An engine’s ability to create horsepower is dependent on the quantity and ratio of air/fuel mixture that is flowing into the combustion chamber where it is ignited and subsequent exhaust gases expelled in a low restriction path, ideally with a scavenging effect to assist the next pulse of gas. Borla exhaust systems are designed to have the optimal diameters and low restriction flow that promote scavenging. The Borla R&D team performs dynamometer testing on new parts to ensure power gains. We frequently see gains in the 8 to 12 horsepower range, sometimes much higher. However, every application is unique and environmental differences can affect the outcome, it is therefore not possible to give an exact number for your specific situation.