2007 Mitsubishi Outlander: AWD DETAILS

Mitsubishi studied real-world usage of 4-wheel drive systems to determine what type of technology would be most effective for vehicle control, and most useful to the compact SUV customer. At the same time, the goal was to come as close as possible to matching the highway fuel economy of the previous four-cylinder Outlander - a significant challenge given the increased size, weight and V-6 power of the new model.
The previous Outlander employed a 50:50 full-time 4-wheel drive system using a viscous coupling center differential. This type of system yields outstanding severe-weather performance, but it can increase fuel consumption in everyday driving. Mitsubishi wanted the new Outlander to deliver the same or better all-weather and severe-condition performance while minimally affecting fuel consumption.
The engineers rejected the increasingly common solution to this challenge, which is to use an automatic "on-demand part-time" type 4-wheel drive system as used by some competitors. Such systems rely purely on slippage at the front wheels before channeling power to the rear wheels. Mitsubishi felt customers in this segment would be best served by a system that could proactively reduce the likelihood of wheel slippage.
All-Wheel Control with Advanced 4-Wheel DriveThe 2007 Outlander gives the driver a choice among vehicle drive modes. Standard front-wheel drive is augmented by the Active Skid and Traction Control (ASTC) system, which includes traction control for better grip on slippery surfaces.
With the optional 4-wheel drive system, the driver uses a drive-mode dial on the center console to select "FWD" for best fuel economy; with "4WD Auto" mode selected, the system uses a rear-mounted electronically controlled transfer clutch to automatically and seamlessly route more power to the rear wheels, depending on driving and road surface conditions. The driver can freely change the drive mode at any time.Two 4WD Modes When "4WD Auto" mode is selected, the Outlander 4WD system always sends some power to the rear wheels, automatically increasing the amount under full-throttle acceleration. The coupling transfers up to 40 percent of available torque to the rear wheels under full-throttle acceleration, and this is reduced to 25 percent over 40 mph. At steady cruising speeds, up to 15 percent of available torque is sent to the rear wheels. At low speeds through tight corners, coupling torque is reduced, providing a smoother feel through the corner.For driving in particularly challenging conditions, such as snow, the driver can select "4WD Lock" mode. In Lock mode, the system still apportions front and rear torque automatically, but enables greater power transfer to the rear wheels. For example, when accelerating on an upgrade, the coupling will transfer more torque to the rear wheels immediately, helping to ensure that all four wheels get traction. In contrast, an automatic on-demand part-time system would allow front wheel slippage before transferring power, which could hamper acceleration.In dry conditions, 4WD Lock mode places priority on performance. More torque is directed to the rear wheels than in 4WD Auto mode to provide greater power off the line, better control when accelerating on snowy or loose surfaces, and enhanced stability at high speeds. Rear wheel torque transfer is increased by 50 percent over the amounts in 4WD Auto mode - meaning up to 60 percent of available torque is sent to the rear wheels under full-throttle acceleration on dry pavement. When in 4WD Lock mode, torque at the rear wheels is reduced by a smaller degree through corners than with 4WD Auto mode.

All-Wheel Control with Advanced 4-Wheel DriveThe 2007 Outlander gives the driver a choice among vehicle drive modes. Standard front-wheel drive is augmented by the Active Skid and Traction Control (ASTC) system, which includes traction control for better grip on slippery surfaces.
With the optional 4-wheel drive system, the driver uses a drive-mode dial on the center console to select "FWD" for best fuel economy; with "4WD Auto" mode selected, the system uses a rear-mounted electronically controlled transfer clutch to automatically and seamlessly route more power to the rear wheels, depending on driving and road surface conditions. The driver can freely change the drive mode at any time.Two 4WD Modes When "4WD Auto" mode is selected, the Outlander 4WD system always sends some power to the rear wheels, automatically increasing the amount under full-throttle acceleration. The coupling transfers up to 40 percent of available torque to the rear wheels under full-throttle acceleration, and this is reduced to 25 percent over 40 mph. At steady cruising speeds, up to 15 percent of available torque is sent to the rear wheels. At low speeds through tight corners, coupling torque is reduced, providing a smoother feel through the corner.For driving in particularly challenging conditions, such as snow, the driver can select "4WD Lock" mode. In Lock mode, the system still apportions front and rear torque automatically, but enables greater power transfer to the rear wheels. For example, when accelerating on an upgrade, the coupling will transfer more torque to the rear wheels immediately, helping to ensure that all four wheels get traction. In contrast, an automatic on-demand part-time system would allow front wheel slippage before transferring power, which could hamper acceleration.In dry conditions, 4WD Lock mode places priority on performance. More torque is directed to the rear wheels than in 4WD Auto mode to provide greater power off the line, better control when accelerating on snowy or loose surfaces, and enhanced stability at high speeds. Rear wheel torque transfer is increased by 50 percent over the amounts in 4WD Auto mode - meaning up to 60 percent of available torque is sent to the rear wheels under full-throttle acceleration on dry pavement. When in 4WD Lock mode, torque at the rear wheels is reduced by a smaller degree through corners than with 4WD Auto mode.[font="arial, sans-serif"][si

 

too much reading.

basically, they no longer have a center differential. Its always front driven, and the rear tires are driven off of a controlled slipper clutch.

 

My point is 07 Outlanders AWD system has NO lag, this system is PRO active it does NOT wait for slippage.

"The engineers rejected the increasingly common solution to this challenge, which is to use an automatic "on-demand part-time" type 4-wheel drive system as used by some competitors. Such systems rely purely on slippage at the front wheels before channeling power to the rear wheels. Mitsubishi felt customers in this segment would be best served by a system that could proactively reduce the likelihood of wheel slippage"

"4WD Auto" mode is selected, the Outlander 4WD system ALWAYS sends some power to the rear wheels, automatically increasing the amount under full-throttle acceleration."

"4WD Lock" mode. In Lock mode, the system still apportions front and rear torque automatically, but enables greater power transfer to the rear wheels."

This is one of the main reasons I bought the new Outlander, I only drive pro active AWD. Audi Torsen, most Subarus, Honda's Borg Warner system are all pro active.

 

My question is: why would you ever want to drive in 4WD Auto vs. 4WD lock? (except for possible better gas mileage) Seems like 4WD lock is better.

 

because you need to differentiate tire speed front to rear on pavement, lest you cause massive driveline windup.

 

I don't think the 4wd "lock" actually locks the center diff (i.e. the lock feature on the STI) The 4wd "lock" on the outlander is just marketing talk for "now it's more awd than with 4wd auto".

To quote the original posters article:
"For driving in particularly challenging conditions, such as snow, the driver can select "4WD Lock" mode. In Lock mode, the system still apportions front and rear torque automatically, but enables greater power transfer to the rear wheels. For example, when accelerating on an upgrade, the coupling will transfer more torque to the rear wheels immediately, helping to ensure that all four wheels get traction. In contrast, an automatic on-demand part-time system would allow front wheel slippage before transferring power, which could hamper acceleration.In dry conditions, 4WD Lock mode places priority on performance. More torque is directed to the rear wheels than in 4WD Auto mode to provide greater power off the line, better control when accelerating on snowy or loose surfaces, and enhanced stability at high speeds. Rear wheel torque transfer is increased by 50 percent over the amounts in 4WD Auto mode - meaning up to 60 percent of available torque is sent to the rear wheels under full-throttle acceleration on dry pavement. When in 4WD Lock mode, torque at the rear wheels is reduced by a smaller degree through corners than with 4WD Auto mode."

 

I don't think the 4wd "lock" actually locks the center diff (i.e. the lock feature on the STI) The 4wd "lock" on the outlander is just marketing talk for "now it's more awd than with 4wd auto".
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keep in mind, the outlander does NOT have a center differential anymore. On the rear diff there is basically a slipper clutch. Its disengaged in 2WD, lightly to heavily engaged in 4WD auto, and techincally (but not) 100 percent engaged in 4WD lock.
you are correct to assume it does allow a tiny bit of slippage in 4WD lock, but not much. 4WD auto just allows the car to determine how much is transferred as opposed to the driver deciding.
at anyrate, the 2WD option is just plain silly, as ever componant is still spinning and you get no increase in milage. It should say "AWD" or "4WD".

 

What does that even mean?

 

it means that the front tires and rear tires travel different distances, and therefor at different speeds when you make turns. All four tires travel in different arcs, speeds, and distances.

if you cannot allow for that, the car will "crab" and "hop" as the tires forcably skip over the pavement.

have you ever driven a true 4WD truck (like an old Ford, etc) on dry pavement in 4WD, and then made a sharp turn?

try this link for a full explination.
http://en.wikipedia.org/wiki/Four-wheel_drive

 

A tech told me that if it is put ina situation where you can no longer move (i.e. stuck) the system will shut down so you don't do any damage to it. Now that is pro active.