Just bought a 2015 Lowrider, I am looking to put a thundercone slipon in place of the stock muffler. No other modifications. Do I have to make any fuel management adjustments? or Can I leave it stock?? Thanks.

 

So air will only flow as fast as it's most restrictive component. The air cleaner is the first point of entry and the exhaust slip-on is the last point of exit. In the stock configuration air flows evenly in and out. Without making both the air intake and exhaust less restrictive you will see no improvement to the performance of the engine. In fact you will lose back pressure resulting in degraded performance and fuel economy. When just adding slip-ons the intake will still be the most restrictive component so fuel system modifications at this point will probably not be needed. If you decide to install a high-flow air cleaner along with the slip-ons then yes, you will need a bypass or flash tuner. You could also bring your bike to a dealer and have them flash a new map based on the new dyno results.