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Discussion Starter #1
Hello everyone,

When driven on dirt, such as driving on non-paved roads or in a rallycross, the RS's ABS system goes into immediate ice mode when the brakes are applied sharply. Has anyone figured out how to disable the ABS without affecting the AWD system's operation, or to raise the threshold at which the ABS triggers ice mode?

I've read through the previous discussions but no real answers have been posted. It's reported that Team Oneil has disabled ABS on their cars but no info as to how has been posted anywhere yet. I have a call in to them.

Others have noted that the drift stick affects the rear brakes through the OBD-II port, so maybe this can be done by a tuner or through a tool such as Forscan?

I notice that on the Boss Mustangs there was a separate ABS relay that when swapped in affected the ice mode operation. Maybe there's an option like that for our cars?

Thanks in advance for any help.
 

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Hello everyone,

When driven on dirt, such as driving on non-paved roads or in a rallycross, the RS's ABS system goes into immediate ice mode when the brakes are applied sharply. Has anyone figured out how to disable the ABS without affecting the AWD system's operation, or to raise the threshold at which the ABS triggers ice mode?

I've read through the previous discussions but no real answers have been posted. It's reported that Team Oneil has disabled ABS on their cars but no info as to how has been posted anywhere yet. I have a call in to them.

Others have noted that the drift stick affects the rear brakes through the OBD-II port, so maybe this can be done by a tuner or through a tool such as Forscan?

I notice that on the Boss Mustangs there was a separate ABS relay that when swapped in affected the ice mode operation. Maybe there's an option like that for our cars?

Thanks in advance for any help.
The drift stick controls the clutch pack in the RDU unit to lock them. I have not seen anything in the forscan thread about any ABS settings, but have noticed the system kicking in immediately when I hit the brakes hard/fast. It releases just as fast though, so I'm guessing you're better off with it as is than trying to change it.
 

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Discussion Starter #3
It releases just as fast though, so I'm guessing you're better off with it as is than trying to change it.
Normal ABS operation releases as soon as you lift and you can go right back into normal braking. Ice mode does not. You have to drive for a few seconds before it resets. It is not something you can safely drive with as-is in certain scenarios.
 

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Discussion Starter #4
The drift stick controls the clutch pack in the RDU unit to lock them.
I did a bit more research on the drift stick, and it does appear that the brakes are applied via the ABS system through code when it is activated. From Ford's description of it:

The Drift Stick is an aluminum lever between the driver’s seat and manual transmission, which uses the innovative Ford Performance all-wheel-drive system in conjunction with the antilock braking system, opening up the rear-drive unit clutches and applying hydraulic pressure to lock the rear wheels to induce drift with the simple pull of a lever.
Not directly what I'm looking for, but it is an instance of code communicated through the OBD-II port controlling the ABS system's operation.
 

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What @Biznatch said makes no sense, if the clutch packs are fully locked the wheels will rotate at the same speed as propshaft which will rotate at the same speed as the transmission. This does not lock the wheels like one wants with a hydraulic handbrake.

The driftstick likely uses the EBD to lock the rear wheels (much like it does for hill assist or colission avoidance) and at the same time open the RDU clutch packs to avoid driveline shock (the only place left to slip is the clutch up front).

On topic, if you threshold brake does it shoot into ice mode? can you not just pull the ABS fuse?
 

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Discussion Starter #6 (Edited)
What @Biznatch said makes no sense, if the clutch packs are fully locked the wheels will rotate at the same speed as propshaft which will rotate at the same speed as the transmission. This does not lock the wheels like one wants with a hydraulic handbrake.

...

On topic, if you threshold brake does it shoot into ice mode? can you not just pull the ABS fuse?
Yeah, the clutch packs obviously can't stop or slow the wheels. I'm not sure what he meant technically, but it is definitely using the abs pump to lock the rears.

Threshold braking on pavement is fine and works as expected. The problem is when on bumpy dirt. It goes into ice mode immediately and won't reset without driving for an extended period of time off of the brakes.

Pulling the fuse puts the whole system into fault and it disables the RDU, so you go FWD with none of the other brake based functions.

In related news, I noticed that in this month's Car & Driver the Type R beat the RS because of a slightly slower lap time and Randy Pobst mentioned that it was because the RS kept going into ABS which hurt the times.
 

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Discussion Starter #7
As an update, I've learned a bit more since posting this thread.

Team O'Neil reportedly accomplished this on their cars by mechanically bypassing the ABS unit altogether, but leaving it in the car and plugged in so that the computers don't see an issue and drop out the rear wheels. This would also eliminate the other brake based functions including torque vectoring/eLSD functionality, hill holding, and EBD, but they're running the front LSD and for their uses don't need the others. This is not an ideal solution for me as it would put me into a different class.

The Mustang GT500, Boss 302, and Fiesta ST "race ABS" modules won't work on this car. It is the first Ford to use a new Continental ABS system so they wouldn't plug in even if the pins were the same, not to mention the settings could work or could be wildly incorrect for this car.

Forscan has access to the ABS module, but it doesn't appear to have any ability to control the operation or threshold parameters. The ABS setting in the Forscan Engineering menu has options for "Without ABS", and "Without Traction Control", but all these do is control the dash light for vehicles that don't have those features.

The wiring diagram shows the wheel speed sensors connecting directly to the ABS unit. Most likely the ABS unit then sends them through the canbus network to the RDU module, but this hasn't been confirmed yet. This means that disabling a wheel speed sensor or it's signal will also put the car into 2wd so that's not an option either.
 

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So I blast around in the dirt and have also done a few weekends of ice racing in the RS, I’ve never had an issue with ABS.

And please feel free to explain in detail the difference between regular ABS and this “ice mode” you keep mentioning. I’ve never beard of such a setting on any foes I’ve owned
 

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As mentioned, Biznatch didn't make any sense. I know with the drift stick there is an updated ABS software that has to be pushed to the car through ProCal. I've gotten the ice braking while on pavement with car still loaded in a corner a little and wanted to just stab the pedal for a moment before more turn in was given but the car decided to hold brake for a moment after I released and ended with understeer as I turned on the wheel after releasing the pedal. I have tried to avoid that but really need to retest with new ABS program/settings, but I bet it's the same, but I've not tried in drift mode while the drift stick is connected, normally have OBD-II logger on the port ( I need and OBD-2 port splitter).

So I blast around in the dirt and have also done a few weekends of ice racing in the RS, I’ve never had an issue with ABS.

And please feel free to explain in detail the difference between regular ABS and this “ice mode” you keep mentioning. I’ve never beard of such a setting on any foes I’ve owned
It's more like panic braking. Very fast application of the brake and steering input. As mentioned I was stabbing the brake fast so I only wanted it to grab for a fraction of a second and as I'm releasing the pedal I turn in more. This worked on my old Civic in auto-x, but the RS dislikes it, I would stab, start turnin, release brake and the car would continue braking at threshold for .5-.75 second, and I would be understeering by then. In the Civic this maneuver would move the weight forward and the turn in could be much harder, often giving me oversteer as the rear didn't have the weight back yet, but throttle mid corner and out pulled the back back into place.
 

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Discussion Starter #10
So I blast around in the dirt and have also done a few weekends of ice racing in the RS, I’ve never had an issue with ABS.

And please feel free to explain in detail the difference between regular ABS and this “ice mode” you keep mentioning. I’ve never beard of such a setting on any foes I’ve owned
That's interesting that you've never experienced it, even on dirt and ice. I've now owned two 2016 RS's and both exhibited it on dirt. My first one was a street car and I never had issue on pavement or in snow, but never had it out on straight ice.

"Ice Mode" is a function of most, if not all, ABS systems where a combination of sensor values indicate to the unit that the car is on ice and has zero traction. In this mode, the systems go to a very high cycle rate and reduce brake pressure. It's commonly noted as being 25% braking pressure, though I haven't seen any documentation of this. The end effect is that you have a completely hard pedal with very little braking force. It almost put me into the woods and I nearly ran over another competitor in the paddock area at last weekend's rallycross, and if you google it there are many accounts of ice mode causing collisions on the track and the street in a large variety of makes and models. It can be very helpful if invoked in the conditions it is designed for, but very dangerous if invoked when you otherwise have traction and need it.
 

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Hmm that sucks, I am sure Ford could release an ABS calibration that disables it (like they do for the other cars W/o the need for new HW).

I have never experienced it but I think im quite gentle on the brakes and my track only has 1 or 2 hard braking zones.

Sent from my SM-G955F using Tapatalk
 

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Oh, the hard pedal!!!! Yes I 100% experienced this during ice racing, at least once per day per weekend. I didn’t notice anything wrong with the ABS per se (only time I really had it kick in was coming into a stop-box) but yes I had the rock hard pedal with no braking before. I see what you’re saying now
 

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Any new insight into disabling the ABS without completely bypassing the hydraulic system? I also hate the intrusive system when driving on snow/ice/gravel.
 

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Small update to this. I found that if you pull the large ABS valve fuse (40 amp, under a protective cover in the engine bay fuse box) that it will fully disable ABS, ESC, and other such controls. It sets two warning lights on the dash, but that's it. Cruise control works normally as well. Pulling either of the two stability control fuses in the same housing result in all systems shutting down - including AWD and the speedometer.

The one issue is, the AWD system is quite muted. You can still switch between Normal and Sport drive modes, but not Track or Drift. It is definitely still functioning, but I would say it's only transferring about %10-20 torque to the rear.

On dry pavement it is not very noticeable, on slippery surfaces you can really feel it's not giving much power to the rear.

Wish I could call this a total victory, but with such weak rear engagement you'd likely be better off keeping systems active, and braking differently.
 

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Discussion Starter #16
Small update to this. I found that if you pull the large ABS valve fuse (40 amp, under a protective cover in the engine bay fuse box) that it will fully disable ABS, ESC, and other such controls. It sets two warning lights on the dash, but that's it. Cruise control works normally as well. Pulling either of the two stability control fuses in the same housing result in all systems shutting down - including AWD and the speedometer.

The one issue is, the AWD system is quite muted. You can still switch between Normal and Sport drive modes, but not Track or Drift. It is definitely still functioning, but I would say it's only transferring about %10-20 torque to the rear.

On dry pavement it is not very noticeable, on slippery surfaces you can really feel it's not giving much power to the rear.

Wish I could call this a total victory, but with such weak rear engagement you'd likely be better off keeping systems active, and braking differently.
In my experience and from the diagrams when you pull this fuse the system sees a fault and opens the rear clutches, so you are 100% FWD. There is no 10-20% mode. It’s either the clutch packs are open or closed.
 

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In my experience and from the diagrams when you pull this fuse the system sees a fault and opens the rear clutches, so you are 100% FWD. There is no 10-20% mode. It’s either the clutch packs are open or closed.
Apparently not. I can still on throttle drift it, albeit weakly. And straight line acceleration is not terribly affected.
By contrast, if you pull the other large fuse (for the ESC valve) it goes full FWD and you can feel a night and day difference.
 
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