The IAG Performance V2 Top Feed Billet Aluminum Fuel Rails are designed to increase the power ceiling on your Subaru’s fuel system. The factory fuel rails function in a series, which means that each cylinder’s fuel is delivered after the other. As horsepower rises past the 350whp mark, the stock rail often does not have the capacity to deliver fuel to the last cylinder effectively*. As a result, that last cylinder can run lean, which can result in catastrophic failure. The IAG billet fuel rails are designed to eliminate this problem. First, our fuel rails operate in parallel format, each cylinder bank receives equal fuel, matching the flow between the rails ensures that each injector sees the same fuel pressure. Second, the bore of our rail is machined to 5/8″ ID and is designed to accept -8 o-ring boss fittings. This configuration greatly increases the volume of the rail which means that more fuel is available at higher power levels. These fuel rails were real world tested to 850hp. The V2 fuel rails also feature a port to add an optional fuel damper between each pair of injectors. Fuel dampers absorb fuel oscillations caused by injectors opening and closing. All Subaru’s are equipped with a fuel damper however its location is some distance from the injectors. The IAG V2 rails locate the damper between the injectors to smooth out the fuel flow.