+36-45 FT-LBS of Torque
Cast Port-Matched Inlet
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 downpipe and chambered resonator with a larger, 76mm stainless steel mandrel-bent system, featuring a bell-mouth cast inlet, high-flow catalyst and various other features. Expect better throttle response, more horsepower and an intoxicating exhaust note, while remaining civilized during normal daily driving. It’s one of the best performance upgrade for the 1.8 TFSI and 2.0 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 downpipe is like nothing else on the market. The investment-cast, bell-mouth inlet provides an ultra smooth transition between the turbo’s 80mm outlet and the high quality catalyst’s inlet. All of the tubing in the system is upgraded from the awkwardly-kinked, 60mm tubing to attractively-brushed, straight-through and mandrel-bent 76mm tubing. The CNC laser cut bracket provides a strong and accurately positioned mounting point to take the weight of the downpipe off the turbocharger, and the internally-corrugated flex section gives the downpipe the flex it needs under engine movement. Finally, the downpipe uses T304L stainless steel components that are TIG welded together with argon back-purging, ensuring the system not only looks great on the inside and out, but stands the test of time.
The APR Cast Downpipe Exhaust System is a “full” downpipe, as it also includes the midpipe section underneath the vehicle. The factory midpipe uses awkwardly-kinked, 60mm tubing with some systems featuring a chambered resonator that poses a large restriction, especially vehicles with upgraded turbochargers. The APR midpipe eliminates the front resonator, giving the exhaust a slightly more aggressive note, while eliminating performance robbing restrictions. Finally, the midpipe uses attractively-brushed, straight-through and mandrel-bent 76mm T304L stainless steel tubing.
The APR midpipe use an OEM-style flex section that is 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. The flex section is constructed from T304L stainless steel and is argon back-purged when TIG welded to the downpipe.
APR’s engineers specified a high-quality and high-flow GESI metal 300-cell catalyst ideal for forced induction application. During dyno testing, the 100mm x 100mm design showed no measurable loss in power, thanks to the catalyst’s design.
Internally the catalytic converter feature a proprietary wash coat that helps to reduce emissions and smell common on cat-less setups. The low-profile catalyst features a fully captured substrate brick, which is furnace braised to the outer mantle and physically captured by the diffuser cones preventing rattling, rotation, and damage to the substrate. Subsequently, a byproduct of running the catalyst is a reduction in noise, making the system as a whole more pleasing to the ear.
Attached to the downpipe is a high quality mounting bracket. The bracket is constructed from T304L stainless steel and is CNC-machined and CNC-bent to exact tolerances. The bracket is TIG welded to the piping and argon back-purged.
APR’s engineers specified a T304L stainless steel, OEM-style exhaust clamp 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 bung. APR’s O2 bung is investment cast from T304L stainless steel and is curved to perfectly fit on the catalyst, without protruding into the pipe, as this would further impede airflow beyond the sensor itself. The bung is TIG welded to the piping and argon back-purging is used to ensure the interior surface is smooth and clean.
A simple and removable, T304L stainless steel reducer, featuring a smooth transition, is included, making the APR Cast Downpipe Exhaust System directly compatible with the OEM catback exhaust system.
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 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 A4 (B8)||91 RON||95 RON||287 HP||341 FT-LBS||+47 HP @ 6,700 RPM||+45 TQ @ 3,100 RPM|
|Audi A4 (B8)||93 RON||98 RON||291 HP||354 FT-LBS||+40 HP @ 6,700 RPM||+36 TQ @ 3,150 RPM|
|Audi A4 (B8)||100 RON||104 RON||304 HP||359 FT-LBS||+40 HP @ 6,700 RPM||+36 TQ @ 3,150 RPM|
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.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.
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.
|Audi A4 / Allroad (8K - B8 & B8.5)||1.8 TFSI EA888 Gen 1 & 2.0 TFSI EA888 Gen 2||Quattro & FWD
LHD - Only
|Audi A5 (8T - B8 & B8.5)||1.8 TFSI EA888 Gen 1 & 2.0 TFSI EA888 Gen 2||Quattro & FWD
LHD - Only
|Audi Q5 (8R)||1.8 TFSI EA888 Gen 1 & 2.0 TFSI EA888 Gen 2||Quattro & FWD
LHD - Only