Scavengers do they work?

billy2

Do scavengers really work?

This is an air inlet velocity stack with a newly integrated scavenger

Is this a giant cheerio?

The break down of the stack consist of 2 areas:

• scavenger zone
• compressor zone

It's an adaptation to a performance enhancing velocity stacks for carburetors. The cheerio acts as a scavenger entrainment pump pulling more air into the stream

It's a simple principle from a flowing air stream to pull more air into the stream

The scavenger geometry guides more air into the flow

Testing, does it really work?

https://youtu.be/J0eKOo0u54I

matthew_stacy

@billy2, I love the tissue and candle tests.  Very clever.  Would be neat to compliment these with CFD analysis.

My intuition says that once you wrap beyond perpendicular the scavenging effect may not increase flow.  I would bet on a smooth transition to a flat flange rather than wrapping into a doughnut.  But I've been wrong before and surely will be again.

I wonder if it would be possible to hack data from a mass airflow sensor to improvise a flow bench.

billy2

@matthew_stacy

Yeah, these were quick and dirty tests and they are showing promise. That's a great idea about the mass flow sensor.

I think the next move is to print one for my bike and use the seat of my pants to determine the effectivity. That's what motivates me these days; what happens when the light turns green.

Prachi

Hey Billy
The scavenger will give a better flow pattern and reduce turbulence through the barrel.
If you repeat the Utube video using a straight tube I think you'll find that the tissue is drawn in from the side also.
With out the bell mouth (scavenger) a vortex will develop at the inlet end that can make for a restriction and non uniform flow into carburetor. You can get just as good flow into carb with a longer barrel and no bell mouth but it would want to be about 8 times longer than the barrel diameter to allow the air to settle into a straighter path.

tony_459

Very cool

billy2

@glen_dewsbury currently I'm finding a lot of turbulence at the opening of the existing inlet. It's nothing more than a pipe cut at a diagonal. 

I originally designed these for motorcycle air inlets and thought it might work for any air inlet.

Thanks for your thoughts on flow, I'll have to mock it up and see the differences.