The automotive industry faces unprecedented pressure to address stringent emissions regulations, evolving consumer expectations, and the urgent need for sustainable mobility solutions. As the global fleet transitions toward lower environmental impact, there is an increasing demand for engineering innovations that can rapidly and cost-effectively modernize existing vehicles. This paper presents a quantitative control-variable analysis, attributing ECU remapping, hardware upgrades (capability envelopes), and water–methanol injection contributions in a production compression-ignited retrofit, achieving 211% power scaling alongside −18% NOx/−30% opacity compared to baseline values. The study specifically investigates the implementation of ECU tuning, hardware modifications, and auxiliary systems such as WMI, demonstrating their vital role in enhancing vehicle performance, reducing emissions, and extending the operational lifespan of current fleets. By providing actionable engineering solutions, this work supports the industry’s urgent transition to more sustainable and efficient mobility, positioning retrofitting as a cornerstone of future automotive development and environmental compliance.
Suciu et al. (Mon,) studied this question.