Here's my current setup... stock carb w/ all emissions equipment intact, except for the exhaust system. The exhaust is a pace-setter header (modified so it will actually work!) leading into whatever the crap-*** catalytic converter is that came w/ the car and exiting through a pace-setter "Monza" muffler (or should I say megaphone ). The geniuses at the muffler shop said they couldn't make the air line to the cat work w/ my header, so they just welded the air line shut on the cat... therefore, my cat gets no help from the air pump.

The system has run fine this way for about a year now, but as expected, the cat doesn't do much converting. On decelleration I get the usual amount of "pop-pop-sputtttter-pop-pop" from unused fuel (I expect) igniting in the exhaust system.

Now for the question:

If I were to replace the non-functioning cat with a new one and reconnected the air line to it, could I expect the decelleration "pop" to be less noticeable, even more frequent, or unchanged?

Please address your responses with the understanding that I AM going to replace the cat with another cat, not remove it from the equation entirely, as the rest of the emissions setup is still working fine.

Flame away

 

I thought it was illegal for them to modify emission systems?

~T.J.

 

Ever rebuilt your carb? If your car is dumping fuel down to your exhaust its more likely to be a problem with ignition timing, or your venturies dumping too much fuel. Just my $.02

 

Yeah I was gonna say the only aftermarket cat you will get wont have a air injection port...

Man just scrap the damn cat... It will sound better, and cost you less.

 

That depends on the ethics of the shop doing the work

What do you mean? I've found lots of generic aftermarket 3-way cats with an air line port.. dynomax for example.

Can anyone answer the original question.. should I expect more or less popping? It's not at an obnoxious level right now or anything. I just wouldn't want it to get any more frequent.

When I said it has the crap-*** cat that came w/ the car, I mean the crap-*** replacement cat that the previous owner had installed.

 

ASE do you have a bigger pic of the car in your sig? Is that your car?

 

ASE, because you have a header it's a two-part answer.

You will get less popping (so it's hardly noticeable at all) - if you get a good cat (like dynomax), and if you get a presilencer installed in your exhaust system. If you only get the cat, I think you'll still get lots of pops.

 

Can you explain why the presilencer would matter? Would it be mounted before or after the cat?

Wattz: Yes that's my car, but I don't have a bigger pic.. the conversion didn't turn out so well from the picture I took of it. You can also see my '96 Magna in that shot.