Is there any harm in the auxiliary portal being constantly open. After playing around on the internet tonight and reading more about the ports I think I saw on mine right above the header where there looked to be where something was removed (vacuum actuator??) and now zip tied. Its raining out or I would go check it out but does this sound like the auxiliary ports are zip tied open all the time?. Does this effect anything?

My main concern is because I want to straight the cat or atleast the pre cat and don't want issues from not enough back pressure. Also, does anybody have experience with Trust mufflers? I bought mine with Trust quiet duals on it and was wondering about how loud it will be with the cat straighted into these mufflers. And could I modify the straight pipe to still accept the air pump fitting so it has some emissions or am I better off deleting this too. Thanks guys!

 

When I bought the engine I have now, and got rid of the old irons, it was only after I traveled the 100 miles home before I realized that I didn't have any 5/6th ports...

Runs ok, idles like ****. Supposedly, the worst problem is it takes a few ft/lbs off of the torque below 4000 rpm. My idle problem might just be old fuel and a leaky intake, I'm still hammering out some kinks.

 

It's more than "a few ft/lbs.". An NA 13B already has little torque down low, and having the ports open under 3800 RPM significantly reduces intake air velocity/torque. I tested once with the ports wired open & not only was it noticeably gutless on the bottom end, but it idled a little rough too.

Some info here & in the FSM: http://mazdarx7.iougs.com/intakeair.shtml

RPM switch writeup: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/activating-aux-ports-vdi-rpm-switches-907824/

 

I guess that explains why my idle is rough and comes into it hard at like 3500....

Now will I have problems with vacuum and back pressure if I did the cat delete? And if so would it be best to keep these opened?

How much louder would this be with no cat and mufflers at the back?

I would keep the air pump if I did this too so would it still stink of hydrocarbons? Thanks guys for the replies!

 

There is no vacuum used in the system. It's backpressure from the exhaust that moves the actuators (~2 psi is all it takes). When the main cat is removed, backpressure is reduced, so you have to get creative to keep the ports functional. Some headers have a small diameter pick up tube, and Racing Beat's presilencer has a similar tube. The stock split air pipe seems to be too large to create enough pressure.

I used RPM-switch controlled solenoids to run them off of air pump pressure.

A good bit louder, but stock mufflers will still keep it down.

Yes, but having the air pump continuing to pump into the exhaust will have a small effect on emissions.

 

I'm running a racing beat downpipe on the stock exhaust manifold and a racingbeat presilencer with rusted out mufflers. It's loud, but no louder than the civics with fart cannons...

Sounds worse though.

http://www.youtube.com/watch?feature...&v=YEZkeAJ9GFs

 

So I found the lever above the exhaust manifold where one of the actuators used to be. Is this the only one? So does one actuator open both he 5th and 6th ports?

Also, what position is the lever in when the ports are open and vise versa?

My lever was zip tied down, I cut the zip tie and moved ye lever and when I moved it up, it idled slightly higher and sounded more ballsie when I revved it so i'm guessing up is open? That's where I have it now and I haven't noticed too much of a difference down low but up top it seems to rev quicker and have a little more power, but its just seat-of-the-pants dyno going on here.... Thanks again!