Eco Tuning: economy remap for lower fuel consumption

Eco Tuning is an ECU calibration for fuel economy: boost and torque are added at low and middle rpm so the car pulls comfortably one gear higher. In our database the option is mostly available for diesel ECUs: Bosch EDC and MD1, Continental SID, Delphi. For tuners: send the original file and get a ready-to-flash file with corrected checksums, on average in 30–60 minutes.

Why an engine is more economical at lower revs

The fuel an engine burns per unit of work is not constant. Plot it on a map of engine speed against load and you get islands. A diesel is most efficient at low to middle revs and high load, where good passenger-car diesels use about 200 g of fuel per kWh. At high revs and light load a noticeable share of the fuel goes into friction and pumping gas in and out, and the same kilowatt costs more.

The same power can be produced in different ways: one gear lower at high revs and light load, or one gear higher at low revs and higher load. In the second case the engine runs closer to its best island. At low revs, though, a stock diesel often lacks torque: the turbo has not spooled up, the smoke limiter holds fuel back, and the driver changes down. Eco tuning adds torque in exactly that zone.

What changes in the file

• Boost at low rpm: a higher target, reached earlier, so the turbo comes on sooner.
• Torque at low and middle rpm: the pedal map and torque limits in that range.
• Fuel for the extra air: fuel is added only as far as it can be burned without smoke in the air the boost provides.

Peak power is not the aim of this calibration, that is what Stage 1 is for. EGR, the particulate filter and AdBlue keep working unless they are disabled with separate options. Sensors and the ECU's logic stay as they are.

How much it really saves

Sellers of eco remaps usually promise 10–15%, sometimes up to 20%. Those are their own figures: ADAC, Germany's largest motoring club, says it has no reliable neutral studies of savings from eco tuning. The physics works in the file's favour on one condition only: the driver uses the extra torque to run at lower revs. Spend it on harder acceleration and the extra fuel eats the whole saving.

Cars that run at a steady pace have the best chance: motorway driving, long routes, commercial vehicles with regular drivers. On short urban trips the effect is usually smaller. The only way to check the result is on your own car:

The trip computer shows a calculated figure. For a before-and-after comparison, brim-to-brim fill-ups and odometer mileage are more reliable.

Who Eco suits and who it does not

How Eco differs from Stage 1

Both calibrations work with the same torque and boost maps, but with different goals. Stage 1 raises power and torque across the rev range, while Eco adds torque where the engine spends most of its everyday driving. If the hardware has been modified, you are looking at Stage 2.

Extra torque low down loads the clutch and dual-mass flywheel like any tune, so check them before flashing. On an automatic, the gearbox control unit chooses the gears and the engine file does not change its strategy: the saving depends on how the gearbox uses the extra torque.

How to order the file

1. Read the original file via OBD or on the bench with the tool you use, and keep a copy.
2. Upload it to the portal and select ECO TUNING. In the comment, state the gearbox and how the car is mostly driven: motorway, town, loaded.
3. Get the finished file with recalculated checksums, on average within 30–60 minutes.
4. Flash the file, clear the faults and compare consumption over several fill-ups.

If your ECU is not in the list below or in our ECU database, send the file with a request: we will check the software and tell you whether Eco is possible.