The story begins—as any great one does—with an idea. And the idea here was to address the inefficiencies with all of the velocity stacks currently available. Primary among these are the air flow issues caused by boundary layer restrictions, the design of the outer lip of the stack and the problem of trying to choose the correct length when purchasing a set of stacks. Velo Stak addresses all of these issues with a completely new design of velocity stack.

Have you wondered why every golf ball that you’ve ever seen has a dimpled surface? Dimples create a thin turbulent boundary layer of air that clings to the surface. This allows the smoothly flowing air above this layer to follow the stack’s surface a little farther into the throat of the stack, thereby increasing air intake. A dimpled surface has about half the drag of a smooth surface.

Velo Staks have a smooth transition from the outer surface of the stack to the entry of the stack. This transition allows the air from around and below the stack (depending on arrangement, up to 40% of the air entering a velocity stack is drawn in from below the planar opening of the stack) to smoothly enter the stack intake area. (The air flow video on the Home Page illustrates this.) Stacks with rolled lips and screens attached create enormous turbulence, resulting in inefficient air intake.

Finally, the length of a velocity stack affects its performance and characteristics. The rule-of-thumb for determining velocity stack length is that the longer the stack, the higher the torque curve in the RPM range. That is, longer stacks will give more torque at higher RPM, whereas, short stacks will produce added torque at lower RPM. For racing purposes, we generally want torque in the higher RPM range as we rarely use the car at low revs, therefore we try to have longer stacks (a Can Am car illustrates this point very well). For street use, the opposite is likely the scenario. Velo Staks are made from a mouldable material that although shatter resistant, can easily be cut to produce a stack of optimum length. This feature is also of real benefit when you realize that the stacks that you bought simply are too long to fit into your engine bay. If you purchased Velo Staks, they can be cut to fit.