The synopsis of my ride report is as I stated: "No more barking and popping."
A little more verbosely: The V7III Racer fitted with Agostini mufflers and the GT-Rx customized ECU map runs beautifully, but on overrun conditions the secondary air injection system causes a certain amount of barking and popping to occur, depending on the specifics of RPM, load, ambient temperature, etc. With the SAS block-off kit installed, that annoyance is eliminated.
Whether there is any actual performance gain is a bit too subtle for me to gauge with my butt dyno. A forty mile ride yesterday evening seems to indicate a slight difference in the throttle feel and sound the bike produces—all to the better.
(Technical notes for context: The SAS is specifically there to preserve the functionality of the catalytic converters in the OEM mufflers, much like the oxygen sensors. With the catalytic converters, the injection of fresh, oxygen-rich air into the exhaust stream on overrun provides the oxygen needed to consume excess fuel on overrun conditions that would otherwise damage and reduce the effectiveness of the cat-cons over time; it extends the burn and keeps the cat-cons hot enough. If you're running non-OEM mufflers without a cat-con, it causes pops and barks in the exhaust system: the cool, over-rich exhaust stream on overrun burns up to a point and then small fragments of the stream explode chaotically in the exhaust system when it encounters too much free oxygen from the injected fresh air. Blocking off the SAS ports and fooling the computer into not noticing the valve is no longer there prevents this 'rich hot mixture encountering excess free oxygen' condition so the exhaust runs a bit cooler and without the chaotic explosions. It degrades emissions output no more than has been done already by removing the OEM mufflers/cat-cons; might actually improve emissions a tiny bit due to not allowing the high-temperature chaotic explosions to form.)
A little more verbosely: The V7III Racer fitted with Agostini mufflers and the GT-Rx customized ECU map runs beautifully, but on overrun conditions the secondary air injection system causes a certain amount of barking and popping to occur, depending on the specifics of RPM, load, ambient temperature, etc. With the SAS block-off kit installed, that annoyance is eliminated.
Whether there is any actual performance gain is a bit too subtle for me to gauge with my butt dyno. A forty mile ride yesterday evening seems to indicate a slight difference in the throttle feel and sound the bike produces—all to the better.
(Technical notes for context: The SAS is specifically there to preserve the functionality of the catalytic converters in the OEM mufflers, much like the oxygen sensors. With the catalytic converters, the injection of fresh, oxygen-rich air into the exhaust stream on overrun provides the oxygen needed to consume excess fuel on overrun conditions that would otherwise damage and reduce the effectiveness of the cat-cons over time; it extends the burn and keeps the cat-cons hot enough. If you're running non-OEM mufflers without a cat-con, it causes pops and barks in the exhaust system: the cool, over-rich exhaust stream on overrun burns up to a point and then small fragments of the stream explode chaotically in the exhaust system when it encounters too much free oxygen from the injected fresh air. Blocking off the SAS ports and fooling the computer into not noticing the valve is no longer there prevents this 'rich hot mixture encountering excess free oxygen' condition so the exhaust runs a bit cooler and without the chaotic explosions. It degrades emissions output no more than has been done already by removing the OEM mufflers/cat-cons; might actually improve emissions a tiny bit due to not allowing the high-temperature chaotic explosions to form.)
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