carbon fibre plenum...

[IttyBitty]

hey all, I've been thinking about making the plenum out of carbon fibre. Actually, there's a lab at our school that does ABS, but it doesn't exactly suit our needs (mainly they can't make anything bigger than 10in. in one piece)...and the cost for materials is a bit much. I remember that Penn. State had that kick ass round plenum out of CF and I was wondering if you could give me some tips as to the resin you used that could withstand the temps...and how to "cook" it - if you had to.

thanks!

-Nika

[Travis Garrison]

Your intake won't actually get that terribly hot (unless you've got something strange going on), so any old resin will likely hold up. Wet layups require very little equipment, so I'd start there. Ask your local supply shop for a two part epoxy thats compatible with carbon fiber.

Fiberlay.com has always been very good to us and if you can't find something local I'd give them a shot. This resin (http://www.fiberlay.com/scripts/silverware.exe/moreinfo@d:%5Cdfs%5Celevclients%5Cfiberlay%5CELEVA TOR.FXP?item=1014Q) with this hardener (http://www.fiberlay.com/scripts/silverware.exe/moreinfo@d:%5Cdfs%5Celevclients%5Cfiberlay%5CELEVA TOR.FXP?item=102038) would be a easy starting place and has held up just fine for our intake.

System three makes some good stuff (http://www.systemthree.com/p_phase_two.asp) that will also work for a wet layup and can be post cured to relatively high temperatures.

If you are really concerned with temperature go for a prepreg fabric, but be aware that means temp resistant tooling, and potentially more $$ for materials and will require a freezer for storage.

As far as "cooking" it...you don't have to cook most wet layup resins...but if you do want to get fancy and go for a high temp resin, you'll just need any old oven like object that can get up to the recomended temperatures (most times in the 250F-300F range) Ideally you'd autoclave it and step the temperature up in the method called out by the manufacturer, but...you're making an intake...you don't need ideal http://fsae.com/groupee_common/emoticons/icon_smile.gif

[flybywire]

Here, Here. Intake plenums tend to run cold on most of the FSAE cars I've seen--except the turbo cars of course....

But get a grip on the forces that will be crushing the damn thing. They're surprising every time.

[Jersey Tom]

Yea. Design it stiff, or it will implode pretty easy.

[Travis Garrison]

Very true, a nice round shape will resist implosion, or...core it http://fsae.com/groupee_common/emoticons/icon_smile.gif

[IttyBitty]

Here, Here. Intake plenums tend to run cold on most of the FSAE cars I've seen--except the turbo cars of course....

we're turbocharged...
our temps are somethere in the 90 celsius range...
I had done a wet layup for our radiator duct last year and used 4-1 epoxy...
but I was told that 4-1 wouldn't be sufficient for the temps...
Travis-thanks a lot for the resin and hardner suggestion, I'll be looking more into it.

-thanks for the suggestions...feel free to give me more.

-Nika
UC Berkeley

[Alexandre D.]

We use a 14:1 epoxy. It's far from ideal but for a plenum, even turbocharged, it's more than sufficient. Ours has more than 2 layers but it's because of some fabrication problems. We're doing a new plenum this year and I'll make it with only 2 or 3 layers. I'm not worried about temperature or pressure at all. That said... I don't know what is your 4:1 epoxy. Get a good slow curing epoxy. It's not that expensive and usually gives better results than fast curing 4:1 epoxy.

[Travis Garrison]

Alexandre: The ratio of hardener to epoxy doesn't really have anything to do with...much of anything. I'd avoid using that to gauge how hot you can take the resin or how fast it will kick....you'll be MUCH better off if you just get the manufacturers specs.

Nika,

We just got a donation of some Jeffco stuff for resin infusion 1401-14 (http://69.239.32.181/Jeffco/Systems/viewCustomers_html?key=1401-14with4101-17) to be exact. It is kind of a pain to work with (time intensive) but post cures up to the temp range you would need. Jeffco also makes some wet layup stuff that might be appropriate for your intake JEFFCO 1310-L6/3102 (http://69.239.32.181/Jeffco/Systems/viewCustomers_html?key=1310-L6with3102) post cure it to 130F and you'll be able to take it to around 190F...

Plus Jeffco is based in CA..they've got a sacramento (http://69.239.32.181/Jeffco/Distributors/Distributors/viewCustomers_html?key=SACRAMENTO) distributor and they're based in San Diego (http://69.239.32.181/Jeffco/Distributors/Distributors/viewCustomers_html?key=SAN_DIEGO) so hey they're at least in state...

[Foz]

We ran a CFRP plenum for the first time in 2005.

http://www.cgcu.net/icracing/images/ic02_assembly/IMG_1132.JPG

Not too sure about the detail as it was not my project, but I know it 8 layers of autoclaved carbon/epoxy resin pre-preg, and it flexes visibly at high revs.

Was designed to run with an intercooled turbo intake system.

With an NA set-up, we have previously tried a re-inforced rapid-prototype plenum which failed catastrophically during testing and fabricated aluminium one which worked fine.

Foz
IC Racing
http://www.cgcu.net/icracing