Can anyone tell me what the hollow pipe that connects the header end of each muffler on my '05 Heritage is for/does? It also serves as the rear mounting bracket for the pipes.

 

Crossover pipe and it's a part of your exhaust system.

 

Well I figured that. Kind of wondered what it's purpose was?

 

With it each cylinder uses both mufflers. Actual adds bottom end power. Since engine cylinders fires two strokes from each other they help empty the other cylinder slightly. Think I am saying this correctly

 

So I am guessing that if I get a set of 2-into-1's like I'm planning I can forget about the need for that feature.

 

Those won't be on your new pipes so yes you can forget about them. For better or worse depending on who you talk to. I recently read an article from a so called expert who stated that as far as getting the best overall performance out of your bike slipons were the way to go.

 

It's a scavenger pipe, it helps to clear remaining exhaust from the opposite cylinder being fired each time.

 

The crossover pipe makes the system "act" a little like a 2 into 1 while retaining the looks of a 2 into 2 system.
Using it the way they do also doubles the effective noise reducing capacity of the system without the need for an enormous, and very ugly can on the end of the pipe.

While it isn't quite as good a dedicated 2 into 1 system, it does increase the total flow capacity of the system while helping to scavenge gasses from the opposite cylinder.
I say help, because contrary to popular belief the uneven firing order of a Harley makes scavenging the opposite cylinder work in one direction at one rpm while it reverses at another rpm.
If the firing order was exactly the same number of degrees of crankshaft rotation, as it is in almost all other engines, it would be easier to design pipes that would work to scavenge gasses more efficiently over a broader range.
But Harley's insistence on maintaining the V-Twin with its single throw crankshaft has been both a blessing, for those of us who love that unique lumpy idle sound, and a curse for the ***** to the wall performance junkies.

 

I've always liked the idea of it being there. And it makes a good solid mount for the mufflers. I left mine on too and used Rush slip-ons. With SE intake and PC-V I'm totally satisfied.

 

Torque, it is used to tune the pipes and give the appearance to 2 in to 2