If any of you read the Evo forum, you know that I recently installed a pair of new old stock Kerker slip-ons on my bike. I found them to be way to quiet for my liking so, I pulled the baffles and removed the glass packing material. Its much louder now but, I did loose some low-mid range torque. High speed is actually better though. Today, I bought some new packing material and re-wrapped them. Again, way too quiet but, slightly better performance. Does the density of the material make any difference in the volume? The stuff I used was very dense. I hate to go cutting on the baffles themselves because they were more than likely engineered for my bike. What kind of experiments have you guys done? Is there a happy median between performance and volume? Thanks

 

Muffler packing conjures up other images.

 

I think for the most part you have answered your own question. Exhaust tone and performance are engineered by some muffler manufactures. Others are designed to make them louder with little thought as to performance. A lot of other circumstances enter into this though. Intake size, carb jetting, timing, the ability of valves and cylinder head to move air and mix appropriately, valve lift and cam timing and a lot of other stuff way beyond my ability to understand or explain. An excellent dyno guy would be a good idea. Hope this helps.

 

I see some packing that is loose and some that is really dense like the kind I used. There must be a reason to use one or the other. The stuff is relatively cheap. I think I'll pick up some of the looser glass tomorrow, re-pack them, and see what they sound like.

 

Give it time, that stuff will carbonize and blow out.

 

^This^
If it was my bike I'd leave it be.

 

What about only wrapping part of the baffle?

 

noise ≠ power...

 

I've thought about that but I think one one the reasons for wrapping the baffles is to direct the exhaust flow through the center of the baffle.

 

What nytryder said...I have straights on my Evo Electra-Glide. Before anybody freaks out, they have 18" baffles in them (not wrapped), and the bike is not really loud. There is a bunch of headwork done, and the valve train all the way from the cam, lifters, pushrods to the springs has been matched to it. It sounds like a whole different animal when you lay into it, but won't even raise an eyebrow next to a cop under normal riding. At 100,000 miles, it still lifts the front end in three gears too.