Street Ryderz
Well-Known Member
This topic has been covered before I'm sure but there is some points of intrest or curiousity I guess as more and more folks are using small displacement dirt bike pipes or simular designs.I'm suprized that many of these pipes really dont hit hard or at all in many cases and yet the user's will swear that they are working and giving a proper boost effect.When going through Jennings and Blair's works and formula's I found it interesting that both are within 10" of each other for our engines displacement and @ 8300 for peak power,but that still is alot Blair say's that 46" from piston face to the end of baffle cone (convergent section)is the starting point for overall length,Jennings formula works out to 34" to start and then states less an inch,So if we split the difference we are looking at 38.5" Jennings says that measurement is from window to just past half the baffle cones length.Now my pipe at this length stages at around 7 grand and falls off around 9300 but it hits hard with both an audible change as well as power boost,How long is the MZ pipe from flange to end of baffle cone?Many of the kx,yz,rm,cr pipes look much shorter than that and makes me wonder if they even hit at all being designed to hit at higher rpm and work with exhaust durations above 170 degrees.Any input here is welcomed.