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The mkiv Supra Owners Club

Carbon vs Fibreglass bonnet


psymon

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  • 8 months later...

hey i gotta say mine isnt any hasstle and is a really good fit

im not too sure about the carbon is a rip off and is just fiber coverd in carbon as with mine when the hood is up you can actually see through it

and they look the bizz

still on a N/A it may not be going fast enough to cause a problem

and as for weight id say there is nothing in it the stock hood is really light

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I have yet to find a Supra or Skyline fibreglass or "carbon" bonnet that weighs less than the stock alloy one. Some of the aftermarkets ones have appalling fit and finish, too. So unless you want to leave a "carbon" bonnet unpainted (and bear in mind the gel coat and lacquer is usually so poor it will whiten in no time, or even de laminate), they are a waste of money, technically. Those with vents and scoops often have them so placed as to demonstrate the makers cluelessness on basic aerodynamics, and instead of removing hot air form the bay manage to pressurise it and cause left and a reduced efficiency from the radiators.

 

You could get a proper autoclaved bonnet made, which would be ultra stong, durable and very light, I had to go that route when i found the aftermarket "carbon" doors for Skylines were such junk. A good moulder doesn't necessarily charge a fortune these days, and if you can get an order of say 10 units together, it becomes a very viable option. I got these doors done as one offs, and they are 2.8 kilos each. Stock bare doors were 38 kilos each.http://www.gatesgarth.com/toys/toys.html

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When Im not working for myself I work for my mate at his composites company. We tend to make numerous things for race/rally cars. Most of the work is 'wet lay' (cheap and cheerful) but recently we've started doing vac formed composites cured in an oven.

 

As a test, we created a pure CF bootlid for an Alfa 75. A standard bootlid weighs 8.3kg, a 'wet-lay Kevlar/Carbon one weighs 3kg, the pure CF vac formed one weighs 1.5kg. The pure CF one is really strong with little flex.

 

As Chris said, you'd probably need a pure CF vac formed bonnet to save weight over the stock one, though they cost a lot more to make (both the tooling and composite) and it may be easier (from a weight saving point of view) to just go on a diet :)

 

With regards to 'bling' composites, few gelcoats are UV stable, and whilst you can get UV Inhibitor to mix into a gelcoat there's no way of knowing that it has been mixed perfectly, which over time can cause the gelcoat to go milky in certain areas.

Edited by Angarak (see edit history)
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When Im now working for myself I work for my mate at his composites company. We tend to make numerous things for race/rally cars. Most of the work is 'wet lay' (cheap and cheerful) but recently we've started doing vac formed composites cured in an oven.

 

As a test, we created a pure CF bootlid for an Alfa 75. A standard bootlid weighs 8.3kg, a 'wet-lay Kevlar/Carbon one weighs 3kg, the pure CF vac formed one weighs 1.5kg. The pure CF one is really strong with little flex.

 

As Chris said, you'd probably need a pure CF vac formed bonnet to save weight over the stock one, though they cost a lot more to make (both the tooling and composite) and it may be easier (from a weight saving point of view) to just go on a diet :)

 

With regards to 'bling' composites, few gelcoats are UV stable, and whilst you can get UV Inhibitor to mix into a gelcoat there's no way of knowing that it has been mixed perfectly, which over time can cause the gelcoat to go milky in certain areas.

 

good write up dude, its allways nice to hear from someone who actually knows what he's talking about

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I didnt realise a cf and fibreglass debate could get so heated. lol

 

The topic has no bearing, its simply an excuse ;)

 

i think the carbon fibre hoods look pathetic when they fade like wise with the rear wings...even when they are laquered back up they never look the same..

 

completely agree....but then again....for some its that chavvy look that matters....

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the carbon that we all use is nothing more than glorified fibre glass and purely cosmetic (dont get me wrong i do like them), proper carbon spends months in and out of ovens so if your on about strength there will be no difference, if its weight again the difference will be minimal and i doudt it would be lighter than a stock bonnet, i think it all comes down to how much your (or your mate) prepared to pay

 

What about this one (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=280131490361)? Is it "fake" cf?

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they are all "wet lay cf" if you like it buy it but and i quote "replaces old heavy OEM metal bonnet. Choose Vis products for perfect fitment, stunning looks and reduced weight (only 13pounds)"

 

they obviously know their stuff :( "heavy OEM metal bonnet" the stock bonnet is aluminium and light as a feather, and as Chris states i haven't seen one yet that fits properly

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The fit can vary for numerous reasons, one of the more common mis-alignment issues is when you have a 2 part mould (ie:bonnet) where you have one mould that makes the outer skin and one mould for making the inner frame. When you come to bond them together, getting the alignment of the inner and the outer composites wrong will have noticecable effect (ie: bonnet edge will align closer to one wing than the other).

 

The thickness of a composite can also cause alignment issues, especially on 'wet lay' composites where the thickness of the composite can vary depending upon how well it was rolled out (and how many layers of composite it is comprised of).

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