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I see your point.
But clearly the pedal wasn't applied either??
Or are you guys saying the pedal is depressed but the application of brakes doesn't occur and the PDR doesn't register the pedal being depressed until later?
Because clearly here the brake being applied corresponds to the accelerator being released and the sound of the car decelerating.
Everything sounds in synch as well.
And here is the kicker in all of these videos the driver never applies maximum brake pedal.
Last edited by dar02081961; 02-21-2019 at 05:54 PM.
That's what I expect. Have you experiencds ice mode with stock pads?
Not correct in my case... if im experiencing this ICE MODE. For me getting on the brakes after 110mph (maybe 70% brake pressure) the front brakes seem to some times shake and feel like its just barely stopping. Some times on a curve the shaking/ non stop sensation is worst and the speeds are much slower( around 70 mph) I was hoping that changing out my oem pads to the power stop or the other popular brand, believe its cabronetics or something, would stop this issue for me. Its really scary smh.
Last edited by GhostBluZ06; 02-21-2019 at 02:47 PM.
I see your point.
But clearly the peddle wasn't applied either??
Or are you guys saying the peddle is depressed but the application of brakes doesn't occur and the PDR doesn't register the peddle being depressed until later?
The pedal is depressed to the floor. The ABS system intervenes and does not allow full hydraulic pressure to be applied to the caliper so braking is only partial. If you get off the brakes and back on them then the ABS will allow full pressure to the caliper. 20 years ago this phenomena was only felt on full and hard brake applications that were within 3-4 seconds of each other and the phenomena was caused by the inability of the piston to cycle in the master cylinder bore fast enough to build up full hydraulic pressure. Today it is the modern ABS system that has apparently been designed to only apply partial hydraulic pressure to the calipers in an event the ABS senses braking on ice. Hence the name; "Ice Mode."
My concern is that the rapid release of the accelerator and a quick very hard application of the brakes in a street panic situation could get a pedestrian or two run over when full braking does not occur. What if those end cones were a couple of drunks wandering out from between parked cars?
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I believe what I am stating here to be correct; remember, the red bar on the PDR does not measure braking force but rather pedal travel. If you experience a true ICE mode, your pedal is rock hard and does not allow for much travel. So you may only see 30-50% on the PDR when you are actually pressing with as much force as your leg will generate. It's basically an unassisted mode but the proportioning is also being monkeyed with behind the scenes, or that has been my experience anyway.
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Originally Posted by GhostBluZ06
No correct in my case... if im experiencing this ICE MODE. For me getting on the brakes after 110mph the front brakes seem to some times shake and feel like its just barely stopping. Some times on a curve the shaking/ non stop sensation is worst and the speeds are much slower( around 70 mph) I was hoping that changing out my oem pads to the power stop or the other popular brand, believe its cabronetics or something, would stop this issue for me. Its really scary smh.
Your issue sounds like pad deposit and/or warped rotors, not ICE mode. Get your rotors cleaned up or replaced (assuming iron and not carbon ceramic, which I would put money on), and then report back.
The pedal is depressed to the floor. The ABS system intervenes and does not allow full hydraulic pressure to be applied to the caliper so braking is only partial. If you get off the brakes and back on them then the ABS will allow full pressure to the caliper. 20 years ago this phenomena was only felt on full and hard brake applications that were within 3-4 seconds of each other and the phenomena was caused by the inability of the piston to cycle in the master cylinder bore fast enough to build up full hydraulic pressure. Today it is the modern ABS system that has apparently been designed to only apply partial hydraulic pressure to the calipers in an event the ABS senses braking on ice. Hence the name; "Ice Mode."
My concern is that the rapid release of the accelerator and a quick very hard application of the brakes in a street panic situation could get a pedestrian or two run over when full braking does not occur. What if those end cones were a couple of drunks wandering out from between parked cars?
With over 125,000 miles between C7 Stingrays and C7 Z06's I have never experienced a condition where I reached for the brake and more than enough stopping power wasn't there. Hopefully I will continue to have such luck.
I believe what I am stating here to be correct; remember, the red bar on the PDR does not measure braking force but rather pedal travel. If you experience a true ICE mode, your pedal is rock hard and does not allow for much travel. So you may only see 30-50% on the PDR when you are actually pressing with as much force as your leg will generate. It's basically an unassisted mode but the proportioning is also being monkeyed with behind the scenes, or that has been my experience anyway.
Bingo, it feels like someone put a brick below your brake pedal as a practical joke. It is not the normal ABS grind, it is just total lock out of the pedal not being able to go down all the way.
And thus, the PDR does record accurately the amount of brake pressure applied, which is only about 30%
As others have stated, the only way to get it back to full braking is to let up on the pedal and start over. A lot of time passes and a lot of distance in that amount of time. It is very unsafe. If we could solve this, it would be a very big deal. People keep focusing on track times, what happens when a kid runs out in front of your vette chasing a ball? Its going to happen when we don't want it to happen.
As I mentioned before in this thread, i knew a lady who swore this happened in her car and she rear ended someone and gave them whiplash. I thought she was telling a tale... but now I realize, her description of the brake pedal, and what happened next, was indeed accurate. Manufacturers are off the hook, it just looks like we dont know how to drive if you look up the data or the PDR happens to be recording.
We could actually get sued even worse if the video shows we did not apply the brakes fully. And it would be any one of us VS GM, as we all know GM is not going to accept liability, they will be pointing at any one of us. If anyone needs help solving this mess, i am here to help, just PM me.
With over 125,000 miles between C7 Stingrays and C7 Z06's I have never experienced a condition where I reached for the brake and more than enough stopping power wasn't there. Hopefully I will continue to have such luck.
I prefer not to rely on luck when I need to stop right now and right here.
Your issue sounds like pad deposit and/or warped rotors, not ICE mode. Get your rotors cleaned up or replaced (assuming iron and not carbon ceramic, which I would put money on), and then report back.
Thanks! Will do, im hoping this is the case as im not using anywhere near the force used im tracking real conditions. (And yes iron not ceramic). Got this car used so far as i know this are still factory 15 z06
Mike I understand what you and the others are saying.
But none of these videos show what you guys are describing.
In all 3 of the videos I sampled the PDR shows less than 1 second between throttle lift, brake application and a notable deceleration showing on the g meter.
Therefore there can't be any delay or situation where it seems as if there is brick between the pedal and the floor.
If that were the case there would be a noticeable delay in brake application and deceleration. And the PDR just doesn't show that is what occurred.
Here are the screen shots to illustrate my point.
Keep in mind all 3 screen shots happen between the end of the 4 second mark and the end of the 5 second mark .....so the following sequence takes place in less than 1 second.
1. In the first screen shot the driver is accelerating WOT at .6g's or so at about 95 kilometers (60 mph).
2. In the 2nd screenshot we can see the driver has already completely lifted throttle at the 5 second mark. (If you roll the video you can see this happen real time).
3. In the 3rd screenshot we can see the driver has already applied the brake and the car is already decelerating at .6g's with at least 25% brake pedal yet we are still at the 5 second mark.
Shot 2 and shot 3 occur somewhere between 5 and 6 seconds.
This sequence shows the car making a 1.2g transition from a .6g acceleration to a .6g deceleration in less than 1 second.
This degree of deceleration (1.2g's per second) cannot be achieved without significant braking force.
The videos do not support the claim of any delay or lack of braking force.
It's going to be hard to convince a court or an engineer the car didn’t have brakes for any period of time with any of these videos.
I am not here to criticize all I have is the data presented and it doesn't support the claims.
Last edited by dar02081961; 02-21-2019 at 05:46 PM.
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On a track it is much easier to prove. Poor-sha has done this, the data shows it even if the video makes it difficult to see. What you can do is overlay the data and then it becomes abundantly clear from deceleration to brake force applied.
This isn’t something where I’ve done the deep data dive but whatever Sean has been using to do his track videos with Cosworth Pi seems to show ICE mode actually happening.
Of course this is completely irrelevant on the street, then again I’m not sure I’ve seen a single instance of this on a street. To get this sort of thing to occur on a public road would require the driver to be guilty of any number of driving violations resulting in dangerous conduct.
I understand what you are saying.... BUT...... I am the person who is experiencing this situation,
along with 4 others in my car.
We have our foot pressed as hard as we can on the brake pedal... yet the "system" is only
providing 25 or 30% braking... not 100%
And therefore the PDR is only showing the amount of braking force which is being applied by the car.
It might also be showing how much pedal travel it is experiencing.... I do not know that.
But for you to say we are not applying the brake enough is just so WRONG !!!!
On a track it is much easier to prove. Poor-sha has done this, the data shows it even if the video makes it difficult to see. What you can do is overlay the data and then it becomes abundantly clear from deceleration to brake force applied.
This isn’t something where I’ve done the deep data dive but whatever Sean has been using to do his track videos with Cosworth Pi seems to show ICE mode actually happening.
Of course this is completely irrelevant on the street, then again I’m not sure I’ve seen a single instance of this on a street. To get this sort of thing to occur on a public road would require the driver to be guilty of any number of driving violations resulting in dangerous conduct.
it may be as easy as locking up your brakes, while still having a foot on the gas. I dont drive like this, but those who do, are subject to it.. as soon as the car senses that the front wheels are locked and the back wheels are still spinning, ice mode initiates i believe. And it would make sense, because that is how the lady drives who wrecked, who i know
Just to clarify again, the PDR brake bar and the captured data is how far you've pressed the brake pedal. It has nothing to do with brake pressure. If you have the fluid boiling or the pads have worn the pedal will move further showing up as a higher red bar. Hitting ice mode or having pad fade will not show up in the brake data, you need to look at the longitudinal Gs against pedal position to see a slow in the decel rate relative to where the pedal is. I have not experienced ice mode but I have experienced pad fade where you keep pressing and the car isn't slowing. This is because the pads have overheated and in effect are melting on the rotor.
Just to clarify again, the PDR brake bar and the captured data is how far you've pressed the brake pedal. It has nothing to do with brake pressure. If you have the fluid boiling or the pads have worn the pedal will move further showing up as a higher red bar. Hitting ice mode or having pad fade will not show up in the brake data, you need to look at the longitudinal Gs against pedal position to see a slow in the decel rate relative to where the pedal is. I have not experienced ice mode but I have experienced pad fade where you keep pressing and the car isn't slowing. This is because the pads have overheated and in effect are melting on the rotor.
Good point.
The PDR icon represents pedal travel. The G meter represents deceleration and acceleration forces.
In these videos the car executes a deceleration in excess of 1.25 gs WITHOUT the brake pedal moving past the 60% mark.
If the pedal bottomed out as one poster claimed or the brake fluid boiled or the system lost hydraulic leverage for whatever reason, the result would be the brake pedal traveling further or to the floor (a soft pedal). This would certainly result in greater than 60% pedal travel indicated on the PDR in these videos.
In another post the poster states the pedal becomes "like a brick". This characteristic is certainly not a characteristic of an overheating brake system that is losing hydraulic leverage. As you said we all know the pedal gets softer, not harder as the hydraulic fluid gets closer to overheating or boiling and the result is the brake pedal travels further.
Here in lies my point.
Regardless of which posters version of the problem we take as an accurate description of the pedal feel, the fact remains in all of these videos the car starts decelerating almost immediately upon brake application. We can see as the pedal indicator increases from zero to 60% the deceleration increases as the pedal travel increases. We can also see the brake pedal never travels past 60% AND the car executes a deceleration in excess of 1.25g less than 2 seconds after brake application. These are the facts as shown by the video and the embedded data.
We are all familiar with a soft pedal as the brake system overheats and losses efficiency.
Soft pedal, boiling brake fluid, bricked pedal or perfectly working brake system.....registering in excess of 1.25g of braking force, with less than 60% pedal applied, within 2 seconds of brake application, is far from "ice mode" in most anyone's book.
If folks want to convince an engineer there is a problem I recommend you find a video that matches the problem as described.
Last edited by dar02081961; 02-21-2019 at 11:47 PM.
Here in lies my point.
Regardless of which posters version of the problem we take as an accurate description of the pedal feel, the fact remains in all of these videos the car starts decelerating almost immediately upon brake application. We can see as the pedal indicator increases from zero to 60% the deceleration increases as the pedal travel increases. We can also see the brake pedal never travels past 60% AND the car executes a deceleration in excess of 1.25g less than 2 seconds after brake application. These are the facts as shown by the video and the embedded data.
Then could this sensation of pushing harder without an increase in braking or activating ABS, just be a loss of brake boost?
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Originally Posted by dar02081961
Good point.
If folks want to convince an engineer there is a problem I recommend you find a video that matches the problem as described.
This is ICE mode. Poor-sha looked at PDR data (several months ago) from prior laps and confirmed via deceleration tables/graphs. Watch the G-meter. It doesn't spike until I start to steer the car, knowing I'm not going to make the turn and begin looking for my exit strategy. Personally, I don't care if you believe it happens or not. I have several of these videos, none of which are spectacular, but all have the exact same thing happen, rock hard brake pedal. I don't blow turns. If I go off, or miss a turn during autocross, something happened.
That is ice mode, the video shows nothing other than the car won't let the pedal go down all the way, and it feels like a brick is under the pedal. Thats it. And in the time a person has to let back off the brake and re-apply the brake... they have missed their turn OR they have ran into the car or person they were trying to avoid hitting. Its a problem.
Again, the solution might be understanding what initiates it, and the posts above that point out that front wheels locking, and back wheels not locking, initiates it, makes perfect sense to me with my experiences with it happening. Thus.. to solve the problem, we need to test stronger rear pads with more initial bite, that also have the potential to lock tires, to keep up with the front race pads that DO lock the front tires when a person jabs the brakes.
If all 4 tires lock simultaneously, MAYBE ice mode will not initiate, and maybe instead, regular ABS function will ensue with the normal grinding... which is fine, predictable, and manageable.
Eric are you running the same pads front and rear? I am and I wonder if that has anything to do with ice mode since I've never experienced it with this car.
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Originally Posted by badhabit_wb
Eric are you running the same pads front and rear? I am and I wonder if that has anything to do with ice mode since I've never experienced it with this car.
I've ran several combinations, generally same front/rear. In the video above, based on memory only, I was running 1.11s front and 2500s rear, but that could have been 1.11s f/r or 2500s f/r as I played with combinations that weekend.
It happened with Girodisc rotors running ST43s front and OEM CCBs rear.
It happened running PFC 01s f/r
It happened running PFC 94s f/r, although with less frequency.
Not sure whether I have a documented case of it on the OEM CCBs though... They are currently back on the car although I might remove them this weekend and put my AP brakes back on for more pad testing.
02-21-2019, 01:24 PM
That is ice mode, the video shows nothing other than the car won't let the pedal go down all the way, and it feels like a brick is under the pedal. Thats it. And in the time a person has to let back off the brake and re-apply the brake... they have missed their turn OR they have ran into the car or person they were trying to avoid hitting. Its a problem.
