Philosophy / Engineering Engine tuning and performance upgrades have a long tradition at AC Schnitzer. To be on the safe side however, we prefer not to extract the maximum possible power but instead ensure greater robustness, which means a longer life of the engine. Many of our performance upgrades are therefore designed for an increase in torque rather than an increase in horsepower. Because torque is what you feel when for example you're "pressed back in the seat" on pulling away. Diesel The performance upgrade consists of a control unit for retrofitting into the vehicle. The control unit ensures that the data is processed depending on the speed and accelerator pedal position and passed on to the injectors. The injection times of the injectors have been changed by us, resulting in a performance increase of up to 20% depending on the model. This increase in performance results from longer injection times, which means more fuel enters the combustion chamber. This results in a higher efficiency of the engine. During development, it is checked in which speed range the highest torque increase is achieved. This is followed by a controlled reduction of the changed parameters for the high speed range >5000 rpm. This prevents the engine from overheating during long, fast journeys. The standard protection parameters for the engine are retained with the AC Schnitzer performance upgrade. In addition, the AC Schnitzer performance increase also has extensive additional parameters for protecting the engine and drive train, such as cold-start and overheating control. Cold Start Control The AC Schnitzer performance upgrades are only activated from approx. 1000 rpm and from an oil temperature of 80° C. Overload / Overheating Control From a water temperature of 115° C, the output is automatically regulated back to the series output. Extensively tested AC Schnitzer performance upgrades undergo extensive test series on race tracks, test benches and in daily traffic. These test series last up to 9 months and several 10,000 km. Warranty Performance upgrade installed - what happens to the warranty? For all AC Schnitzer performance upgrades, AC Schnitzer provides a warranty depending on your home country up to 5 years and up to 120,000 km mileage on the assemblies moved by the engine. For M models, this warranty ends at 80,000 km. The warranty is free of charge for our customers. This gives you reassurance in the event of an incident. Here you can find the complete Warranty Conditions. Homologation Certificate The parts homologation certificate is an official document which allows the use of tuning parts in public road traffic within the framework of the (StVZO) German road traffic licensing regulations (and some other countries). After installation or conversion of the part described in the certificate, the vehicle must be presented to an official inspection body. The inspector determines the correct installation and the authenticity of the part and subsequently enters the modification in the vehicle documents. The official operating license of the vehicle thus remains in force. The parts homologation certificate is part of the scope of delivery. Uniqueness of the AC Schnitzer performance upgrade - Additional control unit with programming - "Plug & Play" - Optimized motor efficiency - more performance = improved agility - Warranty: 3 years in Germany - up to 5 years internationally - Here you can find our complete Warranty Conditions. - homologation certificates for almost all performance upgrades - Increasing torque is more important than increasing horsepower - No need for maximum power to ensure the stability and longevity of the engine - extensively tested - Increased driving pleasure