i like #6 too, i would like to make a few very similar but maybe less aggressive in some areas and more in others. I kinda think volume in the pipe is giving me a good power band just don't want to sacrifice to much HP making one to big

The tuned length from the piston to the beginning of first cone of the pipe which is where the above numbers are figured from is 95mm
so in the case of #2 pipe with its 1097mm + 95mm = 1192mm tuned length, which should be in the 85-8600rpm range.

I am running 35mm( 1-3/8" ) I brought a 1-1/4 stinger piece to chock it down but I was saving that test until later and then I had the frame break cutting my day short.
Mota software says I will make more peak hp with a 1-1/4 stinger but on dyno with both my 553 and now the Liger they both seamed to like the bigger stinger.
My first runs with the #1 pipe had my dune setup on which is a 1-3/8 silencer with a turbine style spark arrestor built in.
when I pulled that off and put a less restrictive 12" 1-3/8" stinger I gained about 1hp.
That made me fairly confident that the 1-3/8 was pretty good size and that running my silencer in the dunes was not hurting me. The first thing most guys do is once they make it past the Park Ranger station they yank off their sparkys. But since mine is not removable I run it all the time, and I have always maintained that if its sized correctly it will not hurt performance.
I see guys all the time remove the factory silencers off their sleds only to go slower with a aftermarket load straight thru silencer.

yep I agree, I run 1 1/4 stingers on my 1200 twin but was making a set of pipes for it with 1.375 a but my whole layout is different and the pipe temp is a bit higher with my new layout so I think the larger stinger will broaden the curve. by the way , what a great thread here , just a breath of fresh air one thing I am a bit confused though, I am doing my math on the tuned length from the piston to the mid point of the baffle cone, I was always under the impression that that is where the reverse sine wave originates from, am I off here?

never mind the tuned length question lol different programs do it from the stinger start point

with the mota its shows to the stinger, but you are right most books will tell you to go by the half way point of the diffuser.

especially if you are comparing differant pipes with differant length diffusers

Snowmobiles tend to run even larger probably 1.5" but most snowmbile guys are running 660 or 1000ft so they will build more heat.