Just How Important Is the Traction Control?

[Norm Peterson]

Even the nannies have their limits, and a split-mu condition (such as right side tires on pavement, left side tires on grass/sand) is likely one of the more severe tests that you could throw at them.


Norm

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[1emglenn]

Hi,

I know this question sounds like heresy, but please bear with me for a moment. I'm not trying to start yet another debate on the subject of good drivers vs. nannies. I'm all for nannies. I'm just trying to understand how they actually work.

The electronic stability system comprises two components:

1. Traction Control - this senses when a driven wheel loses grip. When that happens it cuts off power. You press the throttle and nothing happens. It will allow only as much torque to be sent to the wheels as the least gripping wheel can handle.
2. AdvanceTrac - this senses when the car's trajectory doesn't correspond to the steering input. When that happens it applies the brakes to various degrees to each individual wheel, to keep the car from spinning.

It's generally agreed that turning the traction control off on the street is bad, and that if you do that you'll eventually go backwards into a tree. Or worse, into a crowd. But will you really? Why would you? Isn't it the job of the AdvanceTrac to keep you on track? Turning off the traction control will merely allow one of the rear wheels to spin. But as long as that spin isn't actually causing the car to swerve you should be fine. And if it does cause it to swerve, then the AdvanceTrac will step in.
The car has a limited slip diff. Even if one wheel spins, the other will still receive a good amount of torque. It will still move. One rear wheel spinning doesn't necessarily mean that the car is out of control. And if it actually gets on the verge of getting out of control, then the AdvanceTrac will keep it straight.
So do we actually need the TC? OK, it's a nice thing to have, but is it actually essential? Is it really so dangerous to turn the TC off, as long as the AdvanceTrac is still up and running?

Thank you.

I previously wrote how as a kid I would use wet parking lots to practice on. But, your question brings to mind another incident that happened much later in the 80's. I was on an expressway with a speed limit of 50, but I was headed to work and a little late. I was probably going around 65. We'd had some rain but the pavement was mostly dry with just patches of moisture, not even puddles. I was headed straight when all of a sudden I felt the rear go. Didn't take my foot off the gas, just corrected with the steering. Everything seemed to be working fine the rear started back to straighten out but then instead of stopping continued swinging around the other way. Before I knew it I had pulled a 180. Dumped the clutch and started using the mirrors, driving backwards down the road. I was able to get her off the road without coming in contact with anything or anybody else. Sat there for awhile trying to figure out what had happened. The only thing I could think was that one of the wheels had lost traction do to some oil on one of those damp spots in the road. Today, with traction control the likelihood of this happening is greatly reduced. Maybe on the track you don't want T/C, but for every day driving it is a blessing.

 

[GregP27]

Most of the stupid Mustang drivers videos I've seen are 100% driver's fault. A good many are leaving a car show and are not srtraight when they hit the throttle. Maybe they wonder afterward why a dragster gets straight before launching.

Also, once a car starts getting sideways, the indicated action is to countersteer a bit and reduce throttle. Most of the video morons countersteer way too much and leave their foot on the floor.

That's fine as long as you have done it in a parking lot / open pavement somewhere with no curbs or k-rails about but, if it's your first time doing it, a narrow road with curbs and other cars / people about is really pretty stupid. When it gets to court, the judge will confirm it was stupid.

If you live in a place like Portland, Oregon where it is frequently wet, Advance trac is a lifesaver and carsaver. I'd want it off, along with traction control, on a road course, though. There are too many times when a 4-wheel drift might be required to get around a corner that you entered a bit too fast to have the nannies sending you into a guardrail.

Traction control is great for normal street driving, but I'd turn it off at a dragstrip. Since I don't street race, it is no issue to me normally.

 

[Dfeeds]

Traction control caused me to get stuck in the snow the other day. I was moving up a small incline with about 3 to 6" of snow. I was spinning but moving up, as expected. Traction control decided to do its thing and kill power and when that didn't solve the problem it then wouldn't let me rev passed 1200 rpms no matter what my throttle input was. I couldn't get through the snow and got stuck in place. I turned off TC, waited for the people behind me to drive around, let the car roll back a bit, and continued on without issue.

So there's an example of a limitation of traction control. That situation could have easily been an accident if the person behind me was riding close. It has its use but it's no replacement for driver skill.

 

[Vlad Soare]

I previously wrote how as a kid I would use wet parking lots to practice on. But, your question brings to mind another incident that happened much later in the 80's. I was on an expressway with a speed limit of 50, but I was headed to work and a little late. I was probably going around 65. We'd had some rain but the pavement was mostly dry with just patches of moisture, not even puddles. I was headed straight when all of a sudden I felt the rear go. Didn't take my foot off the gas, just corrected with the steering. Everything seemed to be working fine the rear started back to straighten out but then instead of stopping continued swinging around the other way. Before I knew it I had pulled a 180. Dumped the clutch and started using the mirrors, driving backwards down the road. I was able to get her off the road without coming in contact with anything or anybody else. Sat there for awhile trying to figure out what had happened. The only thing I could think was that one of the wheels had lost traction do to some oil on one of those damp spots in the road. Today, with traction control the likelihood of this happening is greatly reduced. Maybe on the track you don't want T/C, but for every day driving it is a blessing.

What you're describing looks like a job for the ESC, not the TC.
The TC merely cuts off the gas, which you should have done yourself anyway in that situation.

 

[Norm Peterson]

I previously wrote how as a kid I would use wet parking lots to practice on. But, your question brings to mind another incident that happened much later in the 80's. I was on an expressway with a speed limit of 50, but I was headed to work and a little late. I was probably going around 65. We'd had some rain but the pavement was mostly dry with just patches of moisture, not even puddles. I was headed straight when all of a sudden I felt the rear go. Didn't take my foot off the gas, just corrected with the steering. Everything seemed to be working fine the rear started back to straighten out but then instead of stopping continued swinging around the other way. Before I knew it I had pulled a 180.

Seems like you had the right instincts - as far as you took them. No flame intended, but you got caught out by your own initial success, thinking that once you caught the first spin that was the end of it.

You have to be ready for the snap-spin in the other direction. This will generally overshoot past "straight ahead down the road" even when you're really on top of the situation with your steering the other way. But what you do when the first spin stops spinning needs to be just as instinctive as catching the initial tailhappiness.



In this little clip taken from a video of a wet track day session a few years ago, look for the nose to first over-rotate toward the left exiting the corner and the much smaller wiggle that follows where the car passes through 'straight' and just a little toward the right, and finally back to straight. Yup, I got a little too greedy with the loud pedal, and yes I'd turned the TC off just like I do for all of my track day driving (and most of my street driving as well - it's downright ineffective at doing what it's supposed to do).



Norm

 

[accel]

Hi,

I know this question sounds like heresy, but please bear with me for a moment. I'm not trying to start yet another debate on the subject of good drivers vs. nannies. I'm all for nannies. I'm just trying to understand how they actually work.

The electronic stability system comprises two components:

1. Traction Control - this senses when a driven wheel loses grip. When that happens it cuts off power. You press the throttle and nothing happens. It will allow only as much torque to be sent to the wheels as the least gripping wheel can handle.
2. AdvanceTrac - this senses when the car's trajectory doesn't correspond to the steering input. When that happens it applies the brakes to various degrees to each individual wheel, to keep the car from spinning.

It's generally agreed that turning the traction control off on the street is bad, and that if you do that you'll eventually go backwards into a tree. Or worse, into a crowd. But will you really? Why would you? Isn't it the job of the AdvanceTrac to keep you on track? Turning off the traction control will merely allow one of the rear wheels to spin. But as long as that spin isn't actually causing the car to swerve you should be fine. And if it does cause it to swerve, then the AdvanceTrac will step in.
The car has a limited slip diff. Even if one wheel spins, the other will still receive a good amount of torque. It will still move. One rear wheel spinning doesn't necessarily mean that the car is out of control. And if it actually gets on the verge of getting out of control, then the AdvanceTrac will keep it straight.
So do we actually need the TC? OK, it's a nice thing to have, but is it actually essential? Is it really so dangerous to turn the TC off, as long as the AdvanceTrac is still up and running?

Thank you.

Just a general note - IMO on a Mustang these systems are not very pronounced.

I had a BMW e90 and traction control was so intrusive, I hated it. It felt like the engine was loosing power during rains with TC light flashing on a dash all the time.

I have a Subary and once I recklessly underestimated a closed road bend in Death Valley. I literally felt like the car was helping me to stay on the road and the help was very inline with Subaru's advertisement I saw many times. Like inner wheels were braking harder than outer ones or whatever. By all means the car should've just understeered and went off road (i've experienced this many times at autox), but instead it stayed pointed in the right direction. It changed the line to the opposite though.

When I went sideways on a Mustang I felt zero help from whatever systems were employed. Also, I only saw TC light flash on a dash once in all years of ownership driving same roads as BMW. I feel wheelspin daily especially at winter as I'm on pirellis.

 

[Norm Peterson]

I have a Subary and once I recklessly underestimated a closed road bend in Death Valley. I literally felt like the car was helping me to stay on the road and the help was very inline with Subaru's advertizement I saw many times.

Which model Subaru was that?

MY own experience with Subarus (a 2010 Legacy 2.5GT we used to have and the '19 WRX that we do have now) is that the calibration for either the traction control or the stability control is overly conservative. I haven't been able to tell which, but one of them starts getting involved a good bit earlier than necessary. Both cars objected to smoothly leading throttle in a 2nd or 3rd gear turn - in the dry, even - if I left the VDC on.


Norm

 

[Nickel]

My experience is this: Newer Ford car's electronics learn the driver's habits. When I first got my 2016, it interfered a lot so I usually always double tap it to go 2/3rds off is what I call it. Overall, it interferes a lot less now. By leaving it on and doing big hill climbs in very tight corners, I can feel the TC fighting which I've heard is bad for your cam phasers and timing chains. If I'm on my way to work and intend on playing around with other drivers, I leave it full off. Overall I'm pretty impressed with Ford's electronic aids. It definitely knows what it's doing.

 

[kz]

My experience is this: Newer Ford car's electronics learn the driver's habits.

You're not claiming that stability control "learns driver's habits", are you ?

 

[accel]

Which model Subaru was that?

MY own experience with Subarus (a 2010 Legacy 2.5GT we used to have and the '19 WRX that we do have now) is that the calibration for either the traction control or the stability control is overly conservative. I haven't been able to tell which, but one of them starts getting involved a good bit earlier than necessary. Both cars objected to smoothly leading throttle in a 2nd or 3rd gear turn - in the dry, even - if I left the VDC on.


Norm

2016 outback.

 

[JZTRK]

2 months into owning my 2014 GT track pack it spun me around getting on the freeway the car got a little lose and advancetrac flashed power was cut and it came on at WOT when I stabbed it to correct. normally I would power out of a slide like that ever since that all my fords go into neutral and the traction button is held for 10sec and it flashes advance track off

 

[ALLSTOCK]

If I hold the traction switch up for like 10 seconds, shit gets kinda wild...quick.

 

[dn1984]

Personally, unless it's wet out I drive in track mode with everything off (hold down the toggle for a few seconds) because it interferes too much when I'm trying to have fun. These cars are pretty stable. My 2012 was a lot harrier when traction broke. Some of the Camaros I used to have would make my Mustang look like a Subaru in comparison

 

[dn1984]

I'll try to answer the question in the spirit in which it is asked. In the context of track driving, AT is going to help you get better times. This is regardless of driver skill (how scandalous!). This is because, no matter how good a driver you are, it's not physically possible to apply the brakes on individual wheels. AT can help you get around corners quicker than it would be possible without. Don't believe me? Look into any track-focused hypercar. Read about the systems they use to get the best lap times. They will all very proudly talk about their version of 4-wheel braking, regardless of what they call it. Conversely, if the car in question was built with creating a "pure driving machine", they will smugly declare how the vehicle eschews such systems. Then, they will use the driver experience to justify the slower lap times.

In the same context, TC is going to hold you back. It is not going to modulate the throttle as well as a skilled driver will. It is possible for a human to control throttle in an optimal way, as there is only one control for it. A little slip, and a little spin can result in the computer cutting throttle far harder than a driver would need to compensate. It can also lead to overcompensation as both the computer and driver let off on the throttle.

Is that what you wanted to know?

I don't think advancetrac in these cars is really advanced enough to help on the track. I have even had it cut power at the drag strip shifting around 100 in drag mode (when it was stock and on 91, even) when the car itself was fine, just because of the shock of the shift. I've had other times when it has kicked in when the car BARELY gets a little sideways and power cuts for a while. If it was less intrusive and allowed power to come back on sooner then it would be good for the track, but it isn't. It's a purely safety focused system as opposed to the safety + track systems you are referring to.