Deleted.

 

Either 1 or 2. Depends on whether it came with, and still has, RPO N92.

Same

No. The O2 sensor is upstream of the cat.

You'll get as many answers for that as there are people who have cars. Personally, I have the Hooker cat-back, and it seems just fine. Other people like noisier or quieter or ... whatever. But, as far as a bolt-up fit and work right cause no trouble kind of thing, it works well. A bit loud to my taste but about as quiet as you can get (other than Dynomax, which is essentially stock) so it'll just have to do.

There is no such thing. The O2 sensor is the ECM's "eyes" on the fuel mixture. Without that, it won't know how much to inject, and/or won't know whether whatever it injected was too much, too little, or the right amount. Can't think of anything very much stupider to try. It MIGHT be possible with really skillful tuning but with the amount of effort it takes to tune the stock ECM, that's not an option, unless you're willing to update that to something modern. Which, if you were the kind of person who was capable of doing THAT, you wouldn't have asked this other question, because you'd already know the answer.

I don't think any of this really has anything to do with the "power bulge" deal.

 

Hi! Thank you for the reply! This was my first ever post on the forum, what I meant by simulating the o2 was basically making the o2 think it still had a cat but I assume you basically told me even without a cat the car would run fine. What I meant by the power bulge hood is that its introducing more air to the engine so didn't know if it'd lean it out as the hood and the intake part of the hood was not original to the car, its the one with an opening valve for the air from i think an 84. Mines a 91. I also was trying to explain i wanted a quiet exhaust that would still let me hear that hood open up and the front engine noise as well lol! Thank you for the help!

 

People sometimes post here and elsewhere about using a resistor or something (I'm an electronic engineer by trade if not training, so I'm not sure what they're thinking since it doesn't make any sense from the beginning, forgive me if that's not what you had in mind) to "simulate" the sensor in some way. Typically they want to eliminate it and somehow trick the ECM into thinking it's still there (not throw codes). That's what I thought you were asking about. Doesn't work.

Newer cars have a 2nd O2 sensor downstream of the cat(s), which allows the ECM to evaluate how well the cat(s) is/are working, and notify the driver accordingly. Our cars don't have that, only the one in front of the cat, so the ECM can see something about the air/fuel mixture in order to meter fuel appropriately. Consequently our ECMs have not the vaguest clue whether there's a cat back there or not. No need to be worried about that. OTOH you can get cats that flow about the same as a straight piece of pipe, for not all that much difference in price. IMO trying to figure out ways to eliminate it is ahelluvalot of maze with very little cheeeeeze at the end. Especially if you're in a place that does any kind of emissions testing or inspection. What little (if any) you gain is just not worth what you put yourself through to get it.

The "power bulge" hood for the carbed cars lets in air near the center of the hood, a bit off to one side, toward the back, where a carb is located. Your Firebird TPI intake brings in air up front next to the radiator. I can't see how that kind of hood would accomplish anything related to either the engine's sound or how it runs. I'm not sure it made much if any difference even on a carbed car, might have but I don't know. I'm a Camaro person not a Firebird one. My car (83 Z28) has the dual-snorkel intake that gets air from the headlight pockets; since Firebirds in general don't have that available (at least in the daytime), that hood was intended to bypass the restriction of the single snorkel on the air cleaner that they had. No idea whether it was especially effective or not; I do know that some people who had it, could end up with strange rain problems sometimes, especially if they "improved" it any kind of way. I did look at buying a car that had it when it was new (a 84 Recaro T/A) but didn't because the particular car in question had the LG4 motor which i was ABSOLUTELY not interested in whatsoever. Not sure if it will even fit your car, given the variations in Firebird front ends over the years. Somebody else would have to speak to that.

 

Hi, the firebird 5.0L i am looking at buying from a buddy is a TBI not TPI. Thats why the power bulge does anything at all. Its essentially a carb with 2 injectors on top and completely gutted.

 

oops meant to reply to you, i posted above, I forget to hit reply to you and hit reply to the thread

 

OK, so not a GTA.

Have fun with it.