MS-controlled VICS
 

OK, I'm legally retarded when it comes to anything involving the ECU. I also don't quite understand how the VICS works, so this is a two-parter.

One, the VICS. How I think it works:
-There's a vacuum reservoir fed by the IM through a check valve so the VICS has a constant vacuum source, even at WOT or in boost
-The reservoir feeds vacuum to the actuator, which then draws the butterfly valves closed
-When the switchpoint is reached, the solenoid is powered which shuts the vacuum source off and opens the butterfly valves
-SO: what I want is a +12v hot that is on above a certain RPM, regardless of TPS, right?

Two, the ECU. I can use Output 1, which is on JS2 to trigger the VICS. Inside the ECU, I should run a jumper wire from JS2 to an unused spare wire on the center MSPNP connector, then run that wire to the VICS solenoid, and then ground the other pin on the VICS solenoid. Correct?

Side note, how do I get the Output 1 screen to NOT be greyed out when I open my maps in Megatune?


:noob::noob::noob:

Yeap. Or just leave them unhooked such that they stay open all the time.

As for wiring, MS doesn't shoot out voltages to control anything. It spits out a ground and you supply fused positive voltage to whatever you're running. So in this case you'd need to supply that solenoid with +12V when key on and hook the other side of the solenoid to an output on the MS, ASSuming that whatever output you use is strong enough to supply whatever current the solenoid requires.

i haven't looked at the VICS or VTCS much, but I suspect they are "normally open" devices. that is, they only need vacuum IN vacuum. ie if you leave them "off", they are in their low vacuum (near wot or above) state. I know the VTCS is because people unplug it and it remains open. I believe that is done with a spring.

Anyway, the vacuum goes to a solenoid valve yep. you'll want to check your shop manual or wiring diagram to verify that it is indeed +12 you want and not ground. see a lot of accessory stuff is already fed a constant +12 source and just needs a switch to ground.

then on top of that, I'd run a relay out there to take the load off the megasquirt. just make sure the relay is not powered when the car is off or you'll find yourself carrying jumper cables in your passenger seat.

ok next?

Other way around. Like pretty much all the solenoids in the car, the VICS solenoid is supplied with a constant +12 from the Main Relay (the white/red wire) and the ECU triggers it by providing a closure to ground on the white/blue wire at terminal 3Q.




Almost. The CPU, by itself, isn't strong enough to drive a solenoid directly. You need to build a Relay Control Mod inside the MS. If you wanna be conservative, you'd use that to drive a relay to drive the solenoid, though if the solenoid requires 500ma or less to operate, the 2N2222a transistor will be able to drive it directly.



Under "Basic Settings" (at the top) choose "Codebase and Output Functions."

Make sure that the selection X4(JS2) is set to "Output1" and not "Boost Control".

http://img06.picoodle.com/img/img06/...1m_64d98e3.gif

O snapz. I got rid of my EBC (MBC FTW). Can I use the EBC to ground out the VICS solenoid?

Yes. The IRLZ44Z MOSFET is perfectly capable of driving the VICS solenoid directly, and it's already wired in the proper configuration.

As an aside, for anyone who needs to drive any solenoid directly, the EBC modkit will allow you to do this without a relay, on any of the general purpose outputs. Just wire it to JS(x) as opposed to JS2. Thanks for the idea, Sav- not sure why I didn't think of this earlier.

Excellent. I'll wire it up tomorrow, change the output from Boost Control to Output 1, and then set it up. I'll have a dyno chart on Thursday to see if it did anything. :)

Yep, that's how to change it over. Pretty straightforward. There's a couple guys out there running the MSPNP EBC circuit to control VICS.

Well, how'd it turn out?

It works perfectly. Close the butterflies at 2000rpm, open them at 5200rpm. I saw a 12wtq gain. One wire to a +12v, one wire to the MS, just like your boost controller would be hooked up. You change the settings in the hardware as Joe indicates, then set it up.

Isn't the ideal switchover point at 5600?

And, whatever the ideal switchover point on the dyno is, lower it by 200 RPM because the mechanism has a delay.

I did one run with them fully closed and one run fully open. My crossover was just past 5000rpm, and honestly I saw nearly no torque loss with them closed to redline (like 2lb.ft).

Many will probably have seen this plot, but I'll link here again as it has relevance. I performed these tests, under as controlled conditions as I could, when I was setting up the new 2L with '99 VICs head (extensively worked so that may affect the results a little). I was very surprised at the strength of the results, not only notable in DLL but very notable SOTP improvement with the engine continuing to pull strongly to redline.

Edit: BTW I have my switch point set at 5100rpm - perhaps given Jason's comment above I could lower it 100rpm or so.

This is with and without vics on a '99 @ 6psi

http://users.telenet.be/miata/images...urbo_6_psi.jpg



This is vics on a stock 99. From FM's site:
If you look at the chart,
Run 29 (blue) is with hose disconnected and plugged for the VICS actuator. Major drop in midrange torque.
Run 30 (red) is with VICS hooked up normally.
Run 31 (green) is with VICS locked in the low rpm position, you can see that peak hp is the same, but hp plummets after about 6k rpm.

http://users.telenet.be/miata/images...s_FM_small.jpg

Both graphs suggest 5600 is the ideal switchover point. You probably have other results because of all the work that's been done to your engine.

I'm going to put mine on the dyno again and see if it makes more torque just on the long-runners...which it will.

They are not really longer runners - after spending a lot of time looking at the manifold halves and scratching my head on assembly it looks to me as if VICs functions using a resonance chamber to change the timing of the positive pressure wave to coincide with the inlet valve opening.

Hi Frank, You are probably right and why I caveat my reply with the fact that my head has seen extensive work. I can't say how significantly the headwork affects the results though. I sort of guess that it will amplify the difference at higher rpms where the higher flowing head will have the biggest impact?

Bring it back from the dead... So the Trackspeed sourced MS3 is up and running, and tuned... But I bet the VICS has not been hooked up yet. Can anyone give me a step by step procedure on how to get the VICS up and running?

One more thing, I already ordered the EGR plates from TSE... :O

only took you 8 years?!