Airbox material

[escort90]

I made a steel airbox for my car which im pretty happy with but its a tad on the heavy side. I'm looking at making a new one but using a lighter material such as fibre glass or carbon fibre.

Obviously fibre glass is much cheaper than carbon fibre but is there any other advantages of using carbon fibre over fibre glass apart from the slightly lower weight and more rigidity?

[theshrew]

Fiber glass would leave rough surface on the inside of the box i presume not really what is ideal for a intake system. So id go for carbon.

[robmlufc]

You can get an equally smooth finish with fibre glass as you can with carbon fibre. Strength and weight are your plus points for carbon, a fibre glass box shape might not be very rigid. Plus it looks a bit cooler.

[virgil]

Think you've hit the nail on the head there...
Benefits are:
lighter
stiffer
stronger
'looks nice' (but personally i think the max power brigade have chavised the CF look in all but he most obvious high end applications (Zonders etc)


The downsides of CF are:

-cost
-does not form so well to tight bends/corners
-potential electrolytic corrosion of some embedded components

A good compromise might be to use Glass but strengthen with CF where needed?

[escort90]

I was going to make the airbox in 2 halves before epoxying them together using flanges which would then be cut down and sanded so you wouldn't be able to tell it was 2 parts. It would be alright to sand the inside with fine grit sand paper and just making sure there was no dust left?

The fibre glass is half the price as carbon kit for more material so will probably go with fibre glass. Will let you know how it goes.

[Fastdruid]

Depends on how you do it and how much you value the aesthetics but if you make the mold as male and cast round the outside then the inside will be nice and smooth at the expense of the outside being a bit rough.

No problem to sand the inside apart from taking time!

[escort90]

Well I was going to use the mold as the male. I'm going to cut open the metal airbox, fill it with expanding foam then use that to try make a Styrofoam mould.

A mate of mine has just said he'll carbon wrap it for free for practice for me so aesthetics on the outside are not an issue anymore.

[TheEnd]

What size or style are you planning?
You'll need to be careful of large flat sides which could resonate.
It's probably sound fantastic but it could shatter.

[escort90]

Its not very big, only 120mm by 300mm.

Yeah i've heard that. At the moment the metal airbox has straight sides but i'm going to angle the sides to the middle.

[TheEnd]

That should be fine then.
You should find info on how to make sub boxes on the net, they'll show you what to do, and where to brace.
They'd both have similar characteristics of needing to stand up to resonance.

[escort90]

ok will have a look at that, thanks for the info!