AWD Question - Front wheels limited slip?

[metroplex]

I have read several topics on this fine forum and learned that Ford uses their own proprietary AWD design on the Fusion AWD.

 

However, I cannot find any information on if they use some type of limited slip for the front wheels and rear wheels.

 

Basically if the AWD system doesn't transmit power to the rear wheels, will I get power to both front wheels or just one (like with an open differential)?

 

If I broke lose one of the 1 front wheels, will the system start to transmit power to both rear wheels or just 1 (like with an open differential)? I want to find out for sure before I consider a Fusion because I do not want to fall for a marketing ploy of "AWD" when only 2 out of 4 wheels actually get power.

 

The reason I ask is because MSN Autos does not list limited slip or locking diff's for the Fusion's safety features, whereas the Impreza / WRX / STI are listed as having: All-wheel drive, limited slip, and a locking differential.

[akirby]

I have read several topics on this fine forum and learned that Ford uses their own proprietary AWD design on the Fusion AWD.

 

However, I cannot find any information on if they use some type of limited slip for the front wheels and rear wheels.

 

Basically if the AWD system doesn't transmit power to the rear wheels, will I get power to both front wheels or just one (like with an open differential)?

 

If I broke lose one of the 1 front wheels, will the system start to transmit power to both rear wheels or just 1 (like with an open differential)? I want to find out for sure before I consider a Fusion because I do not want to fall for a marketing ploy of "AWD" when only 2 out of 4 wheels actually get power.

 

The reason I ask is because MSN Autos does not list limited slip or locking diff's for the Fusion's safety features, whereas the Impreza / WRX / STI are listed as having: All-wheel drive, limited slip, and a locking differential.

 

Open diffs with traction control. TC will apply the brakes to one of the front wheels if it's slipping to send traction to the other wheel and cuts engine torque if necessary to maintain traction.

 

The WRX locking diff is in the center - locks torque distribution front and rear. The Ford system will anticipate the need for rear wheel torque and engage the rear wheels before slip is detected using the steering angle and throttle position (accelerating around a corner e.g.).

[Ted_@_Landau_Ford_Lincoln]

Open diffs with traction control. TC will apply the brakes to one of the front wheels if it's slipping to send traction to the other wheel and cuts engine torque if necessary to maintain traction.

 

The WRX locking diff is in the center - locks torque distribution front and rear. The Ford system will anticipate the need for rear wheel torque and engage the rear wheels before slip is detected using the steering angle and throttle position (accelerating around a corner e.g.).

 

 

My experience driving an AWD Fusion on snow packed/icy roads is that all four wheels are getting torque. I often turn the traction control OFF and have a blast getting the Fusion going in easily controllable 4 wheel drifts around corners! Balance and predictability is perfect!

[allfuze]

I was saying in another post (Transmission/ transfer case problem) that there was an article this week in local paper about AWD systems stating that 'not all systems are created equal'. Interesting piece.

 

In short, it said that AWD system that spread that power to front/rear wheel at all times, are better than those 'reactive' systems that normally drive 2 wheels, then transfer power to other wheels when slip is detected. In the article they spoke about new Mercedes, they give as example their latest 4matic system as (by default) sharing drive-power 45/55. They also listed a few other brand/models - Audi, Subaru... They also name Saab's new 9-3 (did not know they had AWD, maybe 2009 ?), and BMW upcoming DPC system which splits power front-rear and also left-right without using traditional Stability Control (which applies brakes to spinning wheels).

 

Article gave as an example of a 'reactive' systems that normally drive 2 wheels as the Volvo S80 which works wonders when it actually begins to do its thing. But it says the slip first, grip-later nature of the system and the lag time between the need (when the front wheels spin) and the moment the all-wheel-drive system kicks-in tends to leave the driver feeling as though you lost control.

 

Reason is that when front wheels do begin to slide, the car begins to understeer (and this is at slow speeds). The problem is that firing up the rear wheels after the fact pushes the car farther into understeer before it comes to the rescue.

 

Went on to say that to keep S80 system functioning at its optimum requires the driver to be more aggressive than might be considered prudent. The electronic stability/traction control systems does keep things fine. However, the sensation of losing the car even for a few seconds (especially on a snowy road), can be bad for your heart....

 

I found it interesting that they mentioned Volvo because I heard the Ford Fusion system was based in part on Volvo system. Ford knows Volvo system well since it uses the Haldex in its bigger cars. Even if Fusion AWD is new, I've heard its "philosophy" is similar in way it performs.

 

I tried to find articles that tested, described, compared the Fusion AWD to others, but did not find anything. Would be interesting to see a known magazine (car and driver, ...) test a bunch of cars in a similar environment.

 

I saw the comment above stating that the Ford system will anticipate the need for rear wheel torque and engage the rear wheels before slip is detected. I know its all computer based, etc... but no matter how quick it does things, it still must be a 'reactive' system. Unless you have all 4 wheel driven at all times, I find it difficult to see how any system can "predict" when it will need to send power to other wheels (maybe the Great Houdini can do it !!).

 

I'm not sure if anyone can "share" some of their knowledge here. But its a very interesting topic.

Thanks to all....

[akirby]

I was saying in another post (Transmission/ transfer case problem) that there was an article this week in local paper about AWD systems stating that 'not all systems are created equal'. Interesting piece.

 

In short, it said that AWD system that spread that power to front/rear wheel at all times, are better than those 'reactive' systems that normally drive 2 wheels, then transfer power to other wheels when slip is detected. In the article they spoke about new Mercedes, they give as example their latest 4matic system as (by default) sharing drive-power 45/55. They also listed a few other brand/models - Audi, Subaru... They also name Saab's new 9-3 (did not know they had AWD, maybe 2009 ?), and BMW upcoming DPC system which splits power front-rear and also left-right without using traditional Stability Control (which applies brakes to spinning wheels).

 

Article gave as an example of a 'reactive' systems that normally drive 2 wheels as the Volvo S80 which works wonders when it actually begins to do its thing. But it says the slip first, grip-later nature of the system and the lag time between the need (when the front wheels spin) and the moment the all-wheel-drive system kicks-in tends to leave the driver feeling as though you lost control.

 

Reason is that when front wheels do begin to slide, the car begins to understeer (and this is at slow speeds). The problem is that firing up the rear wheels after the fact pushes the car farther into understeer before it comes to the rescue.

 

Went on to say that to keep S80 system functioning at its optimum requires the driver to be more aggressive than might be considered prudent. The electronic stability/traction control systems does keep things fine. However, the sensation of losing the car even for a few seconds (especially on a snowy road), can be bad for your heart....

 

I found it interesting that they mentioned Volvo because I heard the Ford Fusion system was based in part on Volvo system. Ford knows Volvo system well since it uses the Haldex in its bigger cars. Even if Fusion AWD is new, I've heard its "philosophy" is similar in way it performs.

 

I tried to find articles that tested, described, compared the Fusion AWD to others, but did not find anything. Would be interesting to see a known magazine (car and driver, ...) test a bunch of cars in a similar environment.

 

I saw the comment above stating that the Ford system will anticipate the need for rear wheel torque and engage the rear wheels before slip is detected. I know its all computer based, etc... but no matter how quick it does things, it still must be a 'reactive' system. Unless you have all 4 wheel driven at all times, I find it difficult to see how any system can "predict" when it will need to send power to other wheels (maybe the Great Houdini can do it !!).

 

I'm not sure if anyone can "share" some of their knowledge here. But its a very interesting topic.

Thanks to all....

 

All Ford will admit about their AWD system is that it's very similar to the Haldex system but while the Haldex is 100% reactive the Ford system has some predictive capability.

 

If it detects that you are accelerating around a corner it will transfer torque to the rear wheels. So while it is "reacting" to changes in steering angle and throttle it is not yet "reacting" to a slip condition in the front wheels. So in that regard it is predicting, not reacting.

 

I think the difference is Ford added an electro-mechanical actuator to the center diff that can be controlled by the PCM and doesn't just rely on a mechanical setup like the Haldex.

[allfuze]

So latest Fusion AWD system seems better than a 100% reactive one.

 

I think the key is what you stated: that it is "reacting" to changes in steering angle and throttle - so in this respect it works for 'everyday driving'. Taking that fast corner, "flooring it" from a standstill, etc... will engage immediately if this works as Ford says.

 

But I'm guessing it would still be "reacting" to a typical winter slip condition in the front wheels. eg. you're driving but hit a patch of ice. Unless this is an intelligent car, and even so, there would be no way for the car to determine when to engage the rear-wheels. It would have to 'react' to the slip. Especially if the conditions which enables it to 'predict' are not there (change in steering angle, throttle, ....).

 

In this respect, the "full time AWD" if I can call it that, would be a better system.

[akirby]

So latest Fusion AWD system seems better than a 100% reactive one.

 

I think the key is what you stated: that it is "reacting" to changes in steering angle and throttle - so in this respect it works for 'everyday driving'. Taking that fast corner, "flooring it" from a standstill, etc... will engage immediately if this works as Ford says.

 

But I'm guessing it would still be "reacting" to a typical winter slip condition in the front wheels. eg. you're driving but hit a patch of ice. Unless this is an intelligent car, and even so, there would be no way for the car to determine when to engage the rear-wheels. It would have to 'react' to the slip. Especially if the conditions which enables it to 'predict' are not there (change in steering angle, throttle, ....).

 

In this respect, the "full time AWD" if I can call it that, would be a better system.

 

Yes, it still reacts to slippage just like a normal AWD system. And while full time AWD with a constant torque split to the rear would be better for handling, it would probably do so at the expense of fuel economy and since these are family sedans and not sports cars they made a compromise.

 

It will be interesting to see what they do with the MKS - it was rumored to have a RWD bias instead of FWD - for better performance. But I didn't see anything in the specs.

[Ted_@_Landau_Ford_Lincoln]

So latest Fusion AWD system seems better than a 100% reactive one.

 

I think the key is what you stated: that it is "reacting" to changes in steering angle and throttle - so in this respect it works for 'everyday driving'. Taking that fast corner, "flooring it" from a standstill, etc... will engage immediately if this works as Ford says.

 

That's exactly how it feel... immediately engagement. the only slip you feel is when you accelerate at a rate that's enough to break traction on all 4 wheels.

 

But I'm guessing it would still be "reacting" to a typical winter slip condition in the front wheels. eg. you're driving but hit a patch of ice. Unless this is an intelligent car, and even so, there would be no way for the car to determine when to engage the rear-wheels. It would have to 'react' to the slip. Especially if the conditions which enables it to 'predict' are not there (change in steering angle, throttle, ....).

 

In this respect, the "full time AWD" if I can call it that, would be a better system.

The Haldex system reacts in 1/7th of a wheel spin. (lookup 'Haldex' on wikipedia ). 1/7th of a wheel spin amounts to about 10 - 14 inches of travel when the wheel has traction. That amount of travel would take a fraction of a second, hence the reaction time might not even be perceived when you loose traction at speed. The system in the Ford Fusion is no slower than the Haldex and may even be quicker ...and it feels seamless. If, as you say a full time AWD system would be better, I can't imagine it being any more than minutely so... and likely not even perceptible.

[metroplex]

That's exactly how it feel... immediately engagement. the only slip you feel is when you accelerate at a rate that's enough to break traction on all 4 wheels.

 

 

The Haldex system reacts in 1/7th of a wheel spin. (lookup 'Haldex' on wikipedia ). 1/7th of a wheel spin amounts to about 10 - 14 inches of travel when the wheel has traction. That amount of travel would take a fraction of a second, hence the reaction time might not even be perceived when you loose traction at speed. The system in the Ford Fusion is no slower than the Haldex and may even be quicker ...and it feels seamless. If, as you say a full time AWD system would be better, I can't imagine it being any more than minutely so... and likely not even perceptible.

 

So to answer my question, does the Fusion AWD really transmit power to all 4 wheels (disregarding bias for the time being) or does it have an open diff in the front and rear?

 

I have seen Ford's traction control in action and it hardly functions the same as a limited slip or locking differential. Ford's trac ctrl with an open differential spells doom for traction, while the trac ctrl can only assist a functional limited slip differential.

 

The reason I ask is that I could *live* with a FWD-biased AWD system if it functioned like a FWD w/ a limited slip differential and a RWD w/ a limited slip differential. I do not want an AWD system that can only transmit power to 2 out of the 4 wheels (like a 4x4 with front and rear open diffs).

 

I also read that the Fusion AWD owners are getting abysmal gas mileage in the city. I thought the whole point of a reactive AWD is to boost fuel economy.

[akirby]

So to answer my question, does the Fusion AWD really transmit power to all 4 wheels (disregarding bias for the time being) or does it have an open diff in the front and rear?

 

I have seen Ford's traction control in action and it hardly functions the same as a limited slip or locking differential. Ford's trac ctrl with an open differential spells doom for traction, while the trac ctrl can only assist a functional limited slip differential.

 

The reason I ask is that I could *live* with a FWD-biased AWD system if it functioned like a FWD w/ a limited slip differential and a RWD w/ a limited slip differential. I do not want an AWD system that can only transmit power to 2 out of the 4 wheels (like a 4x4 with front and rear open diffs).

 

I also read that the Fusion AWD owners are getting abysmal gas mileage in the city. I thought the whole point of a reactive AWD is to boost fuel economy.

 

I already answered that in post 2. The diffs are open, and you're wrong about traction control. It won't help from a performance aspect if that's what you're asking, but if you get one front wheel spinning in the mud or ice then TC will apply the brakes to that one front wheel which will transfer torque to the other wheel that has traction. It's not as good as a Limited Slip diff but it does work in most situations.

 

As for the gas mileage, the EPA tests only show a 1 mpg difference IIRC. If you took these same AWD owners with poor fuel mileage and gave the FWD vehicles they'd still get crappy fuel mileage. It's not the vehicle - it's the driver and the route.

[awdpath]

So to answer my question, does the Fusion AWD really transmit power to all 4 wheels (disregarding bias for the time being) or does it have an open diff in the front and rear?

 

I have seen Ford's traction control in action and it hardly functions the same as a limited slip or locking differential. Ford's trac ctrl with an open differential spells doom for traction, while the trac ctrl can only assist a functional limited slip differential.

 

The reason I ask is that I could *live* with a FWD-biased AWD system if it functioned like a FWD w/ a limited slip differential and a RWD w/ a limited slip differential. I do not want an AWD system that can only transmit power to 2 out of the 4 wheels (like a 4x4 with front and rear open diffs).

 

I also read that the Fusion AWD owners are getting abysmal gas mileage in the city. I thought the whole point of a reactive AWD is to boost fuel economy.

 

 

Regarding the Fusion awd poor mileage complaints found on the internet, I think poster "urnews" alone is responsible for at least half of them (LOL).

 

You can think of the front/rear differential as an "eLSD", see under "Electronic" http://en.wikipedia.org/wiki/Limited_slip_differential ( reason why the Fusion awd comes with Traction Control and ABS is a required option for the 2007 awd models)

 

 

I think if Ford were to reveal details about the Fusion awd system, it would be something like this:

 

http://www.autoblog.com/2007/11/30/saab-xw...ystem-up-close/

 

 

As for my Fusion se awd 2007, the gas mileages have been better than the EPA's updated/revised estimates.

[metroplex]

My 2000 Crown Vic and the 2007 Mustang GT both have "Traction Control" where the ABS module modulates the brake for the wheel that is spinning. When my 2000 Crown Vic had an open rear differential, Traction Control was USELESS in mud and snow. All it did was slow down the spinning wheel until the brake overheated or the engine stalled out. With a true limited slip (Torsen or viscous coupling, I used both), the Traction Control worked much more effectively.

 

Thanks for the Saab link. Looking at the diagram (which explains the Haldex a lot better than anything I have seen thus far), it appears the PTU is responsible for the front wheels, while the eLSD manages the rear wheels. I wonder why many of the Internet car sites do not list the Fusion/500 as having a locking or limited slip differential if Ford's in-house AWD is supposed to be similar to the Haldex 4. The same sites will report that the Subaru models have a limited slip differential and locking differential (front and rear are limited slip, center is viscous coupling). The brochure will actually report this as well (Legacy 2.5 GT Spec-B with Torsen rear diff).

 

What kind of mileage do you get in pure city driving? Some of the Fusion AWD owners were reporting 11-13 mpg in the city.

[akirby]

My 2000 Crown Vic and the 2007 Mustang GT both have "Traction Control" where the ABS module modulates the brake for the wheel that is spinning. When my 2000 Crown Vic had an open rear differential, Traction Control was USELESS in mud and snow. All it did was slow down the spinning wheel until the brake overheated or the engine stalled out. With a true limited slip (Torsen or viscous coupling, I used both), the Traction Control worked much more effectively.

 

Thanks for the Saab link. Looking at the diagram (which explains the Haldex a lot better than anything I have seen thus far), it appears the PTU is responsible for the front wheels, while the eLSD manages the rear wheels. I wonder why many of the Internet car sites do not list the Fusion/500 as having a locking or limited slip differential if Ford's in-house AWD is supposed to be similar to the Haldex 4. The same sites will report that the Subaru models have a limited slip differential and locking differential (front and rear are limited slip, center is viscous coupling). The brochure will actually report this as well (Legacy 2.5 GT Spec-B with Torsen rear diff).

 

What kind of mileage do you get in pure city driving? Some of the Fusion AWD owners were reporting 11-13 mpg in the city.

 

I don't think Ford's AWD system is Haldex 4 based. The Ford system can shift torque front to rear but the front and rear diffs are open with electronic traction control only on the front (at least in the Fusion - the Taurus may have TC front and rear).

 

TC is no substitute for a true LSD or locking diff. It does work if only one wheel loses traction and the other one is on a dry surface but not if you're in snow or mud where you need to spin the wheels to dig down and find traction.

[awdpath]

I don't think Ford's AWD system is Haldex 4 based. The Ford system can shift torque front to rear but the front and rear diffs are open with electronic traction control only on the front (at least in the Fusion - the Taurus may have TC front and rear).

 

TC is no substitute for a true LSD or locking diff. It does work if only one wheel loses traction and the other one is on a dry surface but not if you're in snow or mud where you need to spin the wheels to dig down and find traction.

 

 

According to the Fusion 2007 brochure, the Fusion awd can send power/torque to the individual wheel that has traction ( the illustrations below suggest front and rear).

 

Ford Fusion awd illustrations provided by Ford:

 

http://www.fordvehicles.com/cars/fusion/awd/

 

And the Fusion awd "can deliver the precise amount of torque to the rear wheels up to 100 percent" http://www.mazdausamedia.com/article_displ...rticle_id=23516 The Fusion awd is more likely to get stuck resting on its belly in deep snow due to its relatively low ground clearance.

 

My worse winter city MPG is 16 during a cold week( -25/-32F, idling half the time ) and average summer city MPG is about 18-19.

[akirby]

According to the Fusion 2007 brochure, the Fusion awd can send power/torque to the individual wheel that has traction ( the illustrations below suggest front and rear).

 

Ford Fusion awd illustrations provided by Ford:

 

http://www.fordvehicles.com/cars/fusion/awd/

 

And the Fusion awd "can deliver the precise amount of torque to the rear wheels up to 100 percent" http://www.mazdausamedia.com/article_displ...rticle_id=23516 The Fusion awd is more likely to get stuck resting on its belly in deep snow due to its relatively low ground clearance.

 

My worse winter city MPG is 16 during a cold week( -25/-32F, idling half the time ) and average summer city MPG is about 18-19.

 

It does sort of imply a limited slip diff in the rear but I don't think it has one.

 

I do believe that the Taurus has 4 wheel Traction Control therefore it has the ability to apply brakes to a spinning front or rear wheel to transfer torque to the other one (not the same as limited slip but effective in most circumstances). It can do this because it has 4 channel ABS which gives the ability to modulate braking on all 4 wheels independently. This also allows for AdvanceTrac stability control.

 

The Fusion, OTOH, only has 3 channel ABS (design oversight) with only one channel to the rear so it can't provide TC on the rear wheels like the Taurus. That will be fixed at the end of this year.

 

I still don't think the Fusion or Taurus have locking or limited slip diffs in the front or rear.

[awdpath]

It does sort of imply a limited slip diff in the rear but I don't think it has one.

 

I do believe that the Taurus has 4 wheel Traction Control therefore it has the ability to apply brakes to a spinning front or rear wheel to transfer torque to the other one (not the same as limited slip but effective in most circumstances). It can do this because it has 4 channel ABS which gives the ability to modulate braking on all 4 wheels independently. This also allows for AdvanceTrac stability control.

 

The Fusion, OTOH, only has 3 channel ABS (design oversight) with only one channel to the rear so it can't provide TC on the rear wheels like the Taurus. That will be fixed at the end of this year.

 

I still don't think the Fusion or Taurus have locking or limited slip diffs in the front or rear.

 

 

Some details form Ford about the 2008 Lincoln MKZ awd ( 4-sensor/3-channel ABS):

 

http://ford.ca/main/default.asp?language=e...n&model=MKZ

 

"Together with standard Traction Control, AWD can even direct power side to side on each axle, allowing you to continue forward motion if only one wheel has grip"

 

About the Fusion Traction Control:

 

http://www.worldcarfans.com/2060529.005/fo...-control-system

 

"Traction control on the V-6 test car[Fusion] was just right -- perhaps unique in all the industry," Healey wrote. "It allowed tire spin when starting forcefully on slick roads and gradually eased the spinning without trying to stop it, allowing the car to keep moving forward as traction was gained. It should be unusually effective in winter and whenever some spinning helps forward progress."

 

 

From the various sources on the net I gathered, the Fusion 3-channel ABS comes with 4 sensors.

 

I think we can conclude that the Fusion does not have LSD in the traditional sense. However, with ABS sensors/Traction Control, the Fusion awd can perform with similar LSD effects to a certain extent.

[akirby]

Some details form Ford about the 2008 Lincoln MKZ awd ( 4-sensor/3-channel ABS):

 

http://ford.ca/main/default.asp?language=e...n&model=MKZ

 

"Together with standard Traction Control, AWD can even direct power side to side on each axle, allowing you to continue forward motion if only one wheel has grip"

 

About the Fusion Traction Control:

 

http://www.worldcarfans.com/2060529.005/fo...-control-system

 

"Traction control on the V-6 test car[Fusion] was just right -- perhaps unique in all the industry," Healey wrote. "It allowed tire spin when starting forcefully on slick roads and gradually eased the spinning without trying to stop it, allowing the car to keep moving forward as traction was gained. It should be unusually effective in winter and whenever some spinning helps forward progress."

 

 

From the various sources on the net I gathered, the Fusion 3-channel ABS comes with 4 sensors.

 

I think we can conclude that the Fusion does not have LSD in the traditional sense. However, with ABS sensors/Traction Control, the Fusion awd can perform with similar LSD effects to a certain extent.

 

Yes, it can to a certain point where the braking slows the forward progress too much. This seems to happen a lot in snow where both tires can lose grip at the same time. With a true LSD both wheels would spin freely until they found solid ground. Still not sure how you can apply TC to all 4 wheels independently with only 3 channel ABS.

[metroplex]

Yes, it can to a certain point where the braking slows the forward progress too much. This seems to happen a lot in snow where both tires can lose grip at the same time. With a true LSD both wheels would spin freely until they found solid ground. Still not sure how you can apply TC to all 4 wheels independently with only 3 channel ABS.

 

I really want to consider the Fusion, but the AWD seems rather lackluster on paper. Depending on TC for "AWD" traction isn't going to be as smooth or fast as a true AWD system with limited slip front, rear, and center differentials namely because TC/ABS will have a slight delay. It can do all the prediction it wants, but my experience shows that a limited slip differential is going to perform better. I may take a Fusion AWD for a test drive, but the salesperson will probably go apesh*t if I drift it in a snow covered field or parking lot to test out the AWD!

[awdpath]

Yes, it can to a certain point where the braking slows the forward progress too much. This seems to happen a lot in snow where both tires can lose grip at the same time. With a true LSD both wheels would spin freely until they found solid ground. Still not sure how you can apply TC to all 4 wheels independently with only 3 channel ABS.

 

 

For forward acceleration traction, TC( ABS pulsing) applies only to one of the wheels with greater slippage on the axle at any instant in time. With slight modification and computer control (" AWD system monitors vehicle conditions-and driver inputs-100 times a second "), the single rear ABS channel can pulse/brake either rear left or rear right( "eLSD" at work).

 

The Fusion AWD TC slows down wheel(s) slippage, not forward progress ( at least in a controllable manner ). In poor traction conditons, the wheel(s) with greater traction is still able to spin until the computer narrowed it down to one wheel if no forward progress is made(then you are in trouble). Remember, the Fusion AWD preprogramed parameters and along with " An active, on-demand coupler can deliver the precise amount of torque to the rear wheels up to 100 percent "

[metroplex]

For forward acceleration traction, TC( ABS pulsing) applies only to one of the wheels with greater slippage on the axle at any instant in time. With slight modification and computer control (" AWD system monitors vehicle conditions-and driver inputs-100 times a second "), the single rear ABS channel can pulse/brake either rear left or rear right( "eLSD" at work).

 

The Fusion AWD TC slows down wheel(s) slippage, not forward progress ( at least in a controllable manner ). In poor traction conditons, the wheel(s) with greater traction is still able to spin until the computer narrowed it down to one wheel if no forward progress is made(then you are in trouble). Remember, the Fusion AWD preprogramed parameters and along with " An active, on-demand coupler can deliver the precise amount of torque to the rear wheels up to 100 percent "

 

Ford tried to do that (unsuccessfully) with the Crown Vic. Instead of offering a true limited slip differential, they offered an optional traction control system AND advertised it for making the car driveable in the snow (they even showed a picture of a tire in snow with snow packed into the treads). Everyone that has a Vic with the open diff and trac ctrl will tell you that the ABS will just try to control wheel slippage to the point the car stops and the engine stalls out in severe conditions. It will apply the ABS to the right rear wheel (the only one that is spinning) trying to module the slippage so that the left rear wheel spins - but that never happens. From experience, traction control is useful as an additional tool combined with limited slip differentials (or true lockers), and not as a replacement for limited slip (as Ford tried to do with the Crown Vic).

 

I'm not sure I want to get tricked by Ford again with fancy advertising.

[Jimmy G]

Time for some real world testing here in northern Ohio.

Nice and snowy! :happy feet:

[akirby]

Time for some real world testing here in northern Ohio.

Nice and snowy! :happy feet:

 

Real world experience with Lincoln LS owners confirms that when both drive wheels are slipping (or all 4 in the case of AWD) electronic Traction Control will brake the wheels AND cut engine torque to the point that the car simply stops. In slushy conditions you actually have to turn off the TC to force at least one wheel to spin until it finds traction under the slush.

 

It works fine if only half the wheels are spinning. You can feel when the TC cuts in because the car slows dramatically, almost as if the computer took your foot off the gas and tapped the brakes (because that's exactly what it does).

[Jimmy G]

Real world experience with Lincoln LS owners confirms that when both drive wheels are slipping (or all 4 in the case of AWD) electronic Traction Control will brake the wheels AND cut engine torque to the point that the car simply stops. In slushy conditions you actually have to turn off the TC to force at least one wheel to spin until it finds traction under the slush.

 

It works fine if only half the wheels are spinning. You can feel when the TC cuts in because the car slows dramatically, almost as if the computer took your foot off the gas and tapped the brakes (because that's exactly what it does).

 

It goes straight as an arrow from a dead stop and a flooring of the accelerator in the snow. The TC doesn't slow the thing down a bit, that I can tell.(seat of the pants)

With the TC off, the rear end kicks out a little just like a normal and off I go. I noticed the TC working the back brakes when I was doing a donut in a parking lot. It really likes to spin with the TC off!

That was my real world testing this morning.

[akirby]

It goes straight as an arrow from a dead stop and a flooring of the accelerator in the snow. The TC doesn't slow the thing down a bit, that I can tell.(seat of the pants)

With the TC off, the rear end kicks out a little just like a normal and off I go. I noticed the TC working the back brakes when I was doing a donut in a parking lot. It really likes to spin with the TC off!

That was my real world testing this morning.

 

Maybe they've improved the TC logic or it works differently with AWD. On the 2000 LS if you hit a bump while turning the TC would cut in and you could feel the braking and drop in torque - it was just like you had lifted off the accelerator. Very disconcerting. And many folks had problems trying to go up a hill because of that - it would lose all forward momentum. Sounds like they've improved it quite a bit.

[Jimmy G]

Maybe they've improved the TC logic or it works differently with AWD. On the 2000 LS if you hit a bump while turning the TC would cut in and you could feel the braking and drop in torque - it was just like you had lifted off the accelerator. Very disconcerting. And many folks had problems trying to go up a hill because of that - it would lose all forward momentum. Sounds like they've improved it quite a bit.

 

My wifes 2005 500AWD would react the same in the snow. Dead straight on flooring the pedal from a dead stop. They did tell her to turn off the TC if she got stuck in the snow. Never had to try that option.