Small VICS question

[TorqueEffect]

Now I can't seem to find a definite answer for this, and seems like there is some confusion surrounding this.

Are the valves open under vacuum, or atmosphere?

I initially thought by bypassing the solenoid and just hooking the vacuum straight up to the actuator kept the butterfly valves open under vacuum. Or like some people have said they use zipties to "keep the valves open".

But I have also seen people mention that the valves are actually open all the time under atmospheric pressure. So that means the solenoid applies atmospheric to the actuator, not vacuum.

The latter supports my butt-dyno results, as it seems like I have far more low end torque when the vacuum is applied directly, bypassing the solenoid. When vacuum is completely removed from the actuator, my torque in the low end plummets.


Oh and FYI, this is a BP swap in a Ford Festiva, and haven't bothered to run the wire to the ecu for VICS yet. That's why I don't just let the ECU do its own thing and forget about it. But until then, I just want to figure out which is which.

[FE3-323]

vics is vacuum controlled. it pulls initial high vacuum and stores it in the vacuum canister. at a preset RPM the solenoid is triggered once again opening up the flow to the canister. given vacuum is variable*********(key point)
higher RPM has less vacuum. so the pressure differential allows the butterflies to open.

by connecting it directly to vacuum port bypassing the oem system you are essentially making the butterflies flutter open at a variable rate constant of that to your vacuum level, I.E. rev the car & watch what the actuator does.
its a horrible idea for any NA car & will hurt performance.

unless you are changing intake manifolds entirely, leave the VICS system OEM or you will lose performance.(this has been show repeatedly through dyno time)
hope this helps

[TorqueEffect]

Maybe I am just having a hard time understanding it.

I don't know of any vacuum canister, it's just a vacuum line going from the intake, to the solenoid, the from the solenoid to the actuator.
Now what makes more sense to me from what you are saying, there isn't a canister, but the solenoid activates once after startup when vacuum is the highest, and then closes holding that vacuum on the actuator, keeping the valves closed, then at when at the trigger RPM when vacuum is minimal or non-existant, it activate the solenoid again and the pressure difference opens the valves.

So am I correct in thinking that instead of hooking vacuum directly to the actuator which causes valve flutter, I would be better off to ziptie the valves closed until I can wire the VICS to the ECU?

[FE3-323]

yes

[TorqueEffect]

Thanks for the help. Maybe this will clear up some of the confusion for others.

[FE3-323]

no worries!!