making an intake manifold
 

a pics worth 1000 words.

The basic idea from a while back:

http://i35.photobucket.com/albums/d1...pes/pipes2.jpg

http://i35.photobucket.com/albums/d1...s/manifold.jpg


Band saw 1, stock intake 0
screwy dual runner stuff

Attachment 17379

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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.

http://nissansportmagazine.com/image...intake_033.jpg

http://i35.photobucket.com/albums/d1...takesmall5.jpg

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

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Re: making an intake manifold
 

uh oh. 320hp here we come :-*

Re: making an intake manifold
 

Damn not bad.

Re: making an intake manifold
 

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

Attachment 17377

ditto with these rods

Attachment 17378

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.

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....

Re: making an intake manifold
 

um yeah, I got banned, lol.

I might, I haven't been feeling fab work lately, too busy with school.

Re: making an intake manifold
 

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, ass 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.

Re: making an intake manifold
 

in for updates

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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