The dynamics of expansion chambers continue to fascinate and confuse me and I guess that's why we all have questions. I am re using some very old Ocelot chambers on my GT750 project and since I went with a longer swingarm the center cylinder exhaust outlet is very close to the rear brake rotor. I'm not really worried about clearance issues but the oily exhaust is going to get on the rear rotor I'm sure. I was thinking of cutting off the 1 3/4 by 15" long silencers and welding on some nice looking stingers with some bolt on silencers. That way I can angle the exhaust outlets pretty much where ever I want. I've always liked stingers that look somewhat tangled and angled to add to the awesome sound and wicked appearance. Is there any performance advantage going with stingers as opposed to large diameter 15" long silencers??
None. Street mufflers sometimes act as stingers but more commonly, the actual stinger is inside the chamber and the perf. core of the muffler fits over the end of the stinger and continues inside a 2 1/2" diameter tube. I think Pertronix made all or most of the weld on mufflers.
Fitting a longer 'real' stinger and a decent muffler should be fine and may make little to no change in noise or performance.
Cool. Thanks for the feedback. When I purchased this bike the original silencer inserts had been replaced with what looks like multifit pieces that are only about 6" long. I guess I will add extensions to them so they will go all the way up to the end of the cone and offset the center silencer a bit to get it away from the brake rotor.
Yet another issue solved thru communication in this forum.
I think i have asked Richard ( TZ375 ) about this thought before .. what kind of effect the longer stingers you see in use on some customs to get the silencers up higher . Do you need to make the stinger a larger ID as you make them longer to avoid back pressure ?
The answer is theoretically yes, but we see Swarbrick pipes with 6 inch long (short) stingers and Arrow RS250 pipes with what look like 2 foot long stingers.
If you read the books and software, it gets a bit vague when it comes to stingers and the answer seems to me to be "try it and see". I'm pretty sure that stinger diameter and length is about the least critical part of a chamber as long as they are within reason.
