I looked at the stock mufflers on my 2009 Electra Glide Standard and they are obviously very restricted. (I was surprised that the left and right sides are completely different in internal construction.) I'm not looking for more noise, but would like to help cool the engine. I looked at the SE Fatshotz mufflers at the dealer (part no. 80847-10) and they are a straight through design. Will a more efficient exhaust help cool the engine?

 

A more efficient and free flowing exhaust is only one piece of the puzzle. The primary source of excessive heat is the lean fuel delivery inherint to the newer emission compliant bikes. An air cooled motor gets roughly 30% of it's cooling from fuel. The first step to consider is an after market EFI tuner to deliver more fuel to the motor.

 

Nope, to cool the engine you need some kind of tuner to change the air fuel ratio. They come lean from the factory to pass EPA. Or I understand XIED's will cool the engine in idle or cruise.

 

More airflow is a start, but I agree in that you really need to put more fuel in that engine to cool it down. Personally, I have had pretty good luck with the downloads, but to really get the most of a bike and to cool it down, you'll need a tuner of some kind. The only trick about that is getting a tuner tech. that really knows how to do the job.