Now with a high-quality 'dry' part made with pre-preg carbon cloth we get all of the above except F pretty much automatically due to that is pretty much the only way the parts can be made. And with the facility, cost and knowledge involved that means that the companies are typically also taking care of the design properly, too.

However a wet-layup, vacuum-bagged and baked, carbon-epoxy part with a nomex or aluminum honeycomb core for stiffness can still save a LOT of weight over an aluminum part.

[WingsofWar]

Originally Posted by Levi

I think an AS1 with dry CF hood, trunk, doors, roof, underbody panels and lexan windows all round will still be cheaper than a Cayman.


There is something that some do not understand when comparing prices of cars. Fisrt of all I only compare new cars to other new cars and used to used. Then I compare the price of the car as I want it, and not the base price. Usually there is nothing worse than buying a base german car, because it has nothing. You'll easily add 10K of options.

You may say me instead of spending 15K of modds on a BRZ better get a 370 Z. But this having the same purpose, I'll always think of adding 15K of modds, and again for this price I can get a Cayman. But then I'll again think about putting GT3 suspension and powertrain. At this price point you can get a 911 GT3 that doesn't need to be modded. But I don't have 130K and don't think I'll have them. So it is cheaper to build a racecar on the base of an AS1 than any other car. I don't like roadsters for this purpose in case you tell me about the MX-5.

lol i love the mind set of tuners! im totally like this too, which really makes me bias much of the time. That age old battle found at the street races when a guy with a EG Civic with 30k built into it beats a 250k Ferarri.

When we step into the relm of tuner car vs stock car, its an entirely different dimension of playing with numbers. It makes total sense to take a cheaper able car and spend the exact difference in price on modifications to compete with a higher premium sports car or supercar. At the same time it doesn't make sense why you would even target a factory made supercar with a modded car.

Why buy a 80k sports car when i can build a sports car for cheaper at the same performance bracket? Why build a sports car when i can just buy a supercar for the same price and just drive away?

There isn't any right answer, because its situation, to many variables, to many preferences, to much of reality and available burnable cash ready at hand.

[WingsofWar]

Originally Posted by Dimman

Going to nit-pick some of this terminology.

CFRP simply stands for Carbon Fiber Reinforced Plastic. It means there is some but also could even be all carbon in the matrix.

Dry Layup only technically means that the fiber goes into the mold 'dry' and there is no rolling or brushing of liquid resin. I've seen Vaccum Resin Transfer parts made with liquid polyester resin referred to as 'dry layup'. Also, just because the part is satin or not glossy, doesn't mean it is 'dry' carbon.

Be careful with the word 'dry' when buying CF!!!

What people are really looking for when buying 'dry' carbon, is parts made with aerospace-type Pre-Preg carbon cloth.

Composite simply means more than one material. Every fiberglass, kevlar or carbon fiber part is a composite.

What we are technically looking for in a quality carbon-fiber part is:

a) Only CF is used as the reinforcing fiber. (in some cases other high-performance fibers like kevlar may be better suited to certain areas of the part)

b) Epoxy resin instead of polyester or vinylester resins.

c) Proper resin to fiber ratio. Quality vaccum-bagged wet layups can still be very, very good.

d) Also Twill weave (2x2) is slightly mechanically stronger than plain weave.

e) Elevated temperature cure.

f) Proper engineering of the part with regards to stiffness. This can be achieved with core structures.

Now with a high-quality 'dry' part made with pre-preg carbon cloth we get all of the above except F pretty much automatically due to that is pretty much the only way the parts can be made. And with the facility, cost and knowledge involved that means that the companies are typically also taking care of the design properly, too.

However a wet-layup, vacuum-bagged and baked, carbon-epoxy part with a nomex or aluminum honeycomb core for stiffness can still save a LOT of weight over an aluminum part.

Thanks for the nit-pick Dimman! it was definitely needed. Id hate to post wrong information and make me look like an asshat.

[Dimman]

Issue I have is the word 'dry' has become the magic word and less-than-honest manufacturers are taking advantage of it since it is not as easily defined as 'forged' for example.

I don't like seeing people get ripped off by buying a part marketed as 'dry' carbon when it is just a vacuum transferred polyester resin that has been bead-blasted to a satin finish over some black fiberglass.

Misuse of carbon fiber by band-wagon jumping manufacturers has practically turned all of it into rice despite it being one of the better ways of modding a car (using the good stuff properly).

Also is it just me or does that Lotus (in this pic http://www.autoblog.com/photos/carbo...photo-1292571/ ) look like it has some wrinkles in the corner section of the bumper, like it's maybe a vinyl wrap?

[Levi]

I don't care about what others think. I want CF for weight reduction, and I'll pay for it. Also, nobody will know what is under as all parts are going to get body color painted.

[Dave-ROR]

Originally Posted by Levi

I don't care about what others think. I want CF for weight reduction, and I'll pay for it. Also, nobody will know what is under as all parts are going to get body color painted.

As long as you are either willing to A) pay the price for the good stuff that is actually lighter, or B) willing to pay less for likely heavier than OEM pieces

[old greg]

Originally Posted by Dimman

f) Proper engineering of the part with regards to stiffness. This can be achieved with core structures.

Now with a high-quality 'dry' part made with pre-preg carbon cloth we get all of the above except F pretty much automatically due to that is pretty much the only way the parts can be made. And with the facility, cost and knowledge involved that means that the companies are typically also taking care of the design properly, too.

I'm going to nitpick some of your nitpicking

Prepreg with a core material is totally possible and is done all the time. The only really impossible combination is VARTM with a honeycomb core (you need to use a foam core instead).

Originally Posted by Dimman

Also is it just me or does that Lotus (in this pic http://www.autoblog.com/photos/carbo...photo-1292571/ ) look like it has some wrinkles in the corner section of the bumper, like it's maybe a vinyl wrap?

It could also be that the weave was skewed when the fabric was laid up.

[Dimman]

Originally Posted by old greg

I'm going to nitpick some of your nitpicking

Prepreg with a core material is totally possible and is done all the time. The only really impossible combination is VARTM with a honeycomb core (you need to use a foam core instead).




It could also be that the weave was skewed when the fabric was laid up.

What I meant was that the design (use of cores) is not really intrinsic to pre-pregs, while everything else is (except weave, oops).

Basically what I meant is that if you use pre-preg, you automatically have a properly mixed epoxy matrix around the carbon, that won't cure unless it's under proper heat. Whether the manufacturer uses a core is up to them.

Edit: Not doing a good job with clarity lately...

Let's try this again. The use of pre-preg cloth reduces the amount of less-expensive 'substitutions' that can be made. If you get CF pre-preg it is only CF, and only specifically measured epoxy has been already applied to it. The options that a manufacturer can cheap out/make choices on are the weave, the design/core use, and part of the curing method (pressure/vacuum but not heat). And due to the cost of the material, it is less likely that a company will take short cuts.

The likely only variances in pre-preg part designs would be the choice of weave design, fabric weight, core choice and use, and whether it is vacuum-bagged and baked, or pressure-cured under heat in an autoclave. (But I believe it is possible to simply layup and heat-cure it without pressure/vac but I doubt this is ever done.)

Also with that Elise in the pic it looks like wrinkles on the surface, rather than a smooth surface (which should have been against the mold) with distorted fibers. When I've seen bad CF parts, the exterior shape is generally good from the resin filling the mold, but the fibers get pulled apart inside the resin.