Stage 1

In engine tuning, stages describe how far a car moves away from factory condition. Stage 1 is the first step: the engine and its parts stay stock, and only the software in the engine control unit (ECU) is changed.

What a Stage 1 calibration changes

The ECU runs the engine from maps - tables that set how it responds to pedal position, load and engine speed. A Stage 1 file adjusts these targets within the limits of the factory hardware. Depending on the engine, that can include:

• boost pressure targets on turbocharged engines;
• fuel quantity and ignition timing to match the extra air;
• torque limiters that shape how power is delivered;
• throttle mapping, which sets how quickly the car responds to the pedal.

What stays factory

Turbochargers, intake, intercooler, exhaust and fuel system stay as they are. That is the difference from Stage 2, which pairs a calibration with upgraded parts. How much a Stage 1 adds varies by engine, fuel quality and the condition of the car, so compare figures for your exact engine rather than general numbers.

Before you tune

• Compatibility - the calibration has to match the engine and software version of your car, which is why tunes are listed by chassis code, model and year.
• Fuel and maintenance - use the fuel grade the calibration is written for and keep up with service.
• Warranty and emissions rules - engine software changes can affect warranty coverage, and some states, such as California, restrict modifications that affect emissions.
• Going back - MWMods tunes keep the option to restore the factory software.