+32-95 FT-LBS of Torque
Cast Bell Mouth Inlets
Full 76mm Stainless Steel System
APR is pleased to present the ultimate Cast Downpipe Exhaust System!
The APR Cast Downpipe Exhaust System replaces the restrictive factory catalyst cross pipes and resonators with an upgraded 76mm stainless steel mandrel-bent system, featuring port-matched cast inlets, high-flow catalysts and various other features. Expect better throttle response, more horsepower and an intoxicating exhaust note, while remaining civilized during normal daily driving. It’s the best performance upgrade for the 4.0 TFSI following the APR ECU Upgrade and it’s all designed and assembled in-house, using premium materials and world-class manufacturing techniques few can match.
The factory downpipes are less than desirable from a performance standpoint. Both pipes quickly neck down from the massive turbocharger outlet to small and resistive 60mm pipes that are kinked in many areas before twisting and dumping into catalytic converters. APR greatly improved upon this design through the use of investment-cast and port-matched downpipe inlets. Each pipe gradually reduces to the larger and straighter 76mm piping, with the hot catalyst moved further down the exhaust stream to keep under hood temperature down.
The cast inlets, piping and other components are made from the the high-nickel content, premium-grade stainless steel known as T304L. This material was chosen for its excellent corrosion resistance, strength and appearance. The castings are tumbled to smooth and de-burr any imperfections, and all piping is brushed clean before entering the CNC controlled mandrel benders. TIG welding is used at all connection points, and was chosen for its strength and appearance. Each weld is argon back purged during assembly to increase strength and consistency of the welds. The gusseted brackets are CNC laser cut and bent to provide strong mounting points to the factory mounting hardware.
The APR midpipes replace the kinked factory 60mm resonator pipes with new, 76mm mandrel-bent T304 stainless tubing, complete with OEM style low-profile flex sections, GESI catalysts, investment cast O2 sensor bungs, and reducers. The pipes mate perfectly to the factory catback exhaust system without any modification necessary. All connection points use APR’s OEM style slip clamps providing the ultimate in compatibility, performance and easy of install compared to flanges, v-bands and pipe deforming sedges and slip fits common on other systems.
The APR midpipes use OEM-style flex sections that are fully sealed with a corrugated inner lining to improve flow and reliability. The low profile design and minimal use of bradding material eliminates clearance issues common with other designs that can billow, rub, rattle and fray over time. Each flex section is constructed from T304 stainless steel.
APR’s engineers specified high-quality and high-flow GESI metal 300-cell catalysts ideal for forced induction application. During dyno testing, the 100mm x 100mm design showed no measurable loss in power, thanks to the catalyst’s specifications.
Internally the catalytic converters feature a proprietary wash coat that helps to reduce emissions and smell common on cat-less setups. With performance in mind, the catalysts are placed far away from the turbo outlets to reduce turbulence in the downpipes and to help reduce under-hood temperature. The low-profile catalysts feature fully captured substrate bricks, which are furnace brazed to the outer mantles and physically captured by the diffuser cones preventing rattling, rotation, and damage to the substrate. Subsequently, a byproduct of running the catalysts are a reduction in noise, making the system as a whole more pleasing to the ear.
Our system uses OEM-style low-profile slip clamps designed to eliminate the need for flanges, swedging, or slip fittings. By using this low profile design, the exhaust system can be positioned higher in the exhaust tunnel and away from the ground with better clearances compared to flanged setups. Each clamp allows for less turbulence and greater accuracy at the connection points as the pipes simply butt up to one another rather than the ambiguity and voids associated with swedged slip fittings. Furthermore, the clamp doesn’t rely on deforming the pipe to provide a tight seal, making install and removal more convenient.
APR’s Engineers paid special attention to the details when designing the APR Cast Downpipe Exhaust System all the way down to the oxygen sensor bungs. APR’s O2 bungs are investment cast from T304 stainless steel and are curved to perfectly fit on 76mm piping, without protruding into the pipe, as this would further impede airflow beyond the sensor itself. The bungs are TIG welded to the piping and back-purging is used to ensure the interior surface is smooth and clean.
Two high quality oxygen sensor extension harness are included as the catalysts and sensor bungs are relocated further away from the turbochargers.
Included with each system is an OEM gasket, designed to mate between the downpipe and the turbocharger.
|Vehicle||NAR Fuel||ROW Fuel||Max HP||Max TQ||Max HP Gain
Over APR Stage I
|Max TQ Gain
Over APR Stage I
|- Max increases are based on APR's actual measured stock values and not those reported by VAG. | RON = ROW Fuel Grades | AKI = North American (RON+MON)/2 Fuel Grades.|
|- Reported wheel figures measured using APR's AWD Dynapack and APR UK's AWD Dynojet dyno with multiple vehicles, using SAE correction and an average of multiple runs for all figures. Stage II included a high flow downpipe. Crank figures are estimated based on the measured wheel figures. Results may vary depending upon environmental conditions, vehicle, transmission, vehicle health, operating conditions, temperatures, fuel grade, dyno type, dyno setup, other variables and other modifications.|
|Audi S6/S7 (C7)||91 AKI||95 RON||575 HP||669 FT-LBS||+56 HP @ 3,850 RPM||+82 TQ @ 3,350 RPM|
|Audi S6/S7 (C7)||93 AKI||98 RON||586 HP||694 FT-LBS||+52 HP @ 3,950 RPM||+73 TQ @ 3,500 RPM|
|Audi S6/S7 (C7)||100 AKI||104 RON||602 HP||713 FT-LBS||+59 HP @ 4,050 RPM||+83 TQ @ 3,500 RPM|
|Audi S6/S7 (C7)||104 AKI||108 RON||614 HP||717 FT-LBS||+71 HP @ 4,250 RPM||+91 TQ @ 4,000 RPM|
|Audi S6/S7 (C7.5)||91 AKI||95 RON||567 HP||648 FT-LBS||+35 HP @ 3,950 RPM||+61 TQ @ 2,400 RPM|
|Audi S6/S7 (C7.5)||93 AKI||98 RON||588 HP||684 FT-LBS||+36 HP @ 3,850 RPM||+58 TQ @ 2,300 RPM|
|Audi S6/S7 (C7.5)||100 AKI||104 RON||613 HP||689 FT-LBS||+25 HP @ 4,300 RPM||+50 TQ @ 2,350 RPM|
|Audi RS6/RS7 (C7)||91 AKI||95 RON||679 HP||703 FT-LBS||+40 HP @ 4,950 RPM||+74 TQ @ 2,450 RPM|
|Audi RS6/RS7 (C7)||93 AKI||98 RON||712 HP||751 FT-LBS||+44 HP @ 5,050 RPM||+77 TQ @ 2,500 RPM|
|Audi RS6/RS7 (C7)||100 AKI||104 RON||761 HP||793 FT-LBS||+43 HP @ 4,700 RPM||+85 TQ @ 2,500 RPM|
|Audi RS6/RS7 (C7.5)||91 AKI||95 RON||687 HP||777 FT-LBS||+42 HP @ 2,700 RPM||+83 TQ @ 2.600 RPM|
|Audi RS6/RS7 (C7.5)||93 AKI||98 RON||709 HP||797 FT-LBS||+42 HP @ 2,700 RPM||+83 TQ @ 2,600 RPM|
|Audi RS6/RS7 (C7.5)||100 AKI||104 RON||730 HP||811 FT-LBS||+49 HP @ 4,950 RPM||+94 TQ @ 2,650 RPM|
|Audi RS6/RS7 (C7.5)||104 AKI||108 RON||759 HP||889 FT-LBS||+49 HP @ 2,750 RPM||+95 TQ @ 2,650 RPM|
|Audi S8||91 AKI||95 RON||672 HP||691 FT-LBS||+30 HP @ 4,700 RPM||+36 TQ @ 4,100 RPM|
|Audi S8||93 AKI||98 RON||688 HP||727 FT-LBS||+28 HP @ 4,750 RPM||+32 TQ @ 4.500 RPM|
|Audi S8||100 AKI||104 RON||710 HP||751 FT-LBS||+32 HP @ 4,200 RPM||+41 TQ @ 4,100 RPM|
In the past APR worked with other manufacturers to develop a limited range of private-label exhaust systems outside the scope of APR’s internal development and manufacturing capabilities. Understanding the limits of such a program, combined with APR’s desire to deliver higher-quality products in a timely manner with better customer support, APR invested in internalizing the program. With the release of this exhaust system and the others like it, APR is pleased to present our first systems fully designed and engineered in-house from the ground up!
Design and development begins with the use of APR’s professional grade in-house coordinate measuring machines. APR’s engineers have full access to a Romer Absolute arm with integrated laser scanner, FaroArm and Creaform 3D laser scanner for collection of special constraints surrounding the factory exhaust system. The engineers scan the vehicles and create detailed 3D maps of their design environment while designing each system in PTC Creo 3.0 CAD software.
Using APR’s in-house stereolithography 3D printer, rapid prototypes are created for fitment on the vehicle. The design is easily and quickly verified, and if necessary, changes can be made. Once adequate clearances and fitment is confirmed, especially in areas that move under load, physical quick-cast prototypes are created and fitted for final verification through real-world use.
APR’s world-class manufacturing partners from around the globe are responsible for manufacturing each component that falls outside of APR’s internal capabilities. Working closely with each manufacturer, APR’s engineers supply CAD models, materials specs, and other design specifications and work hand-in-hand with the manufacturer to develop the components. The end result is a collection of components, wholly unique to the APR name, awaiting final finishing, assembly and quality control at APR’s 78,000 square foot facility in Opelika, Alabama in the USA.
|Designed for Left Hand Drive (LHD) vehicles only. Right Hand Drive (RHD) vehicles require slight clearancing.|