CSF Charge Cooler Water Radiator - Black - B58 & B48

The tuning potential for the charge-cooled M1/240i, 1/2/3/420i and 1/2/3/425i is huge. However, once boost levels are increased the charge air temperature increases which is due to compressed air heating up. The stock cooling system works okay on a stock car but once boost levels are increased and more heat is introduced it begins to struggle.

Increased heat robs power in several ways, the main being that hotter air is less dense and results in less oxygen which is key for power and with the hotter air the risk of knock is also increased, to counter this the ECU will introduce its safety protocols to reduce power until the air is cool again.