I had gibson shorties on my 00 5.3 ext cab with many mods, so i removed the shorties and installed some as&m. Since I was already cutting the pipes I decided to remove the CATS and install an X-Pipe.

The truck feels very different, it feels like it has no power on the low end. I used to scratch second pretty hard and now it barely does. If i remove my K&N filter it feels very strong again but I can't help it wonder if the cats helped or if they made it worst????

What do you all think??

 

Checking my Signature!

 

sounds like, you lost alot of your backpressure when you took off the cats and installed the x pipe. thats probably why you feel like you lost alot of low end.
quite a few people have done true duals w/ the x pipe so they can probably chip in too. I know big kid and deckhand have true duals, so you might wanna check w/ them.

 

I have two pipes going from the front to the Xpipe, then 2 pipes to the flowmasters and all the way out. If that is true duals I have it!!

 

I might not remove my cats when I get the true dual with X pipe. I will drive it around for a while with cats on then I will take them off and see if I actually loose some low end without the cats.
Anybody else has experience this before?

 

I've got true duals with dynomax bullets. I've still got my cats. My low-end sucks and I think its because of the 3.42s. But, I had really good low-end when I used to have true duals w/ the flowmasters & X-pipe. It must be because you removed your cats.

Just my .02

 

When you removed your cats, what did you do with the o2 sensors? Are you running o2 sims? I'm running true duals with an x-pipe and haven't experienced any problems. I'm still running my cats though.

 

He turned them off with off and removed with edit.

 

i've heard the cats on our trucks are actually pretty free flowing.. and plus when you runnin true duals, you do need some back pressure, so its probably better to just leave them.

 

Has anyone actually dyno-tested from cats to no cats?