Exhaust cutouts?

[Longshot270]

Bypass maybe? If it would fit you could weld a bypass with a similar machenism to the throttle body. With that closed the exhaust will be forced to go through the cat and o2 sensor. When it is open the majority of the gas will take the bypass because of it having the least amount of resistance. You would probably have to have 2 different tunes though. One for when the plate is closed and another when it is open because the second one will have to not only take care of the better flow but also the lack of your o2 sensor's input to adjust A/F ratios. You could also set up the bypass like some chevy exhaust that has the two pipes welded to 2 plates and the plates are bolted together. Just stick a piece of flat metal next to the seal to keep the exhaust from taking the bypass.

[907DAVE]

Originally Posted by UNITY

My problem is where do I put the O2 sensors and do I do any thing to them?

It seems that if I have the cut outs before the cats that I should have the O2 sensors before them both right? If so, do I do that O2 sensor modification in the thread posted ^?

Yes, you must have your O2 sensors before your cutouts. I would place them around 8-12'' before the cutouts to eliminate any false reading caused by the negative exhaust pulses. Do not use the anti-fouler's on them either, they need to be in direct exhaust flow to be accurate and responsive.

As for the rear O2's, I would just leave them alone, no anti-fouler's.

Then all you would need is a "no cat" program designed to ignore the rear sensors to eliminate and P0420 codes, and a "cat" program that will watch the sensors.

Should be no sweat for Bill to handle.

[UNITY]

Originally Posted by 907dave

Yes, you must have your O2 sensors before your cutouts. I would place them around 8-12'' before the cutouts to eliminate any false reading caused by the negative exhaust pulses. Do not use the anti-fouler's on them either, they need to be in direct exhaust flow to be accurate and responsive.

As for the rear O2's, I would just leave them alone, no anti-fouler's.

Then all you would need is a "no cat" program designed to ignore the rear sensors to eliminate and P0420 codes, and a "cat" program that will watch the sensors.

Should be no sweat for Bill to handle.

That is what I was hoping for. So it is doable to "turn off" the rear O2 sensors? Was not sure how that worked on the OBD2 systems. That would be amazing! The power...the sound