CHEVY6000VHO

iTrader: (2)

Bottom line is: The freer the flowing exhaust you have, the more bottom end you lose. Though you gain more on top end.
Depends on what you want to do with your truck really.
If your going to use it for pulling, work, and daily driver 75% of the time, then just leave the cats.
If this truck is going to be an occasional driver and for track purposes, then it would be worth removal of the cats.

Jim

Leroy_454

I have not seen first hand, but have read on here the A/F ratio will go rich. My guess is with a bit of tuning to get the A/F in line you will gain power.

white1

iTrader: (5)

I disagree. Backpresure is bad period. Its the velocity that you generally loose that hurts you. removing the cats with a proper exhaust will yeild more gains thru the whole rpm range. Also a lot of people feel like they lost bottom end because its louder,and we all know louder means faster.

Black Nali

Is programming needed after removal? I reall want to do this but don't want it to cause problems.

ap2002

iTrader: (8)

you'll get a SES light, when you get your tune they'll be able to delete the rear O2's...

thunder550

iTrader: (70)

I think I gained power through the entire RPM range, from idle all the way up. It feels much torquier (if that's a word) down low, and it screams up top. It was a TON easier to tow a 6000 lb trailer than it was before, and I think my overheating problem might be fixed as well *crosses fingers*. Also seeing a 1-1.5 mpg increase.

For the tuning, I was told that I needed to turn off Cat Over Temp (COT) protection, disable the cat efficiency codes, and disable the rear O2 codes. I went and had desTRUCKtive help me since he has HPTuners, but I think it was already disabled with my PCMFORLESS tune, so we ended up not having to change anything. It's been 5 days and still no SES light for me.

Silver-Dollar

iTrader: (1)

Instead of tune, can't you just plug in O2 simulators?

Black Nali

I'M There! Too many Pro's & Not enough Con's for me! I like it loud anyways. I was going to get the electric valve for the cut-outs but I haven't capped them up in over 4 months.LOL Hell, even my wife thinks is sounds Bad ***. And she drives a frickin landrover!

4SHONGO

iTrader: (3)

I'm getting ready to do it myself, hope it is worth it. Muffler shop said they would take them off for $50.

JERRY2500

I did a before and after log of torq with HPTuner and without any tuning i gained 28lbs of torq and it was running super rich. After tuning i loged again and it gained a total of 39lbs of torq. I don't know how acurate it is but the butt dyno felt the gain. BTW it never threw any codes.