let me just start by saying this board is the best. i've been looking at it for about a month now and it is awesome. i just bought my first 3rd gen about a month agofor only 700 dollars. its a 1989 pontiac firebird gta, it has a 350 tpi with a 700r4 transmission( i think). so my first question is:
i bought the car and it came without any exhaust(converter on back). i've went to every parts store and muffler shop and they have all told me that without the converter it will run really bad and they also told me that you cannot put dual exhaust on them because of the computers, they told me you had to run a single cat. so basically my question is: do i have to run a converter? if so can i still run true duals? if not, can i run duals? i would really appreciate your input and thanks alot this message board is truelly amazing. thanks guys.

 

Basically, everything you've been told is wrong.

The only issue your car will have with modified exhaust is you must keep the O2 sensor, which is in the driver's side exhaust manifold. Not a particular problem.

The '89 TPI system used what is called "mass air flow" (MAF) sensing. It takes a direct reading of the amount of air going into the engine, and makes its decisions based on that data (along with others, of course). A "speed density" system goes bonkers when you change the exhaust conditions, but even that can be "fixed" with some PROM tuning.

So, what do you really want to do with the exhaust?

 

i would really like to put true duals on it, but everbody tells me that it wont work and i have to put a single cat-back on it. i called 2 of my nearest muffler shops and none would even touch it with out a converter on it let alone put duals on it, so basically i just want to know the best and most effective exhaust i can put on it(duals, single cat, dual cat) thanks for the help

 

They won't touch it without a factory-located converter because the possible fines are pretty stiff.

How much money do you have for this? Do you have to go through any kind of emissions inspection or testing? The simple "legal" way to go is headers, direct-fit cat, and cat-back for your application. Simple, effective, and the most used by people on this Board. Hooker 2055 headers, Catco 9118 cat, and whatever cat-back turns your crank will run you about $1000, but you can bolt the whole thing in without worrying about nasty looks from the customer representatives at the muffler shops.

I basically have been running such a system, except since I've gone through the last emissions inspection/test that I'll have to do, somehow the cat was "forgotten" when it went back together this last time...

 

we dont have to go thruw any emissions test here where i live so i dont need to worry about that. i plan on running headers but without any of all that smog and A.I.R stuff because i have already eliminated all that stuff. as for money, that really isn't a problem either. im just looking for the easiest and most effective way to do it. and i want it to have a really deep raspy tone that people will get scared of when they hear it lol. thanks