Heatshield Fuel Rail FR Shields™ prevent radiant heat from soaking the fuel rails. These fuel rail heat shields will improve performance and help reduce instances of pre-ignition. We all know the benefits of keeping the fuel that’s headed into the engine cool, but fuel-injected vehicles also need to keep the fuel returning to the gas tank or fuel cell cool? Over a long-distance race, hot fuel returning to the fuel cell can really heat it up, so keeping fuel temps down while returning to the fuel cell can be almost as vital as keeping the fuel delivered to the engine cool. When the warm fuel returns to the fuel cell, it will heat up the fuel in the cell, which causes it to change the chemical balance of your fuel, greatly affecting the existing tune settings. Keeping fuel cool helps to preserve the chemical balance of the fuel and maintains maximum efficiency. FR Shields™ are available in kits to fit either single- or dual-rail systems.