frozenwings

Well I decided to start a new thread revolving around this split air business. I have a regular 12A engine with the stock exhaust still on.... barely. It has the 3 cats, and it ends there. I plan on getting the Bonez system very soon, and will finish it off. But before that I need to figure out the deal with this split air pipe.

On my cat, it is welded shut where it is supposed to be and the pipe is totally gone. I have no idea how to go about supplying air to the new cat once I get it without that pipe The service manual is very vague about it in my opinion, it shows it in a couple diagrams and has a brief description on what it does. Reading one of the diagrams I can see a tube coming off of the back of the ACV right to the left of the port air switching valve (looking at the same picture on page 3 of the emissions for the 12A.) I also noted that it looks like the pipe comes down from the side of the first or second cat. Now what I don't know is when air is supposed to come out of that pipe and how I would test it without have to stick my hand there with the car running. Does it send air to the cat while acclerating or decelerating. Could this be why my car chugs a little while staying at a constant speed? Either that or the cat being clogged from not getting air from the pipe? If by some miracle air does pump out of it, would I just have to weld a new pipe in or what?

Paradox

iTrader: (1)

ditch the air pump, all cats and forget about it. just run a straight exhaust with 2 mufflers, unless you have massive emissions to deal with, then thats a entirely new story...

Roundabout

iTrader: (8)

if your getting a bonez cat, you will need to retain your air pump if you don't want it to burn up FAST.

Roundabout

iTrader: (8)

Like Paradox said, get rid of it. Your not using the air pump/air control valve/split air pipe anyways since it is blocked off on the cat. All your air pump is doing now is robbing your restrictive intake of precious air If you ditch these items, you might as well get rid of the rats nest also. Heres a link to the writeup found in the first gen faq section: http://www.ten15.net/Maz.tutorials/

frozenwings

Haha, are you serious? I live in michigan, and I dont think there is emissions tests or whatever anywhere in the state. My stepbrother suggested the same thing, but I'm not too sure about that. Wouldn't it still get too hot?

Roundabout

iTrader: (8)

If you put a muffler or presilencer in place of the cats, you will need to order one specific for the rx7 or one that will withstand HIGH exhaust temps. Don't go with a glass pack because those will burn out very fast also.

frozenwings

So I'd still be spending tons of money.

EDIT: Also, can you do straight pipe off of the stock manifold? Because if I need to buy headers AND a presilencer, that would be super expensive.

kgray

go with header and straight pipe to stock muffler. i have the same but a hollowed cat and it is a huge increase in throttle response for me.

kgray

or how about a header and a nice single inlet and dual outlet muffler- magnaflow/flowmaster. that might be what i do when i change from stock.

j9fd3s

iTrader: (3)

forget the split air pipe, its a decoy. you really want the air pump air to go into the exhaust ports. its a 15minute deal to rig the acv so it does this

http://www.jimrothe.com/mazda/84_tra...raining_4a.pdf

frozenwings

Well I would love to do a lot of the things to the 7, but I am VERY short on cash. I am seeking the cheapest and easiest route, and if it happens to provide a performance increase then its just a bonus. It seems like there is a cat replacement pipe at racingbeat.com

Is there anyone that knows how well this works?

kgray

If you have a welder, you could do the same for cheaper. You could even go with a used header if you are still short on cash. Talk to trochoid, he did mine.

frozenwings

Pretty much a straight pipe seems like the easiest way to avoid that stupid split air pipe. I need to think about this. If that air pipe thingy is cut off from where it comes out under the car, should it be welded shut or plugged or something?

Roundabout

iTrader: (8)

I have the same setup, and yes it is a good increase....but not good enough for me Im going straight pipe to magnaflow or dynomax soon

Roundabout

iTrader: (8)

forgot to mention that it is going to be loud

frozenwings

Anyone got some used headers laying around then? If not then I will try to run straight pipe off of the manifold. Like I said, I'm not in this for the power, I'm in it so I dont have loud *** right under my seat and so I'm not breathing in all my exhaust.

THanks for that pdf J9FD3S, looks very interesting.

frozenwings

So what exatly do I do with this then J9? Would taking off the catalyst thermo sensor be bad? Where should I have the split air run to instead of the main cat?

Roundabout

iTrader: (8)

take it off, along with the air pump....read the link that I posted

frozenwings

So it wont hurt anything to remove the thermo sensor? Or were you refering to the split air? Because I'm still not exactly sure what the sensor does, but its still down there under my car. I have it zip tied up right now since there is no pipe behind the cat.

Edit: OOOOO. Removing the rats nest involves totally removing the air pump as well? I read that when I first started coming here, and I didnt really understand it well at that point. So removing the air pump doesn't mess up the car at all?

Rotor13B

If your car doesn't stink now it sure will once you remove your emissions equipment, BAD. I wish there was some sort of setup to put a cat back under the car without the rats nest etc.

Roundabout

iTrader: (8)

My car doesn't stink...only the exhaust The only time I smell it is if Im out of the car...got down near the tailpipe today looking at my fuel tank (rotors spinning at the time) and I thought my eyes were going to dissolve.

frozenwings

If I do decide to go with the bonez system and figure out a way to run the air pipe, then would I still need that thermo sensor? The main reason I was going along with all this straight pipe business is that it will avoid messing with the split air. Right now my goal is to get this car into a dependable daily driver for the summer without spending tons of money. It looks like I can get the bonez cat pretty cheap, and if I can figure out a way to get that air hose back it might be worth it just to avoid my car smelling like ***.

frozenwings

Haha so many decisions to make, how do you guys handle all this stress :P

EDIT: Also, this will probably take someone who actually still has a cat. What controls when air goes through the split air pipe? I would like to test it out tomorrow but I don't know if it will push out air with the choke on or with the car idling. Would I need someone to step on the gas while I feel for air coming out? Also does the thermo sensor have anything to do with the split air pipe sending in air to the cat?

kgray

you could go with the bonez race pipe as long as you dont have emissions and it's cheaper
just an idea.

frozenwings

Does the racing pipe bolt directly to the stock manifold?