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Discussion Starter · #1 ·
Howdy,
I just saw on the facebook Scout Owners area someone claim that the Zippers performance intake is the only one that has a velocity stack built in.

Us old time hotrodders know that a velocity stack is a good thing for performance, smoothing and forming and reducing turbulence of the air entering a carberator or throttle body. (One can think of it as a radiused area.)

Can someone confirm whether the S&S or Trask have a velocity stack (radius) where the flat floor of the filter transitions into the throttle body intake?

Thank you!
 

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I don’t have either on my Scout . But I have handled these and others. I think they refer to their set up as a “ velocity stack” configuration because it comes from the larger air filter end smoothly reducing radius/ turn down into the lower part that clamps to the throttle body. Thus causing an increase of air velocity entering the engine- Hence -Velocity stack physics/ operation.
 

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Your answer is no. The zipper, and the thunderworks has a plenum style intake, the others are just an open element style air filter. But that's not a bad or good thing. It a different thing. They offer different properties. One offers a better lower end, one offers a better top end.
 

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Your answer is no. The zipper, and the thunderworks has a plenum style intake, the others are just an open element style air filter. But that's not a bad or good thing. It a different thing. They offer different properties. One offers a better lower end, one offers a better top end.
Lol, I was referring to how the air is squished down ( in simple terms) from a larger portion down into the throttle bodies. Speed of the air increases velocity by doing so. This is what the old straight velocity stacks did. Larger mouth/ opening radiused down to a smaller opening ( right at the carbs, back in the old days). We all remember that a longer same size tracker /runner helped low end.
 

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Discussion Starter · #5 ·
I'd very much like to hear from those that have an S&S or Trask to see if the transition into the round tube is radiused. Thank you!

A square edge into another volume is nearly the worst possible air flow between two shapes... at any and every velocity.

In engineering terms, the velocity stack smooths the transition from one impedance to another, the round tube impedance to another volume impedance. It can be analysed with two port network calculations, if you're into geek stuff.

I just want to know from someone with direct experience that has felt inside the filter. Thank you!
 
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