Similar to the XR intake, they need it to meet drive by noise requirements. Euro 4 and all that. Take it out and see how loud it is - will frighten women and small children.
Holy trumpets Batman! I just did an air filter replacement on my '15 and it didn't have all that nonsense, just a huge square inlet, the way God intended!
They didn't decrease airbox volume noticeably with that, it was part of a tuning effort to decrease audible resonance. Me, I LIKE that intake "honk". Also, above a certain size (different for each engine) it's not the size that matters, but the resonances inside, and how THAT resonance works with the resonance of the exhaust system to pull air completely through the system. Companies now tune all this to the nth degree, to get big, smooth power curves. Best for us novices to leave it all alone.
If you don't like the "Trumpets of Jericho", you can probably replace that with one off of a '16-'16.
Doesn't necessarily have to affect power. There's many instances where the proper design of noise reduction or in track regulations "restrictors" actually increase power. The key is in the shape. I had a 3 liter Yamaha engine (Ford SHO) that breathed through a 1 1/2 inch hole at the inlet of the air cleaner. Thinking I knew better, I removed the snorkel. All I got was a ton of noise and if anything LESS midrange. Same thing when I cut the airbox open on my K13 BMW. I'm curious to see what dyno runs show on the RR, I know with my XR all I get is a ton of noise when I remove the restrictor. I'll keep it in, thanks. Part of the design, and I think they know what they're doing.
I had a 3 liter Yamaha engine (Ford SHO) that breathed through a 1 1/2 inch hole at the inlet of the air cleaner. Thinking I knew better, I removed the snorkel. All I got was a ton of noise and if anything LESS midrange.
My guess is the tubes probably increase the velocity of the air, so sound is restricted by the tubing, but the air speeds up enough to counter the lost surface area.
My .02 anyway.
https://motorcycleinfo.calsci.com/Airboxes.html I like the last part - removing the airbox snorkel is like removing the port from your speaker cabinet - not a good idea. But I'm sure someone will do it, hope they report back for the benefit of us lazy folks that just leave stuff as it comes.
EXACTLY! I'm surprised that they aren't different length, to have multiple resonant frequencies, to broaden/flatten the powerband. Like I've seen some bikes have 2 long and 2 short velocity stacks in the airbox. I've even seen some stack the were make at a 45deg angle, to do the same.
The velocity stacks are on top of the throttle bodies, they have an actuator to change lengths, at least they did in 2016. This is just to tune the noise. I think.
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