An add-on module sits in the injection circuit and lengthens the injector opening time. That is all it can do, and it is precisely this limitation that allows it to be type-approved. It does not touch ignition timing, cold-start phases or the ECU's adaptive corrections.
Yet most of the gain lies in the ignition. Ethanol resists knock far better than petrol, which allows considerably more ignition advance. That is where efficiency, torque and fuel economy come from. A module leaves this margin entirely untapped, because it cannot reach it. A map goes after it, engine speed by engine speed and load by load.
Oil dilution follows the same logic. It occurs when poorly burnt fuel runs down the cylinder liners and reaches the sump, typically during cold starts and on short journeys, when the engine never reaches operating temperature. Since ethanol requires around a third more fuel, indiscriminate enrichment inevitably makes the problem worse. A map, on the other hand, knows which phase the engine is in: it modulates cold enrichment, adjusts injection phasing and manages the warm-up.
Finally, a map works with the ECU, not against it. A module deliberately distorts the injection signal; the ECU, which constantly monitors the mixture via the oxygen sensor, tries to correct what it perceives as a drift. The two systems fight each other, the adaptation values hit their limits, and faults sometimes end up appearing. With remapping, there is only one conductor.
| Criterion |
Remapping |
Add-on module |
| Adapted ignition timing | Yes | No, technically impossible |
| Efficiency and extra consumption | Optimised across the whole range | Flat-rate enrichment |
| Performance | Improved | Maintained at best |
| Cold starting | Managed by the map | Not managed |
| Risk of oil dilution | Greatly reduced | Increased on short journeys |
| Hardware added under the bonnet | None | Module and wiring harness |
| Reversibility | Return to the original file | Removal of the module |
| Type approval and registration document | No type-approval framework | Type-approved module: registration document (carte grise) can be amended |
We do not sell a single solution; we master both: that is why we can tell you frankly where each one reaches its limits. The last row of the table is the only one where the module comes out ahead, and we would rather state it than keep quiet about it.
That is also why we do not automatically switch indirect injection engines to a module, contrary to common practice. We first examine what your ECU allows: whenever remapping is feasible, we give it priority, because the result is better both for the mechanics and for your budget.
