VSC, TRAC & other STAR system experiences

Hank, I understand the confusion about the instructions to "steer into the skid" and I just hope I haven't got it backwards too.

As I understand it, "steering into the skid" will generally (always?) have you doing the same thing as "pointing the front wheels in the direction you want to go." Here's my logic, using the example that started this thread. Say I'm headed directly east and the vehicle starts to spin counterclockwise. The vehicle has rotated and is now pointed northeast, but the direction it's skidding (the direction it's still traveling) is still east. Therefore steering into the skid would mean pointing the front wheels rightwards to face directly east. If you have (or regain) enough traction and take this action before you get too far rotated (say, pointed north), you should recover from the skid.

In this example if you steered more to the left/north (if that's the way you define steering into the skid) I think that would indeed confuse the system and mess up the recovery. In most cases I don't think you need to do any steering at all with VSC to recover properly, but modest corrections that aren't made too fast will probably not be a problem.

I have to admit that I'd been driving cars & trucks & motorcycles in snow for several years and doing all kinds of things with them before I ever heard this bit about steering into the skid. I didn't understand what it meant then, and gradually came to the understanding I related above. Maybe I'm wrong! For certain there are lots of experts on this forum that can set us straight.
 
Steering into the skid

Yes, MicaBlue03, you have it correct. You steer in the direction you want the car to go, this is what is meant by the inane phrase "steering into the skid". If you are turning left around a corner and the rear end slides out to the right the vehicle will now be rotating to the left so you need to turn the steering wheel to the right - whether you have VSC or not.
 
I have been in the snow with mine alot, and it works great, the VSC is bar none better than what we can do. It really pulls you back straight. I do not want to make it sound like we are oblivious to the weather with this stuff, but it sure helps in time of need. DAC works great to.

Toyota leads the way softly and quietly, GM and the rest are finding out everyday that they are way behind.
 
Re: Steering into the skid

dcampen said:
Yes, MicaBlue03, you have it correct. You steer in the direction you want the car to go, this is what is meant by the inane phrase "steering into the skid". If you are turning left around a corner and the rear end slides out to the right the vehicle will now be rotating to the left so you need to turn the steering wheel to the right - whether you have VSC or not.
Click to expand...

Hmmm... Okay, suppose you were driving in the snow around a sweeping left-hand bend on a tight mountain road and the back end of your 4Runner begins to drift to the right. If you were to turn the steering wheel to the right (into the skid) to regain control, you would end up in the guardrail (remember, sweeping left-hand turn) or at least off the shoulder of the road.

With stability assist doing its job, you could just keep your steering angle constant (to avoid the guardrail) and the rear end should fall back in line. So in this case you would not want to steer into the skid.

Keep in mind that this is only an example off the top of my head..... I'm sure there are plenty of other possible scenarios where stability assist would be more beneficial without turning into a skid.
 
Hank said:
but the owner's manual for my dad's ML320 states that you should steer/point the wheel in the direction you want to go (intend path of direction) instead of steering into the skid as that will confuse the VSC system
Click to expand...

Exactly my point.
 
With VSC, you do not have to "correct" your slide...that's the computer's job! You point the steering wheel in the direction that you want to go. Keep a steady hand on the steering wheel and trust the computer, which will be the hardest thing for you to do. Do not panic. Also, keep a steady pressure on the gas pedal...do NOT stomp on the brakes, unless you're about to hit something. VSC will do the braking and dethrottling for you.

Three examples:

1. If you are going straight (and want to go straight) and your 4runner's tail is sliding to the right/left, then keep the steering wheel straight. So, in this example, you're steering INTO the skid (steering wheel straight ahead), which is where you want to go.

2. If you're making a turn around a corner (or taking an off-ramp) and your 4runner starts to slide out (aka plowing ahead or UNDERSTEER), then keep the steering wheel in the direction of the turn! In this example, you're steering AWAY from the skid...remember, you do NOT have to correct the skid yourself...let the computer do it...just keep pointing the steering wheel into the turn, which is where you want to go.

3. If you're making a turn around a corner and your tail slides out big-time (think rally cars around a corner; aka OVERSTEER), so much that your 4runner is pointing into the curb, THEN you will need to steer INTO the skid...BUT, still point the steering wheel to the direction that you want to go. Remember, the degree that you turn the steering wheel should be enough to get you back in the direction of the turn. Do NOT over-correct beyond your turn.

Your job is to tell the computer what direction you need the car to go. The computer will do everything else.

So, remember:

1. Keep steering into the direction that you want to go, regardless of where your 4runner is sliding.

2. Do not panic.

3. Do not stomp on brake pedal unless you're about to hit something.

4. Keep a steady pressure on the gas pedal and steady hands on the steering wheel. This will be the hardest part...trusting the 4runner's STAR system to do it's job.

5. Lastly, remember, STAR cannot alter the basic laws of physics. But it does make us a better driver in an emergency situation. It reacts quicker than ordinary driver's reflex.

Hope this helps.
 
Why not let off on the gas instead of applying steady pressure? Will the systems not work if I'm NOT giving it some gas? I know it will dethrottle for me but why not let off on my own as well?

Thanks,

G3 Trout Runner
 
I am not sure if VSC will still work if you take your foot off the gas pedal. I know that if you stomp on the brakes, VSC turns off, and ABS (along with EBD) comes on. If you're taking a turn around a corner in the snow, you may not want VSC to turn off while you're sliding. As for letting off the gas pedal, i am not sure.
 
computer is faster

before you realize that you are skidding, the computer has already started to compensate. If you let off the gas when you realize you are skidding, it won't affect the direction, just your speed.

Now, if you could change the nerve conduction velocity from your brain to your leg and the muscle contraction speed to let up on the gas before the computer could react, you'd have a different situation. The only one who could do that is "Dash" from the Incredibles, and he is too young to drive. :)
 
In my experience VSC will work whether you take your foot off the gas pedal, keep it on, or accelerate harder. With braking and de-throttling the system may well inhibit attempts at strong acceleration that would result in too much wheelspin though.

As to the question of what's best to do with your feet, I suppose that depends on the situation.

From what Thai said, I suppose the system logic is that if you're braking hard you're more interested in stopping than in maintaining a specific direction of travel. Makes sense to me.
 
Thai said:
I am not sure if VSC will still work if you take your foot off the gas pedal. I know that if you stomp on the brakes, VSC turns off, and ABS (along with EBD) comes on. If you're taking a turn around a corner in the snow, you may not want VSC to turn off while you're sliding. As for letting off the gas pedal, i am not sure.
Click to expand...

I'm not so sure that the VSC turns off just because the ABS is active.... stability assist is almost like an advanced ABS system and it used the wheel speed sensors (as well as the ABS) to work.

In my "testing" of the 4Runner on the snow-covered parking lot, I took a few turns too fast (without using the gas pedal or brake pedal) and the stability assist still worked as intended.
 
Will VSC/TRAC/EBD work if you're in Neutral? We've had quite a bit of rain in SoCal recently and the reporters on the news mentioned that if you're going into a skid or hydroplaning, you should shift into N and let it ride. IMO, I really don't think that's a good idea. But then again, it may have been intended for regular cars w/o any VSC/TRAC. Just thought that it might be worth mentioning.
 
Hank, I've never seen a mention of the STAR system stuff disabled while in neutral, and I can't see any reason why it would be. I can also think of plenty of reasons why you'd want this stuff to work the same no matter whether in neutral or not. Except for traction control, of course, which would be inactive while in neutral.

I gotta guess the reporters are just flapping their lips when talking about shifting into neutral while you're in the middle of a hydroplane incident. Seems like it wouldn't help things and would be a distraction.

For RWD automatic transmission vehicles without ABS there has always been a good reason to shift into neutral when coming to a stop in slick conditions. Even at idle (and especially at the high idle of a cold engine) the torque applied by the engine to the rear wheels can cause them to overpower the gentle braking that would often be applied to all four wheels. I used to see this with some frequency in the winter, with vehicles creeping through intersections--they'd have the front wheels locked and skidding while the rear wheels were powering the vehicle slowly ahead, spinning slightly. My wife had an Oldsmobile that would do this all the time, and shifting into neutral fixed the problem entirely.

Overall, I think that one of the coolest things about the STAR system stuff is that you don't need to know much about it or to change your behavior for it to work well and maybe save your bacon. Of course, it's fun for folks like us to discuss anyway!
 
MicaBlue03 said:
Overall, I think that one of the coolest things about the STAR system stuff is that you don't need to know much about it or to change your behavior for it to work well and maybe save your bacon. Of course, it's fun for folks like us to discuss anyway!
Click to expand...

Yup, 3 pages and counting....:p
 
MicaBlue03 said:

For RWD automatic transmission vehicles without ABS there has always been a good reason to shift into neutral when coming to a stop in slick conditions. Even at idle (and especially at the high idle of a cold engine) the torque applied by the engine to the rear wheels can cause them to overpower the gentle braking that would often be applied to all four wheels. I used to see this with some frequency in the winter, with vehicles creeping through intersections--they'd have the front wheels locked and skidding while the rear wheels were powering the vehicle slowly ahead, spinning slightly. My wife had an Oldsmobile that would do this all the time, and shifting into neutral fixed the problem entirely.
Click to expand...

Wow, talk about needing a brake adjustment!!

Any time you ever see the front wheels locked and the back wheels spinning ahead, you're definitely looking a vehicle with a terrible rear brake adjustment.

There is just no way that an idling engine can ever overpower the brakes in any conditions....
 
We have had some bitterly cold weather the past few days (-35), and coupled with previous compacted snow, and ice, roads have been slippery and a vehicle breakdown could have disasterous consequences. I was to attend a meeting last night, at a town about 40 miles away. The most direct route was the highway, however a serious accident had closed the highway for an undetermined time. I backtracked and detoured on farm roads, fully ice packed, windy, and narrow. Coupled with my Winter Dueler tires, the vehicle performed flawlessly, however I drove safely. On my return trip, I had to apply the brakes hard, and the ABS brakes did an excellent job of stopping me straight.

I am more pleased with the safety systems an overall vehicle confidence, having driven in challenging conditions.
 
Hitman, I think we may be talking about different sutuations. You said:

"Any time you ever see the front wheels locked and the back wheels spinning ahead, you're definitely looking a vehicle with a terrible rear brake adjustment."

Seems like that would be true on higher-traction surfaces or under heavy braking. But here's the situation I was thinking about: It's a cold, slick day and the car is still cold. You're coming up to a stop sign slowly and apply the brakes very gently. As you increase the brake pressure carefully you hope to come to a stop. But instead you feel wheels skidding and you've lost steering authority, so you know the front wheels are locked. You don't know it, but the engine is still turning the rear wheels because the ATF is cold and the idle is high, and you aren't using much brake pressure.

If you know what your rear wheels are doing you can hit the brakes harder and stop them for certain, but of course you have no control. You can try letting up on the brakes to get the front wheels moving again and be able to steer, but then you won't stop.

This situation was made worse because many vehicles had most of their braking biased to the front, for best stopping on dry roads.

These days, the problem is much more rare, except perhaps for automatic pickups in 2WD that don't have ABS. I don't know how many of these there are.
 
leftyrb said:
On my return trip, I had to apply the brakes hard, and the ABS brakes did an excellent job of stopping me straight.
Click to expand...

EBD = Electronic Brake Distribution probably played a HUGE factor in that too. Its suppose to modulate braking on the 4 wheels to keep you as straight as possible and avoid fishtailing...
 
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