I am running V&H true duals and ovals. I am looking at 2 into 1 setups from Dragos and D&D. I have read that they have a stepped header and since this is my first Harley am really not sure what advantage there are to this setup and if it will be louder than the set up I have now. I have a thundermax tuner with K&N high flow and would like a little more umph and a louder sound. What advantages/disadvantages would a stepped header provide. Thanks for any opinions

 

As far as I know stepped headers increase performance in the way they funnel the exhaust out of the pipe. Im not exactly sure of the science behind, but Im sure if you call Frank from Dragos Bike Works he would explain it all. Hes a very nice guy and has a wealth of information on making horsepower and increasing performance.
I had a Dragula 2-1 and it was an excellent pipe. You can pic between 3 different baffles, quiet, medium and loud. Dragula is also ceramic coated and made of stainless steel. Excellent excellent pipe imho.

 

It is to do with maintaining the exit velocity of the exhaust gasses, for maximum performance the exhaust must prevent the gasses from escaping too quickly but must also not restrict the flow so creating too much back pressure, there is an optimal range for exhaust gas velocity and the stepped headers seek to help "tune" the exhaust to match this range along with the other components in the system. A poorly designed exhaust can detrimentally affect the torque at low rpm and the horsepower at high rpm.

 

Here is a very informative article from Hot Bike that discusses all kinds of considerations for exhaust systems and talks about the advantages of a stepped header. http://www.hotbikeweb.com/tech/0805_...s/viewall.html

Our MGS True Duals system has a stepped header design that manages to effectively benefit from carefully placed stepped tubing of specific lengths in the system. We have found that they work very well with most builds from an 88" all the way up to a big bore motor of just under 120". Exhaust principles would dictate that our system should lose effectiveness on motors bigger than 120", but our system is also not supposed to do what it does on an 88" or 96", so who knows. We are actively seeking someone with a big bore motor of 124" or bigger to see how it fairs in performance. Any takers, contact me.

Hope this article gives you the answers you were looking for. Merry Christmas.

 

Thanks for all the replies. A lot of information to consider when looking at exhaust systems.