I have searched the forums and threads and have yet to find and anwser to this question...I have also called racing beat and about 30 Mazda dealers...I get a different anwser each time I speak to a different person.

I know mazda used two different systems on the intake manifold..the VTCS and the VICS...The VICS seems like a dual runner intake system...The VTCS seems like a cold start only system.

I have a 99' ES and the VTCS never deactivtes...there is constant vacuum to the actuator arm that closes the butterflies, aven afterr the coolant temperature reaches 150 degrees or above...

Some people tell me that the VTCS is a on/off system, that should not be engaged when the coolant temperature goes above 149

others tell me it is a variable system that varies the butterflies throughout the RPM range.

Mazda issued a TSB stating that this system is inoperative after the car reaches 150 and the FAQ section says the same thing...but most of the techs at mazda act like they know what they are talking about, and tell me it is a variable system, operable throughout the rpm range..

Haynes repair manual also syays the VTCS is the same thing as the VICS...they just used different named for different years, and that the set-up is a little different.

I don't know who to believe...and I don't think my butterflies should be closed after the car warms up....the only way I can see them open is if I just about redline the engine, and that probably only happens because all vacuum is gone from the engine.

Anyone who is knowledgable of this issue is being asked to please post.

I tried plugging the line and deactivating it, and my car seems to run alot better. Maybe it's psychological, but I believe that 75% of my airflow is being restricted by those stupid butterflies. I would leave the car this way, but if it is a system that should be active all the time..Then I don't want to deactivate it.

Please Help

 

uhh... you don't have VTCS where did you hear that from?

 

Your car has VICS, not VTCS. There is no second set of butterflies on a 99. VICS operation has nothing to do with coolant temp, it is only dependent on rpm and intake manifold vacuum (which varies with throttle position). If my memory serves me correctly, the butterflies should be open during startup, and they should also fully open at ~4800 rpm under heavy throttle and ~5500 rpm under light throttle.

Plugging the vacuum line will jam the butterflies open permanently, which won't really do anything except for reducing low-end torque and possibly reducing fuel economy slightly.

 

My car has 2 cats...soo it's a ULEV...and the ULEV 99' proteges are equipped with the VCTS...right?

 

Hey carguycw...the butterflys are spring loaded....to what position, I'm unsure...I'n unsure about this whole thing now...When there is no vacuum...they are in spring retained position...when the car is started, idling, or cold running, there is vacuum to the line...it seems like there is vacuum to the line no matter what..except when I just about redline the engine...but that's no good for engine...engine do not like redline when stationary

 

also...If it is VICS and not VTCS, then how come I only see 1 set of runners?

 

99' ES 1.8

 

I just checked out The Man's detailed inspection of the VICS/VTCS enabled manifold... this anwsers alot....so I have VICS and not VTCS...great!!...this is all starting to make sense now... Hey MAN<---- sounds kinda hippy....what, if any, damage could be caused if I drove 10 miles with my VICS vacuum line plugged? ...BTW....any info on when or who will have aftermarket can cat by radiator?

 

Nothing. All that will happen is that low-end power will be reduced. Jammed open = reduced low-end power, jammed closed = reduced high-end power and possible hard starting. Neither situation will do any harm to the engine, they're just annoyances.

There's no aftermarket replacement available now, and there probably won't ever be one because AFAIK the design's unique to the Protege and parts makers like to build parts that can be shared between many different cars for better sales. However, replacing the stock primary cat with an aftermarket one probably won't improve performance because the OEM cat is very free-flowing; the problem isn't the design of the cat itself. The problem is that its location eliminates the possibility of installing a conventional long-tube header.

 

hey carguycw....I'm not really looking for a performance upgrade, My cat is bad...I'm thinkin of replacing the cat with headers that are available....will this give noticable power increases?...I can alway replace the cat when I need to go to inspection, but that check engine light bothers the **** out of me...any fixes for it when you install the headers?...and also...are the 200 dollar headers I see advertised total pieces of ****, or will they still give better performance than the cat...if you know of a budget header available for my car...please inform me of a good one...Thanx

 

If you're looking for a performance boost, the best info I've seen is Phantom Cruiser's recent header installation. Do a search and be enligntened.

However, if you're mainly concerned with keeping the car emissions-legal and you live in the U.S. (your sig doesn't say where you're from), and your car has been properly maintained, your converter must be replaced by the manufacturer if it fails within 8 years or 80,000 miles, according to federal law. Read more about it on the EPA's website...

EPA Emissions Warranty Facts
More EPA Info

Good luck!