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· So whats UR excuse?
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Discussion Starter · #1 ·
Ok guys since the Indy Intake is getting such a bad rep what about building off the stock manifold or customize another manifold to fit into the neon. What are the options here I wonder?

The main thing I would think that would make it better is to cut off the TB plenum and weld it back on going straight in and eliminate the 90* turn. Since Im already welding and cutting on it I may as well cut it apart and add some new longer runners while I polish and grind out all the material I can. What do you all think? Best Idea or what? Im sure that I could add an inch or so to the runners if it would make a diff. If not Id just grind away most of the insides. I cant seem to find any good pics of a P&P project on an intake mani.

Any Ideas guys?
 

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You're probably 8 years behind the .org or so. LOL You're coming up with great ideas, but they've been doing these things on the .org forever. If you're custom building an intake manifold, a short runner box manifold with a huge plenum and TB mounted horizontally is the way to go. If you're just modifying the stock manifold, hack of the 90 degree bend as close to the plenum as possible, and hog out the lower plenum inlet as much as you can without ruining the flange, then weld a piece of straight pipe to it. 2.5" is probably just about right (or bigger, depends how big of a TB you want to use :D ). Then hack off the TB flange from the stock manifold, hog it out, and weld it on. Or just custom build a flange, that way you can use whatever TB you want (60mm jeep TB, 70mm mustang TB, whatever). Of course there's always the option of going with ITB's as well, but they require more extensive tuning, and a lot of custom parts.

Some difficulties you may run into with a custom manifold are positioning and machining the injector bungs, and fabbing up a waterneck, or using a PT style waterneck, or hacking the old waterneck off your stock manifold. And of course finding spots for all the vacuum lines and the sensors will take some thinking as well.
 

· HoodooGuru
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Short runner intake manifolds are for forced induction applications rice. An n/a application would suit best with longer runners to keep the velocity there even after the runners have been ported a bit. If I had a dohc I would keep the upper plenum / runners and port them then weld on a new box style plenum to the bottom of them. The plenum needs to be approximately 1/2 capacity of the engine capacity. 1 litre plenum in other words. Plenum needs to taper to cylinder 1 as the log style manifolds tend to make the engine run too lean. Go to the org and ye shall find!
 

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whatever happened to your custom box intake mani Hoodoo? I was hoping you'd get that figured out so you make one for me as well! :D
 

· So whats UR excuse?
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Discussion Starter · #5 ·
Atleast I can come up with some good ideas even if they are a little behind the org's. LOL Thanks Rice tehehe


If anything id make the runners longer to make more power in my NA car. Maybe a sheet metal lower plenum is a good idea with the runners and upper being ground out to the limits.

Would a sand blaster be able to chew out the rough casting I wonder? I mean it is cast aluminum and is pretty soft. If it would work it would be sorta like an extrude hone job. I imagnine it would take alot of preasure on the blaster to make it chew but it does sound possible to me. That will have to be a trial and error thing I guess.

Off to the org with me! To do some more reading!
 

· HoodooGuru
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Im working on my box style manifold at the moment alaska. Pics soon.
I'm also hoping to get some high comp pistons in the beast soon also. Add to that resigning from my job due to a prick of a new boss and me trying to start up my own design business I'm a bit busy! lol
My runners will be 8 inches long for a good n/a application. Plans and pics to come very soon.
 

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The problem with making the runners longer can be described in one word... space. There simply is not enough of it. The longer you make the runners the smaller you're going to have to make the plenum.

As far as sandblasting, I thought of that as well, but after porting my manifold I doubt sandblasting would work... A wire wheel doesnt even do much good, just sort of squished the material and pushes it around. Aluminum is soft sure, that's not such a good thing when it comes to porting though. I don't think its brittle enough to be affected by sandblasting. I used a small burr bit on a die grinder to port it, and then fine grit sandpaper to smooth it out. Burr bit needed to be cleaned on a wire wheel about as often as the air compressor kicked on... the soft aluminum quickly clogs it.

Anyway, just my 2 cents. (too bad you can't cash in on it, you might almost have a buck by now)
 

· So whats UR excuse?
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Discussion Starter · #8 ·
I kinda had my doubts about the sand blaster idea. It was just an idea.

What I plan to do now is get me a spare Dohc intake and cut it apart mid way thru the runners and weld it back together after grinding and polishing it out. The only thing that I wonder about that is getting into the weld to cut it down inside the runners after it is welded back together. That don't seem like such a good idea now unless I would cut it to where I could get to the full runner but still yet reach the weld spatter inside to grind it out and finish it up.

Does anyone know of a how-to (with pics) of an intake manifold P&P? I can not seem to find anything on it.
 

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You could cut off the runners close to the head flange, and then weld pipe to it fed into a box plenum, or a large diameter section of pipe...

And I have a spare DOHC intake manifold... :D
 

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what i would do if u were to do some work on a stock intake mani. id cut the elbow off and make the t/b bolt up straight to the plenum with out the bend to make it straight up. that'll make it shorter run for the air and easier to make a cai for it. then id just port it out. i beleave the bottome of the 1st gen intake manis un bolts, so u should be able to get into it far enough to not cut it.

really to make longer runners ud be better off goin a completely custom setup...
u could cut off the stock intake mani fllange go to a machine shop and get it copied into steel, then ur goin to need some pipe that u would have access to bend some and u might be able to get them long enough with a 3-4" plenum if u got a smaller radiator... now alot of ppl wont like this part but the 92-95 honda civics ( i beleave these years) have a small ass radiator that u could use, about half the size of a neon radiator. and ive known a few neon owners that have done it and its works great.
 

· So whats UR excuse?
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Discussion Starter · #12 ·
I am looking at both options here 95. I work in a machine shop and it wouldn't be all that hard to get anything made and then welded together. I found a P&P how to for the Dohc intake mani. But looking at all that work and time with a die grinder and cutting apart my stock mani. Maybe I would be better off with a custom made box mani. Im searching for sheet metal tonight at work. ROTFLOL I bet they hate it at work when I get in my Mcgyver mode!!!
 

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hmmm u work at a machine shop? dude u should make me a extra flange or 2 for me, id pay for them if need be and for the shipping, that is if u decide to go that way. im looking to make a short runner intake mani for my srt-4.
 

· So whats UR excuse?
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Discussion Starter · #14 ·
If I had a pattern to go by Im sure I could get some made up and milled out. I just need a manifold to go off of. Im not going to take my good one off and hack on it!! LOL

If you had a spare Dohc intake manifold to send me, Id not even charge you for shipping after I made the flanges. Just returning the favor bro!! Get back at me in a PM or something about that tho. Later
 

· So whats UR excuse?
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Discussion Starter · #17 ·
New questions about modifications to N/A Dohc intake mani's.

Has ne1 ever seen the intake manifold spacers? I see that Vitors made some at one time at least.

Question 1. How long (thick) would you need to make each spacer and not go over board. Intake to head spacer and upper and lower plenum spacers. Then there is the TB spacer. Usless IMO if you cut off the 90* bend under the TB. Then again I could be wrong.

Question 2. If I were to make them for my car, wouldn't it be benificial to put a degree of tapper towards the head. (bigger on the plenum side) This would help with velocity and I wont loose so much low end Right?

Question 3. What do you all think would happen with these spacers a good hand port and poilsh with the 90* bend gone and my 55 mm tb. Would it hurt me or help me? Sounds like the makes of a great intake system to me.

Im alreday looking at makeing some flanges for someone and if this seems like a good idea a thicker one wouldn't be hard to make. Anyhow shed me some input here fellas!!! It would be a nice addition to my 2.4 swap in a couple months. I can't wait!! LOL later
 

· So whats UR excuse?
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Discussion Starter · #18 ·
After looking at them on the site, I see they all look like they are the same thickness. Same as the TB spacer. 1/2 inch which makes sense to me. Keeping the same aspect ratio between them. I think I may have been wrong and they dont make the head to runner spacer.
 

· HoodooGuru
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How much to send me a 2.4 block acr? lol. I want one now too!
 

· So whats UR excuse?
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Discussion Starter · #20 ·
Oh dear! I dont know Hoodoo. I could get one pretty cheap tho I think. I know from Dodge your looking at about 2600 bucks (usa) for a rebuilt stock 2.4L PT block. I think if I can find them at U-pullit it would cost about 50 bucks. So you could figure about 100-150$ + shipping. It's not a short drive for me and thats alot of work. LOL At a local junk yard they may ask for several hundred bucks for the block. Im not sure.

Whats this got to do with manifold mods? LOL
 
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