Flowing The Intake Manifold

[soulstylee]

My head is being built up. The shop is now inquiring about the VICS. They're toying with the idea of removing the VICS, and flowing the manifold. Would there be any negative aspects of removing the VICS, or should the manifold not be flowed and leave them in there?

 

[TheMAN]

you'll lose low end power... leave it there... you can try porting it if you want, but you'll have to have custom oversized butterflies machined

 

[Little Beavis]

The VICS has some merit, but the VTCS can be removed. . .

Right? (Well not sure if you have those or not, but if you do, I think there has been plenty of talk about removing them.)

 

[flat_black]

Hmm... Yeah, if you have VICS, keep the setup... But if you have VTCS, like that in a P5, get rid of the thing... It's blocking flow. Generally, if you're porting out the intake manifold, you'll lose torque, and could lose gas vaporization; One trick to removing the gas problem is having the manifold ported out almost all the way, with only a thin layer of material beyond where the edge of the porting 'should be' and where it is, then get it acid etched where the walls get contacted by the gas... That gives it enough grooves and bumps to properly vaporize.

That is, if they can do that, or if you can afford it. =)

 

[Turbo Matty P]

Id be interested in some pictures of that Flat_black. Last intake manifold I had ported was on my 2.5L SVO motor and we just walled it out as far as it would go. It was also running 26psi of boost so I dont think I really lost much low end!

Which would be better: mildly porting the us P5 stock manifold or buying the J-spec manifold??

 

[soulstylee]

My bad, the engine I'm building came out of a P5, so I assume it has VTCS then.

 

[flat_black]

I've never ported an intake manifold this way, but saw it on a Volvo, back when I still had mine... It was ported out almost all the way, and had hatch patterns acid-etched on the bottom of the intake runners, where the fuel squirted. The dyno showed a distinct loss in torque on the low end, and once he did this, it went up a tiny bit. =) I'll see if I can find the guy's address to see if I can get pictures, but it's been a long time. But if you're going for pure power, and don't much care about low end torque or anything, port the hell out of the intake manifold. =) Just keep the revs high!

 

[Turbo Matty P]

well, the low end torque on the P5 is pretty high already. It feels just as torquey as the MSP does, but the MSP pulls harder on the topend. I plan on adding the mazdaspeed cams and MP3 ECU. With a good port-jopb on the intake manifold I should be pretty well off. I'm holding off on the exhaust until I go turbo. No sense in paying for headers and midpipe now and then replacing them in a year.

 

[soulstylee]

Sounds like I'm ditching the VTCS. Hope everything works.

 

[Equinox]

ditch the VTCS, only thing bad is you wont be ULEV while the engine is cold.... and you will have a check engine light, unless you run a mp3 ECU, then no more CEL

 

[perfworks]

ditch the VTCS, only thing bad is you wont be ULEV while the engine is cold.... and you will have a check engine light, unless you run a mp3 ECU, then no more CEL

This is partially true.
You WONT get a check engine light if you just leave the solenoid plug connected. Just plug the vaccum actuator line so you dont have a leak.That in itself will allow the plates to remain open constantly. You dont even have to rmove them unless you plan on taking the manifold off and doing some porting and polishing

 

[twilightprotege]

you cant just remove the VICS pure and simple. if you remove it (even if there were no problems with a CEL) you'll loose high end power. see VICS is not quite what everyone thinks. below the set RPM it's fully open. it allows air to move into a little chamber giving it the effect of a longer runner. at high rpm it closes right up giving the shorter runner length.

an idea i had was to reverse the VICS. you could drill holes to open up the chamber of the VICS and then reverse the little butterfly plates. so at low rpm you'd be running like you were at high rpm before - the plates would be closed and you'll still get the effect of longer runners as the bottom of the VICS chamber is open. then at high rpm you'll have the VICS open. it wont give the effect of a shorter runner, but it will give the effect of more air because you'll have the rear runners open (as usual) plus the air going through the VICS chamber.

does anyone have any thoughts on this?

 

[TheMAN]

uhh no

VICS butterflies are CLOSED when it is NOT engaged... air goes to the narrow LONG runners at low RPM... at high RPM, the VICS butterflies open and allow the short runners to be opened up... BOTH runners are used at high RPM... it does NOT work like a "switch to that pipe" thing

 

[perfworks]

uhh no

VICS butterflies are CLOSED when it is NOT engaged... air goes to the narrow LONG runners at low RPM... at high RPM, the VICS butterflies open and allow the short runners to be opened up... BOTH runners are used at high RPM... it does NOT work like a "switch to that pipe" thing

Damn Edwin you beat me to it!
Good post

The VICS is only operative during 4550 rpms and up. At that point the plates are opened allowing a larger "capacity" of air into the manifold plenum.

 

[Little Beavis]

You can get the VTCS out easily. Just drill off the screw head that hold the plates in there, then pull the rod out through the side. Then drill, tap, and plug the hole in the side. That's it. Very easy.

 

[flat_black]

Meh... Be done with it! have someone fabricate you a whole new tubular intake manifold. Hehee.

Don't listen to me, 'cause I don't know how much that'd cost. =)

 

[PaulMP3]

come jan. we will have a tubular intake mani.

 

[flat_black]

We who? o.o I want one! Hehee. Any details, or you gonna leave me hanging?

 

[perfworks]

Paul if anyone can make it, he will do a great job. Andy knows his s***.

 

[PaulMP3]

We who? o.o I want one! Hehee. Any details, or you gonna leave me hanging?

Andy Wagner from www.wagnermotorsports.net said he is gonna start the project in january It will be going on my car when it is done and ready.