What Is a Two-Step Rev Limiter? How Do They Work? | Engineering Explained

Two-step rev limiters have two separate RPMs for which a rev limit is set, depending on certain conditions. Typically the first rev limiter is used when the car is stationary, as launch control. The second rev limiter is the redline (or slightly past) there to ensure you don't damage the engine by over-revving. Rev limiters work by either limiting fuel, or limiting spark. You can run a lean A/F mixture, or cut fuel entirely. Likewise, you can retard spark timing, or kill the spark entirely, but