New models of the compression engine brake deliver substantially increased retarding horsepower on high performance turbocharged diesel engines. The historical performance trends for “Jake Brake” equipped engines are shown, and the case for higher horsepower discussed. An engine cycle simulation has been used to compute the performance expected from advanced high performance engines. Retarding horsepower is expected to increase because of better use of the turbocharger during the braking cycle and because of timing changes in the engine brake. The authors propose that an advanced model of the “Jake Brake” on 855 in3 Cummins Engines will deliver nearly 550 retarding horsepower. Vehicle safety may improve, vehicle control speed will increase and higher loads will be placed on the driveline in these applications. A challenge is presented to the vehicle, engine and engine brake designers to exploit the potential of the improved retarding.