building an intake manifold, input needed

[torq455]

the Lingenfelter TPI had equal length runners to start with. you can't do that with his intake.

[sharkey]

i wont be needing any of those flanges, the point of building the middle intake is to get away from those small openings in the top flange. i will be making custom flanges for between the middle and upper intake.

im planning to use round tubing. when you look at a sheet metal intake for a v8, typicaly the runners are 2x3" and have rounded corners. with my intake, it would be around 1 1/2 square tubing, and it has sharp corners. coupled with the fact that the round tubing of the same size hasa larger area, this is why im going with round tubing. it will however be flattened a bit, making it more like oval tubing.

building a tpi style intake wouldnt be that plausible for me. the runners would have to have a fairly sharp bend in them to clear the hood of my car, and getting 1 1/2" aluminum u-bends is impossible.

im still unsure what im going to do for a plenum. i know it wont be round, thats for sure. im planning on having the runners come straight out and they will be cut off at an angle and have flanges for the plenum (mabey). the problem with that is the runners for each bank will be about 18" apart, meaning a plenum would end up well over 200 cubic inches, wich is way to large. im tossed up over doing 2 seperate plenums with dual throttle bodies (dodge intrepid setup) or building something like a 3.4l camaro setup were the 2 plenums are fed by a large singe throttle body.

[ForcedFirebird]

So you are keeping the LIM, and ditching the MIM and UIM? I didn't think the MIM flowed that bad, it was the sharp curve where the plenum/UIM meet that was a restriction. The 3.4 plenum falls on it's face at around 4500RPM's due to the extremely short runners.

[sharkey]

the lower intake realy isnt that bad, the ports have been opened up to match the gaskets and heads, and the heads have had extensive work done. i realy dont think the middle intake is that bad either, except for the sharp curve. i had thought about cutting the flanges off and starting from there, but by the time i do that i may aswell build 6 new runners. besides, id still be dealing with some 6" runners and some 10" runners. my runners are going to be 8-10" long, totaling around 17" from the valve. still a little shorter than optimal, however its not practical to make them longer and still have a hood.

[ForcedFirebird]

I want to see what you come up with .

Boosetds manifold was just the UIM, and he turned it into a giant plenum.

[sharkey]

his plenum would be way to large for an n/a motor, however boosted im sure it would have worked very well.

[ForcedFirebird]

his plenum would be way to large for an n/a motor, however boosted im sure it would have worked very well.

On the contrary, it works well on N/A motors. He wasn't the first to use the design/idea. I don't think boosted went to the extent of calculating the optimal size, but if you are looking for long runners, then it wouldn't be good for you anyways.

[sharkey]

well, i picked up the tubing today, the flange should be done tomorow. im hoping ill have most of a lower intake fabbed and at least tacked together by the end of the weekend

[torq455]

and you WILL post pix!!!! Franz attempted his own using the existing lower. pretty cool how it ended up, but he lost most of his lowend and the powerband bacame peaky.

[sharkey]

now why would i poist pics??? i think id rather come up with this idea, do it, get everyone all excited, then leave you all in suspence lol.

i am willing to lose a bit of low end power to gain more up top. my headers are better off for higher rpm, and the motor is built to take 7k.

[torq455]

lol.....yeah you don't spend much time in the low rpm area in the 1/4! specially the 2.8.

[sharkey]

ok i wont have any pics up this weekend as ill have nothing much done. i havent got my flange back and the tubing i picked up for the runners is just going to be too large. being a long weekend none of the metal shops are open today, so im screwed untill tuesday

[sharkey]

well, bringing this back up from the dead, ive got some stuff done, not a lot. my guy dropped the ball on the flange, i dont think he knew what he was getting into when he said he would do it. its rough cut, but now i gotta finnish it with a hack saw and file. the upside is i have all the runners cut out and ready to be welded to the flange.

i still gotta design the plenum and flanges for it. im running out of time, the last street legal drags in october 5th, i want this on and tuned before then.

[IsaacHayes]

Heh, I hack sawed out an adapter from 1" thick aluminum. That was fun!!! But it can be done! Looking forward to progress pics.

[sharkey]

well, spent 3 hours and i have something that resembles a flange. still have a pile of work on it though, im gonna guess another 4-6 hours with the tools i have.