engine mapping is a management file. This file consists of ECU instruction tables. This control unit manages the engine and ensures its optimal functionality. It can be modified by reprogramming the engine.
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Why modify engine mapping
Modifying engine mapping allows replacing the manufacturer’s predefined settings with optimised settings. Several objectives can be pursued:
- Increase power or torque at a specific range
- Reduce fuel consumption...
- And so on.
Improving engine performance
Mapping provides access to the control unit's data. Consequently, it is possible to modify this data to optimise your engine.
Modifying engine power
Since the early 2000s, injection systems (injector opening time, injection pressure, etc.) have been managed by the engine control unit (ECU).
Modifying engine mapping therefore involves changing these values, which will vary differently depending on the engine speed.
The maximum power increase is estimated at over 60%, without damaging the engine.
Reprogramming the ECU thus improves performance to gain engine power and torque.
Modifying fuel consumption
Engine fuel consumption can also be altered by changing the mapping.
Indeed, by modifying injection system parameters, fuel consumption can be adjusted to suit personal driving habits, reducing consumption. These changes typically result in an average 30% reduction in fuel consumption.
Switching to ethanol E85
Modifying engine mapping allows changing the parameters of the engine control unit. By altering these parameters, it becomes possible to adjust the number and duration of injections, enabling the engine to support ethanol.
What tools to use?
Any modification to engine mapping requires appropriate equipment.
- OBDII cabling: To connect diagnostic tools compliant with the OBD2 standard, an adapter is needed for vehicles without a compliant port.
- Diagnostic tool: allows monitoring the effectiveness of the mapping changes, detecting faults to avoid causing irreversible engine damage.
- Power bench: enables precise evaluation of the car's performance. It facilitates an engine assessment by comparing measured values with the manufacturer's reference values (OECD power measured at the power take-off, hourly and specific consumption).
This test helps detect potential injection issues (pump, injectors), filtration problems, etc.
The power bench test also identifies the optimal speed range (consumption/power).
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How to change engine mapping?
To modify your engine's mapping, you need to reprogram the engine, during which you will adjust the engine control unit parameters.
The method to follow
Modifying engine mapping is a four-step operation.
Step one: Vehicle diagnostics
Before any mapping modification, it is essential to perform a preliminary vehicle diagnostic to observe its usual functioning and address any faults.
This is a crucial first step to ensure the mapping change proceeds smoothly.
Step two: Power bench test
The vehicle must then be placed on a power bench to accurately measure its original capabilities.
By precisely measuring the engine's original capabilities, modifications can be calculated and planned in advance, whether for power gains, fuel savings, or even a fuel change!
Step three: Adjusting control unit parameters
This is the longest step, changing the mapping by modifying the control unit parameters (based on the previously obtained results).
Step four: Verifying modifications
Finally, a final diagnostic must be performed to verify the effectiveness of the modifications and address any faults that may have arisen.
Professional mapping modification
For such modifications, it is advisable to consult professionals. Moreover, with growing demand for this service, there are plenty of garages offering it.
DIY mapping modification
It is possible to modify the mapping yourself, provided you know how to use the diagnostic software and understand the vehicle's original codes and parameters. However, DIY mapping changes come with risks.
Indeed, improper handling could damage the engine. Risks range from uncontrolled overconsumption to engine failure.
This is why, although accessible to individuals, this operation is strongly discouraged for novices.
Cost of this operation
The cost of professional reprogramming generally ranges between €400 and €2,500, depending on the car model.
You can always reduce costs by doing it yourself, but ensure you can handle all the steps without issues.
What are the risks of reprogramming?
Although very appealing, this operation does carry some risks.
Incorrect handling
Without perfect mastery of the software, it is possible to excessively modify engine parameters, potentially causing irreversible damage (if the engine's original parameters were not copied and saved).
Legal risks
Changing the mapping alters the vehicle's power, so the registration certificate must be updated
Insurance implications
Unfortunately, your insurance may no longer cover you in the event of an accident because if the vehicle no longer matches its original registration, the modifications made, especially the power increase, change the insurer's risk assessment.
Our advice? Ask your insurer before doing anything irreversible.
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In conclusion
Mapping manages engine parameters. Modifying the mapping therefore means altering the engine's capabilities.
This practice is now accessible to everyday car owners. For €400, you can modify your car's mapping to gain horsepower and torque.