Fabrication Everything From JBwelded/Fluxcored downpipes to Equal length SS Manifolds.

making an intake manifold

Old May 28, 2008 | 11:48 PM
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Big J's Avatar
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Default making an intake manifold

a pics worth 1000 words.

The basic idea from a while back:






Band saw 1, stock intake 0
screwy dual runner stuff

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oh look, perfect fit after it's smashed, no spliting to resize

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why long runners? I make TQ, I'd like to keep it that way.





what I got done today with a little more band saw action and a hole saw:

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Old May 28, 2008 | 11:52 PM
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Default Re: making an intake manifold

uh oh. 320hp here we come
Old May 28, 2008 | 11:52 PM
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Default Re: making an intake manifold

Damn not bad.
Old May 29, 2008 | 12:01 AM
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Default Re: making an intake manifold

one of these cranks will spin 7500-8000rpm and hold together, the other won't

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ditto with these rods

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Old May 29, 2008 | 04:10 PM
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Default Re: making an intake manifold

nice smashing. looks good so far. in for finished pics.

i'd put the stacks inside the plenum instead of on the floor.
Old May 29, 2008 | 06:54 PM
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Default Re: making an intake manifold

Damn J, haven't seen you on MSV in awhile...you must've had a falling out with some of the homo's over there or something. Do you plan on fabricating more of these in the future?? If so let me know what kinda price range we're looking at. I'm tired of looking at my stock IM everytime I pop the hood....
Old May 29, 2008 | 10:19 PM
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Default Re: making an intake manifold

Originally Posted by CspecRun
Damn J, haven't seen you on MSV in awhile...you must've had a falling out with some of the homo's over there or something. Do you plan on fabricating more of these in the future?? If so let me know what kinda price range we're looking at. I'm tired of looking at my stock IM everytime I pop the hood....
um yeah, I got banned, lol.

I might, I haven't been feeling fab work lately, too busy with school.
Old May 29, 2008 | 11:04 PM
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Default Re: making an intake manifold

Originally Posted by weiRtech
nice smashing. looks good so far. in for finished pics.

i'd put the stacks inside the plenum instead of on the floor.
Fluid dynamics says they work better off the floor, but the stacks are modular and install flush using a 3" hole saw. Garrett GT3071R says the air will be motivated to flow regardless, so an X% loss of flow of 1 vs the other I can live with.

There's no well defined formula for intake design that won't make you head explode due to math overload. I went with 1.75" id runner material because it didn't require any extra/special fab to fit when smashed to an oval, and it's about 1/4 larger in diameter the the stock runners (at the middle of the manifold). Granted there isn't an ideal, or any for that matter, taper built into the runners. The funny thing is the factory runners are smaller towards the plenum and open up towards the head, *** backwards of anything I know about intakes and velocity.

The plenum is about 3.1L, about 80% larger than the stock plenum and about .6L larger than the displacement of the motor. The long runners on the stock manifold are about equal, volume wise, to the volume each cylinder displaces. It's part science and part guess work. The runners will be how ever long they can be and fit under the hood and behind the valve cover, probably about 12". My guess peak TQ will be about 5-6k, but factor in the 272/264 cams and I have no clue, lol.

Worse case it overloads one cylinder and blows the motor, or is nothing more than a shiny underhood ornament. Judging by the crap I've seen major companies have put out as intake manifolds (not for this car and probably never) I'm willing to bet it'll do ok.

Old May 29, 2008 | 11:32 PM
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Default Re: making an intake manifold

in for updates
Old Jun 3, 2008 | 11:50 AM
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Default Re: making an intake manifold

I'd build a better "jig" if this wasn't a one off part, and I'd build it totally differently.

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