Topic: What Catylitic Converter Should I get?

[82rustbeast]

I just got my 82 truck running good. So now its just about ready to go in to get smogged. All I need now it a cat. But I have a dilema.

 My trucks engine is a federal 81. I have the wire cut off at the ECU where the OC Thermo Sensor to the cat hooks up.

Actually its two wires, but they both go to the one sensor. But to get it smogged, should I buy the expensive cat with the thermo sensor, and rehook the wires, or could I get by with a universal like $20 one?

Also, my exhaust is a 2 1/4", should I match the cat tube diameter with that if I get the cheapo universal?

[BLACKDOG]

yes, match the tubing dia. 

As for the thermo sensor, are you talking about the O2 sensor?    I didn't know the '81 had a temp sensor.  It sounds like you are describing an O2 sensor.  I could be wrong though, wouldn't be the first time.  If it is the O2 sensor, then yeah, I'd hook it back up 

[bigarms23]

I am running a free flow cat i got from performance products it passes smog each time and the cat only cost 100 which isnt bad

[DTB]

check ebay. they have super low prices on exhaust components

[Duffil]

you don't need that thermo sensor.  I cut mine out long ago, just running a Catco converter, and I am CA smog legal...just passed last week, actually.

[emsvitil]

Match the exhaust tubing with an universal 3-way cat.

[82rustbeast [OP]]

Its called an OC Thermo Sensor. If you look at the Wiring Harness diagram in a Haynes manual, It says OC or Thermo Sensor on the 4 and 8 wires on the Federal Emissions Computer. I would like a cheap cat though. Any more suggestions would be greatly appreciated.

Oh yeah about the tubing size. Its the stock Toyota header with an adapter into a 2 1/4 muffler. So should I still go with a 2 1/4" cat?

Just makin sure everyone understands.

[jimbo74]

my 85 had an aftermarket catco cat had a port for a sensor but didnt have a sensor

my 84 has that sensor, i havent used the truck yet, but i have heard you can just disconnect with no issues... i removed mine

[82rustbeast [OP]]

Should I connect the two wires that go to the sensor together that hang off the ECU?

[jimbo74]

Should I connect the two wires that go to the sensor together that hang off the ECU?

i have heard you can do that or not... i have heard from several sources that it doesnt matter

http://board.marlincrawler.com/index.php?topic=31065.0

[Duffil]

Should I connect the two wires that go to the sensor together that hang off the ECU?

I don't see any reason to.  I cut mine off and used heat shrink to seal them, inside the cab.

[82rustbeast [OP]]

Thanks I'll just go without it. So whadda bout the tubing size? Stock header into 2"-2 1/4" adapter to 2 1/4" exhaust. Go with 2 inch cat or 2 1/4inch?

[emsvitil]

I just cutoff the stock flanges and then used header collector flanges instead with 2 1/4" pipe

[THK Matt]

magnaflow high flo cat.

[82rustbeast [OP]]

I just bough a 2 inch universal cat from work (Napa). I'll take it off after smog anyway.