Something just hit me and it mite be a stupid thing but I would like some input.

What would happen as far as performance if I just cut off the left pipe that goes under the bike and capped it making all the exhaust go 2-1. Just a thought. I like the performance gain you get with a 2-1.

 

that's actually a good question..would it be a poor man's 2>1 'upgrade', or would the change in back pressure and O2's and ECM freak out from the shock and misbehave...or..or..or..all hypothetical speculation from me..

 

The exhaust system is a 2 into 1 into 2 already. So you have the benefits of the 2 into 1. Not a lot of exhaust volume goes through the left side due the restrictions of the design. Capping the left would add maybe 10-20% more back pressure and flow to the right, probably unnoticeable power change. Add in the slight weight savings from removing the left muffler and probably almost a wash. I doubt there is any effect on the O2s since they are back to the old position high and close to the heads.

 

You won't get any performance gain from a 2-1 versus a 2-1-2. As stated you would need to increase flow in the remaining pipe to match the 2-1-2.. If you are going that, might as well utilize the volume of 2 mufflers instead of one and get the same results with less noise since you have more muffler volume.

 

I certainly agree with your last statement. It's what I recommend to owners.
That said, I have noticed the better 2into1's for baggers have longer primary pipes than the OEM pipe. I find a bit better bottom end (earlier) torque with pipes like Fatcat, Road Rage, Pro Pipe HO, and a couple others.
The bigger the build the better the "long primary pipes" compares to the shorter, OEM 2-1-2 head pipe.
Peak numbers are not what I'm referring to but the performance leading up to the peaks.
Bob

 

Good point Bob,

One thing that is kinda cool is that HD chose to lengthen the primaries on the M8s a little. I sure some of it was to move the cat away from the passenger / rider but it probably also helped with low end.

Bruce