Fiberglass inlet manifold

[Ben Wilson]

I've got some weird ideas going on at the moment. One of these is a custom manifold/plenum out of fiberglass.

I'm wondering if I used high temperature expoy and woven cloth, would it be possible to build something which can handle boost?

[kingmick]

yes but if your going to go to the trouble just do it in carbon!` vacuum bagging is the way to go and isnt that hard. then you can you soaker matting that draws the extra resin out to make it lighter and strong. fibreglass is fine but id be using it for your first go just to make sure you get it spot on then do a carbon one. Making carbon trumpets for the race motors to awhile to get the plugs and mould made and workout the layers of carbon to use to get them light and strong, but well worth it in the end!
you can hire vaccum pumps and the bags are easy to get.
For a one off, shape it out of foam and then form over it and then melt the foam out with fuel.
makes for and easy one off mold.

[takai]

Yeah, several of the SAE teams use FG/CF composites which are capable of handling boost.
They do have to use a different epoxy resin though, from memory it is the same resin as is also used for high tensile strength aircraft parts. If you have a poke around at your work you should come across someone who knows what it is. If not ill ask my girlfriends sister who did her thesis on composites (and ironically works for DOTARs now).

[Ben Wilson]

I've thought about carbon, but without an autoclave to get decent compression in the weave, I don't think it's going to be that much stronger/lighter than well layed fiberglass cloth.

It would look pretty though, and I've got some carbon cloth kicking around somewhere...

[Draven]

There are people around with decent compression cookers - if you ask nicely to dump a small item like an inlet manifold in, I'm sure they wouldn't charge you more than a case of beer or something

[Ben Wilson]

That's a pretty big pressure cooker.

Plus, I don't think they would like the way it smells after cooking expoy in there.

[EldarO]

firbeglass, ive recently found out, is ALOT stronger than i thought.

and this is from my experience of using just a single layer!

im certain that it could be made to handle boost...

best thing is, like suggested, you could make the PERFECT mould out of foam then just melt it out... allowing you to get all the airflow characteristics etc perfect...

im also pretty sure that you could even coat the foam in a layer of WD-40 or something similar, and end up with a perfectly smooth surface!

Eldar.O.

[takai]

Uh, im pretty sure that WD40 will melt the foam, seeing as its petroleum based and all.

[Ben Wilson]

im also pretty sure that you could even coat the foam in a layer of WD-40 or something similar, and end up with a perfectly smooth surface!

If you get high quality foam, you can sand it to a pretty good finish. A slightly rough surface may even be better for flow. One technique which used to be used in aviation was using a plaster buck then smashing it out once the fiberglass has cured, you can get a perfect finish that way (as well as using polyester resin which is much easier to work with than epoxy).

[Draven]

uh, I was referring to the industial cookers used for carbon fibre... not a kitchen pressure cooker

[EldarO]

carbon fibre is a whole lot of wank factor, unless its for a full race car, its WAYYYY too overrated...

of course im speaking effort/cost: gain faktah.

Eldar.O.

[kingmick]

carbon fibre is a whole lot of wank factor, unless its for a full race car, its WAYYYY too overrated...

of course im speaking effort/cost: gain faktah.

Eldar.O.

lol beside the extra strength factor you mean!

as to cost factor here is a good one, i worked on and a targa car and had to drop some brake piece of to him! he has the biggest autoclave in the southern hemishere{like half a huge factory}, he builds race yachts etc. it had a huge full carbon kelvla yacht there at the time. blew me away boat is worth millions! i have to say it was the most carbon ive every seen in one place!

[oldcorollas]

firbeglass, ive recently found out, is ALOT stronger than i thought.

and this is from my experience of using just a single layer!

im certain that it could be made to handle boost...

you might want to be careful of what you say you are sure of
sure one layer of fibreglass may seem strong to you..... but it's not that strong really...
not really and not relatively...

think of it this way... you run sayy, 20psi... no.. even 10psi.... the surface area of the plenum is....lets make it small, 1 square foot (keeping with imperial for river ) thats 12x12 = 144 sq.inches... times by 10 pounds = 1440lbs of force...

or to bring it back to metric....(mostly) running 10psi will mean there is a force of about 650kg over that surface area. acting normal to a flat surface (weakest direction)..

still sure that a single layer of GRP will suffice?

[MWP]

There is lots of info on building DIY fibreglass/carbon car parts here:
http://www.racingcomposites.net/unm

[oldcorollas]

Faq!!!!! :d