I see this tossed around a lot on this forum, so lets put some of the "mystery" of over-boost (internally "overpower") to rest.
On the Ecoboost ECUs, Overboost is a complicated function. There's a normal torque table, and an overpower torque table.
The basics are, if your current torque is greater than the normal torque table plus an added hysteresis (5 N*m on all the EB I've seen), the overboost counter increments at a set "count up" rate.
If your torque drops below that normal table minus a hysteresis (50 N*m on all the EB I've seen), the overboost counter decrements at a set "count down" rate. While you're in Overboost, your torque maximum is set to the Overboost table. Once you exceed the counter, its forced to the "Normal" table.
Now, this counter goes up or down by 1 every time, but once it exceeds a preset max (20), it must count all the way down to 0 to reset again and allow overboost.
On most other Ecoboosts, the count up is at 1 second intervals, and count down at 0 seconds. This means as soon as your torque comes below the normal table 50Nm, overboost is instantly reset.
On the Focus RS, the count up is at 1 second intervals, AND the count down is at 1 second intervals. This means you get a combined time of 21 seconds in overboost, but once you go for 21 seconds, you must wait 20 seconds before overboost is available again. Its not an instant reset like on other Ecoboosts people maybe familiar with (Focus ST, Fiesta ST, Mustang EB) because of this count down time.
Now, as for what these torque targets are, you need to read into the ECU. I have looked at both a pre-production, the first release, and the current latest release for the RS in this regard. They all have the SAME overboost settings. Torque, timers, etc.
What are these torque levels? Well, here they are, pulled from the ECU. The ECU does this section in Newton meters, but because I'm a nice guy, I converted to freedom units for those of you who think better in those units! This isn't the only torque limit in the ECU you run into, but its the one in charge of a stock vehicle for the most part! (And yes, Overboost in reverse has a lower torque target at the very top. Why, who knows!)
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On the Ecoboost ECUs, Overboost is a complicated function. There's a normal torque table, and an overpower torque table.
The basics are, if your current torque is greater than the normal torque table plus an added hysteresis (5 N*m on all the EB I've seen), the overboost counter increments at a set "count up" rate.
If your torque drops below that normal table minus a hysteresis (50 N*m on all the EB I've seen), the overboost counter decrements at a set "count down" rate. While you're in Overboost, your torque maximum is set to the Overboost table. Once you exceed the counter, its forced to the "Normal" table.
Now, this counter goes up or down by 1 every time, but once it exceeds a preset max (20), it must count all the way down to 0 to reset again and allow overboost.
On most other Ecoboosts, the count up is at 1 second intervals, and count down at 0 seconds. This means as soon as your torque comes below the normal table 50Nm, overboost is instantly reset.
On the Focus RS, the count up is at 1 second intervals, AND the count down is at 1 second intervals. This means you get a combined time of 21 seconds in overboost, but once you go for 21 seconds, you must wait 20 seconds before overboost is available again. Its not an instant reset like on other Ecoboosts people maybe familiar with (Focus ST, Fiesta ST, Mustang EB) because of this count down time.
Now, as for what these torque targets are, you need to read into the ECU. I have looked at both a pre-production, the first release, and the current latest release for the RS in this regard. They all have the SAME overboost settings. Torque, timers, etc.
What are these torque levels? Well, here they are, pulled from the ECU. The ECU does this section in Newton meters, but because I'm a nice guy, I converted to freedom units for those of you who think better in those units! This isn't the only torque limit in the ECU you run into, but its the one in charge of a stock vehicle for the most part! (And yes, Overboost in reverse has a lower torque target at the very top. Why, who knows!)
