DYNA DRL-400 Two-Stage Rev Limiter The Dyna DRL-400 Two Stage Rev Limiter has been specifically designed to maximize launch performance and over-rev protection in drag racing. The DRL-400 allows a precisely controlled launch rpm limit to be set, while also guaranteeing against over-rev damage due to missed shifts or drive train breakage. Selection between the launch limit and the upper over-rev limit is usually made through the use of a clutch lever switch. Both rpm limits are adjustable via two knobs on the DRL-400. The DRL-400 constantly monitors the engine rpm with great precision and randomly deletes ignition pulses to hold the engine exactly at the desired rpm. The DRL-400 can hold a 270 horsepower engine to a steady launch rpm with less then +/- 50 rpm wavier. Other launch rpm limiters typically make the engine rpm waive through a pounding oscillation. This can be very hard on expensive racing components. The DRL-400 works with all inductive electronic ignitions on 2 and 4 cylinder engines. It is housed in a 3 3/4" x 2 3/8" x 1" plastic case with integral mounting flanges.