Audi RS4 Stage III Supercharger System
APR's B7 RS4 4.2L FSI V8 Stage III+ TVS1740 Supercharger System adds an average of roughly 40% more horsepower and torque across the entire power band, taking the RS4 from 414 horsepower to 626 horsepower on pump fuel and 688 on race fuel! With more than 500 FT-LBS on tap, expect instant acceleration with absolutely no lag.
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, 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.
APR’s supercharger system features a large, 310mm x 540mm x 42mm, front mount heat exchanger responsible for cooling coolant as it’s pumped out of the supercharger’s dual internal air-to-water heat exchangers. This is a critical component 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 exchanger is specific to the RS4 platform, featuring a hand welded design and CNC, laser-cut brackets to provide a simple and clean method of mounting to the vehicle.
APR’s coolant pump connects to the supercharger coolant circuit and continuously circulates coolant through the supercharger’s dual internal air-to-water radiators and APR front mount heat exchanger. The pump provides adequate coolant flow through a system of this size. The pump seamlessly connects to the factory wiring harness through the included APR wiring harness with no wire splicing and is triggered by the included relay system. APR’s CNC, laser-cut bracket provides a simple and clean method of mounting the pump to the vehicle.
Sold separately as brand new pumps or rebuilds of the engine’s existing pumps, the APR High Pressure Fuel Pumps address fueling needs and leaves plenty of headroom for safety and further increased power levels. By increasing the pump’s internal capacity, the fueling system is capable of displacing a higher volume of fuel per minute at every RPM. Read more on our APR High Pressure Fuel Pumps product page.
Horsepower and Torque was measured in APR’s in-house, sounmaster dyno cell, using a dynapack all wheel drive dynamometer. Multiple stock and modified runs were conducted and the SAEJ1349 corrected results were averaged together to represent the differences between a stock and APR Stage III+ B7 RS4. Crank power figures were estimated based on Audi’s factory advertised results.
Click through the tabs below to view output using various fuel grades, power measured at all four wheels, estimated at the crank, and the absolute gain over stock.
|Stock 93 AKI|
|AKI - Anti Knock Index or (RON+MON)/2 for Octane Ratings | RON - Research Octane Number for Octane Ratings | North American Model|
|Rev Limiter||8,250 RPM||8,250 RPM||8,250 RPM||8,250 RPM||8,250 RPM|
|Peak Mechanical Horsepower (HP)||414 HP||418 HP||606 HP||626 HP||688 HP|
|Peak Torque (FT-LBS)||317 TQ||322 TQ||515 TQ||529 TQ||562 TQ|
|Max Horsepower Gain over Stock (HP @ RPM)||+223 HP @ 7,900 RPM||+243 HP @ 7,900 RPM||+305 HP @ 7,900 RPM|
|Max Peak Torque Gain over Stock (FT-LBS @ RPM)||+215 TQ @ 4,400 RPM||+228 TQ @ 4,300 RPM||+261 TQ @ 4,350 RPM|
All too often performance upgrades show improvements during a single dyno pull, but lack the ability to show the same performance in real world conditions. Furthermore the dyno may be unable to illustrate the system’s response and other tuning changes designed to make the system instantly react to the drivers input. Through acceleration testing, APR’s engineers were able to improve power delivery during launches, after gear changes and prove the cooling system was up to the task of sheading heat to keep power consistent.
APR’s local certified quarter mile drag strip is a perfect and safe testing ground for high speed, 130+ MPH sprints. Using Car and Driver magazine’s measured results as a benchmark, APR’s Engineers setout to prove the Stage III+ Supercharger System was capable of increasing the RS4’s performance substantially.
Car and Driver magazine measured the B7 RS4’s sprint from 30-130 MPH in an underwhelming 17.2 seconds. However, with the addition of the APR’s Stage III+ TVS1740 Supercharger System, the vehicle entered a league of performance often shared by exotic supercars. Using 93 octane fuel the same acceleration test was completed 6.64 seconds faster! Through testing higher octane fuels, and eventually weight reduction and tire changes, the gap grew even larger, ultimately resulting in an astonishing 48.2% reduction in time.
Many more acceleration tests were performed, including record setting quarter mile passes, proving an APR Stage III+ TVS1740 Supercharger System is the ultimate upgrade for B7 RS4!
|Vehicle Stage||60-120 MPH||62-124 MPH||60-130 MPH||30-130 MPH||1/4th ET||1/4th Trap|
|Stage III+ PBox and time slip acceleration data collected on the same day and same IHRA certified drag strip with ESP disabled.|
|Stock (Car & Driver Magazine)||11.4||n/a||14.3||17.2||13.2||109 MPH|
|STG 3+ 93 AKI - Full Weight & Street Tires||6.91||7.41||8.62||10.56||11.156||125.41 MPH|
|STG 3+ 100 AKI - Full Weight & Street Tires||6.31||6.76||7.92||9.77||11.070||129.29 MPH|
|STG 3+ 104 AKI - Reduced Weight & Drag Slicks||5.93||6.49||7.37||9.08||10.606||131.67 MPH|
|B7 RS4 Sedan, Avant and Cabriolet||APR B7 RS4 4.2L FSI V8 Stage III+ TVS1740 Supercharger System - Includes Software||T3100052||$17,749.99|
During the install, oil and coolant must be drained and should be replaced to offer superior performance and protection. The APR Supercharger Systems are now complete turnkey solutions, including everything you need down to the oil, coolant and oil filter. During checkout you'll be given the option between Motul Specific 502.00, 505.00 & 505.01 5W40 or Motul Power 300V engine oil as well as Motul Inugel Optimal Ultra Coolant and an OEM oil filter. The Premium Motul lubricant package is included at a much lower than retail price point and the costs are listed below.