I have SLP headers w/out AIR going on car soon to hook up to my cat back. The previous owner of the car removed all AIR parts and pump but left the cat conv. on which is now in need of replacement along with the headers and y-pipe. I have a CATCO cat for use with my car new in a box (purchased before headers) should I put the cat on without the AIR system pumping fresh air into it? Will that ruin or clog the cat if I did this?

 

they work a LOT better with fresh air going in.
it's up to you really.

 

so could you just leave it unplugged then? I need a cat, don't have the AIR system, and never drive it in the rain, so would that be better than just plugging the air intake?

 

I removed my cat and my entire AIR system. The AIR Pump system is only really needed at start up to enable the conversion process before the exhaust temps are at operating levels. In other words, if you were tested for emmissions with out the AIR system but with a good converter your car would likely fail if the engine was cold. This is when the AIR pumped into the exhaust enables the reaction. After everything is heated up, the recation would happen just fine even without the AIR pump because of the geater heat and pressure build up. If they tested you right after driving the car there, you would probably pass the sniffer but you might not pass a visual inspection. This is not a concern for me because I don't have to have my car tested. But, I am putting a new Cat on so that a good muffler shop will hang the rest of my exhaust I think that's all they really look for around here. Then I can unbolt and slip off the converter and replace it with the off road pipe I made. Unless the car runs better with the Cat on than off. Diferent combinations respond to backpressure differently. Whatever. I'm going to finish the exhaust with heavy gaauge aluminumized mandrel bent pipe to an Eddlebrock RPM dual outlet muffler. That I'm getting free because of their lifetime warranty. What about the tailpipes? I think I have decided on the Hooker dual outlet slash cut tailpipes with resonators. That would be 4 - 3" resonated tailpipes and I'll have them moved way out to the corners I think it'll look bad *** ! Have you ever heard a system like that? It sounds like a Ferrari or something. Really Raspy.

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Black 1989 RS Convertible w/43,000 mi.
Excellent Condition
LO3 305 w/TBI
12 PSI Fuel Pressure
6* Timing Advance
MSD Coil And Wires
Open Element 14x3 K&N
Hypertech Thermomaster
160 Degree Thermostat
Low Temp Fan Switch
Eddlebrock RPM Muffler
No Cat/No AIR Injection
B&M Stage 2 Shift Kit
17"x8.5" ATP 5 Spoke Alloys
P 245/45 Goodyear Eagle
HP Ultra Plus Tires
Lakewood Control Arms
Lakewood Pan Hard Rod
Coming Soon:
Hedman Headers & Y Pipe
12 Bolt With 3.73 Gears
NOS System