I'm looking at the LF4 cal file with HP Tuners right now and there are no calibrations which I can find for the exhaust by-passes.
As "Djason" says above, control of the exhaust bypasses lies with the BCM. There is no DIY tuning software which supports changing the calibration of a BCM.
With modern cars, part of what engineers use to design exhaust systems is the acoustic attenuation which comes with exhaust gas flowing through a cat converter. When you remove the cats it's like if, on a car from the "pre-cat" era, you changed to a much smaller muffler.
Reality is that when you cut off the cats, you make a huge change in the acoustic design of the exhaust system and the result is–yes, you gain some performance, but you also gain noise, resonance (ie: drone) and, in this case, an unattractive sound quality.
I think you're going to wait a long time, if ever, for someone to start selling an ATS-V muffler designed to work on a car with no cats. With the EPA moving to, starting in July, outlaw any modification of emissions control systems, even for off-highway use, no aftermarket exhaust mfg is going to see a business case for such a product. My advice is to start designing your own solution to the problem. The guy who sells the cat-less DPs ought to get involved here and support the people who've bought the DPs but hate the sound quality. Betcha he finds that it's one thing to replace the cats with a couple pieces of pipe but it's a "whole 'nother ball of wax" to design mufflers which sound good.
As "Djason" says above, control of the exhaust bypasses lies with the BCM. There is no DIY tuning software which supports changing the calibration of a BCM.
With modern cars, part of what engineers use to design exhaust systems is the acoustic attenuation which comes with exhaust gas flowing through a cat converter. When you remove the cats it's like if, on a car from the "pre-cat" era, you changed to a much smaller muffler.
Reality is that when you cut off the cats, you make a huge change in the acoustic design of the exhaust system and the result is–yes, you gain some performance, but you also gain noise, resonance (ie: drone) and, in this case, an unattractive sound quality.
I think you're going to wait a long time, if ever, for someone to start selling an ATS-V muffler designed to work on a car with no cats. With the EPA moving to, starting in July, outlaw any modification of emissions control systems, even for off-highway use, no aftermarket exhaust mfg is going to see a business case for such a product. My advice is to start designing your own solution to the problem. The guy who sells the cat-less DPs ought to get involved here and support the people who've bought the DPs but hate the sound quality. Betcha he finds that it's one thing to replace the cats with a couple pieces of pipe but it's a "whole 'nother ball of wax" to design mufflers which sound good.
