AWD System?

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"Setting the AWD button to "Auto" makes the Murano act as a front wheel drive vehicle until slip is detected by the traction control system and up to 50% of the power is sent to the rear wheel to improve grip. According to Nissan, when the driver locks the car into AWD mode via a center console switch, power is split at 50%-50% front to rear. This alleviates the torque steer found in front wheel drive Muranos. The car will remain in that mode until the car is over 19 mph then the system will determine the amount of power to send to the back.
It's a not a complex AWD system; it's designed more for confidence against rain and snow rather than hard core off-roading. But we suspect most Murano owners won't take it further than a muddy soccer field or camp trail excursions."


So the way I understand it, when I've selected "AWD" and I drive above certain speeds(19mph), the Murano will "decide" how much power to sent to the rear wheels. What help is this on ice? Thats why I buy "AWD". When I select "AWD" I want power going to the rear wheels. If it starts to lose taction and then power is sent to the rear wheels it is too late. The auto section in the local paper(Wpg Free Press) mentioned how at the press realese of the Murano in California, they drove it onto a sand beach and it got stuck rather easily. The rear wheels never even turned. Does not sound like a good winter vehicle. http://forums.freshalloy.com/ubbthreads/images/icons/mad.gif And with 18" rubber, its not like I could even buy winter rubber (assuming you could afford it) Better off buying a Altima and putting on Blizzaks...

I guess I won't be buying a Murano. Too bad I was really starting to like it.

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I would assume you could "lock" the system into AWD instead of using the "auto" during your treks in sand, ice or snow. Shouldn't that cure your ill?

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you can lock it up to 19mph. above that it sends whatever it wants to the other wheels.

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Murano's AWD is very similar to MDX's VTM-4 system. When you "lock" it in AWD (turn the switch to AWD), it's only good for up to 19 mph (VTM-4 is up to 18 mph), after that it automatically switches back to "auto" mode. After switching back to auto, if the wheel is still slipping (wanting to slip), I'd guess the auto mode will keep the vehicle in AWD.

What PwrLvr wants is a permanent AWD system, which powers 4 wheels all the time. This accounts for about half of the awd market. The main drawback for this type is less fuel efficient. The auto-AWD (also called full time AWD) is good on MPG but makes people wonder about its reaction/engagement time. Well, guess what, losing traction also takes time to happen, it does not happen instantly. From starting to lose traction (wheel rotates faster) to totally lose it (wheel spinning), it can be a split second or maybe several seconds. The key is, the system has to detect (some even claim they can "predict") it and engage the torque transfer fast enough. I don't claim I know how good the Murano's auto AWD is, but I guess it should be sufficient.

BTW, the Pathfinder and Xterra have 4wd-high manual setting, if you want to stay in Nissan family and still want to be sure of your driving mode.

[OP240SX]

It does sound similar to VTM-4, except that Honda's system also directs power to the rear wheels when starting from a stop, regardless of conditions. It is also supposed to predict when wheel slippage is going to occur. Not sure how that works though..

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What I want is a system where I have the option to turn it "on". I do not want "Full-time". Unfortuanatly this is harder to find all the time. For those of us that live in the snow/ice belt, we don't need/want fulltime from May to October. But in winter when the road conditions dictate their may be ice, we want it "on" not ready or close or thinking about it, we want it on. I know of guys with Grand Cherokees who have rolled on black ice. And that system is rated as one of the best in terms of "sensing" traction loss. When your on ice and you lose traction and the awd kicks in, it can actually make the situation worse, and I'm talking from experience.
And I will not buy an the other Nissan SUVs. The Xterra is not at all what I want and the Pathfinder is too small and the rear seat is awful. I guess I'll have to go buy another brand, (unfortunatly) http://forums.freshalloy.com/ubbthreads/images/icons/frown.gif .

[OP240SX]

The Grand Cherokee may have a great 4WD system, but it has no stability control. I don't think it has traction control either. These would help immensely in black ice situations. These will not prevent all accidents, but that is assuming you are not racing around in icy conditions. The Murano has both (but you have to get about every freakin option available http://forums.freshalloy.com/ubbthreads/images/icons/mad.gif ). The new 4 Runner has a great 4WD system, stability control, and traction control. The MDX would also do quite well now that it has stability control along with VTM-4.

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You assume correct. I drive very carefully on ice. (this morning was a prime example!) I've read horror stories about the Toyota system on the Sequoia. Not on ice but more to do with power output interuppted during passing!!! I may try a 4 Runner, but for the $$$ would sooner drive a V8 Explorer. (yes I know the 4 runner has a V8 option) In Canada a 4Runner starts at @ $44,500. For that money I can buy a very nicly equiped crew cab truck or loaded Explorer. Or Murano for just over $40. The Acura is too much $$$ too. I may still buy a Murano, just a little disappointed in this AWD system, thats all.

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Here is part of the article I ws refering to:

"There is a front-drive-only version of Murano in the States, but in Canada, Murano will be offered only with what Nissan erroneously calls "All-Wheel Drive." No insult to Nissan; most carmakers get this wrong.
The Nissan system is actually an automatically-engaging part-time four-wheel drive. The car is front-wheel drive until wheel slippage at the fronts exceeds a pre-set threshold, upon which a series of clutch packs engages variably to transfer up to 50 per cent of the torque to the rear wheels. Alternatively, you can push a button at any speed below 30 km-h to lock the clutch packs, creating a forced 50/50 front-rear split.
Our engineering guru Gerry Malloy, refers to this type of system as "too-late" four-wheel drive, because by the time the system knows you're in trouble, it's "too late" to do anything meaningful about it. As we shall soon see.
Why not do it right?
Especially, as you shall see, since the straight-ahead start-up traction thing doesn't work anyway.

(Okay. Now is "soon" enough...)

You see, we were staying at the lovely new Bacara Resort, north of Santa Barbara, on a beautiful stretch of beach. You've got a vehicle that seems perfectly designed to handle some luxurious resort beach-type driving, so the helpful staff there allowed me to take the car onto the sand at sunrise for some photographs.

Sunrise! Me!

I tried to position it to take the perfect pic - just a wee bit farther back ..... Oops. Those front wheels spun, the car went about 10 cm straight down into the soft sand, and it wasn't going anywhere else. Flick the lock-up switch. No difference.

I wasn't exactly sure where the torque was going. The engine was revving about 3000 rpm, but no wheels were spinning. I guess it was being eaten up by the CVT - something which, for wear-and-tear reasons, I didn't want to do for long.

A John Deere "Gator" came out to help - and promptly got stuck too. I guess this sand was just too soft.

Anyway, a tow truck was necessary to extract the vehicle."

Why didn't the rear wheels get any power? http://forums.freshalloy.com/ubbthreads/images/icons/confused.gif

[jberger]

While I'll certainly agree the Murano is no off road competitor to a jeep. This reviewer must have been high. Who would drive onto a beach, they've never been on before, without 4WD already enabled and locked?

Anytime you head on to unpaved roads you are not absolutely certain of, you engage the lock and proceed slowly until you establish the condtions. "Tread Lightly"

BTW: I see the AWD system in the murano more helpful for the softroad. i.e. Towing the boat up a slippery boat ramp. Better stablity in a sudden downpour, or snow.

Not a studded tire black ice rink race. If that's typically what you find yourself in, I'd suggest a mid 80's K-5 Blazer. Great AWD and if you hit anything it won't hurt you and will be cheap to fix.

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Jberger, I like your summation. I live in NC and really won't do much off-roading. We get about 1 - 2 snows a year and I beleive the Murano will help there and during rain. I bet a good amount of the target market needs about the same amount of AWD as I, like the kind folks in Alabama. I guess our friend HARDDRIVE in Honolulu won't need to worry too much about snow either. Hopefully I will be able to get one, or at least test drive it before winter arrives in NC!

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That's EXACTLY my problem with this vehicle. I was loving it at first, and was looking into it for my wife and partly myself http://forums.freshalloy.com/ubbthreads/images/icons/smirk.gif , but the fact that the computer WILL DECIDE what power goes to the rear is not convincing to me. I don't like the fact that this crossover suv is FWD.
I've always been a RWD enthusiast and nothing will ever change that (even by experience of FWD, for that matter) and can't see myself investing in a FWD and temporary AWD (because that's what the Murano is) for $30k.

Sorry Nissan... you did good until you screwed up the mechanics of the torque distribution http://forums.freshalloy.com/ubbthreads/images/icons/tongue.gif http://forums.freshalloy.com/ubbthreads/images/icons/mad.gif

[MikeSable]

Let me see if I have this straight.

The Murano AWD stays locked in AWD up until 19mph.
You want all-the-time AWD for ice.
Murano gives all-the-time AWD under 19mph.
You'll be driving on raw ice at over 19mph?http://forums.freshalloy.com/ubbthreads/images/icons/confused.gif

BTW, AWD doesn't do anything for bad weather driving except to help starting from a standstill. If you're sliding on ice, no drivetrain is going to save you. Life is not a VW 4-Motion commercial. http://forums.freshalloy.com/ubbthreads/images/icons/grin.gif

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Well I don't know about VW but I own a Subaru and I have had the experience of LSD taking action above 19 MPH on ice and although no AWD system gaurantee safety, but it helps to know that the TQ distribution is taking place while finding traction and keeping the car as controlled as possible... I don't see that happening under 19 MPH which is lame.
So to reflect on your comment... the AWD system in a Murano won't do any good if all your tires are slipping on ice under 19 MPH.
In the snow or rain, I want all my tires to be 'active' for any unexpected road hazards.... try doing that in a FWD/AWD computer activated vehicle http://forums.freshalloy.com/ubbthreads/images/icons/tongue.gif

It doesn't seem you've had the experience to drive a true AWD vehicle in bad weather...with good tires, let's see how much any FWD or RWD vehicle can handle vs. an true AWD. You name the bad weather and I'll be more than happy to show you the performance http://forums.freshalloy.com/ubbthreads/images/icons/wink.gif

[Ayastigi]

I have to agree with the previous post and the value of AWD above 19mph. At my last home in Massachusetts, there was a nice hill before the turnoff for my driveway. When it was snowing/icy out you had to keep your speed up just to make it up the sucker. In my maxima I would start up the hill at 25-30mph and slowly lose speed. Sometimes slowing to crawl near the top. My friend's Subaru was able to maintain speed because his AWD system was constantly engaging when necessary.
I just think it would really bite to lose speed down to 19mph before the awd kicked in and accelerated you...only to cut off again. Like running into a strange speed limiter.
It just doesn't sound like the Murano's system is gonna cut the mustard.

-Cheers

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While having not test driven a murano yet, I don't believe the AWD will be cut off (at or above 19mph) when tires are still slipping. The "auto sensing" system should/would keep it in AWD no matter it is below or above 19 mph.



THe reason this AWD is not always engaged is because "wet" clutch packs are used as the variable torque transfer device. It will wear off very quickly if engaged constantly and will generate excessive heat that way. It is not as durable as viscus coupling or other perminant torque biasing device. That said, I think it is perfectly fine to engage it for a short period of time (say several minutes) once in a while when it is called upon.

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dodsonkg, since you are basically saying that it would not be good for the system to have it engaged for more than a few minutes, does that mean that one should not drive it for like 30 minutes under 19 mph under the permanently engaged mode if it is snowing or raining?

[OP240SX]

I agree dodsonkg. The AWD will continue to work past 19mph. If it's like other similar systems, it will work until the speed of the front tires equals the speed of the rears. Once you get up the cruising speed, it will go back to 2WD until slippage is detected again.

Regarding icy conditions, VDC comes in handy to help prevent skidding before it starts, but it is not foolproof though. 4WD does not prevent this as many would think, but it would help in getting out of that snowbank. http://forums.freshalloy.com/ubbthreads/images/icons/grin.gif

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[EDIT] This was in reply to jemomo.

Well, if it's in the "locked" AWD mode, the clutch pack should be fully engaged to achieve the maximum torque transfer (50% to the rear), which means there's no slipping between the plates, thus the wear should be minimal, and shouldn't generate much heat. So, I wouldn't worry about it.

The excessive wear happens in the auto mode when the torque transfered to the rear is less than the maximum, ie. 0<transfered torque<50%. When the cluch pack is engaged but not fully engaged, there has to be relative movement (slipping between the plates) to transfer variable torque.

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Thanks for the explanation!