gutting the cats?

SleeperMark

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I searched for a while on this one, no luck but i may just suck at searching. Anyway, I am getting my exhaust re-done this week, stock (base model) piping with no 3rd cat, no resonator and Borla Pro XS mufflers. Question is can i gut the other 2 cats on the manifolds? car has 164,000 miles and im sure theyre filthy. Just asking for experience before i run into trouble. My main questions are, will the car still run ok, not lean? And how much louder will it really be opposed to leaving them alone? And no they dont do emissions tests where i live and my mechanic already said he would do it if i gave the ok. Thanks guys
 
I'm not an total expert on this, but I think your would need o2 sensors simulators to prevent any lean or rich conditions. Also IMO gutting the cats wouldn't do anything for performance, and WILL hurt your low end power, but if you don't care about that and just want sound. I say go for it :). Also what year is your car?
 
I'm not an total expert on this, but I think your would need o2 sensors simulators to prevent any lean or rich conditions. Also IMO gutting the cats wouldn't do anything for performance, and WILL hurt your low end power, but if you don't care about that and just want sound. I say go for it :). Also what year is your car?

O2 sims are not used to correct A/F. They are only used so the computer will not throw a code for gutted/no cats. Mils only go in the down stream spot so no engine control from them. Gen1s don't even have down stream o2's.(expt 96)
 
another ? do i want offset/offset or center/offset? i want them to tuck in like the factory
 
Unless the car is having some kind of driveability issue, the cats are most likely fine. Removing cats on a stock vehicle, is not going to help performance. You will lose a significant amount of torque in the process. Plus, because of the size of the cat shell, gutting them will cause flow issues. Since you have a 95 with only 2 primary o2 sensors, you don't need any emulators.
 
95 is odb1. the o2s do not monitor catalytic converters. o2 sensors won't care.
with gutted cats,you will lose some power, there is now a giant bubble in the exhaust, not good for flow. something about an expansion chamber.
offset/offset mufflers you can weld in sideways and tuck up under the bumper cover. look how the factory mufflers are installed, do it that way.

my suggestion, ditch the third cat, x pipe where the cat was, dual pipes out to the back, and your choice of muffler.
 
alright, so ill leave the cats alone. and i have duals with an x-pipe now but the guy did a crappy job so i wanted to put the factory single pipe back in simply because it looked cleaner. i was hoping that bumping up to borlas from stock mufflers would make up for the sungle pipe. plus like i said, i dont want it too loud
 
I wouldn't go back to single, unless the job was done horribly wrong. What wrong with the exhaust, is it leaking or rusting out? Also was the exhaust ran with 2.5 piping?
 
It looks like he used scraps and he has 16 different welds and where he joined the pipe he has the lip facing the front on the inside. So it's probably more restrictive than before. I want to take a part of it and smack him in the head with it
 

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