Cooler Cat's??? (1 Viewer)

[1973Guppie]

Finally got the engine running!

Now I need to figure out what I need to do for exhaust. The existing exhaust used 2 stock Cat's that run super hot under the floorboards. It was reccomended I run shielded mini cats? Anyone have experience with these and do they run much cooler than stock cats to justify the extra $$? My first solution was to have the exhaust shop weld on a shield to the existing cats to help with the heat. The engine being run is a 99 vortec. Any help is appreciated.

Noah

 

[hammerhead]

Isn't that rig old enough to throw out all that yuppie crap? Catalytic converters never did any vehicles any good.

 

[1973Guppie]

Not sure what Yuppie crap is but the Vortec's run in conjunction with several sensors and a main computer, thus the signals must be correct in order for the engine to run correctly. I plan to resolve the situation by using O2 simulators that mimick the signal the stock O2 sensor gives off on the backside of the cat.

Noah

 

[hammerhead]

I understand sensors and computer being nec. items but IIRC cats are unrelated. I weld for a fella on the rock crawling circuit who runs a vortec truggy. Full sensors, no cats.

 

[cruiserdan]

Hammerhead,

Noah lives in Kalifornia. IIRC engine swaps in Kalifornia have to run ALL of the emmissions originally present on the donor engine in order to put plates on the vehicle. Of course my memory could be faulty or maybe he doesn't plan to plate it, in which case it don't matter any way.........

 

[1973Guppie]

The engine will definetly run without the O2 sensors but my understanding is the the front or aft sensors (1 before the cat and one after x 2 pipes / cats) give a signal to the computer to run leaner or richer depending on the flavor of the exhaust going into the cat's. The rear O2 sensors yes you can run without but it will give you a fault code. The rear sensors are basically there for the smog police to make sure that your cat is working. The O2 simulators are placed in the rear (don't even have to install them in the pipe, just attach to the harness and tuck away somewhere) harness connections and give off a signal telling the computer that the cat's work and everything is a ok. this way I don't need to run cat's at all. I am trying to get the computer/engine running without any fault codes, etc. Smog is not a consideration as I am year 73. A big thanks to Ed Gilbert for explaining this all to me!

Noah