Rm4TWO

I purchased an 84 GSL-SE about a year ago and I just noticed there’s no air pipe running to the main cat? From the looks of it, it was missing when I bought it. Are there any negative side effects of running the car without it?

Brianhsval

Your 5th & 6th port actuators will not open without the pipe. All you have to do is take a wire tie to hold it open. You will lose a bit on the low end, but will gain on the high end. The loss is not that noticable.

RX7Rox

The 5/6 port sleeves rely on this split air pipe for exhaust back pressure to activate the actuators to turn the sleeves for additional air at higher RPM's (open around 3400-3800 rpm's). Assuming you have the 13b EFI. Mine's been broken off for a year now and still runs great. There's a chance the converter may plug up over time because this pipe also sends fresh air from the smog air pump. With the tube broke off, you have an exhaust leak under your 7, which is not good.
Mazdatrix sells them... http://www.mazdatrix.com/getprice.as...m=40-7400-N304

Rm4TWO

Thanks. I've been driving it this way for over a year now; I’ll have to try the wire tie idea to see if there is in fact a noticeable difference. If not I guess I’ll leave it as is?

Rm4TWO

Yeah I saw that part on the Mazdatrix site, which lead me to crawl under my 7 and check. Sure enough the pipe is missing. According to the parts diagram, there's an extension that sticks out from the main cat that the air pipe attaches to? That appears to be gone as well? I guess I might be able to plug the hole until I can find a replacement cat?

RX7Rox

Yes there's a flanged extension that sticks out of the converter. When mine broke off, that part was still attached to the air pipe. If you're running stock exhaust manifold this is a cheap alternative...http://www.rx7.com/store/rx7/saexhaust.html

The Bönez Street Exhaust Systems
Does away with the 2 pre-cats and has a silencer with a high-flow cat.

Rm4TWO

That would be nice, but I can't do it. I run my 7 in E Stock where cat removal is a no no.

Brianhsval

If your running in a class where cat removal is a no no then are you sure they will let you mess with the actuators?

Rm4TWO

Probably not, but I doubt the competition I run with locally would mind until I get it fixed properly. However, I wouldn’t dare try this at a national event. I’ve seen people get protested for using a non-stock shift ****.