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Chip Tuning, Gt28Rs Stage 1, Aan/Aby/Adu

SKU: 034-103-2004

Manufacturer: 034Motorsport

034Motorsport is proud to offer 034EFI Chip Tuning for the AAN/ABY/ADU I5 20VT. Countless hours of dyno, street, and track testing go into each of our 034EFI tunes before release, to ensure an unparalleled driving experience.

The 034EFI GT28RS Stage 1 Chip Tuning Package was developed to be the ultimate chip tuning solution for Audi S2/RS2 and UrS4/UrS6 vehicles that have upgraded to a GT28RS Turbocharger. This chipset remaps the factory ECU's boost, timing and fueling to match the larger GT28RS turbo, providing increased power without sacrificing reliability. The GT28RS turbo offers a broad powerband with massive low-end torque, and impressive top-end horsepower, similar to an RS2 turbo, but with better transient response.

This chipset is ideal for someone looking for a strong powerband with fast response and minimal lag.  Power comes on hard by 3000 RPM and holds clean to 7000 RPM.  Compared to the RS2 turbo, the GT28RS offers better transient response, coming back into boost almost instantaneously after shifts. The GT28RS is also very efficient, meaning lower intake air temperatures for similar levels of boost.  Driving through traffic is effortless; downshifting is not necessary, but will be rewarded as this turbo offers plenty of top-end horsepower.

Though not as powerful as the GT2871R or GT3071R, the GT28RS is perfect for the those who want minimal lag and 350+ horsepower.

This tune is recommended for all AAN, ABY, and ADU engines equipped with a GT28RS turbo, and utilizes a 4.0 BAR fuel pressure regulator (FPR) and stock mass airflow sensor (MAF). Does not require upgraded rods or pistons.


  • Dyno Proven 286 WHP & 355 WTQ (Gains of 100 WHP & 160 WTQ Over Stock AAN)
  • Broader Powerband & Improved Throttle Response
  • 27 PSI Boost Peak, Tapers to 19 PSI at Redline
  • Redline Increased to 7200 RPM
  • Air/Fuel Ratio:
    • 11.5-11.8 Under Boost
    • 14.7 Under Light Load & Idle Conditions.
  • Recommended for 91-93 Octane Fuel.

What's Included:

  • 034EFI GT28RS Stage 1 Chipset (Boost & Timing/Fuel Chips)

Required Supporting Modifications:

  • Bosch 550cc EV14 Fuel Injectors (Set of 5)
  • CNC-Machined Injector Adapters (Set of 5)
  • EV1 to EV14 Injector Connector Adapters (Set of 5)
  • 034EFI VariMAP with Installation Accesories
  • 034EFI 1.9 BAR Wastegate Spring

Recommended (Optional) Supporting Modifications:

Please Note:

  • If you are looking for a complete tuning solution, see out GT28RS Stage 1 Tuning Package here.
  • If your ECU is already socketed, then we can ship you the Chip Tuning Package to install yourself with included instructions.
  • This tuning package is not compatible with the 3B ECU.

Note: We now only ship chips which can be installed by the user or an ECU specialist, we no longer offer the service of shipping in ECU's and modifying them.




  • This product is sold for racing and off-road use only.
  • This product is not CARB or EPA compliant, this product is not authorized for use in California on smog controlled vehicles.
  • By purchasing this product, you understand this product is sold for competition use on closed roads and is not legal for use in highway or street vehicles.