track rotor and pads

[Flyhalf]

i had to change OEM rear rotors 2 times in the first 4 events. I found those 2 pics I had. but on top of the uneven pad deposit there was also a damage rotors surface . especially in the inward side. Ford changed both times them. I have now the 2 piece steeda rotors since...15 events. still great condition and no more uneven pad deposit ( also helped by the slotted area) . So yes I do believe they are an issue. especcialy if the speed is very high.
OF COURSE..for normal usage oem rotors are more than ok. even for the front

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[Norm Peterson]

Just don't--no reason to do it at all. Not a single one.

I'm not so sure about this. At least if you're working with a base (non-PP, non-PP2) car. Both PP levels include "unique ABS tuning". There's a reason for that, otherwise all GT Mustangs would get the same ABS calibration.

It's entirely possible when "upgrading" your car's brake system to throw its front to rear balance off from what the ABS assumes to be present, or to the point where you're able to 'ramp up' your car's deceleration too quickly for the standard ABS tuning to accept as "normal braking" (think pads with much stronger initial bite and grippier tires).

I'm not saying that that's always going to be the case, just that it can be. For their late-S197 build (the red car, forget what year) Vorshlag did swap the stock ABS module out for the Ford Racing unit (that lit up the instrument panel) for a reason. Really big Hoosiers, bigger brakes, and a driver who places extreme demands on a car's brakes were parts of that.


The biggest downside I've found for not having ABS available is the risk of locking up a tire under extreme braking. Flatspotting a tire is potentially expensive, and if it's a front wheel that gets the ABS intervention the car could momentarily 'tug' one way or the other as the ABS cycles. I've actually had ABS go inop during two of my track days. On one of those, the two best non-ABS laps were quicker than the single best lap with ABS (but the ABS laps were overall slightly more consistent).

I guess threshold braking is something you learn along the way when the first 38 years of your driving includes no ABS experience at all, and that probably allows you to feel more comfortable should the ABS become inop for any reason.

Don't take any of the above as encouragement to disconnect or disable ABS. Not without at least having a sound reason for doing so. "Because somebody said to" doesn't qualify as 'sound' unless a reason is given and you thoroughly understand that reason.


Norm

 

[strengthrehab]

I'm not so sure about this. At least if you're working with a base (non-PP, non-PP2) car. Both PP levels include "unique ABS tuning". There's a reason for that, otherwise all GT Mustangs would get the same ABS calibration.

It's entirely possible when "upgrading" your car's brake system to throw its front to rear balance off from what the ABS assumes to be present, or to the point where you're able to 'ramp up' your car's deceleration too quickly for the standard ABS tuning to accept as "normal braking" (think pads with much stronger initial bite and grippier tires).

I'm not saying that that's always going to be the case, just that it can be. For their late-S197 build (the red car, forget what year) Vorshlag did swap the stock ABS module out for the Ford Racing unit (that lit up the instrument panel) for a reason. Really big Hoosiers, bigger brakes, and a driver who places extreme demands on a car's brakes were parts of that.


The biggest downside I've found for not having ABS available is the risk of locking up a tire under extreme braking. Flatspotting a tire is potentially expensive, and if it's a front wheel that gets the ABS intervention the car could momentarily 'tug' one way or the other as the ABS cycles. I've actually had ABS go inop during two of my track days. On one of those, the two best non-ABS laps were quicker than the single best lap with ABS (but the ABS laps were overall slightly more consistent).

I guess threshold braking is something you learn along the way when the first 38 years of your driving includes no ABS experience at all, and that probably allows you to feel more comfortable should the ABS become inop for any reason.

Don't take any of the above as encouragement to disconnect or disable ABS. Not without at least having a sound reason for doing so. "Because somebody said to" doesn't qualify as 'sound' unless a reason is given and you thoroughly understand that reason.


Norm

S197 system is different.

I've had lengthy conversations about this with Billy Johnson due to issues I had on track when I deactivated my ABS bis the dyno plug.

If Billy says don't do it, I think he would know.

From my experience with 305 R comps, R16/R12 brakes, I'd suggest avoiding the issues.

I'm not an engineer, but I've dealt with the results first-hand and take the advice if a pro driver and Bosch engineers to heart.

Or...I could just be a clueless, know-nothing.

 

[EFI]

For years NASCAR teams used Ford factory fluid in their cars. Brake fluid doesn't boil. The water in the fluid boils.

How often do NASCAR cars brake from 150mph down to 40mph?

And brake fluid most definitely boils, it even says so on every single bottle. Yes the more water mixed in with the brake fluid the lower the boiling point, but even 100% brand new brake fluid will boil at some point.

 

[BmacIL]

i had to change OEM rear rotors 2 times in the first 4 events. I found those 2 pics I had. but on top of the uneven pad deposit there was also a damage rotors surface . especially in the inward side. Ford changed both times them. I have now the 2 piece steeda rotors since...15 events. still great condition and no more uneven pad deposit ( also helped by the slotted area) . So yes I do believe they are an issue. especcialy if the speed is very high.
OF COURSE..for normal usage oem rotors are more than ok. even for the front

You said that you were also seeing TC/SC intervention issues with OEM rotors, before turning it off. You have not compared apples to apples to say that the OEM rotor is the issue. There is quite literally nothing from an airflow and physics perspective that supports this. There's no forced cooling (via ducting) that it doesn't allow for like the base GT fronts.

When you changed pads for from stock to R12 on the OEM rotors did you resurface them?

 

[Flyhalf]

Let me clear a couple of things.
1. i still have TC and SC still on. Never changed them (of course i drive better now tho however i immediately stop to have issues with the new rotors more than a year ago.
2. Steeda rotors are NORMAL design So take the air inward vs the reverse rotors that take the air from outward (wich has much more air circulation)
3. The first rotor i changed was with oem pads. When i changed i installed the R10 pads directly on a new clean surface.
Temps with the "normal design and 2piece rotors are now 150f -200f less on the rear. That is a fact (measured on track).
And again, i still have them since months without any issues.
Last
Another fact I've noticed is that the squick sound typical of GLOC is almost gone. (Still a little there)

 

[Bluemustang]

Let me clear a couple of things.
1. i still have TC and SC still on. Never changed them (of course i drive better now tho however i immediately stop to have issues with the new rotors more than a year ago.
2. Steeda rotors are NORMAL design So take the air inward vs the reverse rotors that take the air from outward (wich has much more air circulation)
3. The first rotor i changed was with oem pads. When i changed i installed the R10 pads directly on a new clean surface.
Temps with the "normal design and 2piece rotors are now 150f -200f less on the rear. That is a fact (measured on track).
And again, i still have them since months without any issues.
Last
Another fact I've noticed is that the squick sound typical of GLOC is almost gone. (Still a little there)

Wait, you still leave traction control and Advancetrac on? Also, I'm pretty sure the OEM rotors do not have the reverse facing vanes like you describe. This is the first mention I have heard of that?

 

[Flyhalf]

Yes. I go track mode.
This is the rotor. I just took this pic

 

[Norm Peterson]

S197 system is different.

I've had lengthy conversations about this with Billy Johnson due to issues I had on track when I deactivated my ABS bis the dyno plug.

If Billy says don't do it, I think he would know.

Perhaps he can explain why the PP1 and PP2 options both come with 'unique' ABS calibrations. I'm not questioning ABS usage per se here; it's really about running a calibration best suited to track use and it sounds to me that the base/regular production unit calibration isn't it once you step too far away from the car's base OE configuration.

I have no idea what specifically is different in either S550 PP calibration vs base, but my somewhat-educated hunch is that better tires and harder anticipated usage have a lot to do with it. IOW, the same things that we do to our cars to make them more capable on the track, and the same things that Terry found the Boss 302R/302S Racing ABS module better at coping with than the regular production unit.

Braking technique probably has a lot to do with it, as well. I think some people intentionally get into the ABS, and I know that other people actively try not to.


Norm

 

[Flyhalf]

Hey

Perhaps he can explain why the PP1 and PP2 options both come with 'unique' ABS calibrations. I'm not questioning ABS usage per se here; it's really about running a calibration best suited to track use and it sounds to me that the base/regular production unit calibration isn't it once you step too far away from the car's base OE configuration.

I have no idea what specifically is different in either S550 PP calibration vs base, but my somewhat-educated hunch is that better tires and harder anticipated usage have a lot to do with it. IOW, the same things that we do to our cars to make them more capable on the track, and the same things that Terry found the Boss 302R/302S Racing ABS module better at coping with than the regular production unit.

Braking technique probably has a lot to do with it, as well. I think some people intentionally get into the ABS, and I know that other people actively try not to.


Norm

Hey Norm
Reporting my experience.
No issues with abs so far with different rotors and pads and pf course different tire compounds.
I have a pp1. I wonder if the "special" calibration is due to the bigger calipers (6piston vs 4) in pp1 and pp2 vs base.
I tried also different size of tires on track (one very far from Oem circumference. Still not issues.

 

[shogun32]

short of dumping the ABS controller mapping tables, it's all sensor-based on rotational rate-change (decel/accel). The "specific" programming is likely no more than marketing jargon - subject-matter engineers do NOT write the copy.

About the only thing I can think of that would be different from a PP1 vs PP2 car is the slope of the maximum pressure threshold - ie. *if* Ford actually tailored logic based on Cup2 vs PS4S CoF profiles there might be an initial pressure-release on application to bleed slightly when the pedal is stomped so as to not immediately overwhelm tire grip before ABS has a chance to detect/intervene. But any logic that is tire-specific would seem a colossal waste of time and generally unhelpful since the likelihood of people sticking with OE tires on the track is close to nil.

One can datalog the wheel RPM but I don't know if specific line pressures can be too.

 

[Cardude99]

So I have been reading this and think my questions sparked this debate. For the record I have a pp Ecoboost so my brakes are the base gt brakes, not the upgraded 6 pistons. I do not know if I have unique and tuning or not.

 

[Norm Peterson]

short of dumping the ABS controller mapping tables, it's all sensor-based on rotational rate-change (decel/accel). The "specific" programming is likely no more than marketing jargon - subject-matter engineers do NOT write the copy.

Yeah, you'd need to know what the maps looked like. It's why we here can only make guesses and have suspicions.

But I'm sure there's more to it these days than rpm sensing alone. While the maximum deceleration capability of the OE tires could be incorporated into the mapping, the incorporation of stability control systems means that at least the yaw sensor is involved.


I have this SAE book "Electronic Braking, Traction, and Stability Controls, Volume 2" that may include something that could shed a little light.. It's PhD level stuff, so following the derivations and math may well be beyond me. I'm hoping for enough description in the accompanying text.


Norm

 

[Norm Peterson]

No issues with abs so far with different rotors and pads and pf course different tire compounds.
I have a pp1. I wonder if the "special" calibration is due to the bigger calipers (6piston vs 4) in pp1 and pp2 vs base.

Changes to the hydraulic part of braking certainly could demand calibration changes. The SAE book mentioned above has at least one paper that deals with finite element modeling of fluid flow (in a solenoid valve), and that may only be scratching the surface.

I tried also different size of tires on track (one very far from Oem circumference. Still not issues.

I'm sure that there is some tolerance, at least as long as you don't significantly change the amount of stagger in front vs rear tire revs/mile from stock.


Norm

 

[Radiation Joe]

I'm not so sure about this. At least if you're working with a base (non-PP, non-PP2) car. Both PP levels include "unique ABS tuning". There's a reason for that, otherwise all GT Mustangs would get the same ABS calibration.

It's entirely possible when "upgrading" your car's brake system to throw its front to rear balance off from what the ABS assumes to be present, or to the point where you're able to 'ramp up' your car's deceleration too quickly for the standard ABS tuning to accept as "normal braking" (think pads with much stronger initial bite and grippier tires).

I'm not saying that that's always going to be the case, just that it can be. For their late-S197 build (the red car, forget what year) Vorshlag did swap the stock ABS module out for the Ford Racing unit (that lit up the instrument panel) for a reason. Really big Hoosiers, bigger brakes, and a driver who places extreme demands on a car's brakes were parts of that.


The biggest downside I've found for not having ABS available is the risk of locking up a tire under extreme braking. Flatspotting a tire is potentially expensive, and if it's a front wheel that gets the ABS intervention the car could momentarily 'tug' one way or the other as the ABS cycles. I've actually had ABS go inop during two of my track days. On one of those, the two best non-ABS laps were quicker than the single best lap with ABS (but the ABS laps were overall slightly more consistent).

I guess threshold braking is something you learn along the way when the first 38 years of your driving includes no ABS experience at all, and that probably allows you to feel more comfortable should the ABS become inop for any reason.

Don't take any of the above as encouragement to disconnect or disable ABS. Not without at least having a sound reason for doing so. "Because somebody said to" doesn't qualify as 'sound' unless a reason is given and you thoroughly understand that reason.


Norm

Norm,
You must be an old guy like me. I can't imagine relying on ABS during braking. If it kicks in, I change my whole entry line. I've always understood that under threshold braking, especially while entering a corner like 8 at Laguna, if you don't have ABS you will most likely lock a rear tire on corner entry. The tire is lightly loaded, so you're not likely to flat spot it.
Funny that you note a better lap time with ABS off. I've always believed that activating ABS on track is slower than maintaining good threshold braking.
I differentiate traction control from ABS even though TC utilizes the ABS to do it's job. ABS doesn't help me under braking, but TC does contribute to more consistent lap times. I think this is what you experienced. For example; traction control might tap the outside front brake if it detects excessive oversteer on corner entry which might cost you half a second if you relied upon your old fashioned manual correction.

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