My friend has a 2000 GMC Sierra 1500. The exhaust is our problem, he has headers and Magnaflow exhaust. The Y pipe and the cats are our problem. Their are O2 Sensors before and after the cats. I was wondering if we could cut the cats out and weld in pipe the same diameter of the rest of the exhaust and not have problems, with trouble codes and such, or do we need to get high flow cats?
leave it alone. while we can all still breathe. the factory cats flow more than good enough for todays puny engines.
There is no need to remove the cats, or spend money on "hi flow" cats, if your factory cats are still good. The factory cats flow extremely well and have some extra flow capacity, so even if you have done some work on the intake or internal mods to the engine, you should be good to go. However, if you do remove the cats, you will have a problem with the rear O2 sensors throwing codes. Also, if you are in a state that has inspections, it will be a hefty fine for tampering with the emissions devices.
listen to these guys beacause it's good advice leave the cat's in the system if you remove them the s.e.s. light will come on (code for cat. efficency lost) and you wont pass inspection.
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