The additional plumbing associated with turbochargers has always contributed to elevated engine-bay temperatures. APS solved this problem by positioning the turbos up under the chassis, away from the engine compartment.
Each turbo is equipped with its own blow-off valve (BOV). The BOV is designed to release boost pressure from the turbocharger when the throttle is quickly closed. It prevents the formation of a pressure-shock load on the turbocharger compressor and allows the turbo to continue spinning freely during gear changes. This ensures that as the next gear is grabbed and the throttle mashed, the turbos spool quickly and provide near instantaneous boost. APS has designed a lot of performance headroom with these turbos. So much, in fact, that they can support (with a built engine) approximately 1,000 hp at just 15 psi of boost.
When air is compressed-in this case by the turbocharger-it is also heated. An intercooler's function is to lower the charge-air temperature as close as possible to ambient. This enhances power production because cool air contains more oxygen, which means more fuel can be added. And you know what that means: more power and more sh*t-eatin' grins for the driver. Accordingly, APS provides a pair of vertical-flow, high-efficiency intercoolers utilizing lightweight, cast-aluminum end tanks. Intercooler performance is measured by the amount of heat the unit can remove from the inlet-charge air as well as the pressure drop across the entire system. Each APS core measures 10x11x4 inches, and the claimed pressure drop is less than 1.0 psi. As for efficiency, the intercooler-outlet temperature is less than 15 degrees higher than ambient at any vehicle speed over 50 mph.
The APS intercoolers use bar-and-plate core construction for the highest flow and greatest efficiency possible. This type of construction results in an inherently strong intercooler core of high thermal inertia, which means they have massive reserves of cooling capacity. This is important in situations where ambient airflow over the core is low, such as the time between the burnout and launch at the dragstrip.
The intercoolers' design allows retention of the stock air-conditioning system with no degradation of performance. The use of two separate intercoolers allows a generous air gap to channel ambient airflow into and through the air-conditioning and engine-cooling radiators.
Exhaust gases that feed each turbocharger must arrive at the turbine with the maximum amount of gas energy possible. This ensures crisp turbocharger response and high horsepower.
APS designed its High Energy Turbo exhaust manifolds to achieve the ultimate in terms of gas/energy transfer and outright performance. Cast in high-temperature ductile iron, the APS exhaust manifolds are built to withstand extreme horsepower levels. They have been designed to maximize flow and close-couple the turbine housings to the exhaust ports, making for the most efficient transfer of exhaust-gas energy possible. Cast manifolds perform this function much better than any fabricated solution. This is particularly important under spirited driving conditions that require frequent periods of on/off throttle, such as on a road course or during an autocross event. Notice the threaded bosses for heatshield attachment.
APS provides engine-management program data on CD for download into the stock computer. The APS data is designed for 93-octane fuel in an otherwise-stock, LS2-engined C6 Corvette. The stock ECU is reflashed using the popular HP Tuner. The reflash can also be performed by the tuner of your choice with HP Tuner's software. In the case of our yellow convertible, DTE proprietor Phil Rickard performed a full-blown custom tune on the car on his shop's in-house dynamometer. Rickard has extensive experience with forced-induction Corvette applications (he cut his teeth working on Lingenfelter's twin-turbo program in the late '90s) and was able to pull considerably more power out of the car than would have been available with the "generic" APS programming. Given the extensive-and expensive-nature of the APS turbo upgrade, we'd consider a custom tune such as this mandatory for maximum power and reliability.