float_6969 wrote:The problem is that if you let me borrow the 4 port, and it flows better than the 8 port, you might not get the 4 port back!
But seriously, I've got an 8 port, and I'd like to have a 4 port, so that if it does flow better, I can drop the better flowing head on the motor. I suspect the 4 port is going to win though. I plan on doing the testing with the sub mani's attached and the butterfly's open.
of course the bigger single port will 'flow better', but its a difference that you need to choose for application
like i said, barring and rediculous results, i would use the 4 port on a high rev, race-only engine that i didnt need any low end on. the butterflies help the low end by increasing intake velocity. so while yes, the 4 port will flow better, i cant see it increasing power at all in the low end, with a possibility of losing power even more in the band, until very high.
I talked to sweedish mike a bit about it too, apparently they do the same thing there as the guy at mototuneusa (where he decreases the intake port diameter and shows a tangible gain in power)
apparently the baller CAs in sweeden weld the intake ports (instead of JB weld like mototune) and grind them into shape
but hey, im not one to claim fact without a source, so ill leave it at that, and i will try to dyno the ca20 with both the 4 port, and 8 port (with multiple settings, all open, all closed, and a run with it switched) and take a look at the dyno curves with everything else the same (to include stock cams and non adjustable cam gears)
CJ