The APR Cast Inlet Downpipe Exhaust System replaces the restrictive factory downpipe with a larger, 76mm stainless steel mandrel-bent system, featuring a port-matched 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 1.8T and 2.0T engines following APR’s ECU Upgrades and it’s designed and assembled in-house, using premium materials and world-class manufacturing techniques few can match.
Downpipe with Cast Inlet
The APR downpipe features an investment-cast inlet, with a port matched v-band flange, creating an ideal flow path for exhaust gasses exiting the turbocharger. By matching the already oversized turbo outlet, the downpipe is able to maintain exhaust gas velocity, improving performance with minimal variances in cross-sectional area due to the strategic use of cast parts. Furthermore, the cast inlet allows for excellent packaging, satisfying other design criteria while maintaining a larger and constant cross-sectional area compared to mandrel bent tubing built to similar specifications. The end results it simple: Smooth exhaust flow and maximum performance!
The downpipe’s piping is upgraded to attractively-brushed, straight-through and mandrel-bent 76mm tubing, dwarfing the small 65mm factory system. Furthermore, components visible from the engine bay are tumbled for a more attractive finish. A 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 factory midpipe uses awkwardly-kinked, 65mm tubing with some systems featuring an additional midpipe catalytic converter. 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 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.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.
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.
Designed to stand the test of time, the adjustable bracket is CNC machined from 8mm-thick billet T304L stainless steel and the hanger feet are threaded into place, eliminating the need for welds. Weight is removed from the bracket, wherever possible, while not hindering its structural integrity. The bracket attaches to the downpipe’s integrated mounting bracket with the included hardware.
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 Inlet 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 Inlet Downpipe Exhaust System directly compatible with the OEM catback exhaust system.
A high quality oxygen sensor extension harness is included as the catalyst and sensor bung is relocated further away from 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
|- 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 in house Dynapack using a 2016 Golf R in FWD mode, using SAE J1349 correction and an average of multiple runs for all figures. Stage II includes the 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.|
|MK7 Golf R / S3||91 AKI||95 RON||377 HP||403 FT-LBS||+36 HP @ 4,700 RPM||+41 TQ @ 4,600 RPM|
|MK7 Golf R / S3||93 AKI||98 RON||387 HP||409 FT-LBS||+24 HP @ 4,750 RPM||+29 TQ @ 3,850 RPM |