PCM > 02 Sims vs. Sensors > Cats vs. no Cats
08-30-2004, 12:40 PM
#1
PCM > 02 Sims vs. Sensors > Cats vs. no Cats Scenario:
I'm changing from RT highflow cat sections to Mufflex Offoad cat bypass pipes. There are three major restrictions to my current cat sections:
1. the cats themselves
2. the cat 2 1/4" inlets (my Y-pipe is 2 1/2") ... flowing into 3" Borla intermediate pipe from the 2 1/2" cat outlet. The cat inlets are smaller than the outlets.
3. passenger-side cat was replaced a few months ago and this cat outlet pipe needed an elbow installed which was 2 1/2 pipe, however, it was bent/stretched and now is only 2" in diamater ... leaving the left and right engine banks unbalanced from a back-pressure stand-point
Two questions: On my dyno tune, the tuner turned off the rear O2 Sensors and the SES.
1. Am I better off leaving the rear O2 Sensors turned off OR will my PCM react better to O2 Sims with this change to offroad pipes?
2. How much RWHPRWTQ do you think this change will net me ... seeing as there are three major restrictions in my current cat sections?
Any estimates and all suggestions are welcomed. LT's and larger Y-pipe are not an option for me ... though I would love to have the money to do that right now.
I'm changing from RT highflow cat sections to Mufflex Offoad cat bypass pipes. There are three major restrictions to my current cat sections:
1. the cats themselves
2. the cat 2 1/4" inlets (my Y-pipe is 2 1/2") ... flowing into 3" Borla intermediate pipe from the 2 1/2" cat outlet. The cat inlets are smaller than the outlets.
3. passenger-side cat was replaced a few months ago and this cat outlet pipe needed an elbow installed which was 2 1/2 pipe, however, it was bent/stretched and now is only 2" in diamater ... leaving the left and right engine banks unbalanced from a back-pressure stand-point
Two questions: On my dyno tune, the tuner turned off the rear O2 Sensors and the SES.
1. Am I better off leaving the rear O2 Sensors turned off OR will my PCM react better to O2 Sims with this change to offroad pipes?
2. How much RWHPRWTQ do you think this change will net me ... seeing as there are three major restrictions in my current cat sections?
Any estimates and all suggestions are welcomed. LT's and larger Y-pipe are not an option for me ... though I would love to have the money to do that right now.
08-30-2004, 07:01 PM
#3
Any comments on the worth of doing this? Sorry, I should have asked that first question more clearly. I know what the rear sensors are for. I was just wondering what would report a reading that would be more accurate to the PCM, i.e., the rear sensors? OR should I turn them back on with Edit and use 02 Sims instead of the actual sensors? OR does it really matter? Thanks for taking the time to reply. Feel free to elaborate more.
As for the second question ... anyone care to take a stab at it? I'd appreciate any comments you might have about the overall scenario to tell me if you think it's worth the efforts and trouble.
As for the second question ... anyone care to take a stab at it? I'd appreciate any comments you might have about the overall scenario to tell me if you think it's worth the efforts and trouble.
09-01-2004, 11:36 AM
#6
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YOu are better off leaving the o2 sensors codes turned off. You wont gain anything from having them or deleting them as they serve the sole purpose of a sanity/EPA check