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Discussion Starter · #1 ·
All right folks, had some snow/sleet/rain in my area yesterday and I am internally debating (again) about the FWD vs. AWD when I go to order in the spring.

I am 95% sold on FWD because we really don't get much nasty weather around here to warrant it ($3.50-4.00 gas this summer, ouch!) but a definite nice to have on crappy days like yesterday (does everybody need to do 75mph or 30mph in the left lane during a snowstorm...really!)

My question is this, the AWD system in the Acadia is it full-time like say a Subaru or BMW Xdrive system or the same old same old FWD biased most of the time and applies power to the rear wheels when slippage is detected?

I am hoping for the $2,000 AWD price premium that this is the "smart" AWD drive system.

Thanks, for any insight.
 

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I do have the AWD. I live in snow country (mountains 7000') so I have a lot of experience of driving on snow and ice. I believe the Acadia is FWD until slippage occurs, and then it transfers the power to the rear wheels. The system is transparant so you never feel it go from FWD to AWD, but I have to say traction wise it is as good or better than any 4WD vehicles I have owned. Rather you need it or not you will have to decide that issue.
 

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I thought it was 90/10 front to back in normal mode. You can certainly "feel" and "hear" it go into AWD mode when you are slipping the front tires a lot. You hear a noise, you can see the yellow AWD light go on, etc.

I plan on pulling my snowmobile trailer next weekend and I'm hoping for more snow. I'm going to say, compared to my Yukon, it's certainly a different feel in AWD with slippage, than in the normal 4x4 mode. The AWD slows down the wheels that are slipping, using wheel spin and braking to make sure you get the best grip.

However, it's certainly not going to get you out of a mud hole or snowbank, like a 4x4 can. However, with the wheel base, it's the most confident ride I've ever had in day to day conditions and during snow storms. Just remember, you can't stop any quicker than any other car, nor dodge another goofball who has just spun out in front of you. :thumb:
 

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I don't think I have heard mine or felt it go into the AWD mode. I will listen for it next time. You are right about deep mud. This is not an off road vehicle.
 

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Cravenfan said:
I thought it was 90/10 front to back in normal mode. You can certainly "feel" and "hear" it go into AWD mode when you are slipping the front tires a lot. You hear a noise, you can see the yellow AWD light go on, etc.
Are you sure that you are not talking about the "Stabilatrak" light going on. This is not the same thing as AWD. The stability control system has to do with the computer braking a particular wheel or wheels to compensate for instability elsewhere. The manual does not indicate that there is an AWD light but there is a Stabilitrack light which indicates that the traction control and or active stability control systems have stepped in. They are separate functions on top of AWD and are not neccessarily in effect when the system is feeding torque to the rear.

The system does have full time all wheel drive at 90/10 and there is always some torque being passed to the rear.
 

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Yup, Stabilitrak light...I meant to say, when you have major slippage, then the AWD works better than 4x4 to keep you from slidding off the road. However, you are not in true AWD mode, like other manuf's vehicles.
 

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Cravenfan said:
However, you are not in true AWD mode, like other manuf's vehicles.
Why do you say that? If it is 90/10 in normal operating mode, it can send power fore/aft up to some percentage (don't recall the number), and left to right with the tractional control, how is it not true AWD? It never operates in full FWD or RWD based on what I know.
 

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Discussion Starter · #8 ·
"smart" AWD actually controls each individual wheel to maximize traction all the time and calculates potential slippage in milliseconds.

This systems are in Subarus, BMW X-Drive, Audi Quattro, and I believe the old Olds Bravada had it as well.
 

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SEL said:
"smart" AWD actually controls each individual wheel to maximize traction all the time and calculates potential slippage in milliseconds.

This systems are in Subarus, BMW X-Drive, Audi Quattro, and I believe the old Olds Bravada had it as well.
The Acadia's front to rear proportioning system is an electronically controlled clutch system designed to move torque wherever the traction is, up to certain maximum limits. This is the same concept asboth the Subaru and BMW systems, although they do all differ a bit in their default proportions when nothing is slipping.

The basic Audi quattro system (such as on the A4, A6, A8, Q7 ) is actually a very different system utilizing a mechanical torsen differential to control the front/rear split (not an electronic clutch like the other three). It then use the ABS brake controller to mimic differential locking left to right, as do all of the vehicles in this discussion. The Acadia is far more like the Audi and Subaru in AWD design concept than is the Audi, so I'm not sure how you're definition of smart falls in. (I will season the above with the comment that the Audi chassis which are directly borrowed from VW, using transverse engines, like the TT, do use electronic clutch systems,)

For what its worth, I also have an Audi S6 with quattro and the Acadia feels every bit as competent in the slippery, ugly conditions to me, as does my Audi.
 

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SEL said:
All right folks, had some snow/sleet/rain in my area yesterday and I am internally debating (again) about the FWD vs. AWD when I go to order in the spring.
SEL

The Acadia's AWD system is indeed full-time, though normally biased 90-10 front to rear wheels. Your comments on the storm indicate that you also live in New Castle Co. For any conditions that you'll experience in NCC, FWD will be adequate and quite safe. As you know, when the drive wheels spin with FWD, the vehicle understeers (tends to go straight) vice the oversteer (rear rotating to the left/right) condition experienced with RWD.

I elected to get AWD because I live in a semi-rural area with narrow, winding two-lane, roundtop roads and felt that the extra grip of AWD in some rainy or snowy conditions was worth the added costs. However, I had an Audi while in college with FWD and it handled an iced-over W. Chestnut Hill Rd. when RWD cars were unable to climb the uphill sections.

The vehicle I traded, a GMC Envoy, while capable off-road, was a disaster on these roads last winter. It's RWD, with a high center of gravity, and a mechanical "locker" designed to provide power to both wheels in the case of a drive wheel spin at lower speeds. This is great for dirt but not good on black ice.

You'll have 90% of my capability with FWD. Unfortunately, as you've noted, it won't help you when surrounded by drivers with no appreciation of physics.

Good luck with your new Acadia.
 

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Discussion Starter · #11 ·
thanks tekwarrior for the great explanation, we live in the same zip code and have a Envoy currently as well (looking to place an order for an '09 in late April) we both delt with route 1 coming home that day, I think I have been admiring your Acadia on the morning commute....the reason I zeroed in on getting the Acadia!

I am pretty sure I am going with the FWD that will fill my needs (and I feel gas will be $3.50-4.00 a gallon around here in summer time).
 

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I was checking out this old thread to see how the AWD actually works. Some very good information was posted by our members on this subject. The only thing I didn't agree with was a member who was going to get a FWD over AWD due to the price of gas at that time. The AWD is rated at 1 mpg (miles per gallon) less than the FWD. I am getting the recommended 22 or 23 mpg on my AWD. The gas mileage shouldn't even be a thought. If you don't want to pay the difference in price for the AWD that's one thing but I wouldn't base the decision on miles per gallon. Good information on the AWD system though, thanks. :cheers:
 

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I also am getting 22 MPG in my all wheel drive on the highway and about 19.875 around town. I am very pleased with the gas milage and would definately go AWD just in case you need it.
Could someone explain what happens when you hit the button to turn off the stablitrack? I thought I read somewhere to do that in heavy snow when you need even more traction.
 

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We had a Buick Rendezvous prior to the Acadia. The Buick was FWD.
In deep snow, the traction control would work so hard to keep the wheels from spinning, the car literally would not move. Disabling the traction control let the wheels slip, and you could slowly accelerate through the snow.

The traction control is wonderful in those moments when you don't expect to slip and slide, but in MN, it's a good thing to be able to disable it.

BTW, our Acadia is magnificent in the snow. The AWD is seamless. The fact that (IMHO) the Acadia is a little underpowered is a benefit in the snow, as the torque does not build at the lower RPM's, so there is less wheelspin when starting from a stop.
 

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GerryL said:
The basic Audi quattro system (such as on the A4, A6, A8, Q7 ) is actually a very different system utilizing a mechanical torsen differential to control the front/rear split (not an electronic clutch like the other three). It then use the ABS brake controller to mimic differential locking left to right, as do all of the vehicles in this discussion. The Acadia is far more like the Audi and Subaru in AWD design concept than is the Audi, so I'm not sure how you're definition of smart falls in. (I will season the above with the comment that the Audi chassis which are directly borrowed from VW, using transverse engines, like the TT, do use electronic clutch systems,)
You know your stuff. Most people are not aware of the difference between some VW systems and some Audi systems. I've had a couple of A4's and they both had the Torsen center differential and it was a fantastic system.

I am a little bit confused about the Subaru system... the Subaru I owned did not use any computer systems for the AWD, no traction control, no electronic clutch differentials, ect. The system had an open front diff, a limited slip viscous coupling rear diff, and a viscous coupling center diff. Worked a little slower then my Audi for transfer to the rear, causing a little more understeer then I prefer. I liked the quick transfer with the Audi and the subsequent oversteer as I pushed down on that throttle!
 

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SEL said:
"smart" AWD actually controls each individual wheel to maximize traction all the time and calculates potential slippage in milliseconds.

This systems are in Subarus, BMW X-Drive, Audi Quattro, and I believe the old Olds Bravada had it as well.
That's not entirely correct. Audi is a torsen differential, that's mechanical. There is electronic differential locks and audi system can send up to 90% traction to any one wheel, but it doesn't calculate anything. Its a mechanical torsen differential system. I've had 7 Audi/VWs in a row with Quattro (or VW's 4Motion), and there is also a difference between their logitudinal systems (torsen) and their transverse (Haldex system originally developed by VW, but now all audis are quattro and all vws are 4motion regardless of which layout/version they are using), and the Acadia system works as well as any of these. However, haven't really driven the acadia in 2 foot banks yet so I cannot comment on how well that would work.
 

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Excuse my ignorance but does the AWD not work in reverse? I got the front left wheel bogged down in a hole where it wouldn't even spin when I was in reverse, presumably because it didn't spin then the rear never engaged? Do any AWD systems work in reverse? Thanks!
 

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bluefish7 said:
Excuse my ignorance but does the AWD not work in reverse? I got the front left wheel bogged down in a hole where it wouldn't even spin when I was in reverse, presumably because it didn't spin then the rear never engaged? Do any AWD systems work in reverse? Thanks!
I believe nearly all AWD systems work in reverse. I say "nearly" because one article I read stated the the older Honda CRVs aren't AWD when put in reverse (there could be a few others). :shrug: Effectiveness of AWD is dependent on many factors like vehicle position, traction control ON/OFF, etc. Computer-controlled AWD certainly is not as effective as a real 4WD system when someone gets stuck.
 

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bluefish7 said:
...Do any AWD systems work in reverse? Thanks!
Not sure, but a guess would say it does.

Check it out for yourself:
  • apply the parking brake
  • jack up all 4 wheels
  • start the car
  • put the car in R
  • tap the throttle for a second
  • watch to see if all wheels spin
 
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