Which AWD sedan is #1 in snow? What about Infiniti?
02-11-11, 10:10 PM
#31
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Acura, BMW, Nissan, and Audi have torque vectoring. I think some Porsche's have it but I don't know enough about it to talk about it. To my knowledge Audi's sport diff is an option in the S4, standard in RS5 but unavailable in other models. BMW's system was introduced with the X6 but may now be standard in the X5 as well.
In terms of transferring torque front to rear, Audi, VW, MB, Lexus GX, LX, GS, and IS and Porsche use mechanical differentials. Lexus RX, BMW X-Drive, and Acura SH-AWD all use electronically controlled center differentials to send power front to back. This makes them a bit slower to transfer power during slippage but, in the case of the Acura and BMW, allows them to send more power to the rear during spirited driving.
My Ranking for Sporty AWD & High Speed Snow driving (best to worst): SH-AWD, Quattro w/Sport Diff, X-Drive, Porsche(w/o vectoring), Quattro, Lexus GS/IS, 4-Matic, 4-Motion, Lexus GX/LX, Lexus RX.
Poor weather @ Low speeds: Lexus GX/LX, Quattro assuming both axles have traction, SH-AWD
In terms of transferring torque front to rear, Audi, VW, MB, Lexus GX, LX, GS, and IS and Porsche use mechanical differentials. Lexus RX, BMW X-Drive, and Acura SH-AWD all use electronically controlled center differentials to send power front to back. This makes them a bit slower to transfer power during slippage but, in the case of the Acura and BMW, allows them to send more power to the rear during spirited driving.
My Ranking for Sporty AWD & High Speed Snow driving (best to worst): SH-AWD, Quattro w/Sport Diff, X-Drive, Porsche(w/o vectoring), Quattro, Lexus GS/IS, 4-Matic, 4-Motion, Lexus GX/LX, Lexus RX.
Poor weather @ Low speeds: Lexus GX/LX, Quattro assuming both axles have traction, SH-AWD
Not luxury brands but Subie and Mitsubishi have great systems as well.
02-11-11, 10:15 PM
#32
There are AWD systems with all three open diffs, and they are AWD in the name only. In reality they become 1wd once slippage occurs.
Better systems have limited slip differentials - sometimes just center, sometimes center and rear/front and sometimes all three. Some even let you lock center diff mechanically or electro-mechanically (to be used part time only, at low speeds on slippery surfaces).
This is just some of the systems. There are very many types of LDS's, and they all work in combination with stability control and other electromechanical devices. They all however work in a similar way with the same principle.
But all of them however have the same problem - when some of the wheels are slipping, they can only send so much torque to the wheels with traction - often not enough to get the vehicle moving.
Then there are classic part time 4wd system, and there also different types. Some of them can only lock center diff, some can also lock front and rear axles. Their biggest downside is that they are part time only, can only be used when stuck on slippery surface, and manually operated. On a lot of them, it requires for the vehicle to be in motion to activate the locker - and thats kind of useless if you're stuck
But the newest AWD systems with torque vectoring are completely different. They are fully computer controlled, employing electromagnetic clutches to sent torque to any wheel/wheels that has traction. They have quite a few advantages.
First of all, they are full time, completely computer controlled, requiring no input from user at all.
They can send almost all of engines torque to any wheel/wheels that have traction, regardless of whats happening to other wheels. Theoretically, even with most advanced traditional AWD systems if you had 3 wheels on smooth, slippery ice, and the 4th wheel on pavement, your car wouldn't move. Thats not an issue with tq vectoring systems, as they are able to send enough torque to that 4th wheel. Same deal with going uphill when one side of the car is on slippery surface, like shown in the Acura and BMW ads.
Also these systems can be used in high performance applications to enhance handling. The reason you don't see many high power cars with AWD systems is because they will ruin handling and traction. With traditional AWD, if you're coming out of the corner and want to get on the gas, your front wheels will break traction much easier than rears, and the AWD system will keep them burning out and not sending enough power to the rear. You'll just be understeering and chewing your front tires. Similar thing can happen even during straight line acceleration, with front tires loosing grip easier than rears. This is why most performance and high HP cars are usually RWD, or if they are AWD, they have torque slip of around 85% rear and 15% front.
With the torque vectoring systems this is no longer an issue. Computer will detect slip and cut power to the slipping wheels and send it to the wheels that have grip. This is how the Nissan GTR is able to completely destroy cars costing 4 times as much at the track.
And then of course this system doubles up as an aid to the stability system.
02-11-11, 10:25 PM
#33
Acura, BMW, Nissan, and Audi have torque vectoring. I think some Porsche's have it but I don't know enough about it to talk about it. To my knowledge Audi's sport diff is an option in the S4, standard in RS5 but unavailable in other models. BMW's system was introduced with the X6 but may now be standard in the X5 as well.
In terms of transferring torque front to rear, Audi, VW, MB, Lexus GX, LX, GS, and IS and Porsche use mechanical differentials. Lexus RX, BMW X-Drive, and Acura SH-AWD all use electronically controlled center differentials to send power front to back. This makes them a bit slower to transfer power during slippage but, in the case of the Acura and BMW, allows them to send more power to the rear during spirited driving.
In terms of transferring torque front to rear, Audi, VW, MB, Lexus GX, LX, GS, and IS and Porsche use mechanical differentials. Lexus RX, BMW X-Drive, and Acura SH-AWD all use electronically controlled center differentials to send power front to back. This makes them a bit slower to transfer power during slippage but, in the case of the Acura and BMW, allows them to send more power to the rear during spirited driving.
AFAIK, the system in the RX just has an electromechanical locker that engages rear axles if slippage occurs at the front. Probably similar with Nissan/Infiniti (not GTR). Thats not anywhere near as advanced as Acura's SH-AWD, thats similar to old Acura's VDIM system.
02-11-11, 11:26 PM
#34
Great explanation of the way these systems vary. Manufacturers really do a poor job of explaining there systems. Lexus is one of the worst. They never really explained the types of diffs employed in the 2004-9 RX which is pretty disappointing for us owners.
02-12-11, 04:16 AM
#35
a vote for the new Saab 9-5
2010/11 Saab 9-5 with the Haldex XWD is a beast in the snow. I have the car set up on 4 snows and we have had a brutal winter in Boston and the car is near impossible to slip or slide. Great winter car.
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02-12-11, 04:53 AM
#36
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This is hilarious to read.
Honda's SH-AWD system is indeed superior to those in Infiniti, Subaru, Audi, and pretty much all the rest. With dedicated snow tires it will rival even the part time 4wd trucks with locking axles.
Infiniti's with their typical low profile performance tires (especially 20's on the FX) shouldn't even be driven in snow without dedicated snow tires.
Subaru's and Audi's are decent, but they are still just mechanical torsen LSD systems. Get them into a position where one side of the car is on ice, going uphill, and see if they move
Honda's SH-AWD system is indeed superior to those in Infiniti, Subaru, Audi, and pretty much all the rest. With dedicated snow tires it will rival even the part time 4wd trucks with locking axles.
Infiniti's with their typical low profile performance tires (especially 20's on the FX) shouldn't even be driven in snow without dedicated snow tires.
Subaru's and Audi's are decent, but they are still just mechanical torsen LSD systems. Get them into a position where one side of the car is on ice, going uphill, and see if they move
Subaru and Audi rank right behind, the rest are players...
02-12-11, 05:01 AM
#37
Since you live in MO, you probably see more ice than deep snow (except this year). You also already have an MDX, which I assume you're keeping, hence the desire for an AWD sedan. With two young children, you'll still want something fairly tall with a large rear door opening in order to get kids into the car and belted in without killing your back and patience. (Take a test fit with your kids and their car seats before you buy anything.)
After leasing an AWD Lincoln MKZ, and having it be unpredictable on mixed ice / dry pavement - even with winter tires - I can't recommend the MKZ or Fusion. I would also research if the Taurus / MKS AWD system is the same.
Subaru Outbacks through 2009, while having a strong AWD reputation, have been known to "ghostwalk" on ice where the rear end starts wagging. The problem seems to occur mostly when the rear end is heavily loaded. Usually a 4-wheel alignment with a couple hundred lbs. of weight in the back corrects the problem. I have not had this problem with my 07 Outback wagon, but I don't usually carry lots of weight in the back.
That said, I would check out the Subaru Legacy. For 2010 and later, be sure it doesn't feel wobbly at speed. Also be on the lookout for an 05-07 Subaru Outback sedan, especially with the 3.0 engine. These vehicles are fairly rare, but give you some added height in an AWD sedan. Again, be sure you can get the kids in and out comfortably.
After leasing an AWD Lincoln MKZ, and having it be unpredictable on mixed ice / dry pavement - even with winter tires - I can't recommend the MKZ or Fusion. I would also research if the Taurus / MKS AWD system is the same.
Subaru Outbacks through 2009, while having a strong AWD reputation, have been known to "ghostwalk" on ice where the rear end starts wagging. The problem seems to occur mostly when the rear end is heavily loaded. Usually a 4-wheel alignment with a couple hundred lbs. of weight in the back corrects the problem. I have not had this problem with my 07 Outback wagon, but I don't usually carry lots of weight in the back.
That said, I would check out the Subaru Legacy. For 2010 and later, be sure it doesn't feel wobbly at speed. Also be on the lookout for an 05-07 Subaru Outback sedan, especially with the 3.0 engine. These vehicles are fairly rare, but give you some added height in an AWD sedan. Again, be sure you can get the kids in and out comfortably.
02-12-11, 07:18 AM
#38
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Thanks again for the posts. I have a Subaru dealer about 5 miles away so I'm gonna go and check them out. Gonna take a child seat and see how they fit in the back.
As of right now, I'm still thinking about that Infiniti G37x (damn it's gorgeous), maybe a used Acura RL and I'm gonna check out Subaru today.
Also, I guess I could look at the Acura RDX since I don't like the new TL?
As of right now, I'm still thinking about that Infiniti G37x (damn it's gorgeous), maybe a used Acura RL and I'm gonna check out Subaru today.
Also, I guess I could look at the Acura RDX since I don't like the new TL?
03-12-12, 10:58 AM
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There are many AWD/4WD systems and variations. One problem is that manufacturers often don't even tell you in details what type of system a vehicle is using. They simply just put 4WD/AWD label, which doesn't tell even 1/10th of the story.
There are AWD systems with all three open diffs, and they are AWD in the name only. In reality they become 1wd once slippage occurs.
Better systems have limited slip differentials - sometimes just center, sometimes center and rear/front and sometimes all three. Some even let you lock center diff mechanically or electro-mechanically (to be used part time only, at low speeds on slippery surfaces).
This is just some of the systems. There are very many types of LDS's, and they all work in combination with stability control and other electromechanical devices. They all however work in a similar way with the same principle.
But all of them however have the same problem - when some of the wheels are slipping, they can only send so much torque to the wheels with traction - often not enough to get the vehicle moving.
Then there are classic part time 4wd system, and there also different types. Some of them can only lock center diff, some can also lock front and rear axles. Their biggest downside is that they are part time only, can only be used when stuck on slippery surface, and manually operated. On a lot of them, it requires for the vehicle to be in motion to activate the locker - and thats kind of useless if you're stuck
But the newest AWD systems with torque vectoring are completely different. They are fully computer controlled, employing electromagnetic clutches to sent torque to any wheel/wheels that has traction. They have quite a few advantages.
First of all, they are full time, completely computer controlled, requiring no input from user at all.
They can send almost all of engines torque to any wheel/wheels that have traction, regardless of whats happening to other wheels. Theoretically, even with most advanced traditional AWD systems if you had 3 wheels on smooth, slippery ice, and the 4th wheel on pavement, your car wouldn't move. Thats not an issue with tq vectoring systems, as they are able to send enough torque to that 4th wheel. Same deal with going uphill when one side of the car is on slippery surface, like shown in the Acura and BMW ads.
Also these systems can be used in high performance applications to enhance handling. The reason you don't see many high power cars with AWD systems is because they will ruin handling and traction. With traditional AWD, if you're coming out of the corner and want to get on the gas, your front wheels will break traction much easier than rears, and the AWD system will keep them burning out and not sending enough power to the rear. You'll just be understeering and chewing your front tires. Similar thing can happen even during straight line acceleration, with front tires loosing grip easier than rears. This is why most performance and high HP cars are usually RWD, or if they are AWD, they have torque slip of around 85% rear and 15% front.
With the torque vectoring systems this is no longer an issue. Computer will detect slip and cut power to the slipping wheels and send it to the wheels that have grip. This is how the Nissan GTR is able to completely destroy cars costing 4 times as much at the track.
And then of course this system doubles up as an aid to the stability system.
There are AWD systems with all three open diffs, and they are AWD in the name only. In reality they become 1wd once slippage occurs.
Better systems have limited slip differentials - sometimes just center, sometimes center and rear/front and sometimes all three. Some even let you lock center diff mechanically or electro-mechanically (to be used part time only, at low speeds on slippery surfaces).
This is just some of the systems. There are very many types of LDS's, and they all work in combination with stability control and other electromechanical devices. They all however work in a similar way with the same principle.
But all of them however have the same problem - when some of the wheels are slipping, they can only send so much torque to the wheels with traction - often not enough to get the vehicle moving.
Then there are classic part time 4wd system, and there also different types. Some of them can only lock center diff, some can also lock front and rear axles. Their biggest downside is that they are part time only, can only be used when stuck on slippery surface, and manually operated. On a lot of them, it requires for the vehicle to be in motion to activate the locker - and thats kind of useless if you're stuck
But the newest AWD systems with torque vectoring are completely different. They are fully computer controlled, employing electromagnetic clutches to sent torque to any wheel/wheels that has traction. They have quite a few advantages.
First of all, they are full time, completely computer controlled, requiring no input from user at all.
They can send almost all of engines torque to any wheel/wheels that have traction, regardless of whats happening to other wheels. Theoretically, even with most advanced traditional AWD systems if you had 3 wheels on smooth, slippery ice, and the 4th wheel on pavement, your car wouldn't move. Thats not an issue with tq vectoring systems, as they are able to send enough torque to that 4th wheel. Same deal with going uphill when one side of the car is on slippery surface, like shown in the Acura and BMW ads.
Also these systems can be used in high performance applications to enhance handling. The reason you don't see many high power cars with AWD systems is because they will ruin handling and traction. With traditional AWD, if you're coming out of the corner and want to get on the gas, your front wheels will break traction much easier than rears, and the AWD system will keep them burning out and not sending enough power to the rear. You'll just be understeering and chewing your front tires. Similar thing can happen even during straight line acceleration, with front tires loosing grip easier than rears. This is why most performance and high HP cars are usually RWD, or if they are AWD, they have torque slip of around 85% rear and 15% front.
With the torque vectoring systems this is no longer an issue. Computer will detect slip and cut power to the slipping wheels and send it to the wheels that have grip. This is how the Nissan GTR is able to completely destroy cars costing 4 times as much at the track.
And then of course this system doubles up as an aid to the stability system.
I recently got into an accident where my car lost control on ice and got totaled. As a result, I'm the in the market for a new car. Even though AWD won't help with braking and stopping a car, I've decided to get an AWD.
I'm trying to decide which would be safest and best handling car out of Acura TL, G37x, 328xi or even C-class 4MATIC. Sounds like TL's SH-AWD is probably the best.
How does G37x handle - I'm concerned that it's primarily a RWD car and *when* the computer detects loss of traction, it transfers power to the appropriate wheel.
Any help would be greatly appreciated.
03-13-12, 09:36 AM
#41
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Does it make sense to get a front-wheel biased AWD system such as Acura's SH-AWD?
Can a rear-wheel based AWD system, such as in G37x, be an issue in rear wheels spinning out?
Thanks in advance!
03-13-12, 09:54 AM
#42
I am definitely going to get good snow tires. I'm just wondering which AWD out of TL, G37x or 328xi would be best.
Does it make sense to get a front-wheel biased AWD system such as Acura's SH-AWD?
Can a rear-wheel based AWD system, such as in G37x, be an issue in rear wheels spinning out?
Thanks in advance!
Does it make sense to get a front-wheel biased AWD system such as Acura's SH-AWD?
Can a rear-wheel based AWD system, such as in G37x, be an issue in rear wheels spinning out?
Thanks in advance!
G37 is the best value for your money, with the most power and toys for your buck.
03-14-12, 10:47 AM
#44
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Thanks again for the posts. I have a Subaru dealer about 5 miles away so I'm gonna go and check them out. Gonna take a child seat and see how they fit in the back.
As of right now, I'm still thinking about that Infiniti G37x (damn it's gorgeous), maybe a used Acura RL and I'm gonna check out Subaru today.
Also, I guess I could look at the Acura RDX since I don't like the new TL?
As of right now, I'm still thinking about that Infiniti G37x (damn it's gorgeous), maybe a used Acura RL and I'm gonna check out Subaru today.
Also, I guess I could look at the Acura RDX since I don't like the new TL?
I'm partial to Subie's AWD system. We've had many in the family, and the wife currently drives an 08 Imprezza. Even with all-seasons, you'd be amazed at where I've been able to take that car. With winter tires, I've taken it up and down some pretty narly, snow covered fire-roads - traction control off of course. The biggest reason I'd pick Suburu's AWD system though, is it's proven reliability. It's just plain bullet-proof, and will take as much abuse as you can throw at it. No experience with Acura's or infiniti's systems, so I can't comment on them, but for me, the Subie's reputation is well deserved.
03-14-12, 02:11 PM
#45
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