Cold Air Intake .

[Jackpine]

Originally Posted by Mark_123

Here's something interesting too. I took the intake tube off, and sure enough the snorkel is only 2" wide into the fender. I also noticed 6 small holes drilled into the intake tube near the snorkel. Each Helmholtz resonator had a hole drilled in the bottom as well. I'm guessing this is to assist in airflow at WOT????? I bet this is where the occasional air intake whistle comes from when starting in cold weather. The holes would seem to defeat the purpose of bringing in cold air from the fender. Hmmmmm.......

Mark, I think the holes in the resonators act a bit like "shock absorbers" to dampen out the "springyness" of the air inside. It's possibly like the tuned port in a base reflex speaker enclosure.

As far as the 6 holes in the bottom of the intake, these don't make sense to me at all. We used to see a flapper door in the intake that would pull air off the exhaust manifold during cold weather to aid in cold weather starting and running, but it would close when the engine got warm. These things are always open though. You could be right about them allowing additional air in during WOT at high RPM, but it seems like an odd way to do it. Actually, the Bernoulli effect means that regardless of throttle position, air is ALWAYS being pulled in through these holes and mixed with the air coming from the fender well. Their position is not really over anything "hot" though. I wonder if they are part of the silencer system?

I've never heard the "intake whistle", but we don't get very cold here.

I'm tempted to tape over the holes with aluminum tape to see what happens.

- Jack