VICS or not?
 

Has anyone boosted a 99 head with VICS? If so, how did you approach it? Is it worth controlling if you boost? Did you control it or just leave it open?

I have. I let the stock ecu control it. MS can control it seeing how it is like an on off switch.
No idea if it is worth it or not. Some people opt to just take the VICS butterflys out of the intake manifold because they don't want to mess with controlling it.

Thanks. A friend of mine is boosting a '99 in a '94 and we were wondering if the VICS adds anything that would make it worth bothering to set up a control for it.

My first inclination is to leave it wide open all the time with the rationalization that it would give him the low rpm effect it was designed for and that the boost on-set would negate any benefit from the shortened path or reduced chamber size.

Any others?

Check m.net.... it's well documented actually.

All you need is RPM switch to turn the butterflies for the VICS to work fine..... Shouldn't be very difficult.

Dave,

And a 3-way solenoid to control the signal line to the actuator.

I would use it. You can use the VTec function of the EMB, right?

EDIT: And a check valve between the vacuum source and the solenoid to maintain vacuum in the signal line.

well i would say get rid of it. my reasoning would be that thebp gtx and gtr motors (the bpt motor in japan) on the intake mani it didnt have the vics if i recall correctly. and that mani would give you more performance gain in a boosted situation but would give you less performance without the turbo and then the na version intake mani with vics was better for na and not so great for boost......

It gives you more controllable throttle response at light throttle. The better flowing design of the head caused the tip-in to be a bit jumpy (in Mazda's opinion) so it was added. It's similar to the progressive throttle you'd find in say a '94. So I've been told. Sorry to respond to this so late. You want it open by WOT. Maybe 50%-WOT triggered.

The mazda FE3 had vics, and all the MX6 guys have removed for an improvement in overall boosted power. The "theory" is that it's an obstruction under boost, at a sacrifice of off boost power and response.

Yes, definately seems worthwhile according to what I've read at miata.net. When you move the runners is determined on the dyno, but it seems to be around 5400 rpm turbo and 5600-5700 NA. Did the manifold come with the solenoid attached? If so, you can activate the runners with an MSD or similar rpm switch. Or perhaps you could even DIY your own.

I'm going to use one of the outputs on my MS to control the VICS butterflies. Unless I go V8.

Here's the VICS stuff set up on my 99 mani:
http://forum.miata.net/vb/attachment...chmentid=46026
http://forum.miata.net/vb/attachment...chmentid=46023

Ahh yes, nice pics showing everything Paul needs.

IIRC its more of a help for us NA guys that for boost. I dont think it really makes that big of a difference either way

Ahhh damn, I'm trying to remember what my friend did.... I think he swapped the manifold out on his. He put a bit of a frankenstein together iirc. I'll be taking my ride to him to change my clutch whenever that arrives and I'll be sure to ask him.

not sure about miata cause I never dealt with it but did deal with the JDM DSM manifold that had the same setup.

the JDM ecu controlled the butterflys so to setup on the USDM cars people where running a boost solenoid switch to open the butterflys. A few people where running the 5psi others 9psi. The idea is to give better torque low end with small scariface to top end hp.

A local Atlanta had a 20 tq over other similar setups with about a 8whp lost. if I remember the numbers correct