x2 I love both Art and Robert and will always support them but at least for my type of riding the flow control valve did nothing. I think they are mainly for racers (to keep h2o out of the exhaust on the starting line)
Ding Ding Ding.
When your at the starting line you crank up your ski, your holder lifts the back of the ski and you blow out your exhaust and empty most of the water out of the exhaust and waterbox. When you go back to idle. The Flow Valve shuts cutting off the water flow to the stinger keeping the waterbox mostly dry. When the band pops, you do not get any back pressure bogging and can get a quicker jump of the line.
Yes, you can tune it some to open later which may help in freestyle applications when you come off throttle for a few seconds and allows some of the water to be expelled out of the exhaust system giving you a clean hit when you nail the gas.
I ran one, sold it, tried one again and felt a small gain.
This is one of those parts that in itself does not add much. Just like a lightened flywheel. Alone it does a little. But when you start adding up all the little mods you are building a package. This is where you see the benefits.
A stock flywheel in surf will probably work better. With the weight of the flywheel the motor can keep the RPM's going for a bit longer when you have to chop the throttle for a second and then get back on. You are just needing to keep the torque there for grab. With a lightened flywheel this lets the motor rev up faster which can benefit a freestyle ski when your going from 1/4 throttle to WOT for a trick.
Each has its place.