The overrun fuel cut-off serves to reduce CO₂ emissions, can lower fuel consumption and thus improves the efficiency of diesel or petrol engines. In overrun mode and with engine speed above idle, the fuel supply is completely cut off as soon as the driver lifts off the throttle. Only when the engine speed drops to idle level is the fuel supply restarted to prevent the engine from stalling.
In this moment, a diesel or petrol engine runs completely without emissions — driven solely by momentum and inertia. This is easy to verify with a quick glance at the current consumption display. However, the overrun fuel cut-off should not be confused with the 'sailing mode', where the vehicle automatically shifts into neutral — a feature found in some current automatic gearboxes.
During the reprogramming of the overrun fuel cut-off, the fuel supply is not interrupted. In this moment, misfires (Pop & Bang) are generated and the 'burbling' in the exhaust system. The exhaust valve is already open, which means that combustion takes place not only in the cylinder but also in the manifold, downpipe or catalytic converter.
This produces the desired sound ('overrun bang'). Important to know: the overrun fuel cut-off is not completely deactivated — only delayed.
The reprogramming also helps maintain boost pressure for longer — the turbo's impeller continues to spin even after the throttle is released, eliminating turbo lag.
The vehicle responds faster when accelerating — the turbocharger retains its speed, reducing response time and eliminating the annoying turbo delay found in standard setups.
At performmaster, reprogramming is carried out through a completely new calibration of the engine management in overrun mode — not through generic VCDS solutions.
It is possible to deactivate the overrun fuel cut-off only in certain AMG driving modes — giving you full control over when the sound activates.
All presets are activated without overriding the standard protection functions of the engine control unit.
performmaster uses special ignition maps with which all factors — duration, volume and activation delay — can be precisely controlled and individually configured per driving mode.
"Overrun fuel cut-off" is also known as Crackle Map, "crackling", "exhaust bang", "burbling", misfire, or Anti-Lag System (ALS).
Call us or send us an email. You can also reach us via our contact form.
Phone: +49 7181 / 80 74 17 · Email: info@performmaster.de
The PEC Performance System unites all AMG performance upgrade advantages in just one module: increased performance and Vmax delimiter. The operational safety of your Mercedes-AMG comes first. Because the PEC Performance System starts when the engine temperature of your Mercedes-AMG is sufficient. Significant advantages over a classic ECU performance calibration for a Mercedes-AMG.
Just like a classic AMG performance upgrade, the upgrade with a PEC Performance System is active immediately after installation: more horsepower and more torque for your Mercedes-AMG. As simple as the installation is, so easy is also the retro-fitting in stock performance. Performance upgrade for your Mercedes-AMG with the PEC Performance System by performmaster with the innovative CAN-Bus technology. Select your Mercedes-AMG here.