Took my '11, 2.5i, CVT Off Roading this past weekend

[iainb]

Originally Posted by Thai

I am sure that the traction control in the OB is meant for all-weather type driving, not for cross-axle off-road situations.

While I would definitely turn off the traction control off-road my salesman suggested turning it off in the snow too as to not limit power at a spinning wheel.

[Thai]

Originally Posted by iainb

While I would definitely turn off the traction control off-road my salesman suggested turning it off in the snow too as to not limit power at a spinning wheel.

I am new to Subaru. But, in my past cars, you need to turn off stability control because that will de-throttle you when you spin/slip. BUT, without lockers, you need to keep traction control ON. When one wheel is on solid ground and the other wheel (on the same axle) is spinning in the air, you need traction control to send power back to the wheel that is on solid ground. Otherwise, all power goes to the wheel with the least resistance (aka the one spinning in the air). So, traction control is good off-road and in deep snow.

But, like i said, i am new to Subaru. Is there a way to turn off stability control and not traction control?? If there isn't a way, then i would leave it ON and just punch the throttle all the way down...to hopefully overcome the stability control's de-throttling.

[subiesailor]

Originally Posted by Thai

I am new to Subaru. But, in my past cars, you need to turn off stability control because that will de-throttle you when you spin/slip. BUT, without lockers, you need to keep traction control ON. When one wheel is on solid ground and the other wheel (on the same axle) is spinning in the air, you need traction control to send power back to the wheel that is on solid ground. Otherwise, all power goes to the wheel with the least resistance (aka the one spinning in the air). So, traction control is good off-road and in deep snow.

But, like i said, i am new to Subaru. Is there a way to turn off stability control and not traction control?? If there isn't a way, then i would leave it ON and just punch the throttle all the way down...to hopefully overcome the stability control's de-throttling.

Stability control is always on! Traction control is something you turn off for any of the following things.

Any time your doing slow speed driving on challenging road surface which is muddy, sandy, rocky, or snowed where wheel spin is going to happen and will not result in a high speed accident you turn off traction control.

The primary reason for traction control is high speed wet or otherwise slick roads where various systems in the car can pick up on traction issues long before the driver notices and the car will do things to reduce the threat of further traction loss resulting in you spinning or skidding off the road etc. Think driving down the highway in a rain storm or snow storm traction control on. Think driving down the street at 25-40mph in bad road conditions traction control turned on is a good thing.

If you have been in the office all day and the parking lot has been snowed on all day - you turn the traction control off so you can get out of the parking lot! Wheel spin is going to happen and your not going to be doing 25+mph in the parking lot. By turning traction control off before you get stuck you greatly reduce the chances of getting stuck!

IF you turn traction control off after your stuck - You ARE STUCK and have a very very good chance that yes YOU ARE STUCK.

This is a case where user input and error is the biggest factor. Full time AWD has removed user Error regarding knowing when to turn on your AWD and when to turn it off - but till Auto makers find a way to build a computer that can sort out when to turn on and turn off traction control there will always be USER error as to when traction control should be on and off.

Just remembering to turn it off when your facing some rough challenging terrain is generally the largest issue and most common thing forgotten- only remembered when the car stops and gets stuck. LOL Which case your stuck and traction control turned off may not fix the fact your already stuck.

[Thai]

How odd!! So, when you turn traction control OFF, then you're stuck in a cross-axle situation because power is not being sent to the wheel that has traction, right?

This is MUCH different than other off-roaders (4runners, G-wagens) that i have been in.

[subiesailor]

Originally Posted by Thai

How odd!! So, when you turn traction control OFF, then you're stuck in a cross-axle situation because power is not being sent to the wheel that has traction, right?

This is MUCH different than other off-roaders (4runners, G-wagens) that i have been in.

Um no!

The traction control on hard core Off road trucks works the same way though the more advanced systems such as say the newer trucks have different traction control systems or modes. Think decent control etc where the traction control system operates as a speed control using brakes and the traction control sensing system to know how its doing regarding tire slippage.

Basic traction control systems simply monitor tire traction and inputs ie primarily throttle inputs and brake inputs given the primary 99% of on road traction issues are people giving too much throttle or brake for the given available traction and the car simply applies various things to temper the actions ie throttle input etc to eliminate wheel spin.

If you think the basic Traction control is an advanced off road system with multiple modes and levels of logic you bought the wrong vehicle for off roading. Subaru outback is a Legacy wagon if you want it to climb through a snow bank you need traction control turned off because its not going to like the fact your booting it in the sack with throttle while spinning tires - the traction control nanny is going to say WHOA hold the horses and cut power and eliminate wheel spin.

[Thai]

subiesailor...uhh, i don't plan on off-roading much (if at all). It was just a question.

This works differently than with Toyota and Mercedes. Yeah, i understand traction control...quite well in fact. In the other systems, traction control compares the speed differences b/w wheels on the same axle...and modulates the brake of the spinning wheel to keep (some) torque flow to the wheel with more traction (aka the one with more resistance). It may play with the throttle somewhat to prevent overapplication...but for the most part, this part is mild.

Stability control is what kills you off-road, at least in Toyotas and Mercedes G-wagen. Stability control is the one that powerfully dethrottles you when slippage or sideway motion is detected.

So, in a 4runner with fulltime 4wd, you lock the center differential to de-activate stability control. But this still allows traction control to work on the tires. Same on Mercedes.

Going back to what i wrote initially...some questions to clarify my understanding...IN A SUBARU

1. stability control is always on no matter what buttons i push, right?

2. And when you de-activate traction control, then the front and rear axles are completely open without any intervention from traction control??? In a cross-axled situation (one front and one rear off the ground), you're stuck without traction control, right?

3. So, with traction control OFF, if i go fast around a corner off-road, then stability control is still ON to help me out?

[subiesailor]

Originally Posted by Thai

subiesailor...uhh, i don't plan on off-roading much (if at all). It was just a question.

This works differently than with Toyota and Mercedes. Yeah, i understand traction control...quite well in fact. In the other systems, traction control compares the speed differences b/w wheels on the same axle...and modulates the brake of the spinning wheel to keep (some) torque flow to the wheel with more traction (aka the one with more resistance). It may play with the throttle somewhat to prevent overapplication...but for the most part, this part is mild.

Stability control is what kills you off-road, at least in Toyotas and Mercedes G-wagen. Stability control is the one that powerfully dethrottles you when slippage or sideway motion is detected.

So, in a 4runner with fulltime 4wd, you lock the center differential to de-activate stability control. But this still allows traction control to work on the tires. Same on Mercedes.

Going back to what i wrote initially...some questions to clarify my understanding...IN A SUBARU

1. stability control is always on no matter what buttons i push, right?

2. And when you de-activate traction control, then the front and rear axles are completely open without any intervention from traction control??? In a cross-axled situation (one front and one rear off the ground), you're stuck without traction control, right?

3. So, with traction control OFF, if i go fast around a corner off-road, then stability control is still ON to help me out?

Thai - traction control is not connected to the axles or how the drive lines send power. It is connected to the brakes and the throttle. And yes with Mercedes and Toyota and all other SUV's Stability control uses the same systems TRACTION Control uses to temper a drivers input to keep said vehicle right side up and pointed in the correct direction.

Stability control remains in effect on all the big SUV's even when your off road given doing things that will roll you over are still possible. However as I said all high level capable off road rigs have multiple modes of traction control which allow brakes to lock up when braking which results in better stopping or staying put on loose rock etc - however the same system will monitor wheel spin and apply brakes to spinning wheels which is referred to as VDC in many cases with Subarus.

However the newer expensive off road rigs can often be built cheaper by relying on the braking ability of spinning wheels vs actually mechanically designed features like locking diffs and center transfercases which keep wheels turning the same rate regardless of traction changes from side to side or front to back - which case subaru has its limits - you need to let a wheel spin a tad on a subaru before the systems subaru uses shifts power to the wheels with more traction. This has nothing to do with Traction Control or Stability control.

[Thai]

Ok, i found the answer. I am right afterall. Subiesailor, do you have a 4th gen OB?? You got it all wrong man.

The button to the left of the steering wheel turns OFF (and ON) VDC (vehicle dynamics control). This is stability control. According to Owner's Manual: "VDC helps prevent unstable vehicle motion such as skidding using control of the brakes and engine power."

Basically, if you press this button, then you have no stability control. BUT, you still have traction control to route power to the wheel with the most traction. Subiesailor got me all confused thinking that Subaru is crazy.

What i wrote above is true to Subaru and to every other SUVs that i have driven. Traction control on the OB is ALWAYS ON. You deactivate VDC to get rid of the dethrottling which will happen if you're buried in snow. VDC is what kills engine power and does all sorts of stuff to your brakes because it thinks that you're skidding. With it OFF, you still have traction control. And yes, traction control works by comparing speed differences b/w wheels on the SAME axle.

Now, traction control in itself can be a hindrance because it is a REactive system. One wheel has to spin faster than the other for it to intervene. Therefore, you may have lost momentum already before traction control kicks in. This is why pure off-roaders still prefer locker system, which is a proactive system.

And unlike a locker, traction control can only transfer a fraction of the power to the wheel that needs it the most...the rest is lost in heat dissipation from the ABS pulsating the brakes of the spinning wheel(s). This is why there is a limit as to how much power you have in going to the non-slip wheel(s) thru an obstacle or up an incline. Traction control only pulsates the slipping tire(s). In more off-road oriented vehicles (such as FJ Cruiser A-TRAC), the ABS can literally stop a spinning tire for a moment to send even more power to the wheel(s) with traction.

[Thai]

And stability control is FULLY DEACTIVATED when you lock the center differential on a 4runner. There is NO question about this...trust me, i know. Traction control is active all the time. On some 4runners, you can deactivate the rear axle traction control by locking the rear locker. But, front traction control is still active.

[subiesailor]

You do know that stability control and traction control are the same system just different modes right? Traction control does not route POWER!! You need to get that in your head! IT tracks TRACTION and limits power when it becomes an issue! Think of it as ABS for power.