Carbon Fiber Manifold

[Shizuma]

So I'm in the process of making myself another manifold based on data garnished from the last one and have been seriously considering using a carbon fiber/aramid construction for the plenum and velocity stacks. The only thing that's holding me back is that this IM will likely see 10-15 psi in irregular intervals, not to mention the heat associated with the engine bay. While carbon fiber and aramids have excellent resistance to heat conduction and both materials are very strong I was wondering if anyone had any first hand experience with them being used in a boosted IM. I know several companies make carbon fiber intake manifolds (Hondas) but after calling a couple, the information they provided was limited at best (they couldn't give me any info on burst strength, how well the weave resists leaking, or the corrosive effects at the aluminum/carbon fiber interface of parts of the manifold). Anybody here used one of these manifolds or have some info that I may have missed?

[sc2jz]

funny you should post this i want to do the same thing to my 2j and i have a buddy that all he does is carbon for a race team. im sending you a pm im gonna get up with him and see how much it would cost to have him do one he is a good dude so it should not be much more than what it cost to build it.

[Joeggernaut]

just make the entire engine from carbon fiber =).

on serious note I wouldnt think carbon fiber would hold up over the long haul but you never know with advances in material science.

[Shizuma]

just make the entire engine from carbon fiber =).

on serious note I wouldnt think carbon fiber would hold up over the long haul but you never know with advances in material science.

Lol if I could I would. Carbon fiber and similar composites like Kevlar (an aramid) have been used for a long time in F1,F3, Indy, etc so I know it can be done. In fact the resulting IM *could* be stronger than the stock 1zz manifold that Toyota produced and it gets boosted all the time. I just need to get more info on some of the specifics.

[blitzceli]

If you dont have access to autoclave forget it. The resins used (consumer products) will soften with the heat and eventually cave in on itself. There is one resin that will work, but it is very expensive. Your going to need a inflatable blatter to make the runners. Honestly you will see no benefit with a carbon manifold other than wow factor.

There is a thread on mr2oc that has pics of one and discuss alot of info.

[Shizuma]

If you dont have access to autoclave forget it. The resins used (consumer products) will soften with the heat and eventually cave in on itself. There is one resin that will work, but it is very expensive. Your going to need a inflatable blatter to make the runners. Honestly you will see no benefit with a carbon manifold other than wow factor.

There is a thread on mr2oc that has pics of one and discuss alot of info.

There is an autoclave at the place I intern at that I had planned on using for the plenum, I've used it before for smaller pieces (brackets, insulators, etc) but a plenum would definitely be the largest thing I've personally done.. The only reason I was leaning towards a composite plenum/air horn setup is that the shapes that I'll be dealing with would be difficult if not impossible to make with aluminum without either cnc'ing down a large ingot (may do this if carbon fiber is a no go) or casting my own part.

[Boosted2.0]

You might want to think about just doing a casting. Its a lot easier, and you can always just cast the runner shape you want out of aluminum one runner at a time and then easily weld them to flange and plenum.

Carbon is very strong, but its not an easy material to work with and do right. Think fiberglass only 10 times harder and WAY more critical with regards to resin penetration, cure time and temp, baking, etc.

I actually wanted to make my manifolds out of carbon originally, but nixed it due to cost. I will probably make some someday, but only after I have access to an Autoclave or buy one myself.

That being said, there are those who argue that tightweave pre-preg vacuum bagged and baked at 250F is just as strong as autoclave built stuff.

[Shizuma]

I've been looking into casting parts for a while now (one of the linked threads I posted here actually has some good pictures of the process) but just haven't manned-up enough to do it. The process of packing the mold and whatnot looks extremely experienced based and unfortunately I don't have it nor know anyone who does. What I may end up doing is building just a 2-piece plenum first and testing it to see how well it holds up, then if it survives mating it to aluminum runners. The only thing that concerns me about mixing the two materials is galvonic corrosion at the cf/al interface, though I guess I could run some kind of insulating material between the two.

Boosted, do you have any experience with casting?

[Boosted2.0]

I've actually tried some pewter casting (not my rig, but I did pack the mold a few times and do a couple pours. I've also read up quite a bit on sand casting). The process is pretty basic with pewter and lead though - I've never tried it personally with aluminum. I know most manufacturers use wax replacement casting for things like heads and whatnot. You can also take foam and give it a skim coat of ceramic and then let the metal replace the foam. I would think finding the wax would be the hard part. Shaping and packing wouldn't be too mad as long as you keep the parts simple. Single peice casting of complex shapes is a bitch. I looked at it for the manifolds as well. Awesome single part costs, but setup is a $$zip code and the minimum runs tend to be quite high. Very complex too for an amatuer - lots of opprotunities to leave voids and have incomplete pour into areas. The only good news is if you **** up you just re-melt and try again.

ANother idea is to make 2 peice runners (2 clamshells) on a CNC with a shoebox joint and seam weld them. That would let you do a pretty complex design out of a smaller peice of aluminum with a lot less fuss.

OR, if you want to get really cool, draw it in Cad and have someone that has a high temp PVC printer for rapid prototyping make the thing for you as one solid peice - thats my eventual intention for making prototype parts.

Then again if you can make a CNC of it there are places that can make it out of carbon fiber as well, it just costs a grip.

If you want some rudimentary hands on with casting see if they have a local SCA branch nearby - a lot of those guys actually do some pretty cool stuff and they LOOOVE to talk abotu their hobby.