Engine Masters puts a stubborn garage myth to the dyno: does a 3-inch exhaust really outperform a 2.5-inch system, or does it depend on what’s bolted to the other end of the pipe? Real back-to-back testing, presented by AMSOIL, replaces forum arguments with actual horsepower curves. Over six million viewers have watched the results, and builders are still citing them years later. See what the numbers actually show.