I'm going to ask becuase I honestly don't know. What is a velocity stack, what does it do, how does it work? Looks like an air filter without the filter.

http://www.dragspecialties.com/produ...roduct%2F76956

 

Google is your friend haha http://www.google.com/search?q=veloc...20&bih=416#i=0 pretty much a velocity stack smooths the airflow into the engine. You can find some with filters but most with out. An it's not so much a filter as it is a foam insert to keep out the heavy stuff. They are free-er flowing and in turn can produce more horsepower. If you look at top fuel and other drag cars they run them.

 

So if smooth air flow is good, why do they make a vortex "thingy" to mix fuel & air? Seems contradictory.

 

The velocity stack is tuned for diameter and length to optimize the rapid ingestion of air into the carburetor for max flow at a specific RPM. It also functions to capture the fuel/air mist that's blown back OUT of the carb by a reversion wave on an engine w/lots of overlap in the cam profile.

To address Mr. MarineHM's question - smooth air coming IN to the carb is good - turbulence (w/out obstruction) in the boundary layer of the fuel/air mix as if flows through the intake tract is good because it helps to maintain the atomization of the fuel/air mix, preventing fuel droplets from "puddling out" of the intake flow on the way to the combustion chamber.

 

Thanks for the explanation. I'm allways leary of gimmicky things people buy just becuase it looks cool and the product description is half baked. The one I posted ealier looks cool, but I'm not interested in racing my bike, so Im going to pass for something more functional for my style of riding. More gas to ride! LOL Oh yeah, Bear trap foot pegs are still on my list.