I got a 350 TBI that i swapped into a 89 Jeep yj went to get it inspected and told me it failed due to no cat. I ran the casting number, its from a Chevy G20 van, could i put any old cat on it, or do i need to find one for that van (i do not know the year of van just a 350 TBI from a G20). If i need to find one for the van than does anyone have a link i could use to buy one online or ideas how to acquire one? It would just be welded into the exhaust tubing infront of the muffler a little ways.

 

Just need to know if your engine has a smog pump on it (probably does), which would mean you'd need a 3-way converter, and the A.I.R. tube running from the pump to the cat.

If not, you'd just need a 2-way converter.

 

Not to derail the subject but what all do you need to do to remove the smog stuff from the car and still get her to pass inspection?

 

2 choices.....

Move out of the USA (the rest of the world doesn't care about what they breathe, so no emissions requirements) or make it a track-only car.

There is no way to legally take any of it off of a street car. It would be considering tampering with Federal Emissions.

 

how do i find out if it has a smog pump, and what is a 3-way converter and A.I.R. tube? I thought the cat would just be a little box on my exhaust that acted like a filter for gases off the engine, and no tubes or anything running off it. Or atleast i thought that for 20 plus year old engines.

 

If you are in California, it has to be a C.A.R.B (California Air Resources Board) approved one. If you are in California, that opens up a whole new can of worms, for an engine swap Referee to look at.

The older cats needs air pumped into them, to get them hot enough to be effective. That is a 3-way. And had the little tube sticking out of it, to be hooked up to the smog pump.

Not exactly sure when the 2-way cats came out (some time after the LT1s came out (or when they did), maybe around the LS1 time?) the cats could burn off the bad emissions with extra air being pumped in. That is a 2-way.

The A.I.R. tube is the Air Injection Reactor, named for C02 being pumped in to fuel the "fire" inside. The smog pump pumped in air through the A.I.R. tube.

Not sure when the vans got TBI or when the smog pumps stopped being needed. No way of knowing/finding out what year the van was, that it came out of?

 

So do you HAVE to have a 3 way cat if you have after market headers w/o the heat exchangers. The Headers i have on my car don't have the tubes for the smog pump. Can i just get a 2way Cat and call it good? or do i have to get the smog pump and install all the tubing and he like.

 

Well, since you already have illegal headers, why bother to put a cat on? You would still fail for the headers.

 

So....its not as simple as cutting a gap in the pipe and welding a cat on it?

 

For a 2-way, yes. For a 3-way, you'd need to set up the smog pump, belt, hoses, valve, etc.

Get an inspector who doesn't pay attention & you can just run a 2-way. If the exhaust is clean? You'll pass, like mine did.

When I got my GTA, it had a 2-way on it & the smog pump wasn't plumbed to anything. In fact, the pulley was gone & had no belt. Since it had a good cat, it passed at the smog machine. Without a pump, it shouldn't have, but they never looked close enough to notice. And with the pulley off, it wasn't obvious that a belt was missing.

 

Ok well i remember now its an LO5 350 but still can figure out if a smog pump exists, my buddy who knows small blocks is coming by one the 1st or so ill know then. I looked up on autozone for parts, i pluged in a 1987 G20 with the 350TBI (no i dont know for certain this is the year) but it says i can buy a smog pump but the cat looks like a 2-way as you guys say.

http://www.autozone.com/autozone/par...29_64164_5320_

Yes i realize it isnt legal in Cali, but it will never be there, any ideas?