APR Cast Race DP Exhaust System - For A4/A5/Q5 - B8/B8.5 - 1.8T/2.0T

APR is pleased to present the ultimate Cast Downpipe Exhaust System!

Upgrading the restrictive factory downpipe with the APR Cast Downpipe Exhaust System is a great way to increase performance and add a sophisticated growl to the exhaust note. Ideal performance is achieved through expelling exhaust gases at maximum velocity through APR's proprietary, low-turbulence, investment cast downpipe. Designed and assembled in-house, the system utilizes only premium materials and world-class manufacturing techniques to deliver unmatched quality and reliability.

The factory downpipe system consists of smaller, 63" piping with varying bends and multiple restrictive high-cell-count catalysts, all of which contribute to a less than ideal flow path and hindered performance. APR's engineers took a multi-step approach to maximizing flow, reducing under hood temperature, and eliminating unnecessary restrictions all in a unique package only APR can deliver.

Quick Facts

The factory downpipe system consists of smaller, 63" piping with varying bends and multiple restrictive high-cell-count catalysts, all of which contribute to a less than ideal flow path and hindered performance. APR's engineers took a multi-step approach to maximizing flow, reducing under hood temperature, and eliminating unnecessary restrictions all in a unique package only APR can deliver.

Cast Race DP

The Race DP 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 Race DP off the turbocharger, and the internally-corrugated flex section gives the Race DP the flex it needs under engine movement. Finally, the Race DP uses T304 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 Race DP Exhaust System is a “full” Race DP, 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 T304 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 T304 stainless steel and is argon back-purged when TIG welded to the Race DP.

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 brazed 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 Race DP is a high quality mounting bracket. The bracket is constructed from T304 stainless steel and is CNC-machined and CNC-bent to exact tolerances. The bracket is TIG welded to the piping and argon back-purged.

Clamps

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.

Oxygen Sensor Bung

APR’s Engineers paid special attention to the details when designing the APR Cast Race DP Exhaust System all the way down to the oxygen sensor bung. APR’s O2 bung is investment cast from T304 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, T304 stainless steel reducer, featuring a smooth transition, is included, making the APR Cast Race DP Exhaust System directly compatible with the OEM catback exhaust system.

Gasket

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