I was hoping Dennis would see this and post the pic he sent me of his that he just got back from Monster. Here it is. Nothing to write home about for sure. With the size and placement of the holes I see only hotter engine bay air and questionable flow gains, but time and testing will tell.... Dennis is weather locked at the moment but is contemplating a "trip" to warmer weather to do his testing. 308gunner has received his as well as is testing I believe....
View attachment 168554View attachment 168555
2 things you overlook. Or not quite grasping.
1:
This isn't an enclosed engine compartment. But doesn't even matter.
A 1330cc engine at a volumetric efficiency of 100% moves 1.33L of air for every cycle. At say 6000rpm, this is 3000 times per minute or 50 times per second.
50 x 1.33 litres every second is 66.5 litres of air EVERY single second at wot.
Note: As rpm is increased or the VE of a good engine can reach 110-115%, this could be up to 92 litres of air movement - EVERY SECOND.
= whatever hot air is in the small engine compartment has been sucked up, spit out and replaced with fresh cold air in under 1 second at wide open throttle. (as engine compartment air is moved, atmospheric pressure pushes new fresh cold air in within fractions of a second.
2:
A 1.5 inch / 38.1mm hole over a 0.5psi pressure drop will flow 176 cfm, which is 2.93 cf per second.
Two of these holes allows an extra 6 cubic feet of air, every second.
The holes are to provide both colder air and more air, when needed. This is the biggest that the lid can be opened up. Its also a cheap $20 part if a user was to ever return bike to stock.
A third effect is at all rpm and throttle positions. The complete plastic intake itself is heated by the engine and exhaust during partial throttle riding. This heat transfers to the air, heating up and incoming air. At low rpm all the air in the intake system is not used every combustion event. So the air sits and is allowed to absorb heat. However, with new inlets, the new closer to air filter holes allow cooler air intake quicker, thus the engine intakes colder air even at partial throttle.
On an F3, the holes in the air filter lid are 4 inches from the top air entry from direct outside air. Not engine compartment.