VTCS/VICS location

[twilightprotege]

i worked out the speed vs gear ratio and this is what i come up with :

1st 6500 -> 2nd 3621.
2nd 6500 -> 3rd 4623
3rd 6500 -> 4th 4813

see i was thinking the extra power gained (well not lost) in 2nd and 3rd would make it worthwhile....well it's an idea anyway

 

[flat_black]

Oh, also Wrench; Do you happen to have a picture of the bent butterfly, and the rest of the intake manifold? If so, I'd like to see 'em.

 

[thewrench]

here's the pics of the regular 3rd gen mani:

 

[yanp]

What about keeping the VTCS as it is on a P5 with an MP3 ECU? Do I have to remove it or something like that. That doesn't seems to be verry clear for me.

Is there any way to have more gain.

 

[Gen1GT]

Ah, screw it all, and just get a custom intake manifold from Essential Speed.....

 

[flat_black]

yanp: No, you don't have to remove the VTCS. I just want to for a sense of completion. =)

 

[yanp]

do I have to keep it open, close or leave it as it is ?

 

[flat_black]

Leave it as is.... It'll be fine.

 

[Little Beavis]

If you have a P5 and a MP3 ECU you should open the VTCS (why have them "blocking" flow if you have no way of controlling them). Unfortunately I've forgotten whether they are normally open or normally closed during operation. My guess is that they are normally open anyway, in which case you can leave them as is. But there is no disadvantage to removing the VTCS if you have the manifold off. . .and while you won't notice an improvement, it should flow a little better (one less obstruction to the flow through the intake manifold).

 

[dudeondacouch]

There is always the 626 FS-de IM.... which is port matched to the head and doesnt have VTCS.... i think that is what Wrench has but his price is great... i doubt you could find a junker for that price. However I dont know if it will throw a CEL or not... I think its vacuum actuated so probably not.

What are the differences b/w the 626 IM and our FS-DE version? (other than the VTCS)

 

[dudeondacouch]

...so... in a nutshell, the 93 FS-DE is s***, and so are the 94-99 (not as bad as 93 though)... if you are to source parts, the 2000+ FS-DE is the way to go... the 2000-2002 626 FS-DE shares the same long block as the protege, but the protege gets a better performing intake manifold with VICS to aid high end flow slightly... and the 98+ blocks allow for the OEM oil cooler to be installed and it may also be stronger than the early blocks

This guy would know.

 

[yanp]

If you have a P5 and a MP3 ECU you should open the VTCS (why have them "blocking" flow if you have no way of controlling them). Unfortunately I've forgotten whether they are normally open or normally closed during operation. My guess is that they are normally open anyway, in which case you can leave them as is. But there is no disadvantage to removing the VTCS if you have the manifold off. . .and while you won't notice an improvement, it should flow a little better (one less obstruction to the flow through the intake manifold).

thx alot

 

[flat_black]

The VTCS butterflies are normally in the open position, at least as far as I've found.

 

[Little Beavis]

Sorry bad wording. . .yes they are normally open in "operation". I'm curious if you disconnect the "controls" would the VTCS be open or closed.

Damn me. . .I guess English must be my second language, because I sure wasn't very clear on that statement.

Anyone know if you unhook the vacuum controls to the VTCS does it stay open or closed?

 

[flat_black]

Given that, under normal circumstances, the VTCS' electric solenoid, when the car is warm at least, receives no electrical signal, it would make sense to assume that the VTCS butterflies, being disconnected or connected via the vacuum lines, should remain open no matter what... That being said, it may not be the case. However, when I make sure there is zero vacuum (IE, unplug a vacuum line from the intake manifold and let it pressurize to atmospheric levels) the VTCS actuator arm still doesn't move, so it would stand to reason that the VTCS operates (IE, closes the valves) only when it sees vacuum, which is when the solenoid opens up (Receives electrical signal) and lets the vacuum pass to the actuator bulb.

Whew... Did that make sense to anyone? =)

 

[dudeondacouch]

Basically, without ECU control, your VTCS butterflies will remain in the open position. If they were in the closed position without control we would have heard all about it by now!

 

[Little Beavis]

Agree. . .but wanted confirmation. . .which in a very long roundabout way flat black provided.

 

[flat_black]

I'm good at giving long, roundabout explainations. =) But at least I'm thorough!

 

[twilightprotege]

well i did a test yesterday blocking off the vacuum so the vics stayed open constantly. the power felt exactly like gen1's dyno graph. a big loss in power except for above 5000rpm. so i unblocked it.

but i had another thought about it. why not bypass the solenoid completely and have the vacuum line going directly to the vics? that might work to open the vics at the point where there is little vacuum (well enough to allow the vics to spring open)....so essentially allowing the engine (and your mods) to determine when to allow the vics to open....just a thought...

gen1 - any chance you can try this on your next dyno run (assuming your vics is also controled by a solenoid)???

 

[dudeondacouch]

but i had another thought about it. why not bypass the solenoid completely and have the vacuum line going directly to the vics? that might work to open the vics at the point where there is little vacuum (well enough to allow the vics to spring open)....so essentially allowing the engine (and your mods) to determine when to allow the vics to open....just a thought...

gen1 - any chance you can try this on your next dyno run (assuming your vics is also controled by a solenoid)???

Good question...
*waits for answer from more experienced member*