The 2.0 TSI is completely transformed the second it meets an APR Stage III GTX Turbocharger System. Power immediately jumps to 423 horsepower with 387 ft-lbs of torque on tap using 98 octane fuel on a completely stock and unmodified factory fueling system. Switching to APR’s 104 octane race fuel mode, power shoots up to 458 horsepower with 409 ft-lbs of torque all at the driver’s command. This level of extreme performance is just a taste of the system’s full performance capabilities.
At the heart of Stage III GTX Turbocharger System is a GTX2867R turbocharger, which is capable of flowing nearly 50 lbs/min of corrected air flow. This directly translates to large power gains on the 2.0 TSI that continue to grow all the way to redline. The GTX Turbocharger consists of the latest technologies from Le Mans’ winning turbo manufacturer, Garrett Honeywell, and has a track record of reliability and repeatability worthy of complementing an APR Turbocharger System. The internally gated turbocharger features a fully-machined, ten-blade billet 49.7 mm compressor wheel, Inconel 53.9 mm turbine wheel and a dual ball bearing oil and water-cooled CHRA. APR’s Engineers spent countless hours testing turbine inlet and A/R sizes in order to decrease turbocharger lag without negatively impacting peak power. Complementing the turbo’s lightning fast response characteristics is a newly developed anti-surge housing, which enables APR’s Calibration Engineers to deliver massive low-end torque without experiencing compressor surge. Each turbocharger unit is assembled and clocked in house at APR with the necessary brackets to ensure proper wastegate fitment and orientation. Each wastegate is then calibrated for precise operation and control to ensure seamless integration with the expertly recalibrated OEM engine management system.
The factory Bosch MED 17 engine management system is responsible for proper operation of the engine during constantly changing environmental and load conditions. With built in compensational data for environmental variables and varying load conditions, the factory ECU is far more complex and intelligent than units found in other vehicle makes and marques.
With the significant amount of changes included in the APR Stage III GTX Turbocharger System, APR’s Engineers spent months calibrating the engine management system, including hundreds of hours of in-house chassis dyno development. Drivability, gear changes, cruising and part throttle operation were tuned to operate smoothly as if intended by the OEM through proper torque management. Further development was performed putting the vehicle through performance evaluation and durability testing at the drag strip and road course. APR’s Electrical Engineers built new coding functions, strategies and routines into the ECU to control conditions normally unseen at factory power levels. Thanks to APR’s incredible proprietary calibration suite, data logging software and full access to the coding structure of the ECU, appropriate and intelligent changes are made to ensure flawless drivability and excellent performance without compromise.
APR’s Calibration Engineers properly restructured the engine’s volumetric efficiency (VE) model to properly determine the ECU’s calculated load and deliver proper torque management. Thanks to APR’s patented boost control coding and the addition of a 3-Bar MAP sensor, the ECU is able to perform closed loop boost control well beyond relatively low limits dictated by the factory MAP sensor. This directly translates to safer and more predictable operation while additionally producing more power and torque across the entire power band.
Additionally, through the properly reconstructed VE model, accurate open loop fueling is achieved, translating to insignificant fuel trim adjustments. Closed loop fueling is calibrated to control lambda perfectly under all operating conditions. Furthermore, compensations, such as ones related to intake air temperature, exhaust temperature, and altitude, are adjusted to handle the larger variances compared to the factory, low output setup.
APR’s Calibration Engineers have optimized cam timing, ignition timing, engine load and lambda to provide tremendous leaps in power while retaining the OEM knock control strategy. The result is safely achieved power, optimized for various fuel grades found around the world from low quality pump fuel, all the way to high quality, oxygenated race fuels.
Torque Management and Traction Control:
Torque management plays a big role in how the vehicle feels and performs, especially during moments of low gear, rapid acceleration. Typically front wheel drive vehicles suffer from excessive wheel spin during these moments due to the massive torque on tap from the Stage III GTX Turbocharger System. Some drivers can find themselves in situations where they are fighting against wheel spin and traction control when they are simply interested in going forward as quickly as possible. This is further compounded by the fact the factory traction control (ASR) system was designed for vehicles producing far less power and torque, resulting in overcompensated ASR interventions.
APR’s Calibration Engineers set out to perfect torque management and traction control by minimizing wheel spin as much as possible without neutering the driving experience. A multi step approach was taken to achieve appropriate control. With ASR enabled, forward movement wheel spin will trigger appropriate torque intervention levels to minimize spin without hurting forward acceleration. On top of this, the torque management system is fine tuned to deliver only as much torque as the tires can take. In normal conditions the tires will only slightly break loose under full acceleration, resulting maximum acceleration. In higher traction situations, or with ASR disabled, all of the system’s torque is directly on tap!
While the end goal is similar, APR’s torque management system differs greatly from archaic “boost-by-gear” strategies. “Boost-by-gear” strategies rely on a static limitation of boost in an effort to minimize wheel spin, but to work properly they must be dialed in for every situation. The same boost levels in different weather conditions, such as a hot summer day and a cold winter month, can produce vastly different torque levels. Since APR’s torque management system relies on the engine management’s phenomenal torque reporting abilities, it is able to adjust to every environmental situation it encounters. To achieve a targeted torque level, the ECU applies the appropriate changes to mass airflow and ignition.
Through further calibration changes APR’s Calibration Engineers were able to increase the acceleration rate of the vehicle. Ignition delays are reduced resulting in a more responsive pedal without altering overall throttle sensitivity and resolution. Drivability was greatly improved by reducing the throttle lag commonly noticed at slow speeds and while reapplying throttle after decelerating. APR’s Motorsport Rev Limiter allows power to climb all the way to redline without dropping off several hundreds of RPM earlier. Lastly, APR’s tried and tested Motorsport Launch Limiter allows the driver to focus on launching the vehicle, rather than controlling the engine speed.
Part Throttle Drivability:
Beyond wide open throttle performance, APR’s Calibration Engineers spent countless hours optimizing vehicle drivability under daily, part-throttle, driving. The vehicle fully retains its impressive daily driver status and simply has more power on tap should the driver request more with his or her right foot!
APR EMCS and APR Mobile:
APR’s EMCS program switching technology and APR Mobile put control of the ECU in the operators hand to access modes for standard pump fuel, high output race fuel and even reduced output valet modes to protect the vehicle against improper use by other individuals. This technology is patented by APR and is found nowhere else in the world. It’s Performance Without Compromise only APR can deliver!