450 hp and 600 Nm factory. Those are already impressive figures for a daily-use estate. But the Audi RS4/RS5 B9 has more in it than Audi releases, and our own dyno proves it.
At MTR Performance, we fully built an Audi RS4 B9 2.9 TFSI for Stage 2 and then measured it on our Dynojet 424xLC2 4x4 power bench in Rhoon. The result: 510 hp and 840 Nm. That +240 Nm torque gain is what truly sets the RS4 apart after tuning across every rev range on the road.
What is possible with the Audi RS4 B9?
From 450 hp factory to about 520 hp at Stage 2: with the right combination of software, hardware, and fuel. The torque gain of +240 Nm is at least as impressive as the horsepower increase.
Exact results vary per vehicle, software version, fuel quality, hardware configuration, and measurement method.
Why the Audi RS4 & RS5 B9 is so interesting for tuning
The Audi RS4 & RS5 B9 is equipped with the EA839 2.9 TFSI V6 bi-turbo engine. Factory output is 450 hp and 600 Nm, a strong base that responds excellently to software and hardware optimization thanks to the twin-turbo setup.
What distinguishes the RS4 & RS5 B9 as a tuning platform:
- Proven EA839 V6 biturbo architecture with ample factory margin
- Quattro all-wheel drive, excellent traction even at higher power levels
- Automatic ZF 8-speed transmission with TCU tuning potential
- Impressive torque response, the biturbo delivers torque broadly and early
- Practical daily use as an estate combined with serious performance
Audi RS4 B9 Stage 2: our own dyno results
At Stage 2 tuning in addition to custom ECU software, hardware upgrades are also considered to make performance more consistent and reliable, and with the RS4 B9 and its V6 bi-turbo, these upgrades are essential.
Stage 2 hardware on our own RS4 B9:
- Eventuri Carbon Fiber air intake — maximum airflow with minimal intake temperature
- HF-Series Turbo Inlet Kit — optimized air supply to both turbos
- Wagner Tuning intercooler kit — 185% more cooling surface than standard
- Milltek Sport downpipes 200-cell racing catalysts
- Milltek Sport non-resonated catback
- Custom ECU tuning
- TCU AL552 tuning
Our own Stage 2 dyno results:
|
Configuration |
Power |
Torque |
|
OEM |
450 hp |
600 Nm |
|
Measured with hardware |
457 hp |
647 Nm |
|
Stage 2 |
510 hp |
840 Nm |
Increase: +60 hp & +240 Nm. Measured on a Dynojet 424xLC2 with RON98 fuel. TCU AL552 tuned.
The +240 Nm is the figure that surprises RS4 drivers the most. The V6 bi-turbo delivers this torque widely available over a large rev range — resulting in a car that feels immediate and effortless in every situation, not just at high revs.
View our complete Audi RS4 B9 Stage 2 project for all the details.
Why TCU tuning is essential for the RS4 & RS5 B9
The Audi RS4 & RS5 B9 comes from the factory with a ZF 8-speed automatic — a strong transmission, but with standard software not tuned for increased engine output.
TCU AL552 tuning is not an optional extra but an integral part of a well-built Stage 2 configuration for the RS4 & RS5 B9:
- Higher torque limits matching the increased engine output
- Sharper and faster shift points
- Better cooperation between ECU and transmission as one system
- More consistent power under load
In our own RS4 B9 project, the TCU AL552 tune is standard, and this is both visible in the measurement results and noticeable behind the wheel.
2.9 TFSI performance upgrades: what works best for the RS4 & RS5 B9?
After our RS4 & RS5 B9 projects, we have a clear picture of which 2.9 TFSI performance upgrades have the greatest impact.
Eventuri Carbon Fiber air intake The RS4/RS5 B9 engine bay heats up quickly. Eventuri improves this — from the turbo inlet to the front — redesigned as a sealed system that draws in cooler outside air. The result: better airflow and lower intake temperatures, even under intensive use.
HF-Series Turbo Inlet Kit The standard turbo inlet of the RS4/RS5 B9 is designed for production efficiency, not performance. The HF-Series version optimizes airflow to both turbos and removes the turbulence present in the standard system. Plug & play installation, measurable effect on the dyno.
Wagner Tuning intercooler kit The RS4 B9 uses a water-cooled charge air cooler: a system that quickly reaches its limit at higher power levels. The Wagner Tuning kit replaces this with a unit that offers 185% more external cooling surface. Essential for consistent performance at Stage 2.
Milltek Sport downpipes & catback Lower exhaust backpressure gives both turbos more room. The 200-cell racing catalytic converters maximize flow without MOT issues. Combined with the non-resonated catback, this results in a sound that does justice to the V6 biturbo.
Upgrade spark plugs At Stage 2 power levels, standard spark plugs are no longer sufficient for reliable ignition under higher cylinder pressure.
What determines the reliability of a tuned RS4 & RS5 B9?
Temperature management: The V6 bi-turbo of the RS4 & RS5 B9 produces significantly more heat at higher power levels. An upgraded intercooler and air intake are not a luxury but a necessity to achieve high power; without proper cooling, the ECU will automatically reduce power.
Fuel quality: RON98 fuel is required for Stage 2 on the RS4 & RS5 B9. The software is tuned for optimal performance and engine safety accordingly.
Maintenance: Engine oil, spark plugs, transmission oil and filters directly affect how consistently the tune performs in the long term. Check out our maintenance & repair service.
Professional tuning: Every car is tested and validated at MTR on our 4x4 dyno based on the measurement data of that specific vehicle.
Does tuning affect the factory warranty?
This depends on the manufacturer, dealer, and nature of the modification. Audi offers standard factory warranty on new vehicles, but software and hardware changes can affect warranty claims.
We always advise checking your vehicle’s warranty conditions before performing modifications.
Frequently asked questions about Audi RS4 & RS5 B9 tuning
How much hp can an Audi RS4 & RS5 B9 reach with Stage 2? Based on our own project, about 520 hp and 840 Nm on RON98 fuel, measured on a Dynojet 424xLC2.
Why is the torque gain so large on the RS4 & RS5 B9? The V6 biturbo EA839 naturally has a broad torque plateau. With the right hardware and software, this plateau becomes both higher and wider — hence the +240 Nm in our measurement.
Is TCU tuning necessary for Stage 2 on the RS4 & RS5 B9? Yes. The ZF 8-speed automatic needs modified software to properly handle the increased torque and work optimally with the ECU.
What fuel does a Stage 2 RS4 & RS5 B9 require? At least RON98 for optimal performance and correct software operation.
Is the RS4 & RS5 B9 also suitable for Stage 3? That depends on the desired power goals and willingness for further hardware modifications. Contact us for personalized advice.
Conclusion
The Audi RS4 & RS5 B9 is one of the most complete tuning platforms in the current Audi lineup, and our own Stage 2 results prove that.
More than 500 hp & 800 Nm from a V6 bi-turbo estate. That torque gain is what truly makes the RS4 & RS5 special after tuning: a car that responds instantly and effortlessly in every situation, at any RPM.
Want to know what’s possible for your Audi RS4 or RS5 B9? Contact us with MTR Performance or check out our Audi RS4 B9 Stage 2 project for all details from our workshop in Rhoon.
