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Discussion Starter #1
Hey guys,

So for a couple months now I've been looking into projects for my senor project. I currently go to California State University, Sacramento, and am majoring in Mechanical Engineering. My senor project will be the prototyping, manufacturing, and construction of a turbo system for the D17a2 honda engine. I just so happen to own one. Anyways, I wanted to get some feedback from you guys, about one of the components I'll be trying to make. Key word, trying. First step is design, which I'm still on. I believe I've found a process to make the mold for this, and should be doing a mock up withing a couple months, and if it does not work out, I'll end up using the school cnc machine to do my back up process. Anyways, the pictures will expain a lot more, so let me know what you guys think.

The first two are of the basic design of the intake manifold, as I do not have access to a stock manifold, so therefor mounting locations aren't exact. I have the foam right now curred, ready for mock up, and mold making. My plan is to make this a direct replacement to the stock unit. I'll have a N/A and Forced Induction model, and am currently tossing around the idea of variable runner lengths. The prototype will be constructed from fiberglass gloth, then used on an engine dyno, flow bench, and hopefully anything else I can get the school to let me use. Final version will be carbon cloth, or kevlar cloth. Not really a concern, just what looks better.

The last picture is just a teaser for the Forced Induction part of my project.

Suggestions GREATLY appreciated, as well as anyone who has drawings, and/or specs for the intake tract of the engine
 

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I'm about to do an intake manifold for school too, but only the plenum will be carbon. I'm still working on the design, so I'm learning as I go.

Couple thoughts/questions:
- Have you done any FEA to decide how many layers you'll need? I've heard of a few student-designed carbon manifolds imploding from the high vacuum.
- Are you doing a wet or dry lay-up? Are you sure the epoxy you're planning to use is fuel-resistant?
- What is the radius on the edge of the flat section, where the runners meet the plenum? There's also another radius in the middle that looks like it'll make things tricky.
- Will the entire thing be made from a composite, or will you be bonding to aluminum at all? If so, how are you bonding them? I didn't see injector bungs, so I don't know if you're planning to use part of a factory manifold or place them upstream.
- Evaluating flow distribution might be good since it's a senior project, but I highly doubt that you'll have any issues with that design. What's the plenum volume?

Sounds like a fun project. Good luck with everything.
 

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Discussion Starter #6
I haven't really looked into the number of layers to be honest. My best guess is 4 to 8 layers, depending on complexity. I was tossing around and idea of how to seal the whole darn thing, and test it under pressure. I'm more of thinking about stress from positive pressure, rather than vacuum.

Wet layup would be preferred, but the fiberglass test model will be dry. I'm gonna test the foam I'm using to see if it'll stand up to vacuum bagging, if so, that might be the final process. I'll be using epoxy resin, and should be resistant to fuel, but thanks for the info, I'll run a test piece for that.

Are you referring to the radius in green in the attached picture? it's .3" I'm actually reworking the geometry a little bit, so things might change some. I wasn't happy with the plenum part. Thinking about adding more of a feature resembling velocity stacks. Plenum volume is roughly 110-120 cubic inches. Depending on your view of manifold designs, its good because that's aprox the same size of displacement of our engines, which is what I was aiming for. If I ever go with a NA model, I'll reduce the plenum size down, to increase throttle response.

What you see will all be composite. It will hopefully be bonded to a flange like you see in the second attached picture. Hopefully the flange will come from a stock manifold, therefor eliminating the need to add in injector bungs. As you can see in the second picture, there's one with the OEM manifold.

The biggest reason for having flow tests for individual runners, is I thought it would be nice to have O2 sensors on all 4 exhaust runners, and allowing the computer to individually tune each cylinder. If I know the flow on the intake side is EXACTLY the same, I won't need sensors there. It's just a thought though, and I haven't looking into the feesability of that yet.

Thanks for the ideas though. It's nice to have an outside opinion, as I've been staring at this thing for a couple months now, and it's getting hard to see "outside the box".
 

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get rid of that wack ass y7 type intake manifold man, ur runners are suuuuuuuuuuuper long. and no volume to the plenum. make a G/E sheet metal type design out of carbon/kevlar w/e ur useing. and good luck on tuning EACH individual cylinder. thats some $ thats not even worth using. and remember it aint about "equal length runners" that get the same ammount of air to each cylinder. thats been proven that doesnt work from facotyr! #3 still sucks! goo dluck
 

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I was referring to the smaller radii on the outside edges of the plenum. I don't know how well the fabric will conform to the shapes. I think it really depends on the fabric selection and the manufacturing, so I couldn't tell you for sure how it'll work.

110-120 cubic inches sounds fine, since it'll be designed for a balance between power and response.

I think four to eight layers of carbon should be sufficient, but pay close attention to holes, bonding surfaces, etc. where the fibers could get torn and/or stress risers can develop. Like I mentioned before, just keep in mind that I've heard of several imploded manifolds that were made from carbon fiber, and I'd hate to add another to the list.

I was also going to mention the long runners, but I assumed you've done some math to see what lengths you want. Since somebody else mentioned it, how did you design them?

sick1camcivic, he wants a manifold that will directly replace the OEM piece, so it has to have that weird design. Otherwise, I'd agree.
 

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I was referring to the smaller radii on the outside edges of the plenum. I don't know how well the fabric will conform to the shapes. I think it really depends on the fabric selection and the manufacturing, so I couldn't tell you for sure how it'll work.

110-120 cubic inches sounds fine, since it'll be designed for a balance between power and response.

I think four to eight layers of carbon should be sufficient, but pay close attention to holes, bonding surfaces, etc. where the fibers could get torn and/or stress risers can develop. Like I mentioned before, just keep in mind that I've heard of several imploded manifolds that were made from carbon fiber, and I'd hate to add another to the list.

I was also going to mention the long runners, but I assumed you've done some math to see what lengths you want. Since somebody else mentioned it, how did you design them?

sick1camcivic, he wants a manifold that will directly replace the OEM piece, so it has to have that weird design. Otherwise, I'd agree.
ok, a z6 manifold is a direct replacement for y7. so make it that type of design where everything bolts up? i mean. juuuust sayyyynnn lol. thats a waste of time to make it like the y7 garbage. the school like wasting time/money?if so, atleast give it a dam plenum with some VOLUME!!!!!!!
 

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ok, a z6 manifold is a direct replacement for y7. so make it that type of design where everything bolts up? i mean. juuuust sayyyynnn lol. thats a waste of time to make it like the y7 garbage. the school like wasting time/money?
A z6 manifold is a direct replacement if you change out the whole induction system (behind the ports). I think he's just doing something that will only require the replacement of the OEM manifold and nothing else.

If it's a school project, he'll have to make the interchangeability argument, and in general, people will be less inclined to buy something if it requires them to replace other components as well. I'm not saying that I like the y7 layout, but for the scope of the project, I don't think it's a waste of time/money.
 

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well it is for FI if i read correctly. So I mean i cant give an exact number man, im just saying from what I see, i see NO PLENUM. all runner, which is exact same as stock. if you look around, all the manifolds turbo people use have huge plenums, GE,Edlerbrock, on an n/a app i wouldnt be talkn so much siht, but to me, the way i see it, all the boost not literally, but alll the boost is stored in the plenum, say ur running 15psi. 15psi from a small turbo iis less whp than 15psi from a bigger, 15psi on a bigger intake mani, to me, seems like itd be more air in the plenum for each runner to get. even tho both wil read 15psi the same, but....this is only if its a drag car, you will want more of the power to be higher in RPM, so bigger plenum. he doesnt specify autocross/drag.....but me, im all drag, so he needs some volume, and to shape it where it still have some good velocity in the higher rpm. when im not drunk tomarrow ill thin kmore clearer.
 

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he doesnt specify autocross/drag.....but me, im all drag, so he needs some volume
Exactly, it depends on the intended use. I assumed it was going to be an "all-around" manifold that's decent (but not great) for everything. It's already more than the engine displacement, which I wouldn't really consider small.

when im not drunk tomarrow ill thin kmore clearer.
Haha, that's probably a good idea.
 

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Discussion Starter #14
The outside radius is just there for reference and cosmetics. It'll be defined by the cloth used. It just looks better when modeling to have a radius there, rather than an edge.

I forget where I stored my calculations excell sheet, but on there I have 18" calculated for runner lengths. As of right now, they are are 16.12". I'm targeting to get maximum tuned efficiency to be at roughtly 3000 rpm. I cruise on the freeway, right above that. I'm also targeting to be just above 2500 where I'm hoping to have built full boost, and equal length runners will be less of an issue.

The biggest thing I've kept in mind, is that all turbocharged engines run on vacuum until the turbo is flowing enough volume to produce 1 atm. With rising manifold pressure, tunned runner lengths become less and less important, relitively. If this where designed for NA, the rev limiter would probably be set at 3500 rpm. (dependant on runner length only)

Also, the plenum volume can be almost doubled easy. Believe it or not, I had to reduce the volume significantly from my original design, BUT, that's not my intentions. ddd4114 nailed it exactly on the head saying an all around performer. I'm shooting for a design that's a compromise right down the middle.


Good stuff though guys. Thanks for the input
 

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Discussion Starter #16 (Edited)
Crap, that's tricky to explain without my excel sheet. Let's see. Basic runner length calcuations are all over the internet. I used one that seemed decent enough to me, to calculate the runner length needed to get "maxium" horsepower at that specific rpm. Now, understanding that it won't be my real max HP, because that'll be the transitioning point from NA to boost, but the point where tuned intake runner length will be null. Ideally, that's where I'd want BSFC to maximize, but that's where dyno testing will come in.
 

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I hate to say it, but without validation, random equations aren't very useful. Have you done any dyno testing to see if your spreadsheet can accurately predict torque peaks?

Fluid flow in engines is pretty tricky to model, and it would be much better to use a good engine simulator (WAVE, GT-Suite, etc.) to find optimal runner lengths. However, creating a good model in such a software package takes a good amount of time, and it might be out of the question at this point.

When is your project due? When do you need to have the first prototype?

Do you mind sending me your spreadsheet if you can find it?

I'd shoot for minimal BSFC at cruising speed and aim to produce peak torque a little higher. Since the power demand is essentially constant at cruising speed (and can be calculated knowing drag, drivetrain friction, and rolling resistance), your only goal is to minimize energy consumption. When you want to accelerate, you're looking to produce the most average horsepower in the powerband, which means you'll want peak torque to occur at a higher speed. Since you're turbocharging, it's not as much of a concern, but any increase in VE would be beneficial.
 

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Discussion Starter #18 (Edited)
Yeah, that's why my runners are just a little under the calculated size. Good point on the random equations thing. No dyno, as the project is still being designed. The first due date is almost a full year from now, so I'm getting most of the research, and prototyping done early. That'll give me plenty of time for R&D.

***edit, that's not the EXACT reason why I shortened the runners up. It was mostly because I wanted it just above the cruising rpm, but your explination makes much more scientific sence
 

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Cool, sounds like you have a good start.

I assume you'll have a test car/engine to use for the project? See if you can get access to WAVE, GT-Suite, or something similar from your university, and put together a computer model of the y7. Ricardo and Gamma Technologies sponsor Formula SAE teams (not sure if your university has one), and if they haven't already, I'm pretty sure they'll give the school a one-year license for educational use. If you can create a validated engine model (verified via dyno testing), use it to choose runner dimensions, and manufacture a manifold that doesn't break or leak, that will be a pretty solid senior project and will speak well for you as a engineering student.

Good luck with everything. :)
 

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The test car/engine is still in the works. Eventually I'll want to get it all on my car, but not using it for the testing

Yeah, I don't know who is sponsoring our SAE car this year. A couple of the guys said the last couple years, the old team members kinda screwed us over with sponsors, so we're hurting right now. But I'll look into it. What kind of program is it?

Thanks man. I appreciate it.
 
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