› Programming fuel cut-off

Overrun fuel cut-off has been installed as standard in classic combustion engines since around 1980. Initially, fuel cut-off was used in diesel engines, but later the technology was also used in petrol engines.

The overrun cut-off serves to reduce CO2 emissions, can reduce fuel consumption and thus improves the efficiency of diesel or petrol engines. Because in overrun and with an engine speed above idle speed, the fuel supply is completely cut off as soon as the driver stops accelerating. The fuel supply is only restarted when the engine speed drops to the level of idle speed, so as not to stall the engine.

In this way, a diesel or petrol engine works completely without emissions at this moment – solely due to the thrust or inertia. Comprehensible and easy to test with a quick look at the current consumption display. However, overrun cut-off is not to be confused with “sailing mode”. Here the vehicle automatically switches to neutral – with some current automatic transmissions.

“The map for the sound”

AMG sound tuning by performmaster

• For AMG vehicles with OPF
• For C / E / S / G Class
• Programming on control unit
• Retrofit possible at any time
• Motor protection function is retained
• incl. “Missfire” and “Burble”
• Volume can be individually programmed depending on the driving mode

When programming fuel cut, the fuel supply is not cut off. At this moment, the misfires (pop & bang) and the “bubbling” in the exhaust system are generated. The exhaust valve is then already open and this means that combustion not only takes place in the cylinder but also in the manifold, the downpipe or in the catalytic converter. This produces the desired sound (“thrust popping”). Important to know: The fuel cut-off is not completely deactivated, only with a time delay.

The programming of the overrun cut-off not only produces the so-called overrun popping, the reprogramming also helps to maintain the boost pressure of a turbo engine for longer (also known as an anti-lag system). Because when the gas pedal is released, the turbo loses its pressure. When accelerating again, it takes some time before the turbo is fully pressurized again and thus also until the engine delivers full power again.

When the fuel cut-off is programmed and additional fuel is injected, the turbo paddle wheel continues to rotate even after the accelerator pedal is released. Since the combustion is maintained, i.e. the exhaust gases can also flow through the turbocharger, the turbocharger also maintains its speed.

The vehicle simply reacts faster when accelerating and responds more directly, since the turbocharger does not have to be brought up to speed again. This reduces the response time and thus the annoying turbo delay (turbo delay). Anti-lag systems can also be found in motorsport.

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New tuning of the motor control

The programming of the overrun cut-off is not carried out via VCDS with performmaster, but through a completely new coordination of the engine control in overrun mode. And with performmaster you get more: In addition to the desired overrun popping, it is possible to deactivate the overrun cut-off only in certain AMG driving modes.

In order to achieve the desired burble effect, performmaster uses special ignition maps with which all factors such as duration, volume, activation delay can be controlled.

We are able to activate and optimize these presets according to customer requirements without overriding the standard protective functions of the engine control unit.

“Thrust cut-off” is often also found as a crackle map, “crackling”, “exhaust noise”, “bubbling”, misfiring (missfire) , Anti-Delay System/ALS (Anti-Lag System)

Your AMG tuning: We are happy to advise you!

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