Unwanted reactions result in the formation of hydrogen sulfide and ammonia, which poison catalysts. Nickel or manganese is sometimes added to the washcoat to limit hydrogen-sulfide emissions.[citation needed] Sulfur-free or low-sulfur fuels eliminate or minimize problems with hydrogen sulfide. It also boasts the ultimate in customization, including the optional 700+ horsepower Shelby GT S/C version.
When used in the context of aftermarket parts or performance upgrades, "cat-back" is used to indicate which section of the exhaust system the parts replace. Cat-back systems are available as both single- and dual-exhaust. All Thermal R&