catalytic converter

Does anybody know if it is better to keep the catalytic converter in the exhaust system or will you see a performance increase without it?  I am considering having mine removed but wanted to check to see if anybody had theirs removed and the performance gains.  
2005 Duramax LLY
4" turbo back exhaust,
Volant ram air intake,
Edge Juice w/Attitude stacked with Hypertech programmer,
Next?????

You want to loose the whole system and go with a after market one. If you have no budget, yes you will notice a differance without the cat. You can loose the muffler as well. What truck are we talking about? If it's a 07-08 forget what I just said for a while anyway.  
2002 Dodge Ram 6 SPD Fass pump, afe cold air, mbrp 4" ss exhaust, 275hp RV injectors, edge ez, isspro gauges, South Bend clutch, track bar updated to 03-07 style, dss steering stabilizer system, 285 Cooper Discover

"If it doesn't have tit's a trigger or a throttle I'm pretty much not interested!"

I have a 2005 duramax with the LLY.  I currently have a 4" exhaust from the turbo back with a magnaflow muffler.  Sound isn't much of an issue I am just looking for more performance to match my volant ram air intake and I also have a edge juice with attitude that I stack sometimes with a hypertech programmer.  
2005 Duramax LLY
4" turbo back exhaust,
Volant ram air intake,
Edge Juice w/Attitude stacked with Hypertech programmer,
Next?????

if you have an exhaust system and still have your cat there you are kinda defeating the purppose for having an exhaust.. number 1 it will lower your egt's without it cause it makes it more free flowing.. once u get it off take a look inside the cat and see why that would be... on my dodge u cant even see through it   and 2 it make it sound way better at least on my dodge it does the chevy should be the same.. hopefully that helped  

Thanks for the reply inline6er.  Sounds like I have some cutting to do  
2005 Duramax LLY
4" turbo back exhaust,
Volant ram air intake,
Edge Juice w/Attitude stacked with Hypertech programmer,
Next?????

Ya dude one of my budes has an 07' I guess that's what you got we took his off and created a monster.
I made a whole new exhaust for him and opened that   BAD-BOY  up.
Take it off.  

Ya dude one of my budes has an 07' we took his off and created a monster.
I made a whole new exhaust for him and opened that   BAD-BOY  up.
Take it off.  

If you do take your cat off I would at least put a flow through muffler on it to reduce the noise, it can be loud. You dont want to attract any unwanted attention from the police, because if he wanted to be a jerk he could mess with because taking your cat off is illegal for onroad use.  

i have a 06'with 23,000 miles stock , not looking to go extreme really just wanted to go with cold air box and exhaust thought about the 4"turbo back but sounds like thats not worth it need to go from down pipe out ? also worried about the cold air box anyone had any problems with that?(filtration)  

1. Granted, I have an Edge and an AiRaid, but I saw improvements with a Magna-Flow cat-back  I didn't expect to see. To help it out, I bought a 4" straight pipe to get closer to the cat. Take a look at an 03 6.0L exhaust before asking why I am leaving the cat in.
2. Cold air boxes on 03 and up PSDs are a rip off! You pay $200 for a filter and a box that looks JUST LIKE THE OEM BOX!  I did an AiRaid filter and a hole in front of the inlet. Works great, cost $75.  
2003 6.0 PSD, Edge Juice Platinum, Airaid/big ol'hole ram air, 4" turbo-back, TureTrac, 5" lift, 35X14.5 Toyos,& bright RED!!

I have an 05 gmc and i dont have much money but i did put k&n air intake on and cut my cat and muffler off and it made a diff. in mpg and power does throw a little black smoke. But it is stock size exhaust dont have money for 4 or 5in exhaust.  

Since you already have a 4" exhaust, I'm gonna guess the biggest benefit you'll see from the kitty running away is lower EGT's. I kinda doubt you'll feel much of a seat-of-the-pants power increase, though.  
2003 Dodge Ram 2500 Laramie 4x4. H.O. Cummins, 6spd manual trans, 4.10 gearing. Intake, Exhaust, Hot Juice, HTT HTB2 62/12/65, Jake Brake, 305-65R17 (33 x 12.50) Pro-Comp Extreme All Terrains, SBC Con O FE, Fuel Tank Vent Mod,  Various other gizmos.


I-6 Cummins guys are keepin' it straight. Those other boys swing both ways.

A diesel engine doesn't need back pressure. Get a sawzall and cut the cat out of your pipe on the truck. Get some 4" flexpipe and 2 band clamps at Napa for the span you have to cover from kitty getting cut out. Put that in for a cheap fix tight no leaks and no cat. More MPG for me. My LBZ gets 20-22 all summer and the kitty's locked in the outhouse for the smog sissys that monitor us. I just put my Quad Stealth 2 on 135hp adder setting and fog those girlies. Not very often just fun on certain times when you know they are snooty seeing a diesel truck. You can put the cat back in this way for smog checks and just take it back out til next year. Same goes for factory muffler very restrictive and a straight pipe is great for sound and MPG you get more miles to gallon dudes!!! Make your LBZ scream with that and the turbo sounds like a jet turbine engine winding out. It's very noticeable on a factory truck.  

I've never had the opportunity to compare my truck cat vs. no cat. The 2003 H.O. Cummins came from the factory with NO catalytic converter. Bad if you live in CA. Good if you live in OH.  
2003 Dodge Ram 2500 Laramie 4x4. H.O. Cummins, 6spd manual trans, 4.10 gearing. Intake, Exhaust, Hot Juice, HTT HTB2 62/12/65, Jake Brake, 305-65R17 (33 x 12.50) Pro-Comp Extreme All Terrains, SBC Con O FE, Fuel Tank Vent Mod,  Various other gizmos.


I-6 Cummins guys are keepin' it straight. Those other boys swing both ways.

California isn't currently testing diesels so why not take it off and just keep it in the garage or shed. If the testing does happen just put the cat on for the test and done for a year or two until next test. Write congressmen and tell them to not support emmissions testing as well as county and city political birds. Document the fact that new vehicles are all clean out from the factory from EPA rulings. They don't have to know if you took your cat or DPF off. New cars don't get smog checked in many states for 5 years because of the electronic controls on gas enines. The data shows this for a fact. My point do what you want it's a free country. Just have to make it happen and go around the plan the back way sometimes to get what you want done.