Drag pipes are a type of exhaust system that excludes any type of baffle or muffler, thus allowing exhaust gases to flow directly out the end of the exhaust pipe. Drag pipes are most commonly associated with motorcycles, and more specifically motorcycle racing, but they can also be used to describe an open exhaust system on any vehicle.
Drag pipes are often used in racing applications to create maximum horsepower at very high engine rpm's (rotations per minute). Maximum engine horsepower, as opposed to maximum engine torque, is usually developed in the upper end of an engine's powerband, or operational rpm range. An open exhaust system i.e., drag pipes, allows for the rapid evacuation of exhaust gas from the combustion chamber at high engine rpm's, resulting in increased horsepower.
The downside of an open exhaust system is that while it allows for maximum horsepower production at high engine rpm's, engine torque suffers greatly in the low-to-mid rpm range. This is caused by the decrease in backpressure associated with drag pipes. A simple way to prevent this loss in engine torque is to install a baffle in the exhaust system.
To install a simple but effective baffle in an otherwise open exhaust system, you must create the baffle. This can be accomplished by welding a ¾ inch washer onto the top of a ¼ inch diameter threaded bolt. Screw one nut on to the bolt and screw the bolt into the hole with the washer on the inside of the pipe. Screw another nut on to the bolt from the outside of the pipe. Adjust the bolt so that the washer is in the middle of the pipe.
Adjust the baffle. Take the vehicle to a local dragstrip and run the vehicle a few times, turning the baffle different ways until you have found the optimum settings. When using the vehicle on public roadways, the baffle should be at a 90-degree angle to the exhaust gas flow so as to create the most backpressure possible.
