Controlling Tail Happy Legacy Wagon in Snow

[outahere]

So I am goofing around on some deserted, snow covered roads today, in my '05 wagon (stock suspension, Bkizzak LM25 tires). I'm playing with the throttle and kicking out the rear end, making tight U turns with the throttle, etc. The Legacy is more "tail happy" than one would expect, given the 50:50 torque split.

 

On one of these runs I am going around 20-25mph, I kick out the rear end with some throttle application after a right turn, and the rear end starts oscillating left to right to left, like a pendulum, and it ends when I stuff the front end into a snow bank:redface: No harm done, since it was a low speed collision with soft snow.

 

My question is, how do you stop this oscillation of the rear end, when on snow or ice? I know how to prevent it (drive slower, less throttle:lol:), but once it starts, how do you stop it?

[twisted]

were u trying to counter steer when the rear started to kick out?

[f1anatic]

You keep accelerating; and steer in the direction of the skid.

[outahere]

were u trying to counter steer when the rear started to kick out?

 

Yes, I steered in the direction I wanted to go, but the rear end seemed to have a mind of its own:lol:

[outahere]

You keep accelerating; and steer in the direction of the skid.

 

I did not accelerate. It seems that would make the rear end even looser?

[addison]

I did not accelerate. It seems that would make the rear end even looser?

 

 

not with subaru's all wheel drive... its a common mistake, if you want to keep control durring a slide you need to give it more gas

[f1anatic]

Sorry bro. In my first year I almost totaled the car due to the mistake of lifting in a turn where the rear went loose. After that I learned to fight the urge to lift. At some low level skid it is fine to lift and brake but generally, if the back is loose, you have to keep acceleration (or don't accelerate but do not lift off the gas pedal either). This is typical of all AWD and RWD cars. It has to do with the weight transfer.

[RJS5689]

not with subaru's all wheel drive... its a common mistake, if you want to keep control durring a slide you need to give it more gas

 

Yep! Find an open parking lot when it snows, make sure it's clear and just practice it out. It took me some getting used to also. Especially after all that, "take your foot off the gas and steer in the direction you want to go" stuff they feed you in drivers ed. AWD is a great thing, just know how to control it. I thought I knew a lot more about it than I really did. It wasn't until I was behind the wheel learning about it first hand that I truly learned the vehicle.

[outahere]

I found this at canadiandriver.com, written by a journalist attending the Bridgestone Winter Driving School:

 

"The lesson starts with the importance of weight transfer. ..................Weight transfer is physics for cars. Accelerate, and weight transfers to the rear ....... Hit the brakes, and it all comes forward.........

 

The transfer is the same whether your car's front-, rear-, or all-wheel drive. "We hear a lot of urban myths from students," Cox says. "If you're using good technique, the methods are the same whether it's front- or rear-wheel. You do the same skid correction regardless of what type of drive it is. It's only with bad technique that these vehicles perform very differently."

 

Instructor Tania Bourbonnais explains that tires do three jobs: steering, accelerating and braking. "If we do each by itself, the tire can do 100 per cent of the job," she explains. "If we try to do two at the same time, the tire can only do half the job." So braking is done before steering into a turn, and acceleration is gradual as the wheels are straightened....................

 

Correction requires techniques that aren't necessarily intuitive...............

 

On the main track, at 60 km/hr, the back end of my car starts to come around. I know this one: steer into the direction of the skid. But on ice, it isn't enough, and my instructor calls for more throttle.

 

More gas? It doesn't make sense: I want the skid to stop, so why would I increase the speed? But it's all back to physics: acceleration shifts weight to the rear wheels, increasing their grip. I depress the throttle slightly, as part of the skid management. At the last moment, I regain control, and I miss hitting the snowbank.

 

I'm better on the second lap, but it's still not second nature to depress the throttle. This is my homework......................"

[outahere]

But if you accelerate too much, the rear tires will spin, and you will lose the rear end again, right?

[RJS5689]

But if you accelerate too much, the rear tires will spin, and you will lose the rear end again, right?

Oohhhh yeeaaaaa It should be a very gentle input.

 

I don't see how that instructors theory is correct for FWD though. If you give a skidding FWD car more gas, it's just going to continue to understeer. That's a case where I would lift and go for the brakes.

[outahere]

..........I don't see how that journalists theory is correct for FWD though. If you give a skidding FWD car more gas, it's just going to continue to understeer. That's a case where I would lift and go for the brakes.

 

Actually, it was the instructor (Mark Cox, school director), not the journalist, who stated: "If you're using good technique, the methods are the same whether it's front- or rear-wheel. You do the same skid correction regardless of what type of drive it is. It's only with bad technique that these vehicles perform very differently."

[RJS5689]

Actually, it was the instructor (Mark Cox, school director), not the journalist, who stated: "If you're using good technique, the methods are the same whether it's front- or rear-wheel. You do the same skid correction regardless of what type of drive it is. It's only with bad technique that these vehicles perform very differently."

I understand that, sorry that's who I meant to say. My question still stands, if you give more input to a FWD car, it's just going to continue to understeer. What am I missing here guys? I know he's a professional and most likely correct, but I would like the explanation in terms of physics and what is would do. I have lost control of a FWD vehicle before, and I know giving it more gas would have just made my problem worse. I know lift would transfer weight to the front and possibly induce more understeer, but giving it more gas would make the understeer MUCH worse. FWD cars already have an issue to plow, so if the vehicle is plowing, how would more gas help.

[addison]

just blip the throttle over and over and do a perfect donut while the nose of your car remains stationary :-D

[outahere]

.........I have lost control of a FWD vehicle before, and I know giving it more gas would have just made my problem worse. I know lift would transfer weight to the front and possibly induce more understeer, but giving it more gas would make the understeer MUCH worse. FWD cars already have an issue to plow, so if the vehicle is plowing, how would more gas help.

 

If the car is plowing (understeering) the advice from Bridgestone Winter Driving School is;

 

".........Your best chance of correcting an understeer is to lift off the accelerator and stay off the brake. As the car's weight shifts forward, it will load the front tires, improving their grip while you carefully decrease the steering angle. This improved grip and slower speed should allow you to steer smoothly back into the corner........"

 

If the car is oversteerring:

 

".............If your car starts to lose grip on the rear wheels ...... you should gently accelerate to transfer the weight back to the rear wheels, while you steer in the same direction in which the rear end is sliding. Remember to look down the road in the direction you want the car to go, and be sensitive to the feel of the car. ........ If you don't steer back to your original direction before the car recovers, you could end up skidding in the opposite direction. This is known as a counter-skid....."

[RJS5689]

If the car is plowing (understeering) the advice from Bridgestone Winter Driving School is;

 

".........Your best chance of correcting an understeer is to lift off the accelerator and stay off the brake. As the car's weight shifts forward, it will load the front tires, improving their grip while you carefully decrease the steering angle. This improved grip and slower speed should allow you to steer smoothly back into the corner........"

 

If the car is oversteerring:

 

".............If your car starts to lose grip on the rear wheels ...... you should gently accelerate to transfer the weight back to the rear wheels, while you steer in the same direction in which the rear end is sliding. Remember to look down the road in the direction you want the car to go, and be sensitive to the feel of the car. ........ If you don't steer back to your original direction before the car recovers, you could end up skidding in the opposite direction. This is known as a counter-skid....."

Thank you... that's what I was saying. Considering FWD cars do whats called "front wheel skidding" or understeering. Could you link me to the site please...

[outahere]

http://www.tirerack.com/winter/tech/techpage.jsp?techid=119

 

http://www.canadiandriver.com/winter/bridgestonewinterschool.htm

[outahere]

I am beginning to think I did too much counter steering, and that is why the rear of the car was all over the place.

[RJS5689]

I am beginning to think I did too much counter steering, and that is why the rear of the car was all over the place.

Thanks for the links.

 

Yea, over-correcting is usually peoples biggest mistake.

[schwartzki]

mmhmm, subaru awd is a interesting thing, best thing to do is to play with your car in an empty lot and learn how it reacts, i love snow cause i can steer with precision the front or rear wheels. I love the awd.

[fishbone]

So the key is gently accelerate. Got it! Because if I hit the gas on this Stage 2 LGT, I very much doubt I'd be any better off

[05GT Guru]

His story made me think of when i first got my LGT last winter, i did the same exact thing, let off and slid into a snowbank while showing a friend how much fun turbos are on snow, no damage. I have taken the same snow covered turn atleast 50 times by now at even faster speeds and havent spun out since the first time. If this is your first turbo subie it does take getting used to, but now i can calming drive down a snow covered street with the back end wagging like no tomorrow with no worries. Once you can predict what your car is going to do snow driving gets alot more fun. Make sure you know you throttle aswell, you dont wanna get into a turn and then have the turbo spool when your not ready for it, that will also throw you off you comfort zone.

[fishbone]

My throttle response is very different from the stock one with this PDX Stage 2 tune. It's almost I'm either granny-ing along or I'm WOT. There is little grey area and this grey area is further diminished by the initial throttle input and rate of input upon initial start from a stop (if I lay into it, even if I back off a few degrees before boost creeps in, the car will still shoot forward). I'm starting to suspect I got an STi throttle map along with my tune

I will also admit I have not dedicated time to getting to know it other than straight line running like a bat outta hell. It's probably long overdue that I should do it.

[05GT Guru]

I have the STI throttle map and i find it to be very fun, it does what my foot tells it too alot better than stock. The only thing that overrides my foot is the turbo lol

[RobY]

The simplest and easiest explaination is:

 

With awd you have 2 sets of DRIVEN wheels if you loose traction in the rear and you lift off the accelerator the front wheels will still have traction.

 

Since it is mechanically attached to the rear wheels and the engine it will act as a pivot point.

 

The angular momentum will fulcrum around the front wheels causing rear end instability.

 

In a RWD vehicle there is no fulcrum because the front wheels are free spinning and not attached to the drivetrain there is no induced resistance in the front wheels.

 

The best thing to do in an awd subaru in a UNDERSTEER OR OVERSTEER condition is to "point and shoot". Meaning steer in the direction you want to go and depress the accellerator.

 

In this instance you eliminate the front wheels as a fulcrum and the most tractive wheel set will pull or push the car in the desired direction.