My guess is that the only reason the H2 has an induction tube from the front of the fairing is to access cooler air. I agree that any ram air effect would be negligible compared to the action of the supercharger.
Cooler air - For sure. It's a nice intake away from engine heat and high enough to avoid a lot of road debris.
Ram Air effect - The bikes specs are quoted with and without ram air.
H2 - 200hp without and 210hp with ram air.
H2R - 310hp without and 326hp with ram air.
Interesting to me is both those are a 5% gain so someone at Kawasaki determined ram air was worth 5%
(PS: that is also 5% that you won't see on a dyno chart)
Positive pressure from the considerable excess ram air available means air will be spilling *out* of those holes when at speed. There is so much general airflow in the area of the cylinder head that I can't see those holes from the ram air duct doing anything meaningful under those conditions. It has to be some combination of sound management and failure-proofing a blocked main air intake.
Sound management - maybe, but there is a factory air cleaner at the other end doing a fair job of keeping induction noise in.
Failure proofing - I agree it would work well as failure proofing but pretty unlikely that's why it's there.
I think they are there for two reasons. As a way to pull in air if the front gets some debris. but mainly to clamp down pressure in the tube to = atmospheric pressure at any speed. Or to put it another way to Shunt the ram air effect to zero.
Yeah, that's where I'm leaning.
With the holes in the H2 intake it is always "full" of atmospheric pressure air. Those 6 holes would bleed higher velocity air and would stop the rest of the intake pressurising.
So where do Kawasaki's ram air power figures come from?
If you cover the holes and go very fast the ram air effect will generate a pressure increase in front of the compressor that will be multiplied on the output side. The effect may be a less linear boost curve and more difficulty getting fueling right on a Dyno. With different SC gears now available getting more boost inst a problem and easier tuning is essential.
I agree, tuning for a "less linear" air pressure is difficult and would have to allow for vehicle speed along with RPM else a open loop system would get leaner the faster the bike was going. Having said that, the plenum pressure is already measured and fuel mixed to suit.
The H2R has no holes, a much bigger surface area and I have to assume a much bigger ram air effect at the supercharger end of the intake. The H2R doesn't lean out and blow-up at high speeds so it can be allowed for.
I think a lot of the power difference between the H2 and H2R are in the intake design and the fact the air cleaner is at the opposite end.