Vacuum Switches On A Turbo Car
 

I'm a bit slow and am having trouble understanding a basic concept so be gentle. :giggle:

I've got a 1.8 turbo with a VICS intake. The donor car's engine harness was 'expecting' to run a solenoid to activate the VTCS in the original intake but the electrical plug is the same for the VTCS and VICS. It may be the same solenoid too but I haven't researched that.

I want to have the (Adaptronic) ECU open the VICS butterflies at 5krpm and leave them closed below that but the VICS controller opens under a vacuum. How do I get a vacuum at 5krpm on a turbo car?

The MSM donor car has a fistful of green and white check valves all over the various vacuum connections. My track car doesn't have nearly as many devices on it so I currently have it plumbed with straight hoses and T's - no check valves. It runs fine but I'm leaving torque on the table with the VICS butterflies closed.

Also, please no suggestions to gut the VICS and forget it. I want it to function. If I was going to go that route, I would gut and port the VTCS intake and sell the VICS to a normally aspirated guy. Make sense? :makeout:

Thanks for helping my feeble mind figure out this simple mystery...

A vacuum pump would generate more than enough vacuum. Like this one here http://www.summitracing.com/parts/MOR-22640/ although they are very pricey.

Not really sure if that would help your situation though... just a thought

Im pretty sure you'll never get vaccum at that rpm when boosted. Even with a vaccum accumulator you will run out fast. Either a pump or a boost activated solenoid, or hobbs switch/stepper motor setup, maybe.

Run an old style choke cable into the car and change as you please, profit..:2cents:

the VTCS is spring loaded to stay open. Vacuum holds it shut. Can you set up a similar deal with the VICS? I know the VTCS does nothing useful unless you're in vacuum anyway but VICS could be in either state with vacuum or boost so that screws you a little.

How about a little vacuum reservoir tank and a couple check valves? suck when you suck and suck when you blow!

Thanks. I'm sure I'm not the first guy to wonder this. The brake booster, for example takes a vacuum and then holds it with a check valve until it's needed and by the time it is needed, the car is usually in vacuum again. The vacuum to hold the VICS butterflies open needs to stay active the entire run through the gears. There would be dips of vacuum (shift) so maybe that would be enough for anything but I top speed run which I won't be doing in this car.

I won't be using a manual cable but changing to a can that opens under boost instead of vacuum is an idea. What are the cool kids doing?

Maybe a simpler way to phrase the question: What are people doing to run the VICS butterfiles?

I like the packaging of using the OEM engine harness, solenoid and Adaptronic to run the VICS but if it is going to be a rats next of hoses, check valves and other complicated bits adding a dozen failure points, I'll skip it and do whatever is easiest... but not a manual cable into the cabin. :hustler:

uh, the VICS manifold has a built-in vacuum chamber

^^^^^^

I've never had my VICS hooked up - FM told me that it was worth some torque to hook it up - I've got the solenoid, just never bothered to find the vacuum accumulator/check valve.

I told you I was stupid and confused. Does anyone have a diagram to which vacuum port connects to this chamber?

https://www.miataturbo.net/engine-performance-56/vics-operation-57041/
about three posts down

Thank you. That thread answers a lot of questions. Now I just need to split the manifold and see if I have that chamber. I don't remember seeing it. If not, I'll see if I can get reasonable results with just a check valve and go from there.