APR Presents the R8 4.2L FSI V8 Stage III+ TVS1740 Supercharger System!
APR is pleased to present the R8 4.2L FSI V8 Stage III+ TVS1740 Supercharger System!
APR’s technical reach has grown enormously since opening in the 1990’s and currently represents a force of unmatched performance without compromise in the performance enhancement sector for Audi vehicles. Our previously available APR Stage III TVS1320 Supercharger System found its way on to several hundred 4.2L FSIs around the world, making it the most popular and reliable system on the market. With more than four years’ worth of 4.2L FSI supercharger engineering research, development and testing, APR’s new Stage III+ TVS1740 Supercharger System represents the pinnacle of Audi’s German engineering enhanced by APR’s American ingenuity.
In the factory form, Audi’s high revving FSI V8 can leave much to be desired compared to some of the latest technological advances brought forth by Quattro GmbH in recent years. The APR Stage III+ TVS1740 Supercharger System fills the void by adding an average of roughly 46% more horsepower and torque across the entire power band. The results are nothing short of amazing; taking the R8 from 425 horsepower to 642 horsepower on pump fuel and 689 horsepower on race fuel without breaking a sweat! With 550 FT-LBS on tap thanks to the TVS1740’s positive displacement supercharger expect instant acceleration with absolutely no lag commonly associated with other forms of forced induction.
Supercharger, Manifold and Runners
At the heart of the APR Stage III+ Supercharger System is Eaton’s latest Twin Vortices Series (TVS) supercharger unit, the TVS1740. The supercharger system is a positive displacement, roots style pump, utilizing Eaton’s lightweight, four-lobe 160 degree twisted rotors. Cast and assembled as a single, OEM-style-manifold and rotating group housing, the unit is quiet, compact, attractive, easy to install, and requires little to no extra maintenance to the unit itself.
The positive displacement supercharger offers power instantly as the throttle is pressed. Boost pressure builds with no perceived lag commonly associated with other types of forced induction, and provides a large increase in torque across the entire power band. Throttle control is linear and predictable and makes for an excellent driving experience both in daily driving and wide-open acceleration.
Since the supercharger does not compress air as it moves through the roots, it’s extremely efficient during light throttle and cruising situations. Unlike screw-type positive displacement superchargers that are always compressing, the TVS unit can internally bypass unwanted air, resulting in negligible parasitic loss during cruising and thus far greater fuel economy.
The single cast unit and appropriately sized rotating group eliminates potential leak points and allows for a slim, compact design without sacrificing key airflow design characteristics. The unit features a high velocity flow path through the supercharger rotors and an unrestricted discharge port into the appropriately sized plenum. The large plenum equalizes flow across all ports as air feeds evenly through the low-pressure-drop, dual-internal air-to-water heat exchangers. Finally, the ports are separated into individual runners and continue through aircraft grade 6061 billet aluminum extension runners, offering greater operation by eliminating cross talk.
Internally the dual heat exchangers offer technological advances shared by Formula 1 teams around the globe. Each unit features a louvered fin design, which minimizes pressure drop while achieving excellent cooling effectiveness. The extruded multi-rib tubing maximizes heat extraction to be carried away through the large bore coolant recirculation hard lines. Externally, supercharger coolant is pumped through a large front mounted heat exchanger where it’s cooled and circulated back through the charger again.
The factory Bosch MED 9 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+ TVS1740 Supercharger System, APR’s Engineers spent months calibrating the engine management system, including well over 100+ 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. Further development was performed putting the vehicle through performance evaluation and durability testing at the drag strip. 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.
Adding forced induction to a naturally aspirated engine presents several challenges with regards to how the ECU operates. APR’s Calibration Engineers properly restructured the engine’s volumetric efficiency (VE) model to properly determine the ECU’s calculated load. 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, are adjusted to handle the large temperature variances compared to a factory naturally aspirated setup.
APR’s Calibration Engineers have optimized cam timing, ignition timing and lambda to provide tremendous leaps in power while retaining OEM knock control sensitivity. 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.
Beyond power and torque enhancements, APR’s Calibration Engineers were able to increase the acceleration rate of the vehicle through other calibration changes. 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 the factory set redlines without dropping off several hundreds of RPM earlier. And lastly, APR’s tried and tested 4,200 RPM Motorsport Launch Limiter allows the driver to focus on launching the vehicle, rather than controlling the engine speed.
Beyond wide open throttle performance, APR’s Calibration Engineers spent countless hours optimizing vehicle drivability under daily, part-throttle, driving. The vehicle’s pedal maps are recalibrated under both standard and sport mode, providing smooth part-throttle drivability without compromising the driveshaft windup protection. 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! We call it Performance Without Compromise.
Supercharger Coolant Air-to-Water Radiators
APR’s supercharger system features a large, 585 mm x 140 mm x 65 mm front mount radiator and a second 320 mm x 140 mm x 90 mm side mounted radiator responsible for cooling coolant as it’s pumped out of the supercharger’s dual internal air-to-water heat exchangers. An adequate cooling system is critical in any supercharged application to not only keep power consistent, pull after pull, but also to help keep IAT below dangerously high levels.
The heat exchangers are specific to the R8 platform and feature cast aluminum end tanks with threaded connection points and bleeder valves. Each cooler cleanly installs with the supplied CNC, laser-cut brackets, complete with vibration insulators.