Exhaust help

[D-93-b]

So, I have a 96 ext.cab with a 5.7 vortec. Which was swapped out of wrecked tahoe (incase that matters later on). It had the factory duals with cats but 2 football sized glass packs dumped right at the rear end. I got a p0420 code, assumed the rat ******* was trying to clogg, or maybe a peace of the honeycomb broke and was lodged. I attempted to unclog it(with a hammer) no luck. Week or 2 down the road the other one fails(probably because beat it like a redheaded step child). I decided I'd fix it for good. Chopped em off, replaced about half the length in pipe. Left the o2 sensors in the pipes, didn't plug them up. Now it's dumped at the frame kickup. Gas milage is absolutely ****, (I figured as much) it's not that loud untill you stand on it(I'm fine with) but now it's got the typical glasspack "cackle" and I hate it.(still have a few small leaks, welder won't fit between cross member) Would I be better off just spending the money and getting a system with cats, or just new pipes with different mufflers?

 

[b454rat]

Gutting cats shouldn't effect gas mileage. At least it didn't on my Tahoe. Mine was interesting to say the least when i first got it. One cat was there but gutted, the other replaced with a straight pipe. I replaced whole thing with a Jegs offroad intermediate pipe, as they call it. All mandrel bent, no cats but the O2 bungs are welded in. 100% bolt on. I made a difference in mine. Check engine light would come on, but put spark plug anti foulers on both down stream and they never came on again. Glasspacks cackle, thats what they do. Why I will never run them, can't stand em. But, if wanna get rid of it, need pipes going out the back. Larger diameter than the outlet of the muffler....

 

[alpinecrick]

I would replace it with the factory style exhaust. Start haunting ebay/amazon for reasonably priced downpipe/CAT section and midpipe. Walker quality or better.

The 5.7 factory exhaust is a 1 7/8" dual pipe setup, and there is plenty of flow there for a 250hp + motor. If there is any holdup in the system it might be the muffler. Keep in mind the factory muffler is the size of a baby Manatee, and there's a fair amount of room for the exhaust to roam.....