Audi RS3 8VStage 1 to Stage 4 tuning guide

A new file on the factory ECU, flashed through the OBD port. The five-cylinder responds unusually well: APR's Stage 1 alone claims 459–542 hp depending on fuel, and the top figure is on E85. These figures are for the 2017+ RS3 with the EA855 EVO engine; the earlier 2015–2016 European cars use the older engine and different files.

Stage 1 tunes compared

Recommended with Stage 1

• Intercooler upgrade strongly recommended Wagner TuningAPR034MotorsportCTS TurboUnitronic

  The factory intercooler on this car is small. APR says upgrading it is highly recommended even at Stage 1, because heat is what pulls power first.

• Gearbox (TCU) tune recommended APR034MotorsportUnitronic

  The 7-speed S tronic is strong, but a gearbox tune raises clutch clamping and sharpens shifts for the extra torque.

• Colder spark plugs recommended APR

  Tuners recommend colder plugs to prevent misfires at higher boost.

Stage 2 frees up the exhaust after the turbo and runs a file written for it. APR's Stage 2 claims 499–574 hp and 468–530 lb-ft with its inlet, intercooler, downpipe and midpipe.

Stage 2 tunes compared

Parts list

• Downpipe required APR034MotorsportCTS TurboAWE TuningMilltek SportUnitronic

  APR's Stage 2 figures are with its Race downpipe. Race downpipes usually have no catalytic converter, which is not road legal in most countries. If you need to stay legal, buy a catalysed version and expect slightly lower figures.

• Turbo inlet and intake required APREventuri034MotorsportIEUnitronic

  The factory inlet is a restriction on the five-cylinder's turbo at Stage 2 airflow.

• Intercooler upgrade required Wagner TuningAPR034MotorsportCTS TurboMishimoto

  Already recommended at Stage 1, required here.

• Midpipe or cat-back exhaust recommended APRAWE TuningMilltek Sport034Motorsport

  Part of APR's Stage 2 hardware list, and the biggest change to the five-cylinder's sound.

• Upgraded high-pressure fuel pump for Stage 2+ APRAutotech

  APR offers a Stage 2+ file for cars that add an upgraded high-pressure pump.

This is where the RS3 becomes a drag car. APR's Stage 3 file is designed for the TTE700 or a Garrett GTX3582 turbo, 980cc port injectors and a 500 LPH low-pressure fuel pump on E85, and APR's test cars have made over 700 hp on the stock engine internals.

Parts list

• Big turbo required TTEPure TurbosCTS Turbo034Motorsport

  The TTE700 and GTX3582-based kits are the common choices that off-the-shelf Stage 3 files support.

• Port injection and low-pressure fuel pump required 034MotorsportIECTS TurboAPR

  A big turbo on E85 needs far more fuel than the direct injectors can deliver.

• Stage 3 tune required APR034MotorsportEQT

  The file must match your turbo, injectors and fuel exactly.

• Gearbox clutches and TCU tune required Dodson (DSG clutch packs)APR (TCU tune)

  At this torque the stock gearbox clutches are the limit, not the engine.

Because the stock 2.5 already survives well past 700 hp, Stage 4 on an RS3 only starts beyond that. Builders fit forged rods and pistons for extra safety margin and higher boost, together with a larger turbo and a fully custom tune. These are community build ranges, not product claims.

Parts list

• Forged pistons and steel connecting rods required IEJE PistonsWiseco

  Sold as matched sets for the five-cylinder. Choose the compression ratio with your tuner.

• Custom dyno tune required EQT034Motorsport

  Off-the-shelf files stop at Stage 3. Every Stage 4 car is tuned on its own.

• Driveline, cooling and brakes required Dodson (DSG clutch packs)Wagner Tuning

  Gearbox, rear drive, cooling and brakes all have to keep up with the engine.