Build your own intake manifold

[peypey's ride]

My neighbor has the pipe bender for making rollcages. I was thinking of using the same length runners with a slight curve, like, maybe 20 to 25 degs. I cant figure how they would affect air flow much if at all. As far as mounting the TB, maybe, tapping the holes a lillte bit closer to the edges to make it sit a lil more level, rather than just leaving it like you have. And giving a slight angle to the throttle cable mount so that its more level.

 

[GreenGSX]

How'd you come up with $50 for materials? Just the box section and tuning would cost that much. Did you not factor in the 1/2" plate you needed.

Good info by the way and this makes me what to try to make an intake!

I designed the manifold and purchased the materials in December of 2006. I picked away at it over the winter of 2007 and had it on the car the end of April. I think the prices have gone up since then. I checked the website I listed in the first post and the 4" box section was $16.25/foot and the 2.25" OD tubes (yeild a 2" ID with 0.125 wall thickness) was $8.59/foot. I didn't realize the price of the plate material was so high. I got scrap sheets from work. Using the custom cut form on the web page shows $72 for 1/2" plate cut 4"x25" and $51 for 3/8" plate. If I didn't have the free plate to start with I would open the phone book up and look for scrap metal places to check out.

 

[GreenGSX]

My neighbor has the pipe bender for making rollcages. I was thinking of using the same length runners with a slight curve, like, maybe 20 to 25 degs. I cant figure how they would affect air flow much if at all. As far as mounting the TB, maybe, tapping the holes a lillte bit closer to the edges to make it sit a lil more level, rather than just leaving it like you have. And giving a slight angle to the throttle cable mount so that its more level.

Bending aluminum tube is a lot harder than it looks. First off it really doesn't like to bend and it would much rather crack then take another shape. Also, it seems to be a lot of extra work just to keep the TB in a stock location. If fabbing custom IC pipes is hard to do then building this manifold is going to be a challenge. If you're looking for curved runners to add runner length then I would really ask what benefit your expecting beyond what I've shown here. If you can show the benefit then I would ask why you wouldn't just cut the top off a stock manifold and put your own box on top of that?

I don't understand your point about the TB sitting level? It mounts much in the same way the stock does with the only difference in that it sits lower and a little closer to the firewall. As with any aftermarket manifold you are going to have to redue some upper IC piping and the battery may have be moved.

 

[nukefission]

Which TB is that?

 

[GreenGSX]

Which TB is that?

That is a 91-94 JDM (only 1 vacuum port) NT throttle body which was rebuilt to a 63mm bore and machined for turbo shaft seals. It looks funny because I don't use the FIAV/ISC anymore.

www.throttlebodys.com

 

[the_skin_eater]

I do give you props on making that flange like that...Never seen someone do that. ha.

But ya. Ill work on that sometime soon. Def. help you, or anyone out next time.
If I do, Ill link it here or something. Depending too on how you want to weld the runners on, I can make the ports bigger or smaller with comparison to the runner size... I dont know about that though.
Maybe Ill pm you about that later, get some insight on that one.

And ya, aluminum has gone up a lot lately. Should drop back down a lil though...

 

[oldman420]

You wouldn't happen to be thinking about selling any of these at a reasonable cost? I'de imagine for you to turn a decent profit you would have to charge as much as the other guys, but if not pm me.

 

[GreenGSX]

You wouldn't happen to be thinking about selling any of these at a reasonable cost? I'de imagine for you to turn a decent profit you would have to charge as much as the other guys, but if not pm me.

A good used Magnus or JMF can be found for ~$400 and given there reputation for both performance and quality I would say buy rather than build.

If your like me and like build and design your own parts I say go try and build one yourself.

 

[me612]

Awesome thread. I've been looking into building my own for awhile now as well. Obviouslly I want to keep my cost minnimal, and I was really trying to figure out the most cost effective way to incorporate velocity stacks. I love your router method, and can't believe I didn't think of that. So simple! The only difference is that if I can find some D-shaped extruded aluminum for the plenum for a decent price at our local steel yard, I'll probably use that instead of box aluminum. If it's noticably more expensive, well then I will probably just stick to box.

I love it though, and you can totally tell you must do wood work! Great job!

 

[GreenGSX]

Awesome thread. I've been looking into building my own for awhile now as well. Obviouslly I want to keep my cost minnimal, and I was really trying to figure out the most cost effective way to incorporate velocity stacks. I love your router method, and can't believe I didn't think of that. So simple! The only difference is that if I can find some D-shaped extruded aluminum for the plenum for a decent price at our local steel yard, I'll probably use that instead of box aluminum. If it's noticably more expensive, well then I will probably just stick to box.

I love it though, and you can totally tell you must do wood work! Great job!

I know I've used the two terms interchangeably but my runners use radiused entries not velocity stacks. The big difference is that velocity stacks are off the floor while radiused entries are part of the plenum floor. There are two reasons why I didn't use velocity stacks. The biggie is that I couldn't make them and the second is that they were to expensive to buy.

This is a good topic to build on because I also don't understand the benefit of one over the other. The only difference I was able to dig up was that velocity stacks don't pull the air off the floor of the plenum which some have called "dead air".

 

[me612]

I was using that term generically as well. I'm no fluid dynamics expert, but the main reasons I like the radiused flanges are:
1) less welding involved (important because I also will be paying a professional welder to do this for me).
2) nothing protruding into the plenum (again I'm no fluids expert, but a radiused flange just seems like it'd be better to me).
3) cost of velocity stacks
A local buddy of mine is designing his own manifold as well using a CNC'd radiused flange that looks gorgeous in person. He's just been taking too long to actually put together a final product, so I've been looking into just making my own. And ever since seeing his flanges, I've just personally liked the idea of radiused ports. I'd just rather not have to pay to get something CNC'd, and hell anyone with a router can do it the way you did, what a great idea.

Anyhow, thanks again for the write-up! It's great that you took the time not only to build it, but took the time to take pictures of everything as you were making it.

Here's a quick link to the one my local buddy is making http://dsmstyle.com/forums/showthread.php?t=7042

 

[GreenGSX]

I was using that term generically as well. I'm no fluid dynamics expert, but the main reasons I like the radiused flanges are:
1) less welding involved (important because I also will be paying a professional welder to do this for me).
2) nothing protruding into the plenum (again I'm no fluids expert, but a radiused flange just seems like it'd be better to me).
3) cost of velocity stacks
A local buddy of mine is designing his own manifold as well using a CNC'd radiused flange that looks gorgeous in person. He's just been taking too long to actually put together a final product, so I've been looking into just making my own. And ever since seeing his flanges, I've just personally liked the idea of radiused ports. I'd just rather not have to pay to get something CNC'd, and hell anyone with a router can do it the way you did, what a great idea.

Anyhow, thanks again for the write-up! It's great that you took the time not only to build it, but took the time to take pictures of everything as you were making it.

Here's a quick link to the one my local buddy is making http://dsmstyle.com/forums/showthread.php?t=7042

I'm glad you liked the post. Here are a few tips to using a router to mill aluminum.

1. Whenever possible use a bearing guided bit. If you run out of material to guide the bearing (on deep cuts) just sandwich another piece of stock underneath with the same size hole.

2. Take off a little at a time. If you work the bit to hard it will ball up aluminum along the cutting edge and things will get ugly fast. If it does ball up just unplug the router and remove it with a small screwdriver.

3. Lube, lube, lube. Go to Lowes and pick up a little bottle of cutting fluid or use ATF and lube the blade as often as you can.

4. Practice on scrap before you cut the real thing.

5. Protect you eyes. I wear a full face shield and I recommend you do as well.

 

[gixrman]

3. Lube, lube, lube. Go to Lowes and pick up a little bottle of cutting fluid or use ATF and lube the blade as often as you can.

WD-40 also works verywell for lube on aluminum.

Great job GREEN on the intake. I do all my own fab work and would have never though to use a table saw, router to mill aluminum. What blade, tooth pitch did you use for the table saw?

Also did you think about just making a new plenum for the cyclone? Or do you think the runners are still a restriction.

 

[GreenGSX]

WD-40 also works verywell for lube on aluminum.

Great job GREEN on the intake. I do all my own fab work and would have never though to use a table saw, router to mill aluminum. What blade, tooth pitch did you use for the table saw?

Also did you think about just making a new plenum for the cyclone? Or do you think the runners are still a restriction.

Thank you. I got the blade from Harbor freight. It isn't anything special just a carbide blade for cutting metal. I think it was less than $10.

I have thought of just enlarging the plenum box on both a cyclone, 1G and 2G manifolds. I think that will be my next project. At the Hp and rpm I run I don't think the 1G runner size is a limitation. Runner length is the biggest issue.

Here is what I used for a blade and for lube.

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[bmoha2]

I never thought to use my wood working tools for metal fabrication! Outstanding! The amount of detail and precision blows me away! Awesome! Freakin incredible!

 

[arash15]

This just displays a great deal of precision and talent. Much more rewarding than buying a SMIM. Best of Lucc.

 

[black92_tsi_awd]

Can you post a some pictures of the transition on the inside of the runner at the cylinder head mounting flange?

 

[GreenGSX]

Can you post a some pictures of the transition on the inside of the runner at the cylinder head mounting flange?

Nope, its on the car.

I will say the welder filled in the small gaps on the corners with enough weld to allow me to port that transition to my satisfaction. The reason I didn't crush and mash the tubes into the exact shape of the flange is that tubes were to thick to allow me to do that. I tried a couple of different ways to expand the tubes with no luck and you can only crush them so far before they crack. So I gave up on expanding the tubes and just crushed them so they matched the long axis of the rectangular port. Like I said earlier the gaps left on the corners, which you can see in the picture, were filled with weld which I went back and ported smooth.

Also, the head that's on the car is ported with springs/valves so the intake ports are "gasket" matched. If you don't plan on opening up your head to match the gasket the gaps at the corner will be smaller.

 

[v8s_are_slow]

Nice manifold. I've wanted to do it as well, and may do it eventually. Two questions though.

1.) What bit did you use for doing the radius work?

2.) Does anyone know the advantages/disadvantages of radius over velocity stacks? Wondering if the difference would be all that noticeable or even worth the trouble to go velocity stack over radius.

Glad ya did all this, gives me some ideas on doing it myself. And yeah, I like building stuff myself. I was in the Airforce and went to school for machining and welding but as soon as I finished school and broke my foot. Got out of the military cause of it but I definately learned a LOT!!! Very awesome school I went to.

 

[GreenGSX]

Nice manifold. I've wanted to do it as well, and may do it eventually. Two questions though.

1.) What bit did you use for doing the radius work?

2.) Does anyone know the advantages/disadvantages of radius over velocity stacks? Wondering if the difference would be all that noticeable or even worth the trouble to go velocity stack over radius.

Glad ya did all this, gives me some ideas on doing it myself. And yeah, I like building stuff myself. I was in the Airforce and went to school for machining and welding but as soon as I finished school and broke my foot. Got out of the military cause of it but I definately learned a LOT!!! Very awesome school I went to.

I used a 1/2" radius round over bit. It was a Craftsman bit I've had for years. I don't think it matters who makes the bit. Just use a carbide bit and lots of lube and you should be all set.

I don't know the performance differences between velocity stacks and radiused entry runners. I was not able to make velocity stacks and they were to expensive to buy.

 

[jaden]

Does Anyone know where you would get the tubing? I am in Ontario and I cant seem to find the 2.25" OD tubing anywhere. All they have is 2" and 2 1/2" I have tried Just about everywhere i can think of.

thanks

 

[gixrman]

Have you tried online metals?

 

[jaden]

I was on there earlyer and the prices seemed pretty high. I guess thats where ill get it from though seeing as i cant get it anywhere else.

2" x 1/8 wall = $60 total shipped from my ushual supplyer (20FT)
2.25" x 1/8 wall = $150 total shipped from online metals (12ft)

Im building some of these manifolds right now. Its not as easy as it looks (haha) about 15 hours to build each one and $280 in miterials. hopefully going to sell some to people in my area.

thanks for your help and thanks to the OP for the great writeup

 

[gixrman]

Well I can tell from personnel experience that AL prices have gone up substantially over the past three years. I bought a 12x24" T6 back in '09 for $21 and now it's up to about $50 from online metals. The only other place I have bought material is eBay but your risking quality.

 

[Bluefire16]

Great job... ive been looking to get back into the DSM's adn have been looking at things again... think this would be a great test for myself if i get a car again.