Catless Exhaust

[mark1223]

Hello, I'm looking to put true duel exhaust on my truck, 06 seirra 1500. I am wanting to do a manifold back true duels, no cats with glass pack. I've been told can't be done due to the o2 sensors. I was wondering, if I got a tune for the truck, could I tune it to deal with the missing cats. The pipes would have a bung in em for the sensor. Thanks for the help. yes, I know it will be loud.

[GMstrong]

More then likely the SEL will come on without the cats but there are some scanners/tuners out there that will delete sel.I lost alot of bottem end when i did that to my 90 gmc sierra so i just switched back to a high flow and a glasspack.you'll see little to none performance gain.

[mhenshaw]

You are wasting your time if you don't get headers, than manifolds suck.

 

I would install a high flow cat and no muffler, it will sound better and perform better than the glasspack will. You should get a h-pipe or x-pipe too.

 

Im guessing this is your first truck?

[mark1223]

second, but first with exhaust mod.

[GMstrong]

I cant agree more with the muffler delete.When i got my high flow cat i ran it without the glasspack and was extremely surprised in the difference in throttle response.I try to talk people out of glasspacks.I jumped the gun on mine.

[renegadeking]

i heard on here that the factory cats flow just as good as the high-flow cats. Cats will not give you any performance. i think true dual exhaust is kinda pointless on these trucks because the pipes go side by side until the rear diff. thats why i put on a single pipe that splits into two, that way i get a bit off back pressure for the bottom end. thats what i was told from my racing expert dealer. you will need to tune out the cats for sure.

[GMstrong]

Going to have to disagree with that one.My cat was 28 pounds my high flow was 3 pounds and i felt a huge difference in throttle response and hp.Regardless of what people say cats get clogged especially when they are 20 years old and the motor has 200,000+ miles on it.The only reason i switched to high flow cat was because mine was obviously clogged and plugs i only paid 30 bucks for my high flow cat its a catco.

[[email protected]]

Going to have to disagree with that one.My cat was 28 pounds my high flow was 3 pounds and i felt a huge difference in throttle response and hp.Regardless of what people say cats get clogged especially when they are 20 years old and the motor has 200,000+ miles on it.The only reason i switched to high flow cat was because mine was obviously clogged and plugs i only paid 30 bucks for my high flow cat its a catco.

 

30 bucks for a cat? Huh????

[GMstrong]

Yea buddy had one at his shop its a 3" catco high flow cat.He ordered for someone but they never came to pick it up so me and him threw on my 90 sierra after i gave him 25 bucks and a 6 pack which comes out to about 30 bucks.

[FChaf217]

Hello, I'm looking to put true duel exhaust on my truck, 06 seirra 1500. I am wanting to do a manifold back true duels, no cats with glass pack. I've been told can't be done due to the o2 sensors. I was wondering, if I got a tune for the truck, could I tune it to deal with the missing cats. The pipes would have a bung in em for the sensor. Thanks for the help. yes, I know it will be loud.

 

It can be done. Read this:

http://forums.evolutionm.net/evo-engine-tu...o2-cel-fix.html

There are a few methods for going catless and fooling the computer. One is the "mechanical 02 sensor fix", see this picture:

http://forums.evolutionm.net/attachments/e...cer3inchdp5.jpg

Note the small 1 inch tube extended from the cat replacement pipe, see the blue wires/02 sensor screwed in to it? It's limiting the exhaust on the 02 sensor. It works, I've done it (off road only}.

 

There is a cheaper trick called the Spark Plug Defouler Trick. It involves taking 2 auto parts store "spark plug defoulers", welding them to the exhaust pipe and threading the 02 sensor in them. That works too. Good luck. I think you can get 20-25 hp going catless with glasspacks while using exhaust manifolds.