This is the new iRacing GTX5 .21 GT engine, based on the well known O.S. R2104 engine. The motor sports a new crankshaft with redesigned counter weight giving the engine better balance and has been given a special DLC treatment for longer life. It boasts 5-port line for improved torque in the low to middle power range giving lots of power, even in high traction tracks. The new cooling head comes in a silver finish and has been machined to reduce weight while the cooling head button now sports a silicone O-ring to prevent dust from entering the engine.