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Wagons Subaru Crew Subaru Legacy & Outback 2009 Outback - AWD systems
64 messages, Last post on Dec 15, 2008 at 11:18 AM
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I have heard that all new Outbacks for 2009 will feature VDC (traction/stability control) as standard equipment. I'm wondering if this will make a difference to the AWD systems offered - does anyone know? I have read that for 2008 and earlier, manual transmission models were mated to a "continuous AWD" system in which torque is normally distributed 50/50 (front/rear) through a viscous center differential that changes this distribution if slipping occurs. This appears to be a purely mechanical system without electronic controls. In contrast, automatic transmissions were mated to an "active AWD" system which is essentially a front-wheel drive system since the torque is normally distributed 90/10 (front/rear). An electronically controlled transfer clutch then changes this ratio depending on feedback from electronic sensors that monitor wheel slippage, braking, throttle, and who knows what all else? It sounds like the sensors used for "active AWD" may be the same as those used for VDC. So I'm wondering if I can still get a manual transmission with "continuous AWD" for 2009. It seems more likely that placing sensors everywhere for VDC would enable "active AWD" on all models. The official Subaru websites don't have any product info out there yet for the 2009 Outbacks so I can't find out. Does anyone know??
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Replying to: jim2345 (Aug 30, 2008 9:55 am)
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Replying to: jim2345 (Sep 02, 2008 7:13 am) Later, VDC was used as a seperate label for their traction and stability control system only. So it's now stand-alone, basically. |
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In my earlier post I described what I had just discovered by reading the 2008 Subaru Outback product info - that the manual and automatic transmissions are mated to entirely different AWD systems. The manual transmission comes with a "continuous AWD" system that normally splits torque 50/50 front/rear. A viscous center differential will adjust this split should slipping occur. This appears to be a purely mechanical system without electronic controls. The automatics are mated to an "active AWD" system in which torque is normally split 90/10 front/rear. A variable transfer clutch adjusts this split based on feedback from electronic sensors that measure wheel slippage, braking, steering, etc, etc. Now that Subaru has confirmed that the same AWD systems will be offered for 2009 in the 2.5i Outbacks, I have a choice to make and would like some help from people who know something about these AWD systems. I feel I need AWD because my 200 foot driveway is steep and anything more than an inch of snow keeps my wife's FWD Sable at the bottom (sometimes she slips backwards toward the street and gets stuck sideways). I am also a skier and do most of my driving in the winter months up in the mountains in NH. I drive in snow a lot - both on highways and winding mountain access roads. I don't go off-road (on purpose). I like a manual transmission for performance reasons and for driving fun (not to mention it will cost $1000 less than the automatic). But what about this difference in AWD systems? Does anyone have an opinion about which will work better for my needs?
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I much prefer the 50/50 manual system. It's a subtle difference and probably not noticeable for normal driving, but I find better control with the 50/50 split. I have a 300 foot steep driveway that slopes away from the sun and in my mother's 90/10 I can feel the front wheels spin and the rear wheels engage. I don't like that, and by then you're already losing momentum. Also, I like to have fun in the snow. With the 50/50 I enjoy my driving so much more. I have a better feel for how far I can push the car. The 90/10 feels more like a FWD, especially when turning and the wheels begin to slip, but then the rear wheels engage. I'm sure other opinions will differ. In the end, either AWD system will far outperform a FWD Sable.
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Replying to: jim2345 (Sep 03, 2008 6:48 am) I would take turns and hit the gas, and the rear end would break loose, rally style. The AWD should shift power to the front and it would pull me out of the skid. If I did it juuuuuust right, I would get it to wag the tail 2 or 3 times. Very controllable, very safe. Towards the end I had snow tires on for a season, and it was virtually unstoppable. We have an 09 automatic now, but haven't had snow yet. |
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Replying to: ratbert1 (Sep 03, 2008 7:21 am) What you said about losing momentum is right on. Momentum is everything for making it up my snow covered driveway. Also, from your description, it sounds like you can feel the system working on the "active" AWD system. It would drive me nuts to have the car constantly exceeding the limit of FWD adhesion before the system clunks in. I don't need any more white-knuckle thrill rides on snowy roads. I'm going to get the manual so I can have a better snow-beast, have more fun driving, and save $1000. Thanks again!!
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Replying to: jim2345 (Sep 04, 2008 4:11 am) Also, I live in Fairbanks, Alaska, so snow and ice is the rule for a solid 6 months per year. My driveway is about 50' of steep (maybe 10-12% grade?), before leveling out. While I never noticed the "lag" or "momentum loss" that was cited here with the automatic, it certainly lacked some of the fun-factor of the manual. The auto wins hands down in dealing with deep snow at slow (or no) speeds. The manual transmission's clutch is grabby, so getting it started under high resistance, low traction conditions either spins the tires or results in a nice odor.  Granted, it was new, so it probably would have mellowed out with some more use. But, which did I prefer? The manual - no contest. I enjoyed it for all the reasons cited by the rest of you. In winter conditions, though, I tossed the auto around just as easily and precisely as the manual. You will not regret your choice of manual if that is your natural preference, but that is the only reason that makes it the clear winner.  In case you are wondering why I had both, I purchased the manual as a personal, long-term car (life had other plans), and the auto as a short-term investment (easier to resell and better resale value). |
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Replying to: xwesx (Sep 04, 2008 8:36 am) So you're basically saying the choice of AWD system doesn't matter - both are fine in the snow. More important to get the kind of transmission I prefer - right? This keeps me in the manual transmission camp. But I need to ask you - did either of your Outbacks have VDC? This could explain the difference between your experience and ratbert's. And of course, all the new Outbacks will have VDC - which I'm not completely sure I'm ready for. I was talking to a friend this morning who told me about a guy in Michigan he knows who had a BMW sport wagon (3-series) with BMW's X-drive. I think this system is similar to an outback with VDC. He said this guy was on a side street stopped at the intersection with a main truck route. It was snowing and he thought he could scoot out in front of an 18-wheeler that was far enough down the road but coming on pretty fast. When he stepped on the gas to get out and get going, his wheels began to spin. The next thing that happened was that the sophisticated X-drive system took over the controls, braking the spinning wheels and ignoring his repeated stomping of the accelerator pedal to accelerate out of there. He had just enough momentum to limp strainght across the intersection before the trruck (which couldn't stop) missed him by a foot or so. . . |
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Replying to: jim2345 (Sep 04, 2008 9:48 am) My Sienna has an instrusive traction control system and my van struggled to get up my driveway with just 2" of snow. It got through eventually, but I may turn it off next time.
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