by WesRagle » Sun May 19, 2024 1:47 pm
Hi Bryan,
I glad you are happy with the "Cold Air Induction". I'd like to piggy back onto your post with some info that surprised me while considering this same topic.
First, I was surprised at the volume and velocity of the incoming air charge. Check my math but I think this is right.
2180 cc -> 133 cid
Since every other down stroke is an intake stroke, 133 -> 66 cubic inches of intake per rev.
Assume a volumetric efficiency of about 0.7 and 66 -> 46 cubic inches per rev.
At 3400 RPM -> (3400/60) * 46 -> 2600 cubic inches of air per second.
For a single 2" scat that goes to 2600/Pi inches per second velocity in the scat. That's 830 inches per second or close to 50 mph.
That's a lot faster than I would have thought. I think that, and the pulsing nature of the intake, is the reason that a sealed cold air intake, like you built, is needed to realize the benefit.
And the potential benefit is the ratio of the absolute temperature of the incoming charge. If you assume under the cowl temperature is 50 Deg. F hotter than an outside ambient of 85 deg F, that amounts to ~ (459+85+50)/(459+85) = 1.09 or approximately 9%.
I also think cooling the aero-injector from the inside out helps with the burps :-)
Wes.
Wes Ragle
Onex #89
Conventional Gear
Long Tips
Hummel 2400 w/Zenith Carb
Prince P Tip 54x50
First Flight 06/23/2020
42.8 Hrs. as of 10/30/21