Ok now we're way off my initial intent... but how is the ESP going to use the brakes to keep my car straight when the tires are still only spinning 40 mph (because they're in 2nd gear) and my car is still travelling 125 mph? See? (let's say it's a standard)
And we're talking purely hypethetical guys... I know enough about cars.. and plenty about snow driving. I'm just trying to illustrate the real world stuff I drive in all the time... 55 mph on snow.. in a slight bend.. I'd rather use the brakes than tap the Tip down a gear. I can control the brakes much better.
< Message edited by ungawa -- 1/24/2008 1:27:51 PM >
ORIGINAL: ungawa I already know the answer to this I think... but I just want to hear it out of someone else's mouth.
My wife has an 03 A4 Avant (tip). She's under the impression that she can have better braking in snowy conditions if she uses the tip to downshift. I told her to use the brakes instead since they have ABS. If she 'over-downshifts' in snowy conditions, there's nothing to stop her from slipping... right? (Say she's going downhill on a curve) She's basically found the one way to render traction control and her ABS useless... right?
what your wife is doing is right... ABS and Traction control are still functional in Tip.
as Grelot said; " dont push on the brake pedal like an unexperimented driver.. do it the other way... push alittle bit more on the gas and the car will automaticly take is position on the snow... if your pushing on the brake pedal.. you're dead!! "
I totally agree with Grelot... as that has been my experience as well.
I completely disagree. you should not rely or even use downshifting to slow you down on ice because when using this it will slow you down with all 4 tires evenly at the same time which is not acceptable on icy road because your rear tires will lose traction before your front tires possibly causing you to lose control. This is the reason truckers do not use their JAKE brake on icy roads. While driving on icy roads it is far safer to threshold brake because 60-90 percent of your stopping power is in your front wheels and your car is set up this way. Another thing....TC is only useful in accelerating, all it does is cause a rev limiter effect so your wheels will not spin faster than you are traveling. I promise you it does nothing for you in breaking situations, that is what ABS was designed for. So to answer your question your wife is not right and will be far safer not downshifting on icy roads. She should brake normally. Anybody that tells you different is wrong and should do a little more research themselves
< Message edited by richrich -- 1/24/2008 1:51:26 PM >
ungawa, to make it simple, if you are on a giant sheet of ice spinning at 125....your Fooked...with a capital F. No system is going to be able to compensate for that situation. In normal driving, the system generally applies the brakes to one wheel to pull the car out of the spin. It would do the same thing on the hypothetical ice sheet, but with no traction on any tire, it would pretty much just sit there and blink at you.
The system saved my bacon big time in my Jetta GLI when I was going about 120 down the highway racing with my friend (this was when I was a little dumber than I am now) and I went through an old construction zone with dirt and pebbles all over the highway. The rear of the car kicked out and the ESP system lit up like a Christmas tree and with the rear of the car wagging back and forth like a fish, the ESP finally got it to settle down. Normally there would've been no way for me to react fast enough and I would've rolled the car.
Also, as someone mentioned ESP is not necessarily the best thing to have on in the snow. My old A4 didn't have it and it was a peach to drive and let Quattro do its job especially in deep snow and ice. Sometimes you end up fighting the system as it tries to "correct" what is otherwise the right move at the time.
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2004 Audi A6 2.7T S-Line - His 2004 Pontiac GTO (12.773 @ 109.72, 1.945 60') - Retired 2003 Chevrolet Avalanche Z71 - Hers
ungawa, to make it simple, if you are on a giant sheet of ice spinning at 125....your Fooked...with a capital F. No system is going to be able to compensate for that situation. In normal driving, the system generally applies the brakes to one wheel to pull the car out of the spin. It would do the same thing on the hypothetical ice sheet, but with no traction on any tire, it would pretty much just sit there and blink at you.
The system saved my bacon big time in my Jetta GLI when I was going about 120 down the highway racing with my friend (this was when I was a little dumber than I am now) and I went through an old construction zone with dirt and pebbles all over the highway. The rear of the car kicked out and the ESP system lit up like a Christmas tree and with the rear of the car wagging back and forth like a fish, the ESP finally got it to settle down. Normally there would've been no way for me to react fast enough and I would've rolled the car.
Also, as someone mentioned ESP is not necessarily the best thing to have on in the snow. My old A4 didn't have it and it was a peach to drive and let Quattro do its job especially in deep snow and ice. Sometimes you end up fighting the system as it tries to "correct" what is otherwise the right move at the time.
You are confusing braking with accelerating or RACING. Of course it helped you out in that situation you werent DOWNSHIFTING through a corner on icy roads. It wouldnt have done a thing for you if your were on an icy corner, had recently downshifted and lost control
I think you are confusing what ESP is. Just because Audi tied the TRACTION CONTROL and STABILITY CONTROL into the same button, does not mean that they don't both do different things. The traction control keeps my tires from spinning when I accelerate. Stability control keeps the car from spinning out. They are both turned on/off with the ESP button.
Stability control would help me on the icy road even if I am downshifting and braking. I was trying to illustrate how the system works outside of the context of our icy road/lake scenrio. I am not confusing braking with acceleration. ESP uses a gyro to sense the cars side to side motion. When it picks up that the car is going into oversteer or about to spin out, it applies the ABS system to regain control of the car. The system works regardless of which pedal you are pushing.
You could be accelerating hard and throw the car into a turn and it would try to right the car.
You could be braking hard into a turn and it would try to right the car.
You could just be coasting into a turn and it would try to right the car.
In the icy corner, it would try to keep the car from spinning out, how succesful it would be would depend on how much grip the tires have at that moment.
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2004 Audi A6 2.7T S-Line - His 2004 Pontiac GTO (12.773 @ 109.72, 1.945 60') - Retired 2003 Chevrolet Avalanche Z71 - Hers
I am aware of what ESP is....I dont believe some others know everything about it (hint...hint). How can a system designed to use breaking to control a car, stop the car from going into a skid when it's the engine restricting the tires from rolling at the current speed?
< Message edited by richrich -- 1/24/2008 3:03:22 PM >
...but how is the ESP going to use the brakes to keep my car straight when the tires are still only spinning 40 mph (because they're in 2nd gear) and my car is still travelling 125 mph? See? (let's say it's a standard) ...
Well, magic. Actually the specific example (stopping at 120 mph with spin out) will not work but hypothetically it is done with ABS. It is the beauty of 4 channel ABS and ESP. So lets say you are making a swift left turn on a slippery surface. Traction gets lost. Car goes forward while the steering is pointed to the left. Computer senses that you want to go left based on yaw sensors, and notices that your front wheels are loose. It applies brake to inside (Left) tires and tries to send more torque to the outer wheels as well as rear wheel where there is traction. Because each channel of the brake system is individually controllable, computer can stop one wheel at a time if needed. This is what ESP does. And in conjunction with the quattro system, which sends torque via torsen differential with electric differential lock (depending on the year and model), it further enhances the stability. Both ESP and quattro system works in acceleration and deceleration, but they are not to same.
You can overcram your brain with worthless info found here.
Ok now we're way off my initial intent... but how is the ESP going to use the brakes to keep my car straight when the tires are still only spinning 40 mph (because they're in 2nd gear) and my car is still travelling 125 mph? See? (let's say it's a standard)
And we're talking purely hypethetical guys... I know enough about cars.. and plenty about snow driving. I'm just trying to illustrate the real world stuff I drive in all the time... 55 mph on snow.. in a slight bend.. I'd rather use the brakes than tap the Tip down a gear. I can control the brakes much better.
I have to chime in here.
55 mph on snow.. in a slight bend... - If you sense that you are moving too fast and you are already into the turn your best hopes are to let off the accelerator and steer into the curve without making any jerky motions. If you are already into the curve and then "tap" the brakes, that sudden jerk (on snow/ice) could break the tires free and you'd be more likely to slide off the road. The same applies to downshifting in the middle of the curve as well. Just keep in mind all that weight shifting back and forth and how much traction you really have. If you are already into the curve there isn't a whole lot you can do.
Now, if there is no way you're going to make the corner and it is a dire situation I say foot to brake hard and dump the parking brake. Parking brake?? That's absurd! Not really... if you are going THAT fast and lose control in the corner what is to say your foot won't come free from the brake pedal. We all know about the Department of Redundancy Department, right?
Agree or disagree, that is what I would do.
Of course, all this depends on the situation. Speed, weight of vehicle, sharp curve, slight curve, straight away or s-curve after the initial curve, plowed snow, fresh powder, ice, etc, etc. There are many variables.
ungawa, to make it simple, if you are on a giant sheet of ice spinning at 125....your Fooked...with a capital F. No system is going to be able to compensate for that situation. In normal driving, the system generally applies the brakes to one wheel to pull the car out of the spin. It would do the same thing on the hypothetical ice sheet, but with no traction on any tire, it would pretty much just sit there and blink at you.
Well with all due respect.. that is a bit different from what you said earlier... and the reason I continued my little debate. You said that the ESP would be able to (or have a slight chance) to keep the car straight. But while in gear and restricted by the engine, there would be no hope. In a scaled down - less dramatic manner, this is the same situation my wife puts herself into by using the tip to slow herself down in touchy situations. The... negative slip?.. in this situation was what I was curious about. When the engine is the force restricting the tires from having a good grip on the road, the esp, traction control, and abs wouldn't seem able to do anything. I was just pointing out that this is the one situation I can think of that the audi hasn't mastered. I'm not complaining! I friggin love these things! Audi driver for life here.
Thanks HSgasser for the links. I'll check those out. Still got lots to learn here.
Thanks richrich for seeing a bit to what I'm getting at. =)
Khardysius I agree.. Gentle movements keep you on the road. The last time I jerked the steering wheel on a snowy road, I ended up right in a snowbank. That was about 16 years ago and I can honestly say I haven't lost control of a car since. *knock knock* And yes, every situation is different.. there's no catch-all.
richrich, you are very right that if I am driving straight down the road and I downshift the car and begin to skid forward, the traction control function of ESP will not kick in to save me and as long as I keep skidding straight, nothing would happen. However, if the downshifting causes my car to SKID RIGHT OR LEFT, aka step out of line, ESP will activate and straighten out the car.
The discussion here (as far as I interpreted it) was never about whether ESP would prevent the car from skidding forward under engine braking. To me the post that got all this started was asking about lateral motion. To me the word "skid" referred to the car sliding sideways. I want to turn right, but my car slides left. In that case ESP would work to right the car. It could easily use the brakes to slow one wheel more than the other wheels (to straighten the car out) regardless of the force of the engine braking. This is what hxgaser described so well in his post.
"ESP works in all regimes like: acceleration, coasting, light braking, hard braking, engine drag (just a FYI...engine drag and engine braking are the same thing) and load shift and enhances vehicle stability even during extreme steering maneuvers (panic reactions)."
So, regardless of the way the skidding (side to side) is caused, the ESP system will work to pull the car back into the intended path.
ungawa, I don't think that I ever changed my answer to your question. What I was trying to get at is that on our hypothetical ice sheet travelling at 125mph, when we force the downshift, the car would most likely spin out like a top ESP WOULD kick in to try and right the car and stop the spin. If any of the tires had any amount of traction, it may actually prevent you from spinning out. My second (seemingly contradictory) post was more about being humorous in what would happen if you were actually spinning out on an ice sheet going 125mph....I don't think anything would stop you.
I hate having these conversations online as it is so hard to illustrate what you are talking about.
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2004 Audi A6 2.7T S-Line - His 2004 Pontiac GTO (12.773 @ 109.72, 1.945 60') - Retired 2003 Chevrolet Avalanche Z71 - Hers
personally, when i bought my A6 with quattro, i was thinking it would be like my girlfriends jeep on 4X4, or better than my DeVille at least.... to my surprise it wasnt.
I dont know if its due to the A6 being lighter in weight, but this thing fishtails like a mofo when there is only a little bit of snow on the ground... granted its better than a RWD car only, but still i was shocked to fishtail.
I then went to an empty parking lot, and was amazed at how easy it was to do donoughts in that car (granted i had a blast doing it). My other car which is front wheel drive cant, e DeVille is MUCH heavier, but i still thought the Audi would be better in snow.
NJGOAT, I have to agree with you on all your points. From my current experience with the Chicago snow this week, i think ESP is a better system for driving in most bad whether conditions.
Well I lost control on I-75N up in Toledo, OH due to black ice/rain in my old 92' Lexus es300 (I have driven up there all the times in all seasons)... After that I bought this Audi and what sold me was the conering ability in the snow displayed by the Audi salesman. But I do understand AWD, ESP, etc... Nothing can save your A$$ when your car doesn't have traction.
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2001 A6 2.7T 89K
GIAC X-Chip and Tip chip Bilstein PSS9's Milltek Cat-back Exhaust K&N air filter 35% tint
Very interesting discussion, I’d like to introduce a recent driving experience and ask for thoughts. I routinely drive my 2003 A-4 on I-80 through the Sierras between San Francisco and Reno. I’ve made the trip dozens of times this winter in every road condition imaginable without the least concern for traction loss or skid. For better or worse, I drive in tip mode, stay off the brakes, “downshift” to maintain desired speed. I’ve never once slipped or skid.
Last night I passed chain control expecting a routine drive of some 40 – 50 miles thru heavy snow accumulation from previous 24 hours. I started uphill at 30 – 35MPH behind an SUV when the tail of my car abruptly kicked out to the left, pitching the vehicle nearly sideways to the direction of travel. I let off the gas, turned into the direction of skid (uphill), ESP illuminated, the car corrected. ESP light turned off. I thought this was a one-off and continued as usual. No other traffic at the time (4x4, AWD, 2WD w/ chains) was having problems with the conditions; most traveling 40 – 45MPH, many faster.
Long story short, at speeds over approx 25MPH the ESP repeatedly illuminated and the rear of the car would start to kick out to the left, driver’s side. I had the distinct impression as I was driving that the nose of the car appeared to be pulled slightly to the right, as if the wheel alignment was off. When hitting heavy bumps, even at 20MPH, the ESP illuminated and the car felt as though the tail was going to kick out to the left. I considered turning off the ESP, thinking it was somehow causing the problems.
Spent the better part of 50 miles behind a truck doing 20MPH or less. Once back on clear pavement, no more problems. Had tires checked today, reasonable tread (about 10K to go) and properly inflated; I’ve rotated ‘em about every 5k for the past 30K; very even wear.
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RE: Winter driving - 
