Rogue iAWD

[deanson]

I just read this description of the Rogue's AWD system:
"The Rogue will automatically convert to a 50-50 power split between front and rear wheels when accelerating from a stop. As the vehicle gets to cruising speed, that basis will revert back to full front wheel drive in order to be most efficient. Another common activity which results in traction loss is turning, so I-AWD predicts potential problems and automatically transfers to a 70-30 bias when taking moderate to sharp turns."

But I read this in a owners manual about the AWD lock. That the lock will turn off at 6 mph. So does this mean that 6mph is "cruising speed"? How is the using the "lock" button different for the starting in a 50-50 split? I thought that is what the lock forced to happen i.e. a 50-50 power split. Also the manual did not mention anything about a 70-30 bias of torque. I'm thinking about getting a Rogue but I want to make sure I understand the AWD system.

[AZhitman]

Welcome aboard!

Let me see if I can get one of our Production guys from Nissan to answer that. Hang tight, browse the forums, and I'll be right back!

[AZhitman]

AWD LOCK SWITCH (if so equipped)
each time you push the lower part of the AWD LOCK switch, the AWd
mode will switch as follows: Auto Lock Auto.
Select Auto or Lock mode, depending on the driving conditions.
LOck MOde:
for driving on rough roads.
Push the lower part of the AWD LOCK switch when the vehicle is stopped or driving less
than 6 MPH (10 km/h). The AWd LOck indicator light in the instrument panel will illuminate.
LOck mode will change to AuTO mode automatically when the vehicle speed is over
approximately 6 MPH (10 km/h).
LOck mode will automatically cancel when the ignition switch is placed in the Off position.
AuTO MOde:
for driving on paved or slippery roads.
Push the lower part of the switch. The AWd LOck indicator light will go off.

[Eikon]

When Philipa (the Rogue forum moderator) gets a chance to read this, he'll give you the best info.. but until then, I'll take a stab at answering your questions.

You are correct about the i-AWD system predicting situations in which traction may be lost and automatically adjusting for it ahead of time. It does this by setting the traction at 50-50 from a stop, when traction is most likely to be needed. It also adjusts to 70-30 during moderate turns as that is another time when traction is frequently lost. Instead of trying to react after traction is lost, the Rogue's system uses predictive technology to get the jump on things.. then can further adjust as needed.

The setting for the 50-50 from a stop may last from 0-6 mph. I'm not sure about the exact speed.. if you say 6mph.. that sounds good to me.
The lock button, as I understand it, is a way to manually engage that 50-50 bias when you choose. The idea is that it can help you through more difficult traction situations.. ie.. trying to make it up a long steep snowy/icy driveway. In a case like that, you would want to keep the 50-50 bias past 6 mph to keep traction as well as possible. You would NOT want to use the manual AWD lock button at regular driving speeds or highway speeds.

Hope that helps a little bit! Get the Rogue.. you will love it! I love mine!!!

[deanson]

Yes that is exactly what the manual states but that seems at odds with the description of starting off with a 50-50 split. So if the first description of the iAWD is correct that it in fact starts off in a locked 50-50 split every time you accelerate from a start then I don't see how using the locking button adds anything. Is my understanding of the lock correct? That it forces a 50-50 split? So if it always starting in a 50-50 split why use the locking button? Is see the manual where it states: [100:0] ↔ [50:50]. for the AUTO setting. But I'm still trying to figure out the lock vs 50-50 split when accelerating for a stop.

[Eikon]

Again.. I'm not 100% sure on this.. but here is how I understand it..

From a dead stop, the vehicle will "predict" possible traction loss and start off in automatic 50-50 awd lock from 0 to 6 mph. The system will automatically disengage the awd lock after 6 mpg and slide the traction setting back toward the FWD bias. This is under the normal setting.
Now, let's say you are on a very slippery road and want to keep the 50-50 bias at speeds above 6 mph. For this, you can manually engage the AWD lock with the button provided and this will override the transition back to fwd bias at higher speeds.

[deanson]

Your description of the AWD description sound like what I want. Then the manual states: " *2: LOCK mode will change to AUTO mode
automatically when the vehicle has been
driven at a high speed. The AWD LOCK
indicator light turns off."
I wonder what speed is the manuals reference to "high speed" refers to? Do you know if all the years work this way or is it only the 2011 models?

[philipa_240sx]

Hello deanson and Welcome to the NICOClub Rogue Forums!

Most of the answers provided are generally correct. But to answer a few of your questions:

I wonder what speed is the manuals reference to "high speed" refers to? Do you know if all the years work this way or is it only the 2011 models?

Nissan does not actually publish a transition speed at which the AWD lock disengages. It's nowhere to be found in either the owners manual or any of the service manuals. Our best guess is it's dynamic and based on speed and duration. There are some protection features that also disengage the AWD under certain conditions (see the owners manual). Some of these features were first introduced on early Murano's which started to experience transfer case and AWD clutch issues due to stresses imposed by the AWD lock system.

A few other points:

- AFAIK, the AWD system is the same for all Rogue model years. It traces it's design back to the X-Trail (Canada, Japan, Europe) and the Murano.
- The AWD system does indeed start at 50:50 from a standstill to avoid wheelspin. It reverts to FWD around 6mph as others have mentioned.
- The amount of torque sent to the rear wheels is infinitely variable from 0 to 50%. It's not on/off.
- The amount of rear wheel torque is based on more than just wheel slip. The AWD computer also uses the lateral yaw/decleration, and steering wheel sensors, and individual tire speeds to compute the torque split.
- The Rogue also uses a form of traction control which applies brakes to transfer torque from the spinning tire to the opposite wheel. In effect it performs like a limited slip differential.

[Eikon]

damn, ^ that guy is good!

[deanson]

Okay, last night I was tired and missed some information in the Rogue basic features FAQ. In the FAQ it indicates that it will hold the lock until approximately 30 kph which is 19 mpg. That's more of inline with what I was hoping and just like the Honda Pilot. I can certainly deal with a 50-50 split from a start until 6 mph. That does seem like it would get you going. Does the Murano AWD operate in the same fashion? I hoping to get a Rogue but I'm worried that some car sales man will point out the Murano to her and I might then get out voted since wives always seem to get 2 votes to our 1 vote.

[philipa_240sx]

Does the Murano AWD operate in the same fashion

It should be as both the Rogue and Murano share a nearly identical AWD system. The Murano setup is obviously a bit beefier to handle the V-6 engine.

...I might then get out voted since wives always seem to get 2 votes to our 1 vote.

She is the BOSS!

[pawprint]

My 2 cents.

My last vehicle was a Murano. I cannot tell any difference in the AWD systems from a drivers point of view. One difference that I could tell was the weight of the Murano felt more powerful while driving through snow. The Rogue still feels rather light. However, the extra weight of the Murano wasn't really needed in everyday driving.

There are 3 main reasons I didn't purchase another Murano.
1. Premium fuel (recommended) and yes, it did make a difference not using it.
2. Poor gas mileage
3. Fully loaded = HIGH sticker price!!

The one problem I encountered with my Rogue a couple weeks ago was on snow & ice. I don't believe any of my systems, or those on other vehicles would have helped. I was going down a long hill and gaining speed. I didn't have my foot on the accelerator and was hesitant to hit the brake. Hitting the brakes on ice (even with ABS) could throw me in a ditch.

Anyway, I was going down this hill on a 2 lane road, gaining speed, and a car was on-coming. I moved over, closer to the edge of the road so they could pass and that mess tried to pull me in.

I jerked the steering wheel to the left, then started fish-tailing. I jerked the steering wheel to the right. I went back and forth a few times, doing exactly as taught when in a skid.

I was SO lucky, my Rogue never left the road & I successfully survived the skid. It was textbook, as if someone else was driving the car (because I really didn't think I would survive that one.)

My point of the story, I don't believe AWD or any other systems are working when I'm not accelerating, but coasting down a hill. Without accelerating, I'm not giving the tires pull or traction. I really wanted to stop, and would have slammed on the brakes if it was a wet or dry road. I HATE driving on ice.

Still, overall, I'm happy with the Rogue. She's the "Little Engine that Could".

[deanson]

yes, when the gas pedal is up there is no 4wd action, no matter what type of system your vehicle has. At that point is just the laws of physics, mass and velocity.

[Pescakl1]

Did you try to lock the overdrive in order to get some engine breaking?

When it is icy and downhill, it is a good way to keep the car "under control", but don't wait too long, it is better to do it at a slow speed. When too fast, you could lock the wheels for a bit and lose the car during that time.

Nice job controlling the car, anyway. Good for you.

[Nick 568]

Anyway, I was going down this hill on a 2 lane road, gaining speed, and a car was on-coming. I moved over, closer to the edge of the road so they could pass and that mess tried to pull me in........

.........My point of the story, I don't believe AWD or any other systems are working when I'm not accelerating, but coasting down a hill. Without accelerating, I'm not giving the tires pull or traction. I really wanted to stop, and would have slammed on the brakes if it was a wet or dry road. I HATE driving on ice.

Yeah, you can NOT get too far over to the side of the road when it's snowy/icy. You WILL get pulled in. Ever watch Ice Road Truckers? They talk about their trucks getting pulled into the ditch if you get too far over, all the time. It's absolutely, 100% true. Only difference is on a car, a skilled driver can pull it out. On a big semi, there's usually no hope.

No, when decelerating, the AWD doesn't do a thing. AWD is for accelerating. NOT stopping. You can still use it in a situation like yours to help you, but you have to make sure you know when to put on the power in that type of situation so it doesn't throw you further into the ditch, or across the road.

As Pescakl1 said, if you can use engine braking to slow down from a slope. My Rogue has the paddle shifters, and they're invaluable in my opinion when it comes to keeping your speed in check down slopes that are pure sheet ice. (basically, every single sloped neighborhood road in the winter here)

[pawprint]

I don't have paddle shifters, but I was able to un-click the overdrive lock button which slowed me down safely.
I have read that some people can actually accelerate out of a skid. All I could think of is wanting to stop, not accelerate.

My very first encounter in a ditch was about 19 years ago in my little 1992 Sentra. I hit the brakes on a curve, landing me in a ditch, backwards! It happened so fast.

[Juelze]

I'll tell you one thing. We got hit with a big storm up here in Green Bay, WI and I put my Rogue in AWD lock and backed it out of the driveway and drove to work. I was going 55mph for several miles before the AWD lock finally went off by itself. Not sure if it's faulty or not, but it definitely happened, in fact I think I have a picture of it. Yup, here it is for those who don't believe me:

http://dl.dropbox.com/u/3309035/IMG_20110221_083303.jpg

[philipa_240sx]

yes, when the gas pedal is up there is no 4wd action, no matter what type of system your vehicle has. At that point is just the laws of physics, mass and velocity.

This is partially true. However, if you have a part time 4WD system (LIke those found in many older trucks and SUV's) with a locked transfer case (no center diff) it will produce some braking or skidding action even if you are coasting or braking. Reason: at least one front and one rear wheel will want to turn at the same speed with a locked centre diff. My '87 Pathfinder had such a system. It makes turning and high speed handling a little tricky!

Many electronically controlled AWD systems usually disconnect the rear axle under braking and possibly even coasting as well.

[philipa_240sx]

I'll tell you one thing. We got hit with a big storm up here in Green Bay, WI and I put my Rogue in AWD lock and backed it out of the driveway and drove to work. I was going 55mph for several miles before the AWD lock finally went off by itself. Not sure if it's faulty or not, but it definitely happened, in fact I think I have a picture of it.

I don't doubt it. Like I said, there is NO defined unlock speed... at least it isn't documented anywhere in the manuals.