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Discussion Starter #1
The last 13 years I have been driving trucks that did not feature any kind of traction control or vehicle stability systems. As a motorcycle guy and ex-roadracer I am not really a huge fan of electronic safety systems making choices for me.

Now that the snow has flown and I have had a chance to drive our new 2013 Xterra in slippery conditions I have learned a fair bit about how well or not these systems work and how them impact the driving experience. As TC and VSS are separate and distinct systems I will discuss each separately.


Traction Control:

At slow speeds in slippery conditions in areas like parking lots TC is horribly annoying and pointless. At low speeds it is much easier to spin the back tires but the ramifications of spinning the tires slightly at very low speeds is virtually nil and thus the system kicking in under these conditions is totally pointless. The system kicking in constantly every time you try to press the accelerator is horribly annoying and in deeper snow where the front wheels are holding the vehicle back, the TC renders the vehicle nearly immobile as there is little traction but the system won't let the drive wheels spin so you press the gas and nothing happens. Makes me want to get out and whack the vehicle's computer brain with a large mallet.

At higher speeds, I can see some point to the TC as losing traction momentarily could cause some loss of control which is a lot more difficult to regain. IMO the TC should not be active below 40 k/hr.


Vehicle Stability System:

This is where the vehicle brain selectively applies the brakes in order to straighten out a slide or spin. The primary problem with this kind of system that I can see is that it is a purely reactive system and has no ability to prevent a spin or slide occurring. It can only kick on once the vehicle has lost control and try to bring the vehicle back to going straight forward. The problem is that the system doesn't know where the vehicle is going. It may be able to straighten out a sliding vehicle but that can be a problem if the vehicle is going straight off the road.


Practical Application:

One of the things that concerns me about these kinds of systems is that many drivers may take the attitude that they do not have to pay attention or drive properly because the safety systems will save them and make the vehicle uncrashable.

I purposely pushed these systems to and beyond their limits because I wanted to know what they were capable of and what I discovered is that they are not even close to being infallible. I was able to turn my truck fully around on a snowy road with the TC and VSS enabled.

In another forum a number of people suggested it was impossible for a human to outperform the computer. My experience shows otherwise. In most cases I find myself beginning to correct a skid or slide before the TC/VSS systems kicked in. The reason is these systems are purely reactive. They don't know what is going to happen. As the driver, I know that when I come around a corner and push the gas the back end is likely to slide so I can be prepared for the slide before it happens. Thus I can begin to correct that slide before the computer system even knows it is occurring.
 

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I don't get where you are talking about VSS (VDC on the Nissans) doesn't work if you are are sliding straight off the road. At that point ABS would be the system in play. VDC is for Over/under steer.

You do realize there is a VDC OFF button right?

As far as being able to spin the truck around with the systems on..... they cannot create traction that is not there. They also cannot defy the laws of physics. They are there to help not to take over and be a parachute.
 

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Interesting take on these systems. I'll agree that a well trained driver can outperform most any stability control system. I can't even count the number of times I've read articles about how professional drivers get mad at the electro-nanny's in cars today as they try to get lap times down on a track. I've run into one exception recently. It's the Ferrari 599, which has such a finely tuned stability control, it lets the driver wring every last ounce of speed out of the car before kicking in. But, our X's don't have that kind of engineering behind them...

IME, the VDC on our trucks is pretty good. Driving quickly on dirt roads and having washboard bumps suddenly make the truck get sideways was a good example of how the VDC works well. It knew the truck was starting to point the wrong way and straightened it out. Whether it was in a straight line, or a corner, it kept me from getting out of control. Whether or not the driver could respond as well is another question. I would guess Nissan set the VDC up so that the average or poor driver wouldn't get into trouble. For that purpose, it works fine.

I can't comment on snow conditions. I CAN tell you that not having any traction control on a car that's on any icy road, with lousy tires and facing a slight uphill from a dead stop, takes a lot more skill to get a car moving than some people have. It's all about the driver being able to "feel" what's happening with the vehicle. Not too many people are in touch with their vehicles to the point where they know when the tires are slipping or right on the edge...

Your racing experience is what taught you those things. I've raced bikes in the past as well. Didn't get past amateur level though... but, without that experience, there's no way I would know when a vehicle of any type is close to the edge of losing control.

Nissan isn't targeting advanced drivers with their VDC and I'm sure that applies to most every car company out there. You can always turn the VDC off. At least we have that option. Too bad they don't equip the X with a button to turn off ABS. But, that's just a fuse...
 

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These systems are designed for the 98% of the drivers who don't actually know how to drive properly and control their vehicle and who aren't planning for a skid/slide because they don't know they are going too fast or that hitting the gas will kick the rear end out.

I'll swap my ABS actuator with yours :)

My VDC relay has taken a crap and is totally non-functional, you can skid and slide on every turn :) (ABS still works though)
 

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Discussion Starter #5
I don't get where you are talking about VSS (VDC on the Nissans) doesn't work if you are are sliding straight off the road. At that point ABS would be the system in play. VDC is for Over/under steer.

You do realize there is a VDC OFF button right?
Yes, which was one of the primary reasons I chose the Xterra. I was initially looking at the Tacoma but it doesn't have a way to turn off the horribly annoying stability control, which turned me off that truck.


As far as being able to spin the truck around with the systems on..... they cannot create traction that is not there. They also cannot defy the laws of physics. They are there to help not to take over and be a parachute.
The VDC is supposed to be able to prevent the vehicle spinning in the first place. All the media and hype about these systems is they prevent the vehicle getting out of control. In 15 minutes I was able to show that is not true.
 

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Discussion Starter #6
Interesting take on these systems. I'll agree that a well trained driver can outperform most any stability control system. I can't even count the number of times I've read articles about how professional drivers get mad at the electro-nanny's in cars today as they try to get lap times down on a track.
I am a long way from a professional driver but they certainly annoy me.


IME, the VDC on our trucks is pretty good. Driving quickly on dirt roads and having washboard bumps suddenly make the truck get sideways was a good example of how the VDC works well. It knew the truck was starting to point the wrong way and straightened it out. Whether it was in a straight line, or a corner, it kept me from getting out of control. Whether or not the driver could respond as well is another question. I would guess Nissan set the VDC up so that the average or poor driver wouldn't get into trouble. For that purpose, it works fine.
Kind of. In most cases it is an early warning that the vehicle is beginning to slide but as I discovered it is a long way from being foolproof.

We have a fair number of gravel roads around here and washboard is a fact of life. It is not exactly difficult to control the rear end slide under power when accelerating over washboard.

I can't comment on snow conditions. I CAN tell you that not having any traction control on a car that's on any icy road, with lousy tires and facing a slight uphill from a dead stop, takes a lot more skill to get a car moving than some people have. It's all about the driver being able to "feel" what's happening with the vehicle. Not too many people are in touch with their vehicles to the point where they know when the tires are slipping or right on the edge...
As an example, last night I was out in a grassy snow covered field. From a stop the rear wheels spun immediately and we went nowhere at first. However the spinning tires cut into the snow and begin to produce a tiny amount of forward movement. The more they move the more snow can be cut into and thrown backwards which fairly quickly results in us driving away.

With traction control and VDC the system detects wheelspin and applies the brakes and you sit there with your foot on the gas going exactly nowhere. With our 4WD this isn't so much of a problem but in a non-4WD vehicle with a non-selectable TC system it becomes a HUGE problem.

In the end these kinds of electronic nannies are here to stay because as someone else noted they are designed for the 98% of drivers who don't know how to drive. As long as I am able to turn the thing off when I want to I will be satisfied. Its when the nanny systems are non-optional that I get cranky.
 

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The VDC is supposed to be able to prevent the vehicle spinning in the first place. All the media and hype about these systems is they prevent the vehicle getting out of control. In 15 minutes I was able to show that is not true.
its supposed to help

stilll can't prevent some idiot from yanking on the wheel when they shouldn't
 

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I will live with the few annoyances from time to time (that I can turn off with the push of a button for the most part) to allow it to cover my ass on the few times that I really needed it. When you expect the back to step out is one thing. When you are not expecting it to is when the VDC shines.

And it does know where you are trying to go (not just straight), there is a steering angle sensor to give that input. And yes, it will help go through a turn that you are plowing through.

Infallible? You are underestimating the power of stupidity. It is still possible that you put the system into an impossible situation it can't recover from. But that takes extreme situations (usually imposed by doing something totally stupid).

I have hung the tail out for decades, especially in the snow. I have looped a few vehicles around from time to time. I actually got rid of a truck and got the Xterra because the Xterra had VDC that the truck didn't. Not that it is needed, you don't need A/C or power windows either, but because I realize the value of such a system.

One of the last cars you could get in the US without any computer stability controls was the Viper. One of the reasons it was out of production for a year was they had to develop a computer stability system for it so it was legal to sell. Every new car and light truck has the system. At least it isn't as bad as what Toyota was selling a few years back. That was a fall on your face, I just killed it, pulling out of a parking lot and a tiny tire chirp on sand. The Nissan system actually gives you a little wiggle room before it steps in.
 

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I was quite impressed one day when I met an oncoming car around a narrow outside corner and I drifted out a bit farther than I meant to, dropping off the edge of the road. It was wet and raining with standing water and my back end lost traction and drifted out.

I back steered of course and held directional control of the front end, but the rear end caught the road back all at once and I felt the momentum build, and the body lean switching direction. So I was preparing for a fishtail with my rear end swinging out the opposite direction it had initially swung.

During all this I was also feeling and hearing the individual brakes activating, and as a result the VDC system prevented the backlash. I was prepared to start steering opposite lock, but it never happened, as soon as my rear end caught traction, it just stayed put and I drove on.

Could I have driven out of it without VDC? Probably, but possibly not, depends on just how far the rear would have fishtailed out. Given the amount of momentum I felt, it would have went out. I've driven out of fishtails before in vehicles without traction control, but not that quickly.

What if another car was coming when this happened? The VDC helping may have made the difference between me regaining control in time to avoid an accident, or my rear end drifting out into the oncoming lane. Given I wasn't intending to go wagging my tail down the road, the system kicking in and assisting me I have to admit was welcome. Much as I'd like to, I can not react to and individually control what wheels get braking, but the computer can, and in that instance it slowed the wheels necessary to kill my twisting momentum and bring me back in line with my direction of travel without additional efforts from me other than maintaining directional control and some very light braking.

That said, I'm not a big fan of control being taken away from me. I'm not big on ABS, I don't like computer systems being able to override control inputs, so this disturbs me to some degree, that I have been impressed by the systems ability to actually help me recover from situations better than I'm capable of with just driving skill.

My take on it is this. For my Xterra, the electronic aids are nice. I'm growing to appreciate them and learn to understand what they will do and try to work with it. I think it can go too far, like some systems I've heard of that can turn the steering wheel for you and brake on their own to avoid objects.

But take the E-limited slip, that has been awesome on many occasions, like having LS diffs front and rear without the added mechanical complexity and wear parts of a true LS, and in the case of the rear leaving you with a full lockup diff that acts like a LS when unlocked. Plus a real LS will open if you lift a wheel, the E-LSD doesn't.

As for the systems on the Xterra now, I think is an added benefit just like the advent of power steering and hydraulic brake boost. You don't hear many people saying "I wish my truck had manual steering." Overall you never know it's there until some unusual driving situation, and in that case you can (mostly) turn it off if it's causing you grief.
 

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The VDC is supposed to be able to prevent the vehicle spinning in the first place. In 15 minutes I was able to show that is not true.

Again, software cannot create traction that is not there and cannot defy the laws of physics. If you swerve on ice and snow and put too much sideways momentum on the rear-end, how would it correct it? There simply is not enough grip at the tires.

VDC, ABS, TC work well but are not magical.
 

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I can't stand these nanny bots trying to control my driving. I disable them every chance I get.

All these aids are making it more dangerous on the highways. People think they have these aides so they can drive faster, more reckless in poor conditions because they believe the car will keep them on the road.

We need a ban on all driving aides!!!
 

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I'm sure these have reduced the amounts of wrecks and not increased them.

But it is obvious there are people that think it does mean that they can swerve on slick roads and not spill a latte lol.
 

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Discussion Starter #14
Hi Saputin. I think you need better tires. Especially if you're still on those Rugged Trails. This recent freeze thaw cycle has created some truly slippery conditions that make me glad to have the snow boots on.

I have to try to get the VDC to engage, traction control is a more frequent visitor.
Bahh, I've never had dedicated snows and never felt the need for them. M&S tires are fine if you know how to drive. With 4WD I don't think there is a need for snows.

I get the TC and VDC engaging all the time. Even had them kick in on dry pavement.
 

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Bahh, I've never had dedicated snows and never felt the need for them. M&S tires are fine if you know how to drive. With 4WD I don't think there is a need for snows.

I get the TC and VDC engaging all the time. Even had them kick in on dry pavement.

Well if you have VDC and TC kicking in on dry pavement then you are driving aggressive.

4WD does nothing to help you stop in snow.
 

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the stability control monitors the steering angle and throttle sensors to know when to expect a loss of control, so its not only reactionary. it also has g-sensors to know when you're sliding. I've had mine kick back on to straighten out a slide even with the vdc turned off.

the traction control is there to prevent tires spinning, period, if you want to be able to spin the tires, turn off the vdc. it turns back on just as easy once you're out of the parking lot.

personally, i leave the vdc on when conditions are variable and can jump up and surprise you, but when theres sleet/snow on the ground or its wet i'll turn vdc off so i can control things myself rather than relying on the computers to know what i want to do better than i do.
 

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Discussion Starter #17
the stability control monitors the steering angle and throttle sensors to know when to expect a loss of control, so its not only reactionary. it also has g-sensors to know when you're sliding. I've had mine kick back on to straighten out a slide even with the vdc turned off.
The system may monitor all those things but it has no clue what is coming next. I am almost always beginning to correct a slide before the VDC kicks in.

I had a suspicion that the VDC would kick back in, even when turned off, if things got really out of control. So I specifically tried to spin the truck and the VDC did in fact not kick in when it was turned off. I was able to completely spin the truck and do donuts ... so it ain't doing anything when it is turned off.
 

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The system may monitor all those things but it has no clue what is coming next. I am almost always beginning to correct a slide before the VDC kicks in.

I had a suspicion that the VDC would kick back in, even when turned off, if things got really out of control. So I specifically tried to spin the truck and the VDC did in fact not kick in when it was turned off. I was able to completely spin the truck and do donuts ... so it ain't doing anything when it is turned off.
That is my experience as well. You can still here the ABS pump cycling away, but that is just giving you the limited slip action so all the tires are spinning. But you can slide it and do doughnuts with it off.

If it "kicked in" while off, you simply are not a good enough driver to tell the difference between the VDC activating and getting a random bit of traction. So many people think they are some awesome driver that they are not. Usually the better they claim to be, the worse they really are and will never admit it.
 

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Guess im one of the few that is thoroughly impressed with VDCs ability to get my vehicle straight again. I've luckily never been put in a situation I couldn't have handled myself luckily, but VDC handles it with no over correction. Yes it's not perfect, some situations it's downright annoying (climbing a loose hill). But there are situations road conditions can put a driver in that even the best can't outperform a computer actuating all the brakes independently. Also with so many manufactures doing full time traction control or as stated above, ones that don't actually turn off, I'm thankful for what Nissan has done with VDC


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That is my experience as well. You can still here the ABS pump cycling away, but that is just giving you the limited slip action so all the tires are spinning. But you can slide it and do doughnuts with it off.

If it "kicked in" while off, you simply are not a good enough driver to tell the difference between the VDC activating and getting a random bit of traction. So many people think they are some awesome driver that they are not. Usually the better they claim to be, the worse they really are and will never admit it.
Well I guess you don't have to believe me any more than I have to you, but it did kick back in, the vdc light started flashing along with the slip light when it went into snap oversteer in the wet. I can go turn donuts all I want too without it kicking back in, it's when you're sliding sideways that it intervenes.

The difference between you "correcting before the computer knows what's going on" and reality is that the vdc knows the type of inputs that are likely to unsettle the vehicle, and begin correcting at the very moment you're making ham fisted moves. My old mazdaspeed3 would be grabbing brakes on the outside tires at the same moment I was yanking the wheel and lifting throttle, before I was even completely off the gas it was correcting for the coming lift throttle oversteer.
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