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Discussion Starter · #1 · (Edited)
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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That's a great write-up, and I appreciate it being based on concrete data - thanks!


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)
Hmm, that contradicts what they've said in every interview I've seen about it on the RS. I wonder if this was a late change?
 

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That's a great write-up, and I appreciate it being based on concrete data - thanks!




Hmm, that contradicts what they've said in every interview I've seen about it on the RS. I wonder if this was a late change?
thats NOT at all what ford sold this car saying... it was 20 seconds at a time, any time you mash it...
 

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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.
I think this explains TONS! The next question is, is it possible to remove the count down timer for the RS and if so, is it safe to do so. Thanks @Bugasu !
 

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Discussion Starter · #5 ·
I think this explains TONS! The next question is, is it possible to remove the count down timer for the RS and if so, is it safe to do so. Thanks @Bugasu !
It would be something tuneable. I know Cobb has it planned already on the chopping block :)
As for any way of doing it outside of a tune, I don't see it being a possibility.
 

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@Bugasu Thank you for the clarifying of what and when overboost works.

I find it interesting that it takes so long to 'reset' when every published mention I can think of has said you just need to let off the throttle or shift to reset and regain overboost. Now the real questions: Do you know why this is? Is this defeatable?
 

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That's a great write-up, and I appreciate it being based on concrete data - thanks!




Hmm, that contradicts what they've said in every interview I've seen about it on the RS. I wonder if this was a late change?
I agree, also they said peak power was unaffected by overboost but this table contradicts that. Idk how I can argue with hard data though. I've been preaching that overboost doesn't contribute to peak power but that is apparent not correct. I stand corrected.

Edit: I'm OK with the two tables, but the reset counter is pretty crappy. In street driving it would never come into play, but on a road course I can definitely you getting stuck on the slow table
 

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I don't recall Ford ever saying that, but I have seen it in reviews.

Did Ford say this?
I know its Forbes, but they quoted "Paul Seredynski - Global Ford Performance and Powertrain Communications Manager".

Forbes Welcome

Forbes said:
But the overboost function on the Focus RS lasts 20 seconds, and if you shift or lift off the throttle and then reapply it, the timer resets again for another 20 seconds, says Ford spokesman Paul Seredynski. Thus, the overboost function is practically permanent, allowing for the Society of Automotive Engineers to officially rate the Focus RS’s 2.3-liter EcoBoost engine at 350 hp and 350 pound-feet of torque.

EDIT: Also from the owners manual.

Your vehicle has an engine overboost feature to allow additional torque delivery. The overboost feature controls a variety of engine parameters to deliver additional torque. This feature widens the engine speed range of the peak torque curve, giving maximum performance while passing another vehicle or launching from a standing start.

The system allows a maximum of 20 seconds of engine overboost. After this the system reduces turbo charger boost and maximizes it at a predetermined limit. Once the turbo charger boost drops below the predetermined limit the system resets and a further 20 seconds of engine overboost is permitted.

Note: You do not need to take any action as the system allows overboost when you demand it.
EDIT2:
It would be something tuneable. I know Cobb has it planned already on the chopping block :)
As for any way of doing it outside of a tune, I don't see it being a possibility.
Sorry, I should've clarified that I was referring to something via a tune. I didn't figure there'd be any other way to do it - but thank you again!
 

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Discussion Starter · #10 · (Edited)
I know its Forbes, but they quoted "Paul Seredynski - Ford Spokesman".

Forbes Welcome
I think its quite possible at one time it was instantly re-settable like all the others, and it may have been due to that familiarity that they stated it as such. Ultimately, it probably came down to calibration and durability engineers.
The table also appears quite odd, and I had to double take to make sure I was seeing it right. The Overboost has a higher torque cap @6kRPM then it does @5.5kRPM.
Being that its a cap, it may be they used one of the many other ways of torque shaping on the ECU to do that.
 

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Sounds like the car should be rated differently to me. If they use near permanent overboost to justify an inflated HP, then a half-the-time overboost should be rated lower.
 

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I wonder if this is related to the inconsistent dyno pulls. It seems to make sense. I recall reading and hearing overboost was on demand when ever. If so is true then they should have clarified it in detail. I guess there are limits set forth from ecu. My question is can this be adjusted to have overboost constantly. My 2013 ST was stock as I didn't want to mod the car knowing I would be getting the RS. I sure hope so as I plan on keeping up with these guys. Land vehicle Vehicle Car Motor vehicle Transport
 

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This is NOT good news for me. I like to run my cars at various types of racing events and making high speed runs at Bonneville or Mojave/Texas Mile need to have instant reset.
I hope there is a safe tune around the overboost reset by the end of the summer. I would like to see my RS hit 165 MPH at the Mojave Mile in October.
 
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Looks like this might get ugly as Ford is not delivering what is promised.

Unless there is some other way they have in the stock tune to instantly reset the timer.

I can see a class action lawsuit brewing for those that want advertised overboost without an aftermarket tune that can void your warranty.
 
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