Disabled the driving aids. Here are my impressions.

[diss7]

Originally Posted by Deep Six

I have 4 track days running Khumo V710's (30 UTQG) HP+ fronts HPS rears. I use the 5 sec Track Off (because I can never remember the pedal dance sequence or I'm late as usual for a session). Two heavy braking points 130-70 and 105-45 and I have not felt the slightest bit of ABS modulation. In my AMG the ABS was so pronounced the vibration could be seen in go pro videos. This car however had DTC 70 all around and was braking from 155 into the first turn.

Interesting results. I would rate the V710 over the tyre I am using (123s) so would've expected similar findings to what I have experienced.

Edit - It would be interested to hear your feedback from first removing the abs fuse, and finding your new braking points / lockup points, and then reinstalling the fuse and seeing if these points are the same. I don't blieve they will be.

[strat61caster]

Originally Posted by diss7

I'd really like it if someone decided to try to replicate my findings, independantly from myself.

I would as well, I think we can both agree that talk is cheap. Unfortuneately I do not have the resources, time, and in all likelihood skill required. Only a four year degree and a hobby.

[Deep Six]

Originally Posted by diss7

Interesting results. I would rate the V710 over the tyre I am using (123s) so would've expected similar findings to what I have experienced.

A factor very well could be that I am not running W2W or TT so brake pressure is deliberately applied to maintain 30 minute session durability. However after checking the car in the hot grid post spin the brakes were smoking like chimney stacks. I'll be back on the track in 3 weeks I'll deliberately brake with more intensity and see what happens. I'll also try pulling the fuse as well. Even though the TC is turned off I still get the flashing TC light on a nearly constant basis but I don't feel any intervention. When I bought the car in May I did a track weekend with just a brake fluid upgrade. Tried all three TC modes and I first hand witnessed the rpm's drop up to 800 when the TC activated even though the pedal was floored.

[diss7]

Originally Posted by Deep Six

A factor very well could be that I am not running W2W or TT so brake pressure is deliberately applied to maintain 30 minute session durability. However after checking the car in the hot grid post spin the brakes were smoking like chimney stacks. I'll be back on the track in 3 weeks I'll deliberately brake with more intensity and see what happens. I'll also try pulling the fuse as well. Even though the TC is turned off I still get the flashing TC light on a nearly constant basis but I don't feel any intervention. When I bought the car in May I did a track weekend with just a brake fluid upgrade. Tried all three TC modes and I first hand witnessed the rpm's drop up to 800 when the TC activated even though the pedal was floored.

If the TC light is flashing, it is doing something.
It could be the auto LSD feature, or EBD, both still work using the setting that you are.
Without the auto LSD, you'll feel the car 'spring' out of corners more. Its hard to describe. Basically, its not dragging the rear inside wheel.

[stugray]

Originally Posted by diss7

It pulses the brakes in the same way that it would if slip was detected.

WHY?? what could that possibly accomplish except make you NOT stop when you are already stopping. Use logic. There is absolutely zero reason for the ABS to do anything unless it detects wheel slip.

[Byebye]

Originally Posted by diss7

READ the previous information I have posted.

If works to G or slip.

If you're on ice or snow, its going to be slip that triggers it.

If you are on a dry road, with stickier tyres, you will reach the g limit before lockup, this is when its the g that is activiating the ABS.

I think you may be referencing the yaw sensor which in correlation with steering angle and wheel speed(variations from slip)will apply the ebd. Disabling the vsc should eliminate the ebd. But from you are saying it sounds like it doesn't. Disabling the abs does not necessarily mean you are disabling ebd. In today's modern ebd and abs if you are emergency braking and turning ebd can apply abs to any of the wheels seperately if needed. So in essence you are experiencing more control because you've taken abs away from ebd and are controlling the slip yourself.

When you mentioned that you can feel braking in cornering that could be the ebd. If you can eliminate ebd and abs you will be free of the aids.

Disabling abs on a dd? Not for me. I have professional drivers training and first thing you learn is emergency braking. Find, know, and learn what lock up feels like and you will never need to rely on ABS.

[diss7]

Originally Posted by stugray

WHY?? what could that possibly accomplish except make you NOT stop when you are already stopping. Use logic. There is absolutely zero reason for the ABS to do anything unless it detects wheel slip.

You tell me why it does it.

It doesnt change the fact that it does do it.

My assumption was that it is seen as a precursor to lockup, so it chimes in early. But I don't know the reasoning, I didn't design the system.

[stugray]

Originally Posted by Byebye

Disabling the abs does not necessarily mean you are disabling ebd.

The ABS manifold also controls EBD (as far as I understand it).
If the ABS manifold has no power to actuate the valves, you dont have ABS or EBD.

[stugray]

Originally Posted by diss7

It doesnt change the fact that it does do it.

My assumption was that it is seen as a precursor to lockup, so it chimes in early

We are taking your word that it does it. I do not believe it.

Why would the system release the brakes 'as a precusor to lockup'?
Logic (and the engineer in me) says this is not possible.

If it IS doing what you say, then it sounds like a bug/flaw in the system.
That is kind of like a smoke detector that bursts into flames if it detects a fire.

[Byebye]

Originally Posted by stugray

The ABS manifold also controls EBD (as far as I understand it).
If the ABS manifold has no power to actuate the valves, you dont have ABS or EBD.

If that's the case than you could test that by leaving the vsc on and over steering the car. If what you are saying is true you should be able to drift all day.

But again does turning of vsc disabled ebd?

[diss7]

Originally Posted by stugray

We are taking your word that it does it. I do not believe it.

Why would the system release the brakes 'as a precusor to lockup'?
Logic (and the engineer in me) says this is not possible.

If it IS doing what you say, then it sounds like a bug/flaw in the system.
That is kind of like a smoke detector that bursts into flames if it detects a fire.

If you don't believe me, than test it yourself. I'm not the only one with sticky tyres that goes to the track.

[Byebye]

Originally Posted by WolfsFang

There is no way the abs uses a g force sensor. How will it know if you are on ice or snow.

Sent from my XT1060 using Tapatalk

The ecu uses deceleration to calculate g-force.

[stugray]

Originally Posted by diss7

If you don't believe me, than test it yourself. I'm not the only one with sticky tyres that goes to the track.

I dont know how I would test it unless wheel slip rates can be logged over the OBD port.
If you logged x,y,z accels (on the phone and car if available) & all 4 wheel slip rates, then you could do some test runs.

If the ABS kicks in before any wheel slip and the G-force reaches a repeatable value, then that would show G-force alone can engage ABS.

If however: regardless of G-force the ABS kicks in at a particular wheel slip value, then we would show G-force is not used to engage ABS.

I'll have to look through the list of PIDs default in the Torque app.
I dont recall seeing wheel slip or velocity in the list.
If we knew the custom PIDs they could be requested.
I'll look into it.

[bestwheelbase]

What's the story about the damaged car in post 181?