I'm tired of dealing with the hassels of not having a cat and want to reinstall it,I feel mildly guilty, and it's a pain to find someone to pass me every couple years.

I do need some info though. I have a AIR pump laying around and the check valves, but I don't remember how any of it was plumbed. The tube that ran behind the accessory bracket was destroyed in the process of removal.

Initially I considered running the AIR tube outlet into the Y pipe just ahead of the cat or getting a cat that the air tube outlet ran straight into the cat itself. I've been advised on another site that this could cause the cat to burn up and that the outlet for the AIR pump should be as close to the heads as possible (as far upstream from the cat). I intend on having the cat in the stock location (94 firebird). I do have longtubes and intend to keep them, I know the y pipe routing will be less than ideal. My cam is ground on a 114 so I don't anticipate having any issues with fuel burning up the cat.

Can someone explain how the system works?
Any suggestions on reinstalling it?
Any suggestions for a cat?

 

You got good advice on where to direct the AIR flow.

Even the 3rd Gen F-Bodys with the AIR feed on the cat had a connection up on the manifold. When the car cold started, the AIR flow was into the intake manifold, not to the cat. Only after the cat warmed up did they AIR flow divert to the cat. Those cats were dual-bed.... first bed was "reducing" to get rid on NOx, second bed was "oxidizing" to get rid of CO and HC. The oxidizing bed needed the extra oxygen. The 4th Gen cat is "monolithic", not requiring the air injection between the beds.

The AIR initially burns the excess fuel from the rich startup. You want it to burn in the manifold and Y-pipe, hitting the cat with the heated exaust, not letting the unburned fuel build up on the cat and then ignite, melting the cat.

Shoebox has some photos and diagrams of the AIR system on his website:

http://shbox.com/1/4th_gen_tech1.html

 

What kind of problems do you have during inspection? I assume they can tell you don't have a cat by the sound, and then look to see that it's gone. But are they opening your hood and looking for the AIR system? You may be able to just reinstall the CAT and leave the AIR system off.

I just removed my AIR system due to the pump failing (didn't want to spend the $$ to replace it). In the past, I've never had an inspection station open the hood on my Z. They just hook up the inspection machine to the ALDL connector and test from there.

Thomas.

 

I've had them look under the hood, checking under the car happens first and is a dead giveaway, plus as I mentioned, I would just feel better knowing my exhaust is clean. I just want the cat on the car and working properly without killing a cat every year or two because it doesn't have the AIR pump on it. I pulled it off about 5 years ago and I look back on it now and think it was irresponisble and immature.

So I would need to weld some fittings for the AIR tubes into the front primary. From the air pump outlet hose I need to have a tube going up to each check valve.

Would there be a problem with having a T at the end of the AIR tube outlet to go to each valve?
Anyone happen to know where I can get some M22 fittings to weld into the front primary?

 

or would it be better to inject the air into each primary with something like this? http://store.summitracing.com/partde...5&autoview=sku


My guess is it's not worth the added expense.

 

MY truck hasn't had the AIR pump on it for over 4 years and no problems burning up the cat. I wouldn't think there is that much fuel being pushed at cold startup to build up on the cat and melt it..if there is something is way off in your fueling tables before its in closed loop.