APR Cast Downpipe System - A4/A5/Q5 - B8/B8.5 - 2.0T

We have one of these downpipes left in stock at our Aberdeen, MD shop location.

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.

Quick Facts:

• More power and less turbo lag
  +40-47 HP and +36-45 FT-LBS over APR Stage I (B8 A4 2.0T).

• Full 76mm downpipe system
  Say goodbye to the tiny, kinked, 60mm tubing and chambered resonator.

• Bell-mouth investment-cast downpipe inlets
  Ultra smooth cast inlet for unmatched performance.

• GESI High-flow catalysts
  Strong and reliable catalyst, with reduces emissions, smell and noise over catless setups without the performance hit.

• T304L stainless steel construction
  Premium grade materials to resists corrosion and stands the test of time. 

• Argon back-purged TIG welding
  Clean, strong and attractive welds both inside and outside the pipes

• OEM-style low-profile slip-on clamps
  Easy to install with tons of clearance. Resists leaks and doesn't deform the pipe.

• OEM-style internally-corrugated flex section
  High flow without the failures common with braided setups.

• Investment cast secondary oxygen sensor bungs
  A perfect fit that doesn't protrude into the pipe. 

• Compatible with the OEM catback exhaust
  Bolt-on and go

• In-house design, assembly and quality control
  All critical aspects of the system are handled internally to ensure the highest quality fit and finish.

• All hardware and instructions included
  All included for a headache free install.

• APR Stage II ECU Upgrade price waived
  Upgrade from APR Stage I to APR Stage II for free.

• Limited lifetime warranty
  The best system with the best warranty

Components:

Cast Downpipe:

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.

76mm Midpipe:

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.

Flex Section:

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.

Catalytic Converter:

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.

Bracket:

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.

Clamp:

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.

Oxygen Sensor Bung:

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.

Reducer:

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.

Gasket:

Included with each system is an OEM gasket, designed to mate between the downpipe and the turbocharger.

Calibration Report:

Vehicle     NAR Fuel     ROW Fuel     Max HP     Max TQ     Max HP Gain over STG1    Max TQ Gain over STG1

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

- APR recommends and tuned with Sunoco GT 260 for 100 AKI mode and Sunoco GT 260 Plus for 104 AKI mode. Never use lower octane than specified by the mode.
- 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.

 Applications:

• Audi A4 / Allroad (8K - B8 and B8.5)  1.8 TFSI EA888 Gen 1 and 2.0 TFSI EA888 Gen 2 Quattro - LHD
• Audi A5 (8T - B8 and B8.5)  1.8 TFSI EA888 Gen 1 and 2.0 TFSI EA888 Gen 2 Quattro - LHD
• Audi Q5 (8R) 1.8 TFSI EA888 Gen 1 and 2.0 TFSI EA888 Gen 2 Quattro - LHD