Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB
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Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB (https://www.ft86club.com/forums/index.php)
-   BRZ First-Gen (2012+) — General Topics (https://www.ft86club.com/forums/forumdisplay.php?f=23)
-   -   Feeling the Nannies for the first time. (https://www.ft86club.com/forums/showthread.php?t=33236)

Goody 04-09-2013 07:31 PM
Feeling the Nannies for the first time.
 
I have about 500 miles on my BRZ and thought it would be nice to learn about the "Nannies." So I drove out to the sticks (family property) and visited some wide gravel corners. I had my first noticeable intervention when I tapped the accelerator near the apex of the turn. I wanted to see how much the back would kick out at ~30MPH on gravel and figured this would do it. I figured I might very well slide out or spin out but this was a seriously big, flat corner with great visibility and no roadside hazards other than grass --so I accepted the possible consequences of sliding around a little bit! Anyways, the rear started sliding out and BAM! The car started doing all sorts of weird stuff and rather suddenly I was heading out the corner going 15MPH in a strait line.

The reason I bring this up is that I am still really confused about what exactly the "Nannies" do to make the car safer. I would love to hear some stories or some impressions/knowledge from those who have them.

My best description that I can muster about the "take-over" was as follows:
Steering got a bit heavy when I tried to use just a fraction of counter-steer.
Brakes were applied rather abruptly but only for a moment.
Throttle was cut/reduced.

Which system did what and how would VSC "Sport" mode change that?

Redirection to old posts or links to knowledge that has credibility= :happy0180:

kurbkilla 04-09-2013 09:13 PM
The problem was the fact that it was on gravel. The traction control is for "solid" paved ground, with gravel the road way can "move/slide" confusing the sensors.


For gravel I would drive with all systems off. But I would keep the TC on for the streets.

Hope that makes sense.

Goody 04-09-2013 09:20 PM
Quote:
Originally Posted by kurbkilla (Post 853703)
The problem was the fact that it was on gravel. The traction control is for "solid" paved ground, with gravel the road way can "move/slide" confusing the sensors.


For gravel I would drive with all systems off. But I would keep the TC on for the streets.

Hope that makes sense.

Makes perfect sense. Good insight. Thanks!

continuecrushing 04-09-2013 10:32 PM
[ame="http://www.youtube.com/watch?feature=player_embedded&v=j8qggahGNH0"]Toyota 86 Traction Control Demonstration [SKIDPAD] - YouTube[/ame]

Ganthrithor 04-09-2013 10:39 PM
What the fuck is wrong with youtube? For the last day or two I haven't been able to watch videos at any resolution-- even 240p shit sits there buffering for several minutes after every few seconds of video. It's not my internet connection, youtube's just been unusable.

OrbitalEllipses 04-09-2013 11:16 PM
Brakes would be EBFD. From what I understand the ABS pump is able to individually modulate each caliper to control wheel spin and wheel lock such that the tires have maximum traction. Throttle response and loss of power comes from VSC/TCS IIRC; it senses wheel spin and reduces input so the wheel stops spinning.

shiumai 04-09-2013 11:22 PM
Quote:
Originally Posted by kurbkilla (Post 853703)
The problem was the fact that it was on gravel. The traction control is for "solid" paved ground, with gravel the road way can "move/slide" confusing the sensors.
how is gravel different from sand, water, ice or snow? all of them can produce a loss of traction between the tire and road surface causing the car to move/slide. gravel shouldn't confuse the sensors any more than any other medium that causes loss of traction. (I'm asking sincerely).

Goody 04-09-2013 11:52 PM
Quote:
Originally Posted by shiumai (Post 853936)
how is gravel different from sand, water, ice or snow? all of them can produce a loss of traction between the tire and road surface causing the car to move/slide. gravel shouldn't confuse the sensors any more than any other medium that causes loss of traction. (I'm asking sincerely).
This is another good insight. Maybe "confuse" should be changed to "activates" and instead of thinking this is the sensors doing the work it should be the program(s) running the systems. Thinking of it from this perspective makes it seem like the wheel-spin would be registered and the computer would "try" some algorithms to get that to stop. Aside from that it would be very interesting to see just what the computers take into account when deciding if it needs to step in and change things.
@Shutter. I have watched that video many times but it doesn't give any perspective from the driver. Whos is it? What are they trying to do? Watching them spin out and slide around makes me think that they are either not able to actually navigate that course properly given the state of the "driver-aids" or they are purposefully accentuating what the car is capable of with them off... which brings up my original idea for people's personal experiences/thoughts regarding what the "Nannies" do to the car--or don't do.

continuecrushing 04-10-2013 01:47 AM
Quote:
Originally Posted by Ganthrithor (Post 853848)
What the fuck is wrong with youtube? For the last day or two I haven't been able to watch videos at any resolution-- even 240p shit sits there buffering for several minutes after every few seconds of video. It's not my internet connection, youtube's just been unusable.
Right?! I've noticed this as well...


@Goody-If I'm not mistaken, the skidpad has a plate built into the ground and when the vehicle passes over it, the plate moves toward the outside of the turn(so if you are turning left, the plate will try and move the rear of the vehicle right) to simulate loss of traction from the rear of the vehicle.

(Edit)-Now that i watch the video in fullscreen, I dont think they have any moving plates, but the pad is meant to be very slick because of the water, so even when just trying to accelerate the back end tries to swing around.

I havent watched the video with sound yet(we're moving, and no speakers on pc yet) but it does help to show how much each vehicle mode will allow the car to rotate/how it can help save you when the rear end tries to come around! As to how it tries to prevent too much oversteer, I dont know...In for more research!

strat61caster 04-10-2013 01:54 AM
Quote:
Originally Posted by Goody (Post 853991)
This is another good insight. Maybe "confuse" should be changed to "activates" and instead of thinking this is the sensors doing the work it should be the program(s) running the systems. Thinking of it from this perspective makes it seem like the wheel-spin would be registered and the computer would "try" some algorithms to get that to stop. Aside from that it would be very interesting to see just what the computers take into account when deciding if it needs to step in and change things.
@Shutter. I have watched that video many times but it doesn't give any perspective from the driver. Whos is it? What are they trying to do? Watching them spin out and slide around makes me think that they are either not able to actually navigate that course properly given the state of the "driver-aids" or they are purposefully accentuating what the car is capable of with them off... which brings up my original idea for people's personal experiences/thoughts regarding what the "Nannies" do to the car--or don't do.
You're overthinking it.

[ame="http://en.wikipedia.org/wiki/Traction_control_system"]Traction control system - Wikipedia, the free encyclopedia[/ame]

Any time the system detects wheel slip the brakes are applied to the individual wheels to regain traction. The video demonstrates how much slip the system allows before kicking in and regaining traction for you. They're aren't any algorithms or "alternatives" to try, it's a feedback loop; if slipping apply brakes => is it still slipping? if yes apply brakes more, if no take brakes off. Overly simplified; yes (there's some complicated maths) but conceptually it's a pretty simple system.

#87 04-10-2013 02:24 AM
not sure, i do know if you stomp the gas with all systems on you can still spin out.

LeeMaster 04-10-2013 03:48 AM
Quote:
Originally Posted by shiumai (Post 853936)
how is gravel different from sand, water, ice or snow? all of them can produce a loss of traction between the tire and road surface causing the car to move/slide. gravel shouldn't confuse the sensors any more than any other medium that causes loss of traction. (I'm asking sincerely).
Gravel is a combination of sand, rocks, and dry mud. Small rocks can move around a bit which will definitely throw off any sensors from the nannies. Combine that with sand and you start to lose traction which forces the nannies to activate more than it should. Think of vibration + air lift, nannies are sensitive in that area because they are designed to activate the instant they detect something wrong. We all know gravel produces uneven road surfaces even on the smoothest ones and will cause the suspension to do more work which will trigger the nannies if driven hard. This is why there are dirt tires and snow tires and street tires etc(as we all know).

When driven on tarmac, the roads hold up together and the only thing the computer will have to work on is debris and water(Suspension loves tarmac). Ice roads youre totally f**ked without the proper tire, and if your car is on sand like in southern Iraq then youre screwed..

Turdinator 04-10-2013 03:48 AM
Quote:
Originally Posted by Goody (Post 853466)
I have about 500 miles on my BRZ and thought it would be nice to learn about the "Nannies." So I drove out to the sticks (family property) and visited some wide gravel corners. I had my first noticeable intervention when I tapped the accelerator near the apex of the turn. I wanted to see how much the back would kick out at ~30MPH on gravel and figured this would do it. I figured I might very well slide out or spin out but this was a seriously big, flat corner with great visibility and no roadside hazards other than grass --so I accepted the possible consequences of sliding around a little bit! Anyways, the rear started sliding out and BAM! The car started doing all sorts of weird stuff and rather suddenly I was heading out the corner going 15MPH in a strait line.

The reason I bring this up is that I am still really confused about what exactly the "Nannies" do to make the car safer. I would love to hear some stories or some impressions/knowledge from those who have them.

My best description that I can muster about the "take-over" was as follows:
Steering got a bit heavy when I tried to use just a fraction of counter-steer.
Brakes were applied rather abruptly but only for a moment.
Throttle was cut/reduced.

Which system did what and how would VSC "Sport" mode change that?

Redirection to old posts or links to knowledge that has credibility= :happy0180:
With a nice safe corner like that why didn't you try the car in VSC Sport and then fully disabled just to feel the differences? I know i would have. Sounds like a fun afternoon. :burnrubber:

kolpap 04-10-2013 03:50 AM
The "nannies" are a conjunction of all ABS, EBD, TRAC, and VSC working together to keep the car under the driver's intended control although for most people they just get in the way. In your case, I would assume that VSC would be the prime moderator in determining how sideways you should slam into a tree if there was one.
From what i can work out, the VSC computer will individually brake whichever wheel needs brake force applied under it's parameters and TRAC cuts power to avoid further oversteer allow minimal slip angle.

Setting VSC to sport mode would basically set the parameters to allow you to have a little more slip angle, backing off the TRAC throttle intervention but not more than a pre-set factory setting and trying its best to keep the car recoverable.

Of course turning all the systems off would allow you to slide all day long.


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