intake manifold design?
 

Lately I have been toying with the idea of making a plastic, large plenium intake manifold.

I got the idea down at my buddys machine shop and they were making parts out of ABS black plastic and this other stuff that had strands of fiberglass in it that was even better. I wanna design and test a manifold using this type of material because its been proven to work on many stock vehicles, but for those that dont know plastic and composites will dissapate the heat and not absorb the heat from the head as much as an aluminum manifold will.. if anyone is familiar with the hondata intake manifold gasket these use the same principal

I Have plans of turbo and the only fear with a plastic manifold and turbocharging is that when the manifold heats up and is under boost it will balloon, to solve this problem i have the proposed idea od layering a single layer of carbon fibre over the whole thing, not enough to make the manifold retain any large amount of heat, but enough to hopefully keep the manifold from balooning, of course i would have to use a high heat epoxy when i impgrenate the carbon and what not but i will figure those details out when i actually start purchessing materials

I drew up some pictures of a design i made for it on Rhino 3D, dont mind the randon square thing in the picture, it just showed up when i renenderd the photo

Whats everyone think about this idea? pros? cons?

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Re: intake manifold design?
 

you should make it with velocity stacks in the plenum for each runner. Hmm this might work except i would make sure the plastic will withstand probably at least 250 degrees? Maybe more? Underhood temps can get pretty hot, especially on a boosted car. You also have to make sure the flanges will be thick enough not to crack and seal evenly, and plus youll have to find a way to mount injectors and the throttle body. Sounds like a lot of work but i think itd be pretty cool if you tried this. Any particular engine you wanna try this on?

Re: intake manifold design?
 

the other thing to consider is how it will affect intake temps... it could end up dissipating heat worse than aluminum. i wouldnt know either way but its something to look into.

Re: intake manifold design?
 

The LS1 uses a plastic intake manifold. I think if you added some velocity stacks, that ---- would be hot.

Re: intake manifold design?
 

yeah I'm working on changing teh plenium design a bit right now so i will take a thick wall pipe cut a side channel out of one side and use flat 3/4 inch thick and machine the holes for each runner, maybe add velocity stacks and what not

I am not sure but I have heard around the machine shop that this stuff i'm looking at is rated full structural integrity to 295 degrees, more than enough, especially since from what i have researched an aluminum intake manifold on a boosted engine runs anywhere from 150 degrees to 200

For the head flange part I am planning on hacking off a stock manifold, weld on some short aluminum pipes just long snough to clear the injectors before having some type of mating between teh plastic composite and the aluminum

also i have heard that heat wont transfer from teh head to the intake as much through plastic as it does with aluminum, hence the concept of hondata's headgasket? correct me i'f i'm wrong here, I am open to any sudjestions

My test engine I want to run it on is the b18 i'm building for my 95 sedan, turbo'd...... but this motor wont be in teh car untill middle of next winter, I think I may run it on the stock D for testing and use what i learn from that to creat a better bulletproof manifold for teh B

Anybody have any other concerns or comments on this project, I expect at least a little flamming from the quality personalitys at HMT ;) but honestly any sudjestions to connect the plastic composite to the aluminum would be prime, I have figured JB weld and window weld may be solutions but I'm sure someone has a genious idea of how i could do it

Re: intake manifold design?
 

yeah the plastic intake manifold will conduct FAR less heat than an aluminum one will. 295 degrees should work fine. The hondata intake gasket is designed to prevent the head from heating up the intake manifold from the heat transfer. Velocity stacks i think will help alot

Re: intake manifold design?
 

Get Minor Threat to post up the links I gave him in re thermoplastic welding/forming/deformation temps/chemical resistance. If you use any old plastic laying around chances are it will come apart on you.

Re: intake manifold design?
 

If it wasn't Good Friday tomorrow, I would be at Homeboy Depot buying ABS pipe..

Re: intake manifold design?
 

WTF does good friday have to do with you not going to home depot????

Re: intake manifold design?
 

Everything around here is closed, it's a holiday.

Re: intake manifold design?
 

Where do you live? Glad that ---- doesn't go down in the US.

Re: intake manifold design?
 

ahaha i'm in in canada and everything is closed

well for the thought of keeping things together I plan on asking the company "GE polymer" about that and i'm sure they will have a sudgestion, I'm working on a new model for you guys that includes velocity stacks, The way I'm changing it is going to make for more machining in one sense but less in another, I'll show you when i'm done I should be done the drawing in 15-20 minutes max ahaha I'll post it up when im done

Re: intake manifold design?
 

New design! pros, cons? I know the stacks look lame but i just threw the drawing together, I will try and make a more detailed one later, but this should give you an idea

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Re: intake manifold design?
 

You nearly never see it done on i4's, but angling the throttle body stand-off by 30-35* entering the plenum chamber will give a more even distribution of flow across the plenum.

Re: intake manifold design?
 

so angling the TB towards teh bacl of teh TB or angling it towards teh rummers?

Re: intake manifold design?
 

Back of plenum I believe, I've seen it done on a few manifolds.

I'm in Canada as well.

I'm making mine DIY style, most machine shops can do it, but if you're one-offing parts it's cheaper to go buy a premade intake.

Re: intake manifold design?
 

AEBS Typhoon, best cheap IM ever. Better than vicky x or the like in 300 range.

Re: intake manifold design?
 

Do they make a D-series one though? I havn't found one.

Re: intake manifold design?
 

Yeah all this will cost me is materials, I get all my machining for free, its my best friend's fathers shop and he loves when i even come in and hang out because I am really interested in custom fabbing stuff, the scrap pile is fair game for anything i want to work with and he just lets me and my buddy play with the welders and ----, its pretty awesome!! I'll go in to the shop on tuesday and talk teh design over with some of teh guys there and hopefully get a good game plan set

Re: intake manifold design?
 

Velocity stacks will probably not improve performance on a forced incduction engine. They are mainly used in NA applications, because the air in the center of the plenum moves faster than the air near the walls of the plenum, and moving the runner inlet toward the center of the plenum will increase velocity in the runners. This is fine when the air is being drawn into the engine. In a forced induction application they are just going to be in the way, causing turbulence and most likely hurting overall power. A nice flat bottom with radiused inlets would work nicely.

Re: intake manifold design?
 

can anyone confirm thsi info? cause if so, it'll make my life easier!!

Re: intake manifold design?
 

But don't most of them scrap them for aluminum when going forced induction or nitrous?

Re: intake manifold design?
 

Boosted engines still flow air in the same way, high to low pressure. I believe that it will be at least as important, if not more important, because the air will be higher desnity and the pressure drop will be higher, so flow rate will be higher. THat would cause even more turbulance than on a naturally aspirated engine.

N/A engines don't suck air in, air is being forced in by atmospheric pressure.

Re: intake manifold design?
 

i believe there is still a suction pulling in air with a n/a engine.... take the head off an engine and put a piston or the piston (if single cylinder) at TDC and put your hand over the top of the cylinder and turn the crankshaft.... there is deffintly a suction proving that a cylinder will pull in air, or put your hand ocer the intake of a running motor...... it sull suck the ---- outta your hand

or better yet where the ---- do you think vaccum comes from for opening your BOV? if a cylinder didnt pull in air then a BOV would never work....... so hence whhy dont ya shuve your dick in your cold air intake and test out jizz injection :S

yes any empty space is filled by atmospheric pressure, but in terms of a motor, i believe you are wrong

Re: intake manifold design?
 

Does anybody have any links to a high powered 4 cylinder engine with velocity stacks in the intake manifold?

Re: intake manifold design?
 

https://www.homemadeturbo.com/forum/...?topic=59093.0

http://full-race.com/catalog/product...roducts_id=477


the top link isnt much of stacks but stacks none the less \

heres a link showing how to make sweet stacks if anyone is interested

http://forums.vwvortex.com/zerothread?id=2517182



but velocity stacks are oviously not going to hurt if full race is putting them in their manifold, im not in love with the company or think their the greatest but still, they have top of the line ----

Re: intake manifold design?
 

Ok those are different than what I was picturing. When I think velocity stack I was thinking of the runner extending into the plenum a few inches, then having the bellmouth. The radiused inlet on the bottom of the plenum was what I was saying would a be a better way to do it.

Re: intake manifold design?
 

Here's a pic of the full race manifold for a 4g63.

Re: intake manifold design?
 

yeah by no way do i plan on going half way into the plenium thats ridiculas ahaha


I deffinitly wanna do something like the full-race style set up, I like that design a lot

Re: intake manifold design?
 

i think your best bet is to start off going with a proven design and making your mani close to that. there are other things to consider besides air flow characteristics when building your manifold- most of which i don't have a clue of. what is your goal for power? what other modifications do you have? how big is your tb? what psi are you running? do you plan to keep your iacv?...

as for the velocity stack debate... has anyone had a chance to look inside a champ car cosworth intake manifold? those velocity stacks stick quite far into the plenum, almost to the roof. these engines are boosted, mind you they are only running 2psi and 6psi on "push to pass", but the stacks are very unique. i made up some stacks for a couple intake manifolds that i was planning on building. i will probably still use them but i know i can make something that is much better flowing after having seen the design of the stacks on the cosworth engine.

as for thermal soaking properties of your "composite" manifold, if the hondata gasket is effective, why not just pick one of those up and make the whole intake manifold out of one material? phenolic is probably the material they are using for their gaskets to prevent heat transfer, atleast that is what i'd make a gasket out of. i'd try to stay away from using two different materials just to save on headaches down the road if it isn't built properly. i'm not saying it can't be done because it is done and very effectively so. but it is hard to compare a homebuilt garage racer to a sponsored team of highly qualified engineers.

i have a lot of (borrowed) ideas that i'd like to do some r&d with in building a good race manifold for boost and apply it on a honda but i just don't have the time to do it. i'm sure in the next year or so i may just get the chance to apply a couple of them atleast... unless someone contacts me and is willing to pay me enough to cover my mortgage to experiment on their drag car i'll just have to wait to experiment on my own car.

Re: intake manifold design?
 

The champ car engine is ultimately tuned and built as N/A, it only boosts for a max of 60 seconds during a 2 hour race. I don't think the velocity stacks are tuned for boost. If they were then the engine wouldn't be producing maximum power for 99% of the race.

Re: intake manifold design?
 

Boost, NA, same thing. Notice the Victor X manifold the big boost guys love is rated as a NA piece for 7000+ rpm powerbands? Think about it.

Re: intake manifold design?
 

the reason for this "suction" is because as volume increases(piston moving down), pressure decreases, so the greater pressure outside of the engine cylinder wants to be equal with the pressure inside the cylinder so you get "suction"

Re: intake manifold design?
 

I said it, and was disbelieved.

Re: intake manifold design?
 

Engineering is ignored by people who think Legos are the pinnacle of fabrication.

We are dealing with airmass. Airmass is power. Flow characeristics mutate subtly as pressure/density changes, but for the most part plenum size dictates efficiency at a given power level. If you know your desired power level you can dictate plenum size for best efficiency. Not that I care about efficiency one whit, but it goes hand in hand with balanced flow between cylinders.

Uhm, this is the first time I've seen this thread on a real computer (instead of my phone) so I can see the pics. A few pointers:

1) the only TBs I've seen cocked to flow along the back of the manifold were modified stockers... the restrictive small plenums in big power boost situations forced most of the air into #3 and #4, this helped them. Flow is still somewhat imbalanced, but it is a BIG improvement.

2) if you look toward the AIR mani, or the Full-Race copy of the AIR manifold, you see a large non-restrictive plenum that tapers as you go back towards cyls #2 and #1. This keeps pressure constant as the air travels deeper into the manifold, so that flow is pretty well balanced across a decent range of power.

3) Look at the manifold below. It has the cocked throttlebody and no taper - but it does have a nice big angle to transition as much airmass as posible exclusively into #1. The engine this was pulled off of had the single most fucked up #1 piston I have ever seen. Ring lands die, even on forgings, whatever. THIS piston had broken *rings*, there were a couple pieces about 1/4" long that ran vertically as everything in that area was shattered and mangled. The Manley rods and the top faces of the pistons were great, though... hell, the other three pistons were tits.

http://www.redpepperracing.com/galle...7514-3/abw.jpg

Re: intake manifold design?
 

the "Think about it" Reminds me of the moving Falling Down. When the nazi military shop owner was holding the can of ziklon b and said it about 4 times.

Re: intake manifold design?
 

using them in a V style engine is okay because you do not have to support any weight hanging staright off the side of a head.

The "sawy hoarse" style of IM on a V engine doesn't have to handel much at all compared to what is being suggested.

Re: intake manifold design?
 

Common modified Toy v6 manifold
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Toy v8 manifold "Top Secrit" style.
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Re: intake manifold design?
 

just because it is common, does not mean it is the correct (or best) way to do it.

Re: intake manifold design?
 

Sure it does.
1) That's the fastest way to do it
2) Nothing else will fit under the ------- hood, while fitting between the fuel rails.


You stick to Honda's. I'll stick to Toyota's.