general_macbeth

Ok, I have read a lot of stuff out there as to why to and why not to block off the ACV and the EGR. I have an 88 na with CATs. I do have a rough idle problem, especially when it's warming up. I'd like to free up space, but I'm worried about various problems that some say are possible, like backfiring my way to Hell.
Anyone out there that has actually done this and has input one way or the other?

Shainiac

iTrader: (7)

EGR is no biggy. I removed mine on account that it was jam-packed with carbon. just use plenty of Black RVT or a new gasket. As for the ACV, assuming your removing your air pump too, prolly not the best idea with cats. The ACV supplies air to cats and with out it and the air pump, your cats could get too hot. Thought about hollowing your cats? Im assuming you dont have emmissions in your area or you wouldnt be asking this first question.

general_macbeth

Ya, I'm in Illinois, and they just got rid of emissions on my car (awesome). I'd like to keep the cats, just to make myself feel not too bad (ribbons on SUV's). Now, with the EGR blocked, will I in fact get an even rougher idle?

NZConvertible

That will only happen if you **** it up somehow. Removing the ACV and EGR should have no negative effect on how the engine runs. Hundreds of people have done this successfully.

RotaryEvolution

iTrader: (30)

removing the EGR should have no ill effects, if anything it could smooth out the idle but that is not likely. the key is knowing each part's function, the function of the EGR valve is to recirculate the exhaust gases into the intake system to reburn as an inert gas to reduce NOx levels which is a deadly gas to humans. the EGR valve does fail but generally not in a negative impacting way, the diaphragm inside it crumbles over time rendering it useless and the gases can no longer pass into the intake system. rotary engines already recirculate a fair amount of exhaust gas anyways and EGR valves are a piece of crap idea that was forced onto Mazda to implement because of piston engines which do put out NOx gases. only an EGR valve that has carbon on the seat that is not fully closing all the way can have an impact on idle of the engine.

the purpose of the ACV is to divert air to either the air pump muffler(RF fender of the car, rather hidden) to dump air when not needed or to pump it to the catalytic converter to heat the back half of the catalyst to keep the efficiency of the catalyst even all the way across and to burn as much raw fuel (Hydrocarbons) as it can. by removing the ACV the catalys will have a reduced lifespan as the second half of the converter begins to plug up with unburnt fuel that cannot be burnt off efficiently.

arghx

iTrader: (3)

You know it's interesting... if rotary engines don't have much of a problem with NOx emissions, I bet a direct injection rotary would be awesome in a super lean burn mode (leaner than stoich), which is possible on gas direct injection motors such as the MZR series that Mazda produces. I'm pretty sure this is because the gas is squirted right on the piston from the head and somehow that makes it burn more efficiently without driveability problems.

Recall that 14.7 is the best ratio to have the least average emissions--richer=more hydrocarbons, less NOx, leaner=more NOx, less hydrocarbons. Most piston engines produce too much NOx for super lean burn to be viable without special catalysts which will not work long-term with US-grade fuel. So maybe a rotary direct injection motor can run a super lean burn, which is superior for gas mileage obviously, without producing excessive emissions.

general_macbeth

considering I still have my cats, though, what's the worst that can happen if I remove the ACV?

Rx7TyreBurna

iTrader: (1)

I took off my EGR. It was caked in carbon. Almost a solid sheet of carbon when i pulled it off.

I don't know about the cats though. I am guessing if they get too hot they can start to break up and then you will end up getting pieces stuck in other parts of your exhaust. ???? I am not a guru though. Just a guess.


GL