Throttle cut
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Definition
Throttle cut is any condition which causes the ECU to reduce the throttle pedal angle, even if the actual accelerator pedal potentiometer is at WOT.
The two main causes of throttle cut are
- ESP activity (a.k.a. traction control)
- The ECU senses that one or more wheels are losing traction. It does this if ESP is enabled and the ABS wheel sensors show a large discrepancy in wheel speeds.
- Boost deviation
- Actual boost pressure exceeds desired boost pressure by around 200-230mbar (3-3.3 psi). The ECU will only restore throttle angle once actual boost pressure falls to at or below the desired boost pressure.
Examples
Throttlecut.csv shows a 3rd gear run where the ECU cuts throttle.
Notice the throttle plate angle drops suddenly from 100% to 43%-48% when the deviation goes over ~200mbar.
| TIME | RPM | Throttle Plate Angle | Boost Pressure Desired | Boost Pressure Actual | Deviation |
|---|---|---|---|---|---|
| 497575 | 4025.75 | 99.6078431372549 | 2327.109375 | 2490.625 | |
| 497645 | 4046.75 | 100 | 2315.1953125 | 2508.90625 | 193.7 |
| 497716 | 4114 | 100 | 2302.1484375 | 2503.0859375 | 200.9 |
| 497786 | 4151.5 | 99.6078431372549 | 2271.1328125 | 2508.2421875 | 237.1 |
| 497856 | 4200.5 | 45.8823529411765 | 2263.1640625 | 2488.203125 | 225.0 |
| 497926 | 4230 | 43.921568627451 | 2248.3984375 | 2457.65625 |
Notice the throttle does not return to 100 until the boost pressure actual returns to almost exactly the boost pressure desired.
| TIME | RPM | Throttle PlateAngle | Boost Pressure Desired | Boost Pressure Actual | Deviation |
|---|---|---|---|---|---|
| 499748 | 5183 | 48.2352941176471 | 2200.546875 | 2222.8515625 | |
| 499819 | 5211 | 48.2352941176471 | 2208.0078125 | 2226.5625 | 18.6 |
| 499889 | 5246.5 | 48.2352941176471 | 2216.2109375 | 2217.34375 | 1.1 |
| 499959 | 5294.5 | 77.6470588235294 | 2220.234375 | 2194.8046875 | -25.4 |
| 500029 | 5319 | 100 | 2227.1875 | 2166.2109375 |