When it's time to replace exhaust

[Offpiste]

Good day…
When it is time to replace the exhaust system….
1) What is best system that may increase fuel economy and hp?
2) can the O2 sensors and cat be “deleted” by programming?
Thanks much

 

[BlueC]

When it is time to replace the exhaust system….

That depends on a few things, including local laws and regulations. In general, I'd replace when you start having leaks/holes in the system that could allow gasses into the cab, if the muffler is becoming too loud, or if it starts falling off.

1) What is best system that may increase fuel economy and hp?

Don't get bogged down here trying to get some expensive free flowing system chasing power. These Jeeps don't make enough power to utilize big pipes or much more flow. I suggest focusing on quality of materials (stainless vs steel) and muffler sound. The stock system should be fine. You might find a muffler that flows better with a little extra sound, but it won't make any significant change in power or fuel economy.

2) can the O2 sensors and cat be “deleted” by programming?

The O2 sensors will have to remain. Removing the cat may be illegal in your area. If you decide to delete the cat, you will have to figure out a way to "trick" the rear O2 in order to make the computer think it’s there and working. With modern catalytic converters, there really isn't a reason to remove it. Today's cats are essentially free flowing and actually do work to reduce emissions. I suggest keeping a cat in the system.

 

[Jerry Bransford]

No aftermarket exhaust system, by itself, is going to increase mpg or HP. Especially not mpg which was the Holy Grail that all of Detroit worked on to wring every possible mpg out of their products due to the ever increasing demands of the EPA. The days of easy mpg gains are long-gone.

The O2 sensors can't be deleted as they are used by the computer to calculate the air/fuel mixture. They are a key part to the engine running properly no matter the altitude or temperature.

The main catalytic converter on older TJs can be deleted but it requires an aftermarket "fake O2 sensor" be screwed into it to keep the computer happy, or at least prevent it from generating a continuous bad catalytic converter code.

The pre-catalytic converters on newer TJs might be deletable but that'd require the PCM to be reprogrammed or you'd see a constant Check Engine light. Maybe Mark @Wranglerfix at www.wranglerfix.com might be able to help on that.

 

[Rickyd]

That depends on a few things, including local laws and regulations. In general, I'd replace when you start having leaks/holes in the system that could allow gasses into the cab, if the muffler is becoming too loud, or if it starts falling off.



Don't get bogged down here trying to get some expensive free flowing system chasing power. These Jeeps don't make enough power to utilize big pipes or much more flow. I suggest focusing on quality of materials (stainless vs steel) and muffler sound. The stock system should be fine. You might find a muffler that flows better with a little extra sound, but it won't make any significant change in power or fuel economy.



The O2 sensors will have to remain. Removing the cat may be illegal in your area. If you decide to delete the cat, you will have to figure out a way to "trick" the rear O2 in order to make the computer think it’s there and working. With modern catalytic converters, there really isn't a reason to remove it. Today's cats are essentially free flowing and actually do work to reduce emissions. I suggest keeping a cat in the system.

having a cat is a bonus to keeping the noxious fumes down when in traffic or on the trail with the top down too.
Theres definitely some nostalgia to the stink from my 70 k20 with no cats,but it can give you a headache.

Cats help make your rig quieter too.