OlderThanMe Posted February 6, 2008 Share Posted February 6, 2008 So I was thinking... For my VH45DE I could go into Solidworks and design what I'd want the ideal intake tract to look like, then make a mold from wax (or floral foam etc...), spray gel coat, lay a layer or two of fiberglass, then some high tensile strength stainless steel mesh inside the fiberglass and lay more fiber over the mesh. I then have a fiberglass manifold that will most likely be ugly but flow like nothing else. What I'm trying to do is create the ideal shape for the intake runners but not be up to my neck in machining and cost. Obviously an aluminum manifold would be ideal since it is quite strong and light weight... but it can't be molded. I'm also a little on teh poor side to have all of teh equipment to cast such a complex manifold. I've also considered Carbon Fiber for a first layer but it is a bit brittle for the strength. I'd like to hear some discussion on the idea. Thanks guys! OTM Quote Link to comment Share on other sites More sharing options...
Dayz Posted February 6, 2008 Share Posted February 6, 2008 Aren't you going with forced induction? I believed that M3 and LSX are all changing their composite manifold in favor of an Aluminum one. Is it because the composite one isn't strong enough? Dayz Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 6, 2008 Author Share Posted February 6, 2008 TurboBricks thread on composite manifolds "Advanced Iduction Research" Honda manifold The Endyn website that sells that manifold also has some great reads about working with engines that have 4 valves per cylinder. They really make power with what they have as a Honda motor... Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted February 6, 2008 Administrators Share Posted February 6, 2008 Below is an anecdote by a CF (carbon fiber) manifold distributor, and his thoughts on FG (fiberglass) manifolds, with respect to E30 M3's... "We dont make a FG airbox for a few reasons: it is not as strong structurally. FG will shatter, develop cracks, and/or deform more easily over time and in the harsh environment of the engine bay (heat and vibration). Not to mention, if you ever get intake reversion which is when during the overlap phase (both intake and exhaust valves open) the hot exhaust gases enter the airbox and mix with fresh fuel mixture -- you can have gas combusting inside the airbox. This can happen on fast throttle transitions. The engine doesnt like to suck in dust and other bits and pieces out the FG airbox. CF is more thermally stable and stands up to underhood termperatures better over time, so you dont have migration problems. CF has great thermal isolation, which means the outside of the airbox can get hot, but the inside remains cool. For a cold air intake system, that makes CF the much better alternative. The factory race teams didnt (and dont) use CF because it looks nice, they use it because the material is superior in literally every category. So from an engineering perspective, CFK is the clear winner. If you look at 20 year old CF airboxes, unless theyve been damaged during a crash, they are still in great condition structurally. If they are not visually in good condition, that can be fixed relatively easy. As with many things, sometimes the higher initial investment ends up being the less expensive solution over time." Hope this helps. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted February 6, 2008 Share Posted February 6, 2008 If you're really wanting to put the R&D into something like this, I'd say take the leap and do it with CF cloth. It's the same concept as FG, just more expensive to buy the materials for . But, like ron said, CF is better suited. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 6, 2008 Author Share Posted February 6, 2008 Ron, Thanks for that! Since the price for some decent carbon fiber is about $55 a yard and I may be able to get by with two yards for my motor. Then just put fiberglass over the carbon. I'd need to find a gel coat or at least something to spray down before laying the carbon that is very heat resistant. For some reason I'm thinking of some form of ceramic coating. That sounds brittle though. Maybe if it was suspended in the first layer of gel coat it wouldn't be brittle. TR, You going to help with R&D funding? hehe. J/K! Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted February 6, 2008 Share Posted February 6, 2008 Hey if you were doing this for the L6 I'd be all for it man, 50/50 Can't wait to see how this turns out once you get started! Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 6, 2008 Author Share Posted February 6, 2008 Hey if you were doing this for the L6 I'd be all for it man, 50/50 Haha! I might!! IF this one works with the V8... I'm thinking of using two seperate plenums because of heat expansion across the engine may be enough to crack the manifold in half...which would be bad. Nissan routed things across the engine with some stress relief so I am guessing with the hyperetutic aluminum block there are some expansion things to deal with. Quote Link to comment Share on other sites More sharing options...
Sideways Posted February 6, 2008 Share Posted February 6, 2008 Shouldnt the layer of CF be on the inside of the manifold? Or am i just reading your idea backwards Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 6, 2008 Author Share Posted February 6, 2008 Yeah... I'll create a plug of what I want the INSIDE of the manifold to look like. Then spray the first coat and then add layers of fiber. Then I'd either melt out the wax plug or use some chemical to melt the foam out, depending on what I use. Quote Link to comment Share on other sites More sharing options...
hughdogz Posted February 6, 2008 Share Posted February 6, 2008 Does all CF require a vacuum sealed bag and oven to cure? The reason I ask is I saw a "How it's made" on CF bodied cellos and that was part of the molding process. What a cool idea! Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 6, 2008 Author Share Posted February 6, 2008 Does all CF require a vacuum sealed bag and oven to cure? It might... but an oven isn't a big deal. Carbon fiber musical instruments have always intrigued me. Light weight, very high rigidity for best sound, and very close similarity for production. Just expensive! Quote Link to comment Share on other sites More sharing options...
mannyvig Posted February 6, 2008 Share Posted February 6, 2008 Carbon fiber musical instruments have always intrigued me. Light weight, very high rigidity for best sound, and very close similarity for production. Just expensive! The music snob inside me is screaming- "But they sound awful" Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted February 6, 2008 Share Posted February 6, 2008 No, an external heat source is not required for the epoxy resin to cure. The external heat source just allows the curing process to be excellerated and monitored more closely for more consistant production of parts. Vacuum bagging is not necissary either, but is a good idea, especially with complex shapes, to set the cloth into the mold, and bleed off the excess resin. I wouldn't worry about trying to re-invent the gelcoat that is used with carbon fibre, you can get different gel coats, and if memory serves there are different thermal barrier ratings, or tempuratures that it will stand up to well. the most difficult part about working with carbon fibre is to get the thickness correct, as in just the right amount of resin used, and getting the carbon fibre cloth to form to odd shapes. You will probably find that you will need a few different shapes of carbon (for lack of a better term), as in some straight cloth, and for the runners, using a tube carbon would be easiest. This is litterally woven in a tube that when stretch closes up (smaller diameter) or opened up by scrunching it from end to end. This lends itself very well to the transitional shapes that are needed or desired for the runners. Carefully planned could even use curved runners. Quote Link to comment Share on other sites More sharing options...
Careless Posted February 6, 2008 Share Posted February 6, 2008 Below is an anecdote by a CF (carbon fiber) manifold distributor, and his thoughts on FG (fiberglass) manifolds, with respect to E30 M3's... Hope this helps. I never read on it, but accepted that aluminum being metal would cool the intake charge better than CF, much like an intercooler does. but I also always wondered if the minuscule heat transfer from the CF chambers would keep temps even lower than metal pipes exposed in the engine bay. Is this anecdote in reference at all to metal intakes as well, or is it a strict FG vs CF comparison? Quote Link to comment Share on other sites More sharing options...
Lunar240z Posted February 6, 2008 Share Posted February 6, 2008 you'll want to search for a high heat tolerant epoxy resin to use with CF in this application. Search around here for info http://www.racingcomposites.net Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 15, 2008 Share Posted February 15, 2008 Read your epoxy curing instructions to determine if vacuum bagging will help you. In many cases, curing the epoxy under several psi of 'tension' will increase it's strength. This would be equivalent of say 6" Hg of vacuum in the bag. It helps remove entrained bubbles, etc. The epoxy directions will give you specific conditions under which the strength can be optimized (say cure at 3psi pressure and 180F for two hours). Many times a simple I/R heat lamp can provide all the heat you need. A thermocouple or thermal bulb on/in the curing 'box' can be linked to control the heat source to keep temperatures constant. I need to read some of these links when I have more time, it looks like good information to review. Quote Link to comment Share on other sites More sharing options...
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