TECH: Your Intake Manifold

[Cp1]

So this might seem pretty silly to some of you guys here to have a tech article on just the upper and lower intake manifolds but for the sake of removing emissions completely i think it worth a look.

When you do either a non-sequential conversion or the complete removal of emissions (Kevin Landers offers on his non sequential tech, that doing one without the other is actually a waste of time and i agree) you may go one of two ways and use either a block off plate kit to plug all the ports on the upper and lower manifolds or a much more involved route of welding the ones that matter shut. this is important to know because if you weld them (like i will show you) you DO NOT WANT TO WELD EVERYTHING because you will create pockets of permanently trapped air. which heats up and may cause localized heating to your nice cool intake air or it may expand and crack the intake. the possibility of that is small but why not take some precautions.



In the picture above ive labeled where all these ports go a-a, b-b, etc.

You can see that it is only necessary to shut the bottom ports because as you know heat will rise and therefore escape out the top. the most heat will come from the exhaust manifold/turbo which is next to most of these ports.
from that photo the only two ports needed to be shut are B(which travels to your EGR Valve on the opposite side) and C (which goes to your airpump solenoid assembly)

With those closed youll want to make sure you use either a long flat belt sander with a very fine grit to make sure you level the mating surface again before you mount it back to your engine.



The out side of the manifold will look like the photo above now you can see that it is only necessary to close off the right hand side of the port where 'B' has been labeled. this is normally where your EGR valve is and the left side is where spent Exhaust gas is coming from and the right is where it will be dumped back into your intake. if you take a good look into that right hand port you will see very small holes drilled out into each of the minor Diameter intake runners. it is not necessary to close those little holes just the big one you can see them through.

if you want to go one step farther like i did i actually ground off a lot of the casting that i didnt need with a sharp BALL-END MILL and a die grinder. this picture will show you what i did:


After bead blasting that will look great so dont worry about looks right now. You'll also notice that ports labeled 'A' and 'D' dont go anywhere when you remove stuff so theres really no need to block them off is there? nope so just leave it.

Now for the Upper. if you plan on doing a full on conversion and removing your double throttle and youve still got that tig handy you might as well try blocking some more stuff.




Youll notice the filled in spot below the hose there used to be for the PCV system and since i didnt need the two extra little ports above it those went too. BE CAREFUL though youll want to think this through because if you remove all the little vacuum lines that go to your intake you wont have anywhere to attach accessories like a boost gauge or vacuum meter. so leave enough of them for expansion. or youll be looking for a new upper intake manifold.
You should also note the amount of grinding i have done removing excess casting left over from the conversion. this is how clean it looks (almost like factory) after a slight bead blasting.

you dont have to go crazy just take your time and plan things out. The old adage measure twice weld once applies more than ever.

Hope that help in your quest to map things out.

[albertomg]

Originally Posted by Cp1

....this is important to know because if you weld them (like i will show you) you DO NOT WANT TO WELD EVERYTHING because you will create pockets of permanently trapped air. which heats up and may cause localized heating to your nice cool intake air or it may expand and crack the intake. the possibility of that is small but why not take some precautions.

No offense, but that I think that is just about impossible. How did you come upon that hypothesis?

I also don't understand the fascination with removing all emissions 'crap'. My car works just fine with all emissions 'crap' installed and puts down nice power - 350 rwhp using seq twins.

[RXtacy]

Originally Posted by albertomg

I also don't understand the fascination with removing all emissions 'crap'. My car works just fine with all emissions 'crap' installed and puts down nice power - 350 rwhp using seq twins.

It removes a lot of clutter from under the UIM along with getting rid of the air pump making IC piping much easier, and overall just simplifies the vacuum system making tracing promblems easier.

[Cp1]

Originally Posted by albertomg

No offense, but that I think that is just about impossible. How did you come upon that hypothesis?

I also don't understand the fascination with removing all emissions 'crap'. My car works just fine with all emissions 'crap' installed and puts down nice power - 350 rwhp using seq twins.

1st point: I completely agree it is next to impossible to heat the air to such an extent that it would cause significant enough pressure to cause cracks, considering the already intense heat of tig welding, your exhaust wont be able to match that. But i dont want anyone blaming me for whatever reason.

however, if you block off the only escape route for heated exhaust air which is actually cast into the LIM right next to the rear intake runner you are actually heating that runner more than the other three. that said, that is localized heating and you probably want that hot air to be able to escape. not just continue to heat up.

2nd point: Someone already said it yes the main benefit is the simplicity of not having it. if your car works fine it would be silly to remove it just for that reason.

[Nexcis]

While we are on the subject, I've yet to get a straight and reasonable (logical) answer (not from you but in general) as to why it's a "complete waste of time to do a simplification without going non-sequential".

Anyone?

[SPICcnmFD]

Originally Posted by Nexcis

While we are on the subject, I've yet to get a straight and reasonable (logical) answer (not from you but in general) as to why it's a "complete waste of time to do a simplification without going non-sequential".

Anyone?

If you look at the simplified sequential(which is what I run) it pretty much just gets rid of all the emissions hoses. It really doesn't simplify the sequential system at all. A better name would just be "emissions removal diagram".

I don't consider it a waste of time because now I can actually see where everything goes withought having to have a diagram. I did remove the metal manifolds so all I have is vac. lines. Now if something happens I can just remove the hose and replace it instead of trying to trace which line on the manifold it runs through, which can be a major PIA to see.

[Nexcis]

See, that's what I've done as well (minus the removal of the metal manifold which I probably should). But when I was asking questions about it a few years ago, I was told that it was a waste of time if I wasn't going to go a head and go non-sequential.

I personally will always stay sequential, I love the concept, I love the "perma-"boost from it.

[SPICcnmFD]

Thats probably just ignorant people that went non-seq because they couldn't figure out how to work on a seq. car. After a while of looking at diagrams and working on the car, it really isn't that hard to figure out how all the seq stuff works.

If I was going to go non-seq. I would go single. There is no point in having twins IMO if you aren't going to run them seq.

[Cp1]

Originally Posted by SPICcnmFD

Thats probably just ignorant people that went non-seq because they couldn't figure out how to work on a seq. car. After a while of looking at diagrams and working on the car, it really isn't that hard to figure out how all the seq stuff works.

If I was going to go non-seq. I would go single. There is no point in having twins IMO if you aren't going to run them seq.

I agree, the factory system can get to be a bit of a hassle especially for people that normally dont like to or arent interested in diagnosing potential problems. the simplicity of not having to deal with it ever is what i think motivates a lot of people to convert.

I also agree with the 2nd point you raise but i think that for most people leaving the twins in place is only a temporary measure while they like myself accumulate all the parts needed to go single. think of it as a pre-emptive half way modification that will still allow you to drive the car.

[blwnrtr93]

I bought my car knowing the seals were shot in the factory secondary turbo and started working on a single swap. After dropping more money on it than I wanted to, I got a good deal on a set of non-seq twins and decided that they would help me to eliminate alot of the costs of the single conversion and stuck with it.

[SPICcnmFD]

I can understand going non-seq while you are waiting for a single. But if I was going to drive around for a while I'd much rather have seq. twins.