Best Upgrades for the Gen 2 4.0t [EA825]
Audi’s 4-liter twin-turbo v8 has been in production since 2012. The first generation of this motor (designated EA8124, which we covered here) powered the flagship A8, as well as S/RS variants of the A6 and A7. In 2017 (Porsche Panamera), and 2020 (Audi models), the second generation 4.0t, designated EA825, replaced it. Depending on the vehicle, this engine has a base output of between 500 and 641.
So far, this motor has proven to be an incredible platform. It’s capable of unbelievable power with small modifications, and with more work, output over 1000 horsepower is obtainable.
We’re going to go over the current (2023) best modifications for the EA825 platform, so you have an idea of what you can expect to get out of your car when you are ready to start modifying it.
What Cars Use the EA825?
The pool of vehicles using the EA825 is different from the previous generation. The S6 and S7 no longer utilize the 4.0t. In their place, Audi’s new performance-focused SUVs, the SQ7, SQ8, and RSQ8 are powered by the EA825. The RS7, S8, and new RS6 Avant also utilize it. Outside of Audi, the Porsche Panamera, Lamborghini Urus, and Bentley Continental, all utilize this motor.
Best Upgrades for the 4.0t
The upgrade path for the EA825 is less complicated than the previous generation. This is due to the second gen 4.0t only being offered with one turbo size, meaning an OEM upgrade (RS7 turbos on an S7) is not possible.
ECU Tune (Stage 1)
Far and away the best upgrade for this engine (really, any turbocharged engine) is an ECU tune. On all platforms except the Urus, an ECU tune can net as much as 265 horsepower and 265 torque on an E40 fuel blend. The gains will vary significantly depending on the fuel used, but even on 91 octane, well over 100 horsepower and 150 torque is obtainable.
The EA825 is unique in the fact that an intake system yields absolutely massive power gains. On most vehicles, an intake system provides a small performance boost, better induction sound, and an aesthetic upgrade.
APR, Eventuri, Integrated Engineering, and Unitronic all offer intake systems for the 4.0t, with potential gains of 60-80 horsepower on tuned engines. On this platform, an intake system is a very good investment for improving power.
Downpipes and Stage 2 Tunes
For vehicles that are for off-road use, upgrading the OEM downpipes to higher flowing aftermarket units will allow the car to be reflashed to what is considered Stage 2. With upgraded downpipes and tune, you can expect to see over 800 horsepower out of the EA825. Keep in mind, downpipe upgrades will prevent you from passing emissions tests and may not be legal in all areas. This modification is for track vehicles ONLY.
Hybrid Turbos and Stage 3
To take the EA825 to the next level, the OEM turbos need to come off. The upgraded turbos available for this engine are hybrids, meaning they retain an OEM appearance, but utilize a larger compressor and turbine wheel. The larger internals allows the engine to move more air and make more power as a result.
Unitronic and Integrated Engineering both have, or are developing, software and hardware to support hybrid turbos made by TTE. With an accompanying tune, Hybrid turbos can produce over 930 horsepower and 830 lb-ft of torque.
The upgrades above all significantly improve the power output of the EA825. The next section highlights some supporting mods that help make that power consistent and safe.
The factory intercoolers are not able to maintain low intake air temperatures on tuned vehicles. Combine that with hot summer weather and heat soaking and power loss is inevitable. The EA825 uses two intercoolers. Upgrading them to larger, more efficient units will allow your engine to make consistent power pull after pull.
Some tuning companies require a TCU tune at all stages, and some only require it for higher outputs. TCU software optimizes the shift points of the transmission, increases the clamping pressure of the clutches, and ensures the gearbox can safely handle the increased load being placed on it.
Get your EA825 Tuned at Alex’s Autohaus!
If you live in Utah and drive a flagship Audi, Porsche Panamera, Bently, or even Lamborghini, stop in at Alex’s Autohaus! Our tuning experts will provide you with the guidance you need to reach the power goals you have for your vehicle. Ready to take the plunge? Give us a call or schedule an appointment today!