APR High Flow Downpipe Kit: For Audi 4.0T

Quick facts:

• More power and better response
  Expect a decrease in turbo lag with power and torque gains as high as 59 HP and 95 FT-LBS of torque over APR Stage I!
• Full 76mm Race DP system
  The APR system is a full Race DP upgrade as it replaces the kinked 60mm catalyst cross pipes and resonated midpipes with straight through, 76mm mandrel-bent tubing.
• Port-matched investment-cast Race DP inlets
  The factory inlets are restrictive. APR's cast system allows for massive, port-matched inlets that smoothly neck down over a long distance. The result is improved flow, better response and more power.
• Dual, high-flow catalysts
  GESI's encapsulated catalysts are known for their strength and performance. Expect lower emissions, reduced noise and less exhaust smell compared to catless setups, all without negatively impacting performance to over 1,000 HP. Furthermore, with the catalyst moved, expect a cooler engine bay!
• T304 stainless steel construction
  Premium grade T304 stainless steel 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
  The APR slip-clamps are easy to use, resist leaks and pipe deformation better than swedged setup, are lower profile than vbands and flanges and don't require replacement gaskets.
• OEM-style internally-corrugated flex sections
  APR's flex sections are internally corrugated to increase flow and prevent failures common with braided flex sections.
• Investment cast secondary oxygen sensor bungs
  APR's obsession to details resulted in investment cast oxygen sensor bungs that sit on top of the piping, preventing material from protruding into the exhaust stream, disrupting flow.
• Compatible with the OEM catback exhaust
  Bolt-on and go! The system is fully compatible with the factory catback exhaust.
• Designed, assembled and quality controlled in-house
  All critical aspects of the system are handled internally to ensure the highest quality fit and finish.
• All hardware and instructions included
  New OEM gaskets, oxygen sensor harnesses, clamps, brackets and install instructions are included to make the install as headache free as possible.
• APR Stage II ECU Upgrade price waived
  With every APR Race DP purchase comes a free upgrade to Stage II from Stage I, saving consumers hundreds of dollars!
• Limited lifetime warranty
  The best system on the market also carry the best warranty in the industry!

Features and Benefits

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 photos below show illustrate the differences between the factory and APR exhaust system inlets.

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.

Dyno Testing

Videos

S8 Adapter - FIT0003

The Audi S8’s factory catback exhaust system is located in a slightly different location compared to other models. As such, the APR Adapter is required for proper fitment with the factory catback exhaust. The fit kit consists of two OEM clamps and extension pipes. The system bolts directly between the APR Race DPs and factory catback pipes.

NOTICE: THIS MOTORSPORT/RACING PRODUCT IS NOT DESIGNED TO MEET ANY FEDERAL EMISSIONS STANDARDS IN THE USA AND IS NOT FOR STREET OR HIGHWAY USE. THIS PRODUCT IS NOT C.A.R.B. COMPLIANT AND IS NOT FOR SALE OR USE IN CALIFORNIA, USA. APR MAKES NO CLAIMS THIS PRODUCT COMPLIES WITH ANY EMISSION LAWS IN ANY JURISDICTION. IT IS ENTIERLY THE RESPONSIBILITY OF THE PURCHASER TO INFORM THEMSELVES OF ANY LAWS OR REGULATIONS WHICH MAY PROHIBIT USE OF THIS PRODUCT.