APR is pleased to present a completely reengineered supercharger Coolant Performance System (CPS) for the Audi B8 3.0 TFSI. Through extensive motorsport testing in GRAND-AM Road Racing, APR's Engineering Team discovered the OEM supercharger cooling system was inadequate at higher boost pressures and power levels and therefore developed the APR CPS to improve both performance and reliability.
Performance
Compressing incoming air such as all superchargers and turbochargers do to deliver increased volumetric efficiency and thus more power at every point of combustion creates heat that must be properly cooled again prior to entering the cylinders. Most all automotive enthusiasts have experienced this with even normally aspirated cars whereas in the cool winter days our cars clearly perform better than in the hot summer months. When increasing engine power or during spirited driving, and especially during brutal motorsport racing, the OEM supercharger cooling system quickly becomes taxed, creating a loss of engine performance.
Reliability
Heat is a major concern regarding the health of your engine and APR pays close attention to reliability. The engine's ECU takes many steps to reduce power output when temperatures rise, however it can only go so far. By reengineering the supercharger cooling system, APR is able to not only keep performance consistent but also ensure your engine is more reliable by having done so.
Following APR's mantra of "Performance Without Compromise" APR's Engineering Team left no stone unturned in the quest to deliver a completely reengineered performance cooling system. The APR CPS consists of three major components:
APR CPS - Coolant Separation Reservoir
Audi chose to directly tie the supercharger cooling circuit into the engine cooling circuit to achieve a greater volume of coolant and ease of service. Unfortunately, engine coolant temperatures can easily soar beyond 100c which results in less ability to aid in cooling the dual air-to-water intercoolers located in the supercharger manifold.
By separating the engine and the supercharger cooling circuits, coolant temperature drops significantly which yields a 6% cooler intake air temperature (IAT) during back-to-back pulls. This, however is only the first step in solving the cooling inefficiency as increasing the volume of coolant is necessary to ensure repeatable performance.
The main centerpiece to the Coolant Separation Reservoir is a CNC machined overfill reservoir. The reservoir is e-coated black and proudly displays the APR Logo. This small addition to the engine bay is both visually appealing and functional.
APR CPS - Coolant High Flow Pump
The ability for the dual air-to-water intercoolers to reduce intake air temperature depends heavily upon the system's ability to pump fresh coolant through the intercoolers and out to a front mounted radiator. APR's engineers selected a pump capable of flowing significantly more than the OEM coolant pump. The result was a 48% flow increase which when combined with the Coolant Separation Reservoir dropped IAT's 11% over stock.
The upgraded pump is an unobtrusive and out of sight addition, as APR's engineers have created higher than OEM quality brackets and wiring harnesses to seamlessly connect the pump to the factory wiring system and chassis without any interference with existing components.
APR CPS - Front Mount Coolant Radiator
Properly functioning air-to-water intercoolers rely heavily on the temperature of coolant flowing through the system. Increasing the volume of coolant and increasing the surface area of front mounted radiators significantly reduces coolant temperature. With an increased volume of coolant, coolant takes longer to warm and with an increased surface area, coolant temperature is reduced at a more rapid rate.
The APR Front Mounted Radiator towers over the 5.5 inch tall OEM radiator and stands 17 inches tall in comparison. This massive increase in size results in a much larger coolant capacity and a 138% increase in frontal surface area. When combined with the APR Coolant Separation Reservoir and APR Coolant Pump, IAT's dropped significantly, resulting in a 23% decrease during brutal testing. The result is power that remains consistent pull after pull even with almost no time to cool down between runs.