[vector1]

fyi using pipemax program to model exhaust on my build

the dia of the primaries was in the 1 3/4 - 2" range with length 27-30".

collectors were best hp/tq 2 5/8-3 1/2 dia. by 16, 32, or 65" long.

worst hp/tq length was 24, 48, 97.

first of importance is supposed to be primary dia., followed by collector dia. & length, followed by primary length.

seems most of the numbers i put in the program the above numbers are close.

the collector length is considered from the point the primaries merge to exit.