Stage 1 remap: ECU tuning on stock hardware

Stage 1 is an ECU calibration for stock hardware: the torque, boost, fuel and timing maps are reworked and the factory limiters raised, with no mechanical changes. On turbocharged engines that usually means 15–30% more power, on naturally aspirated ones no more than 5–10%. Some gearboxes, DSG among them, have their own Stage 1: a shift calibration. For tuners: send the original file and get a ready-to-flash file with corrected checksums, on average in 30–60 minutes.

Where the headroom in a stock engine comes from

Factory calibrations are written for the worst case. The engine has to run the same in summer heat and at altitude, on fuel of varying quality, meet emissions limits and outlast its design life with margin to spare. For that the software carries separate limiters: for ambient pressure, for intake air, coolant and oil temperatures, for smoke and for the gearbox.

Sometimes it is simpler than that: one engine is sold in several power outputs, and the difference comes down to software or small parts such as injectors and the intercooler. Stage 1 takes part of that margin, raising the limits to where the engine, turbo and drivetrain still have reserve. The hardware stays stock, so the gain is capped by what that hardware can do.

How the ECU decides how much torque to deliver

On control units from the last twenty-odd years (Bosch ME7 and MED17, EDC16 and EDC17, Continental SID and Simos and others) the accelerator pedal does not control fuelling directly. Pedal position and engine speed are turned into a torque request in Nm. The request is checked against a set of limiters and the ECU takes the lowest value. Only then is torque turned into commands: how much fuel to inject, what boost and timing to run. Older EDC15 units are built around injection quantity rather than torque, but their limiters do the same job.

The limiters a torque request passes through:

• Gearbox protection. The engine ECU holds torque limits, including per gear, and the transmission control unit can ask for a torque cut over CAN, for example during a shift.
• Smoke limit (diesel). How much fuel can be burned in the air that is in the cylinder right now. Until the turbo spools up, this is the limit that holds torque down at low rpm.
• Overheating. Based on calculated and measured temperatures, a diesel cuts fuel, while a turbo petrol engine enriches the mixture to keep exhaust temperature within limits.
• Limiters and corrections. The rev and speed limiters and the correction for ambient pressure, in other words for altitude.

From there diesel and petrol go separate ways. A diesel ECU converts torque into injection quantity per stroke and, based on it, picks rail pressure, injection start and duration, and the boost target. A petrol ECU works out the cylinder filling needed for that torque, and from it the boost to run and the throttle opening. Ignition timing is set with an eye on knock.

What changes in the file and what stays

Stage 1 edits calibration data: maps and limiters, while the ECU's algorithms stay the same. A typical file has anywhere from five to twenty maps changed, depending on the ECU and the engine.

Sensors and actuators stay as they are. EGR, the particulate filter, the catalytic converter and AdBlue keep working unless they are disabled with separate options. The rev limiter and the speed limiter are left at factory values. The gearbox control unit is flashed separately: it keeps its own torque limit whatever is written to the engine ECU.

How much Stage 1 adds

These are guidelines: the result depends on the engine, its condition, the fuel and the gearbox. Engines that already run close to their limit from the factory gain less. Figures for specific engines are collected in our Stage 1 and Stage 2 figures database.

What to check before flashing

Software does not fix faults, and the extra load exposes them quickly. Before Stage 1, go through this list:

• Fault codes in all modules and their history, especially for boost, rail pressure, misfires and knock.
• Boost under load: actual against specified, intake leaks, MAF readings.
• Diesel: injector corrections, rail pressure actual and specified, DPF differential pressure and ash load, EGR condition.
• Petrol: spark plugs and coils, knock retard, lambda adaptations.
• Clutch: in a high gear from low rpm, floor the throttle. If the revs rise faster than road speed, the clutch is slipping, and the tune will make it worse.
• High-mileage engines: compression and oil condition.

What to look at in the logs after flashing

Clear the faults and log a long pull in third or fourth gear. Watch these values:

• Boost: actual follows specified with no dips or overshoot.
• Rail pressure (diesel): actual holds specified all the way to the limiter.
• Knock retard (petrol): occasional events are normal; constant retard on several cylinders means checking the fuel and the plugs.
• Intake air temperature and, if there is a sensor, exhaust gas temperature.
• Fault codes after the drive, including in the gearbox module.

If boost falls short or the engine goes into limp mode, the cause is most often found in the hardware: an intake leak, sticking turbine vanes, a weak high-pressure pump. Describe what the log shows in the order and we will look into it.

Clutch, gearbox and engine life

Extra torque loads everything behind the engine: the clutch and dual-mass flywheel, the gearbox, the driveshafts. A worn clutch will be the first thing to slip after Stage 1, so check it before flashing.

Automatic and dual-clutch gearboxes have a rated torque limit. VW, for example, specifies the 7-speed DSG 0AM (DQ200) for engines up to 250 Nm and the 6-speed 02E (DQ250) for up to 350 Nm depending on the engine. The gearbox control unit knows its limit and will still restrict torque if the engine asks for more. The limit inside the gearbox is raised by a separate option, Torque Unlock, and that only makes sense if the particular gearbox has margin.

Engine life and fuel use depend mostly on how the car is driven. Use all of the extra power all the time and the turbo, pistons and clutch wear faster, and consumption goes up, because extra power comes from extra fuel. Driven as before, the car uses about as much fuel as it did. Keep servicing in mind as well: a dealer may spot modified software and refuse warranty on the engine or gearbox, and a software update at the dealer often wipes the tune.

Stage 1 for the gearbox

In our database Stage 1 is also available for some gearbox control units, for example DSG DQ38x and DQ500. For a gearbox it is a separate file read from the TCU: a calibration of shifting and clutch pressures for an engine that makes more torque after its own tune. A stock gearbox is set up for factory torque and for economy: in D many gearboxes change up early, and clutch pressures are calculated for the factory engine.

What can be changed depends on the gearbox and its software version. For DSG (DQ250, DQ381, DQ500) and ZF 8HP automatics, a gearbox Stage 1 usually covers:

The torque limit inside the gearbox is raised by the separate Torque Unlock option covered above. If only the pressures need changing, there is Oil Pressure Optimizations, which also explains in detail how the gearbox chooses its pressure. Before flashing, check the gearbox oil level and condition and the TCU fault codes; after flashing, reset the adaptations so the gearbox can relearn.

When Stage 1 is not the right choice

If the car already has a downpipe, a bigger intercooler or a different turbo, a stock-hardware calibration was not written for it, and you need Stage 2. When fuel consumption matters more than performance, Eco Tuning is the better fit: it adds torque at low and middle rpm so the car can run at lower revs. EGR, DPF and other disables are done in the same file, in one order with Stage 1.

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 STAGE 1. In the comment, state the gearbox (manual, DSG, automatic), the fuel (95 or 98 RON) and anything on the car that is no longer stock. Add any disables to the same order.
3. Get the finished file with recalculated checksums, on average within 30–60 minutes.
4. Flash the file, clear the faults and check the engine under load with a log.

If your ECU is not in the list below, send the file with a request: we will check the software and tell you whether Stage 1 is possible.