building an intake manifold, input needed

[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]

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

[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]

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]

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]

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.

[torq455]

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

[86euro]

I like the original idea. If you based the design off of the Lingenfelter TPI, but shrank it down a bit, I think it would work out well for what you want.

[torq455]

agreed! you don't see muscle car intakes that are round from Edelbrock! all rectangle.

wouldn't those flanges act as spacers to add a little more volume and help take that 135* bend out some--make it more gradual?

[ForcedFirebird]

I agree on some points about the Trueleo intake. With mods, I heard of people outflowing their capability.

Sharkey, do you need some flanges to get started? These are machined to a Fel-pro gasket, I mad 5 sets for boostedrs, and he may still have some left (I think he was trying to sell them). Otherwise I could dig up the program and make more. They are 1/2" aluminum...

http://i158.photobucket.com/albums/t87/forcedfirebird/100_2707.jpg

[geoffinbc]

Well that Trueleo Intake has good intentions but the execution is all wrong. First off I don't think I would have used a round plenum. It works but looks ugly. Also I think I would have stuck to rectangular runners. The runners should start at the lower intake and match whatever size the user ports them to and the taper out from there. But at no time should it go to a round tube. Infact I would start with a rectangular piece of tubing at the largest dimension I wish to have and then cut sections of the tubing out and taper the runner gradually to the final size of the ports. I would then build a box plenum with a removable top for any blending or addition of vacuum ports or nitrous ports I wish to add. It just makes cleaning the inside easier. The the last step is actually getting someone to weld it properly. Those welds look like the fell on top of the metal they do not look good at all. Especially for something costing $600.

[torq455]

sad!

[sharkey]

well, with a 60mm throttle body it pulls decent from about 3000-5000, but it just falls off. the stock intake aparently only flows enough air to 4500rpm with a stock cam. sure the small ports and high velocity give good low end, however its just a dog higher up. the other downside of the stock intake is the runners in the middle intake are way smaller at the top, effectivly slowing the port velocity down before it mixes with the fuel and enters the cylender. this is also part of the reason for the bump in the intake port on the head, because the port velocity slows down so much it creates a dead spot in the runner.

[torq455]

higher velocity!! those smaller runners, with a bigger cam, will have much higher velocity to fill the cylinders with. that will make more lower-mid torque. i've talked to a couple of guys with a stock intake +62mm TB that have said awesome idle and amazing down low torque. with headers it would pull strong to 5500 rpm, but that about it.

[sharkey]

yea i lready have marks on my hood from the fiero intake. i looked long and hard at the trueleo intake, but its just too tall.

i would have gone with the 272 cam, however i have emmissions testing here and was afraid it wouldnt pass. and why bother going with a bigger cam when i cant flow enough air through the intake as it is???