or short
i consider the original / stock exhaust to be the best compromise from all factors ; design , constructive/ functionality , power , sound, consumption....
bcos i hate absolut extra louder and i need no halfe hp more bcos i drive on racetracks wehre is every 1/1000 sec top important
(01-08-2020, 05:01 PM)alprider_imp Wrote: [ -> ]it can be a desing-construction thing (examp. access to the oil filter)
but
an exhaust is a highly complex matter ( not just in terms of sound)!
different gas pressures or flow velocities resulting from different pipe lengths and shapes....and bringing them together in the right place , like 4into1
or why is the 4in1 considered sportier sometimes (power) ? why for what we have sometimes a "interference tube" at the exhaust, my honda VTX 1300 had it ?
well i cant find a english site...but with the online translater
https://www.motorradonline.de/zubehoer/a...lles-rohr/
and I quickly found no scientific page on gas flows (speeds/pressures) in (exhaust) pipes.....
maybe because it is lighter
For an inline four with a standard firing order (no cross-plane trickery with the crank), the 4 into 1 provides the most efficient exhaust scavenging. The pressure pulses of exhaust gases travelling down the pipes at regular intervals creates a venturi effect at the collector which helps draw the last of the spent gases out of a cylinder that is completing an exhaust stroke. An optimally designed system will be a bit more efficient and/or powerful over a given rpm range.
As a bonus, a 4 into 1 has less mass than a comparable 4 into 2 system made of similar materials.
For turbo or supercharged engines, this is not a concern. The boosted intake charge blows the spent gasses out during the short valve overlap that occurs at TDC. In such engines, the individual pipes don't even need to be joined as no scavenging is needed.
See this excellent video:
https://www.youtube.com/watch?v=m2hZql6tD7c
(01-08-2020, 04:29 AM)Lord Popgun_imp Wrote: [ -> ]Helmholtz resonator
Sorry, that's all I know about exhaust theory 
You have an exhaustive knowledge, PG.
I LOL'd at work MTC. Now my co-workers are looking at me...
buuuuut we have no superrcharged/turbo engines..and so its just a bit science how you get the best header/collector - air flow, suction effect ...aaand the back pressure (right term ?) also plays a role in relation of torque...
isnt?
but i spreak from the pressure in the headers and not in the endpart of the exhaust , yes there its better if is nothing more inside
in the text ( my link) from this exhaust company Akrapovic is it some explained too
(01-08-2020, 12:32 PM)LongRanger_imp Wrote: [ -> ]Hi Doc, we've missed you. Hope you're doing well.
Very kind of you!
Doing very well...lots of trips to ranch with grandsons.
Still have a double image when looking very far right, but not an issue.
Trip after snow storm of Nov 29 was first time in 19 years I had to chain-up 4WD the last 1/2 mile.
(01-09-2020, 06:23 AM)m in sc_imp Wrote: [ -> ]MORE DETAILED EXPLANATION.
https://youtu.be/jjPeP_Nn2B4
well yes It has been a long time since I have dealt with the topic...amongst other things I now got a little mixed up the 2 + 4 stroke too ...
now yesterday evening i took time and browsed the net and sorted the individual puzzle pieces again...
too terms like : low rpm-engines and thin tubes, interference pipes, the importance of valve timing.......
the little fresher has done well..