Time to build a new intake manifold..

[R.O.R-2.0]

So, im going to be building a new intake manifold soon..

and ive been kinda looking around, to see whos manifold i want to copy..

ive been toying with the idea of dual plenum, but it seems easy to mess up your calcs..

a single plenum would be easy enough, but are they really that good for even boost distribution to all 4 cylinders?

heres a few pics ive pulled up online, just for ideas.

this ones a single plenum, looks easy enough to build. i dont like how the runners meet the flange at an angle tho. looks like its not ideal.





i cant get any pics of a PP intake, but it uses a stock lower section, and a modified upper section. i like his design the best. apparently the lower half of the stock intake is not as restrictive as it looks..

im really leaning towards basically just copying Daves manifold.. not a 100% copy, but close..

anyone know the size of the slit in the pipe between the main plenum, and the intake plenum?

or does anyone have a BETTER idea than any of mine? i dont have much space to work with..

heres a shot of how close the manifolds are:



i really dont have much room to work with. i think the only option i have is to modify a stock intake manifold..

[CRSMP5]

why not be like the toyota one in pic... this added to itb on a 16 rocco... basicly a header for a intake??

[R.O.R-2.0]

why not be like the toyota one in pic... this added to itb on a 16 rocco... basicly a header for a intake??

because i have SEVERELY LIMITED room to work with. did you see how little clearance there is between the intake and exhaust manifolds? there is roughly 1" from the back of the stock manifold to the tubes of the turbo header.. the picture i posted, is of my engine bay. theres no way on earth you could fit a manifold that doesnt have a shape similar to the original..

so, whatever manifold i use, has to be very low profile.. the turbo header ive got is made to be used with an OEM style pancake intake manifold. it works nicely with a PD, or stock TD, or stock AAZ/TDI intake as well. but it has to be a flat intake. thats why i was favoring the PP design, since it uses the lower half of the existing intake manifold..

also, spacing on the toyota manifold is all wrong for any sort of 8v.. i believe it was even a slight bit different from the spacing of the 16v head..

i dont have near enough room for a toyota header intake manifold..

[CRSMP5]

missed what i was saying.. design your own "header" style manifold.. up over to the room on top of the turbo? all equal length runners, big collector to branch off of? the pic was for design idea.. know no room for that..

[R.O.R-2.0]

missed what i was saying.. design your own "header" style manifold.. up over to the room on top of the turbo? all equal length runners, big collector to branch off of? the pic was for design idea.. know no room for that..

dunno how i would make tight enough bends to come off the intake ports and not hit the header. even cast elbows are too wide of a bend..

there is literally NO ROOM for anything bigger than whats on there now. if it was any thicker, or different in any way, it would be basically IMPOSSIBLE to get the bolts out of the manifold. and how it is now, you have to install the header first, then the manifold. removal is exact opposite.

basically, i NEED the tight bends of the stock manifold ports just to clear the turbo manifold..

i like the idea of a dual plenum more than a tubular intake anyways.. alot less work to copy daves manifold, than to roll my own.

[CRSMP5]

you have round not d shape right?? if round you can do a 70-90* angle cut on the pipes goin into the flange at the head so the basiclly go verticle up... now if d shape not so easy... but same idea applies.. 

you could also cut the runners off the one your using.. extend them up and do what you want.. but IMO if you wanna seek 100% same for each..  i do not think any plenium style will ever be 100% even..

why not add a intercooler into the mix?? runners extended up.. tipped back, intercooler, flange to go directly to turbo?? intercooler eliminates plenium.. no long boost pipes for lag.. so on...

[AudiVWguy]

I think your on the right track with starting with the stock one and building up from there. Wow, that's tight.
I found this place, it might give you some ideas.

http://www.rossmachineracing.com/intakepartspage.html


And this intercooler end tank from Treadstone.

http://www.treadstoneperformance.com/product.phtml?p=1311&cat_key=449&prodname=Treadstone+EV125

This would allow the air to flow more evenly across and into the cylinders.

[R.O.R-2.0]

you have round not d shape right?? if round you can do a 70-90* angle cut on the pipes goin into the flange at the head so the basiclly go verticle up... now if d shape not so easy... but same idea applies.. 

you could also cut the runners off the one your using.. extend them up and do what you want.. but IMO if you wanna seek 100% same for each..  i do not think any plenium style will ever be 100% even..

why not add a intercooler into the mix?? runners extended up.. tipped back, intercooler, flange to go directly to turbo?? intercooler eliminates plenium.. no long boost pipes for lag.. so on...

ive got an intercooler. its a front mount. hooked up even. what does that have anything to do with wanting a different intake manifold tho?

i dont have an intake flange, or a way to cut one. and im not going to buy one, so that pretty much counts out the custom manifold..

if dave cross thought it was good enough for him, then its good enough for me. basically, from where i am now, i can not get ANY WORSE of a manifold.. i have the worst possible designed manifold on the planet.. anything i do, will be better than what its got..

i still think dual plenum will be the ticket. how would it be WORSE than a single plenum? the slit between the 2 plenums is to keep the pressure equalized..

[CRSMP5]

why intercooler... if your trying to even out the flow of air to the head.. using a intercooler as plenium should do that...

your original question is on making a manifold that solves improperflow... my suggestions do that.. plenium designs.. duel/single.. slit or not.. i cannot see how 1 end will not have less/more then the other.. hell why not weld up the middle hole.. add hole on top of 1-2 and 3-4 and Y the 2 together??

now.. for my stupidity... if you have no way to cut the stock one.. how do you plan to make a custom one? the flange to the head is the biggest piece of the puzzle..

[R.O.R-2.0]

why intercooler... if your trying to even out the flow of air to the head.. using a intercooler as plenium should do that...

your original question is on making a manifold that solves improperflow... my suggestions do that.. plenium designs.. duel/single.. slit or not.. i cannot see how 1 end will not have less/more then the other.. hell why not weld up the middle hole.. add hole on top of 1-2 and 3-4 and Y the 2 together??

now.. for my stupidity... if you have no way to cut the stock one.. how do you plan to make a custom one? the flange to the head is the biggest piece of the puzzle..

its not that i cant cut a manifold flange, i just dont feel like starting from scratch. and im not going to pay big bucks for a lazer/plazma/cnc cut flange.. dave cross built 193hp with a stock turbo, and this type of intake manifold..

Chris, do you KNOW what a passenger performance intake manifold is? they are SUPER easy to make.. i can cut the top of my manifold off with the band saw i have in my shop.





he cut the manifold parallel with the valve cover rail, and just extended the original plenum.

i also thought about cutting the top of the intake manifold off, extending the plenum a bit, and just adding another inlet. so i would have 2 inlets on my intake. it would basically be a 1->2->4 manifold, kinda like a backwards tri-y header.. that should distribute the air fairly evenly over all 4 cylinders..

im just not happy with the stock intake. cylinders 1 & 4 have got to be just STARVING for air. it biases #3 really bad. there was a light film of oil in the intake manifold and charge piping, but it only got fed into the runner for #3..

i used to always get a carbon streak out #3 exhaust runner as well, and im sure it was because any oil that comes thru the charge piping, was ingested by #3 cylinder, not any others.. the other 3 runners of the manifold werew CLEAN.

another thing, the 1.5"x1" opening of the intake manifold & elbow can NOT FLOW GOOD..

again, i have VERY LIMITED space to work with here..



and, another shot of everything.. intercooler piping was kinda challenging this time, having both pipes on the same side..

[8v-of-fury]

Kev, is that marine exhaust tubing you are using as your intercooler pipes?

[R.O.R-2.0]

Kev, is that marine exhaust tubing you are using as your intercooler pipes?

well, most of the charge piping is 3116 Caterpillar coolant pipe..

then that piece connecting the intercooler to the intake, yes, thats marine billows hose.. that stuff works good to make charge pipe couplers out of also.. but, go figure, my family builds custom boats, so i have access to lots of left over scraps of things that were used for boats they built.. and the Racor filter, its off a boat as well.. so is the pink gates heater hose..

it withstands oil, pressure, water, anything. and it has wire inside it so it doesnt expand real bad with boost..

the piping is FAR from ideal. it was just thrown together to work..

once i have a turbo setp that i feel comfortable running, i will go to an exhaust shop and have some tubes bent for the car..

only reason i havent gone with real boost tubes yet, is because i keep swapping out, or killing turbos...

[R.O.R-2.0]

Factory BOV, and secondary manifold inlet are now both deleted..



getting ready to make it a dual plenum

[AudiVWguy]

If I remember right it's not the same distance from the near end to the far end. I think the front part of the slot is a little wider than at the end. You can test this for even flow by using a leaf blower and holding it above a large tub (bathtub?) of water and see the ripples that are created are coming out even from the manifold holes. Change the slot as necessary to get even output.

[R.O.R-2.0]

If I remember right it's not the same distance from the near end to the far end. I think the front part of the slot is a little wider than at the end. You can test this for even flow by using a leaf blower and holding it above a large tub (bathtub?) of water and see the ripples that are created are coming out even from the manifold holes. Change the slot as necessary to get even output.

those are just lines on the aluminum. not sharpie lines for the slit i cut. those do look a bit like sharpie lines tho! the slit starts at about ~1/2", and tapers down to ~1/8"..

PICS TO FOLLOW!!