I have a stock FLHR 2009. Just what is gained by adding true dual header pipes. From the pictures I've seen one side has a lot more bends than the other and takes the same path as far as crossing over to the other side. From a back pressure point of view, it would appear the 2 into 1 and back into 2 would be better. What is gained, sound? I have very limited knowledge and would appreciate comments from the more experience Harley wrenches.

 

There's a lot of posts on this topic - so if you want to read up on everyone's opinions I suggest starting with a search. Having read a bunch of what's been posted in the past it would seem that the only perceived benefit of true duals vs. 2-1-2 is the sound. I run the equivalent of true duals on my Softail and they sound great. I also have the bike tuned to give me great performance. Frankly I've yet to see a really good quality technical explanation of the whole back pressure argument (the effect of one cylinder on the other, pressure waves, etc) but such explanations are out there - somewhere.

 

I have an 09 UC and when I asked several knowledgeable mechanics about the benefits for my bike, they all said that the 09 stock headers are much better than on previous models and switching to true duals would bring very minimal improvement sound wise, heat wise and performance wise.

 

Nothing for performance however they do look good and if you are having a problem with a cylinder it does make it easier to do diagnostics and it also gives you a little more chrome !

 

Common sense tells me that the 2 into 1 back into 2 stock system would be better from a performance point of view, unless you can have similar length pipes with similar number of bends. Now I can see that the sound may be better.

 

For sound, first you need first the right slip-ons <g> and then I believe that a # set of cams would do much more than true duals. I've heard one of my friends' bike with stock cams and 255s and the difference was very noticeable. More lope with the 255s.