Carbon fibre vs fibreglass

[mr_sikma]

my mate got defected here in sa for a carbon fibre bonnet on a honda accord wasnt engineered though.

i also thought they were completely illegal.

i reckon they look tough as and i want one maninly just for looks :D

[Steve Whitney]

Originally posted by mr_sikma
i reckon they look tough as and i want one maninly just for looks :D

you ricer!! :p

[walkie]

Originally posted by The Pupat
CF in any road car is really rice (and yes I'm including high dollar exotics in this).

I disagree. Weight is the arch enemy of speed. Rice is weight's mate. Anything that helps your power to weight is antirice if you ask me.

[Spammy]

The Ricer's overweight mate in the passenger seat is the enemy of speed and in many cases the dealer of speed.

[Tirlista]

Originally posted by Spammy
...the dealer of speed.

Or weed.

[The Pupat]

Originally posted by walkie
I disagree. Weight is the arch enemy of speed. Rice is weight's mate. Anything that helps your power to weight is antirice if you ask me.

yes but the tiny difference between CF and alumium space frame is bugger all when you put full glass, PS, leccy windows, stereo, pleather seats, carpets, sound deadening.... and what not, that you would have in a roady.

[Evo_Lee]

Re: Carbon fibre vs fibreglass

Originally posted by Balor
My apologies if this has been covered before.

Is one or the other (fibre glass / carbonfibre) stronger?

Apparently I could get both engineeered however:

Do they behave very differently under duress / impact?

I guess design would play as much a part as material, but any info appreciated.

1) There are basically 3 types of light weight bonnets you can chose from...CF, FRP and aluminium bonnets. There is also wet CF over FRP for those who can't afford a full CF bonnet. But to answer your question CF is stronger

2) I'm a little confused, you can engineer a CF bonnet or FRP on a road car? IIRC, both are illegal due to the way it doesn't collapse as one piece in a crash.

3) As stong as CF and FRP is, they both will crumble to pieces in an accident.

Now as much as I like CF bonnets due to it's reduced weight, I agree with it being totally inappropriate and expensive for street use. Also for your purpose of extracting heat, the answer is vents and not whether to use CF or FRP bonnets. But any rearward facing vents is also illegal for street use, as they feel there is chance of engine bits blown towards the windscreen.

If you could get a CF or FRP bonnet engineered you'll definitely need vents. If you haven't notice they balloon anywhere from 1-1.5 inches above the bonnet line at high speed, so bonnet pins are also necessary...but bonnet pins are also illegal for street use.

So where does that leave you, best bet is an aluminium bonnet with forward facing vents only. An aluminium bonnet came standard on my car and I've compared the weight to a CF bonnet, which is only 3kg lighter. 3kg is nothing, having already taken out the jack and spare wheel for circuit...the carpets and rear boot cardboard together weight about 3kg.

Not knowing what car you have and what mods you have done, can I ask how do you know your manifold is excessively hot? The easiest mod would be to wrap the manifold with billion cooling tape or fit a cooling plate over the manifold.

Saves getting an expensive CF, FRP and aluminium bonnet or cutting holes in your bonnet. With vents also don't forget water/rain getting in, engine bay will get dirty easily and give you a rusty looking manifold (unless it's stainless) and bolts.

[Balor]

Thanks for that info

Car is an SR20DET powered S14a. Mods are the usual: injectors / pump / 400hp turbo / manifold / cams / exhaust / FMIC / throttle body / ram air / power FC + EBC / RB25DET MAF / bov / oil cooler + supporting ancillaries in drivetrain / suspension etc. Peak power is up 130% over standard and everything has been running beautifully except that I sometimes melt washer lines due to heat generated by the manifold (yes I can relocate these).

The manifold is ceramic coated steampipe chosen simply as it's more tolerant than stainless for heat cycling and torsional stress.

Being an S14a the manifold sits reasonably close to the ABS. I'm not sure how tolerant an ABS unit is to heat of this nature? I guess it's not something one could easily test, but I've never heard of a unit failing due to excess underbonnet temps - but you never know...

A fellow club member attached a thermocouple attached to his S14 exhaust manifold at Wakefield and saw temps as high as 940 C after extended peroids of high boost. Since this was measured on an external boss on the factory manifold I can only assume that the exhaust gas inside the manifold would be somewhat hotter still. And I know for a fact that his (and mine) AFRs are somewhat richer than they need to be (ie around the 12:1 - 12.2:1 mark)

What is a cooling plate?

[Evo_Lee]

Originally posted by Balor
What is a cooling plate?

Cooling plate or turbo cover whichever you like to call it. From the factory the Evos comes with one, which I'm still using but starting to look a bit rusty.

Here is a ARC stainless one for low mount only. ARC International, Monster Sports, WRC Custom, J-Speed etc make them. Not sure who makes one for the Silvias, maybe you have to do a custom one off job.


You could place a turbo cooling plate over the turbo or alternatively a large plate behind the turbo from those I have seen here.

[400HJ]

fibreglass bonnet

does anyone know where to get an ADR approved fibreglass bonnet for a HJ kingswood, i have to cut a hole in the bonnet for my carbi and air filter. alternativley can you change the bonnets brace as i have to cut part of it out making it eligal

[Nero]

HJ panels?...try Alfa fibreglass, top quality work.

[GHZ28]

my mate got defected here in sa for a carbon fibre bonnet on a honda accord wasnt engineered though.

i also thought they were completely illegal.

On a road car, one of the prime purposes of a bonnet is to keep engine bay fires, in the engine bay, hence the specification of metal bonnets, unless original manufacture is non-metal. For instance, 4th gen camaro, body panels are GRP, but the bonnet is metal.

You need to check your ACT regulations, and a phone call will do that.

And as someone else said, bonnet vents allow the ingress of water and other debris, creating a mess. If you insist on vents, my suggestion is NACA ? sp?vents to assist with the egress of air out the back of the engine bay in the normal manner.

[CussCuss]

yes but the tiny difference between CF and alumium space frame is bugger all when you put full glass, PS, leccy windows, stereo, pleather seats, carpets, sound deadening.... and what not, that you would have in a roady.

your assuming just because someone has a cf bonnet they are going to put in all the other crap, a ricer may have a cf bonnet, but a cf bonnet does not instantly make a ricer. i agree 100% with walkie

[THE ASH]

can I be first to say - thread from the dead.

[Dave]

does anyone know where to get an ADR approved fibreglass bonnet for a HJ kingswood, i have to cut a hole in the bonnet for my carbi and air filter. alternativley can you change the bonnets brace as i have to cut part of it out making it eligal

There are no ADR approved glass bonnets, you can still get booked.