Thats what I've been trying to say. The O2 sensors should keep the ratio in line, thats what they're designed to do. Unless you change the the air going in the eng drastically, to the point that the ECM can no longer supply the proper fuel mix do to the parameters being way off, a tuner shouldn't be needed. If you are only changing the exhaust, the bike will run fine with the stock program. My bike runs just as good as it did with the baffles in the mufflers as it does with the baffles removed. And IMO they sound just as good as any aftermarket pipe does.

 

Oh, if only the Harley FI system was that smart... It does not have a mass air flow senser like most all modern automotive systems so the ecm really has no idea how much air in actually going into the engine. The ecm monitors manifold air pressure, air temperature, throttle position, engine rpm and o2s (only in closed loop/cruise) to manage fuel delivery. It is only a calculation based on engine configuration in the ecm (tune/map). The ecm will adjust fuel/timing off the o2s but only in closed loop and will not change the tune programed/flashed in the ecm. At least that is my understanding???

 

From what I have heard the klockwerks supersavers look and sound good. I'm leaning towards these and they are in 4"

 

I have the Screamin Eagle Street Cannons on my '14 Street Glide and just love them! IMO way better than stock...have a real nice growl when you get on the throttle.