The best updates for the Gen 2 4.0t [EA825]
Audi’s 4-liter biturbo v8 has been in production since 2012. The first generation of this engine (designated EA8124, which we covered here) powered the flagship A8 as well as the S/RS variants of the A6 and the 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 horsepower of between 500 and 641.
So far this engine has proven to be an amazing platform. It is capable of incredible power with minor modifications, and with more work, an output of over 1000 horsepower can be obtained.
We’re going to run through the best current (2023) mods for the EA825 platform, so you’ll have an idea of what you can expect to get out of your car when you’re ready to start modifying it.
What cars use the EA825?
The set of vehicles that use the EA825 is different from the previous generation. The S6 and S7 no longer use the 4.0t. In its place, Audi’s new performance-focused SUVs, the SQ7, SQ8 and RSQ8 are powered by the EA825. The RS7, S8 and the new RS6 Avant also use it. Outside of Audi, the Porsche Panamera, Lamborghini Urus and Bentley Continental use this engine.
The best updates for the 4.0t
The upgrade path for the EA825 is less complicated than the previous generation. This is because the second generation 4.0t is only offered in a turbo size, meaning an OEM upgrade is not possible (RS7 turbos in an S7).
ECU Tune (Stage 1)
By far the best upgrade to this engine (really any turbo engine) is an ECU tune. On all platforms except the Urus, an ECU tune can generate up to 265 horsepower and 265 torque on an E40 fuel mix. Gains will vary significantly depending on the fuel used, but even with 91 octane, you can get over 100 horsepower and 150 torque.
intake
The EA825 is unique in that an intake system produces absolutely massive power gains. On most vehicles, an intake system provides a small performance boost, a better induction sound, and an aesthetic upgrade.
APR, Eventuri, Integrated Engineering and Unitronic offer intake systems for the 4.0t, with potential gains of 60-80 horsepower on tuned engines. In this platform, an intake system is a very good investment to improve power.
Stage 2 downloads and tunes
For vehicles that are intended for off-road use, upgrading the OEM downpipes to looser aftermarket units will allow the car to return to what is considered stage 2 service. With the downpipes and improved tuning, you can expect to see more than 800 horsepower from the EA825. Please note that downloadable updates 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 have to come out. The upgraded turbos available for this engine are hybrids, meaning they retain an OEM look, but use a larger compressor and turbine wheel. Larger internals allow the engine to move more air and, as a result, produce more power.
Unitronic and Integrated Engineering have, or are developing, software and hardware to support hybrid turbos manufactured by TTE. With an accompanying tune, hybrid turbos can produce more than 930 horsepower and 830 lb-ft of torque.
Modes of support
The upgrades, above all, significantly improve the EA825’s power output. The following section highlights some support mods that help make this power consistent and safe.
Intercooler upgrades
Factory intercoolers are not capable of maintaining low intake air temperatures on tuned vehicles. Combine that with the hot summer weather and the heat soak and the loss of energy is inevitable. The EA825 uses two intercoolers. Upgrading to larger, more efficient units will keep your engine making consistent power pull after pull.
TCU Tune
Some tuning companies require a TCU tune on all stages, and some only require it for higher outputs. TCU software optimizes transmission shift points, increases clutch holding pressure and ensures the gearbox can safely handle the increased load placed on it.
Get your EA825 Tuned at Alex’s Autohaus!
If you live in Utah and drive an Audi, Porsche Panamera, Bently, or even a Lamborghini, visit Alex’s Autohaus! Our tuning experts will provide you with the guidance you need to achieve the power goals you have for your vehicle. Ready to take the plunge? Call us or schedule an appointment today!
