I did a search for this but didn't come up with anything despite the fact that I am sure I saw this posted here.

I will soon need a new muffler on my 96 ram 2500. I am thinking of going to a dual exhaust and removing the cats. Is there a problem with doing this ? Will it screw with the ECM because of the o2 sensor(s)

Will Dual exhaust with dynamax free flow mufflers help with gas mileage at all ?

 

If you have down stream o2 sensors I wouldn't remove the cats. You will get a check engine light and may cause a lean/rich condition. Put on high flow cats and your exhaust will flow just as well and you won't offend the smog police, or your trucks ecm.

 

Or you can take the cat off and swap out the downstream O2 sensor with an O2 simulator. Then you should be all set, unless you have to take an emissions test.

 

or just hollow them out[IMG][/IMG]

 

Im with JD, o2 simm unless you have to etest. The Fastman 02 simm you need for no cat
If you have etests, get yourself a hi flow cat. Etesting here so I use Magnaflow cats. Straighten out the pipes going into the cat as much as possible for best results. (engine side)

 

I have a question, and please dont think me as stupid, just wondering.

I can see why removing the front O2 sensor would screw up a car, as it reads all the gas's on the way out of the motor. But why would removing the cat mess that one up beings it is after the O2 sensor. Now corect me if I am wrong, the after cat senor is just to read out going gas's after the cat right? So if a cat was working right and flowing freely then the sensor really does nothing? The reason I ask this is you always hear of the front O2 sensor needing to be changed but never the rear. My rear sensor is still the original on my truck, been there since 1997 and 140K, the front has had to be changed.
So please if some one can clear this up I would appriciate it.

Also, where is the best place to get a highflow cat?

 

the downstream o2 is call a cat monitoring sensor. It looks at whats coming out of the cat. sends this info to the computer and the computer compares it to what the upstream o2 is telling it and together with input form the other sensors on the motor the ecm decides what the best fuel/air ratio is. If memory serves correctly, if the down stream o2 goes out the truck will go rich.(poor fuel milage)

 

Well I do have both o2 sensors so I guess I will go with a hi flow cat and get new sensors. So now for the second part of the question, can I expect better mileage after I switch to the dual exhaust ? I am not sure if I want headers, but not likely, I don't want the truck to be to loud.

Also I live in Northern British Columbia so smog tests are not an issue for me.

 

where in northern BC do u live i live in prince george

 

i keep hearing about these o2 simulators..... where can i get one... and if i use one will i get better gas millage with a dual exhaust or is it still going to run rich and cuase poor gas millage?