I know this could open a can of worms, and that there is no definitive answer due to many variables, but,
Regarding header primary tube diamenter, what are the pros and cons of 1.5" vs 1 5/8"?
My engine: F1000 spec (stock internals) 2005 Kawasaki ZX10-R 1000 cc. I expect to make air box and Power Commander upgrades in the near future.
Background & additional info: I have in my possession (temporarily) a Muzzy header that has shown good HP on the dyno. It is a 4-2-1 design. My original intention was to copy its specs as much as possible while making a header that fit my chassis. Once I started measuring things, I realized that the Muzzy's primary tubes are 1.5" near the head, and then gradually expand to 1 5/8".
I anticipate that complexity will mean extra cost. If my budget doesn't allow something that elaborate, I may need to choose between those two sizes. Of course, that means the plan to copy the Muzzy and expect the same results goes out the window, but since my current header is sub par (I cobbled together something that would fit), I think there's still room for improvement. I'd also like a better header before I go to the trouble of coating it for lower engine bay temps.
Thanks for your thoughts.