Lots of drag strips now require sportsman cars in many classes to run a muffler. While some racers will go the route of adding actual mufflers to their cars, that may not be the best route. Adding a full tilt muffler means adding weight and possibly making a pretty significant change in the performance of the car. In the world of bracket and index racing, this could be the difference between winning and losing. A better solution is the AFCO Vortex cone. This cone, which is inserted into the header collector will knock the noise down 1-3 db, cause minimal changes in the performance of the car, and will meet the “muffler” requirement at many tracks. Fact is, most facilities do not actively monitordb levels and only check for required equipment. If these babies conform to your rules and cause virtually no issues with your racing performance, why would you not choose them?
SCROLL DOWN TO READ WHAT AFCO HAS TO SAY ABOUT THEIR VORTEX CONE HEADER INSERTS -
Vortex Cones: How restrictive are they and do they reduce the noise (dB) a lot?
Vortex cones cause very little restriction. An in depth look at their design explains why. We will use a 3.50” cone as the example. As most of you have noticed, these cones have many small holes in the cone portion. Each hole is .125 in diameter. If you add the area of all of the holes you would have approx. 9.5 square inches. The area of a 3.50” opening is only 8.3 square inches.
As a result, the exhaust must first flow through a total opening of 9.5 square inches (the cone) and then the 8.3 square inch opening of the pipe itself.
This is why it has little or no restriction.
Noise reduction:
Typically a Vortex Cone will reduce the noise level between 1 to 3 db.
1 to 2 dB reductions usually cannot be noticed by the human ear. You may notice more of a tone change than a reduction.
3 dB is usually noticeable.
These cones work great for applications where:
• A muffler is required but dB levels are not checked
• An exhaust system is just a few dB over the limit and needs a subtle reduction to meet the requirement.
• Excellent for any application requiring a muffler with minimal restriction.
http://www.dynatechheaders.com/access_vortex.html
