Dual exhuast on 1991 Z28
 

I own a 1991 Z28 camaro. I bought it about a month ago. The original owner put an exhaust system on it that looks true dual, but it's not. It's single from the motor, to a single cat, to a big muffler, that comes out as two 2 1/2 inch pipes so it looks true dual.

Now the question. I live in Oregon where you have to meet a pretty strict emissions standard for new tags every 2 years. The car barely passed last time, took 5 tries and tons of driving around to get it to pass. That was probably because the main vaccum hose was cracked, which has been fixed, so it should pass no problem now. So what I want to do is make the car true dual exhaust. I've heard that it is almost impossible to route a second pipe under a third gen. My grandpa also seems to think if we go full dual that the computer on the car will not reset itself to the new amount of air flow and will not run. He thinks that with the computer in it we will never get it to pass emissions.

I'm looking for someone that has gone dual on a third gen camaro. Wouldn't you just add a second pipe, a second cat, and then reprogram the computer in the car? Anyone that has down this would sure be helpful.

My car is a 305 V8; Tune port injection; automatic.

Where I'm from in Texas, we have yearly emissions testing. On my 89 Silverado, to go true dual, I was told to add the extra Cat, but also i'd have to add a O2 sensor, and get a tune on my computer. Never did it and don't know how true it is. But if you were to go true dual, your car would still run. I ran with open headers on my 89 every once in awhile. and the truck ran fine.

Our testing is every two years here. That sounds about what I was thinking. I'll have to look into how much all that would cost when I go to do exhaust next time.

Anyone else?