alpha Racing Radiator Cap 1.8 Bar BMW S1000RR/HP4 (2010-, 2015-) at 1.8 bar of pressure, fits OEM radiator, and WSBK radiator. Due to the higher pressure created by this part you can use a smaller coolant reservoir and the heat conduction is improved. Increase your BMW's cooling capacity with tuned engines using modified engine ECU mapping (with more aggressive ignition timing), and racing engines with alpha Racing camshafts, increased compression alpha Racing pistons, and thinner head gaskets that generally run higher operating temperatures. Used in WSBK. Weight: 0.06 kg.