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2019 Subaru Outback Touring 3.6R, Crystal White Pearl
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Discussion Starter #1
Greetings, I was told the other day by a Subaru salesperson that the AWD system in the 2018 Outback Touring 3.6R is biased 60 front/40 rear.

This seems to be counter to what I've come to presume about the OB and the AWD?
 

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Lawn ornament XT
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Important things to know about Subaru AWD:

F/R torque split can vary from roughly 90/10 to 50/50. Another way of saying it: It's a front wheel drive that can divert up to half of its torque to the rear wheels. It can never work the rears harder than the fronts.

That torque split is modulated tens of times per second. It's totally dynamic, taking its inputs from the throttle position, wheel speeds and a couple of other data points. Bias is somewhat misleading- Yes, it does have a starting point, but it will have changed status before you have time to think about it.

Not all Subaru transmissions are alike, this info should be valid for the CVT in yours but won't necessarily be true for other models.
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
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Greetings, I was told the other day by a Subaru salesperson that the AWD system in the 2018 Outback Touring 3.6R is biased 60 front/40 rear.
Doesn't make it correct. They be wrong.
 

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2019 Subaru Outback Touring 3.6R, Crystal White Pearl
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Discussion Starter #4
Important things to know about Subaru AWD:

F/R torque split can vary from roughly 90/10 to 50/50. Another way of saying it: It's a front wheel drive that can divert up to half of its torque to the rear wheels. It can never work the rears harder than the fronts.

That torque split is modulated tens of times per second. It's totally dynamic, taking its inputs from the throttle position, wheel speeds and a couple of other data points. Bias is somewhat misleading- Yes, it does have a starting point, but it will have changed status before you have time to think about it.

Not all Subaru transmissions are alike, this info should be valid for the CVT in yours but won't necessarily be true for other models.
Ok thanks for the info. So just driving down the highway at say 50-75 mph straight line what would the power distribution most likely be, 90/10 perhaps?

I always thought it was 50/50 all the time.
 

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Ok thanks for the info. So just driving down the highway at say 50-75 mph straight line what would the power distribution most likely be, 90/10 perhaps?

I always thought it was 50/50 all the time.
There are MPG savings to be had by limiting the power distribution to as few components as possible. In practical terms that means the car is going to try to be FWD as much as it can.

Wheel speed data alerts the computer to wheel slippage, and when this occurs the system reacts towards 50/50. However reaction alone isn't good enough, so they also use throttle data. Throttle angle is a fair predictor of what is needed next, so the system will also goose the ratio towards 50/50 when the gas pedal is pushed down.

So yes, for a steady-state cruise under light throttle most of the power is going to the front wheels. If you get the right interface + app or diagnostic tool you can see the live data stream showing the clutch pressure ramping up and down.
 

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2016 Outback Premium 2.5 CVT w/EyeSight+SRVD
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I was told the other ... that the AWD system in the 2018 Outback Touring 3.6R is biased 60 front/40 rear.
That is indeed the default torque split. But, as rasterman correctly points out, it is constantly being modulated (multiple times per second) by the ECU and TCU, depending on driving conditions.

From the Subaru Global web site:
The active torque-split AWD system usually distributes torque 60:40 front and rear, however sensors constantly monitor the vehicle's condition in areas such as changes in grip of the front and rear tyres or vehicle speed. The electronically controlled MP-T (Multi Plate Transfer) adjusts torque distribution to the front and rear tyres in real-time to suit driving conditions, as well as the transmission and driver inputs.
If you get the right interface + app or diagnostic tool you can see the live data stream showing the clutch pressure ramping up and down.
Yep ... There's no substitute for your own data. In my case, on both my 2015 Legacy 2.5 and 2016 Outback 2.5, under constant-load highway cruising conditions the MTC (Multiplate Transfer Clutch) duty cycle usually runs about 35-40%. (I have found no Subaru data source that directly relates MTC duty cycle to actual torque split. As you correctly state, the possible torque-split range runs from ~90F/10R [MTC disengaged, duty cycle 0%] to 50F/50R [MTC fully engaged, duty cycle 100%].)
 

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And as far as I know, at most we can have 50:50 torque split
 
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