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My MO's faster than yours
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THE MYTH OF 4WD


"A common misconception is that 4WD and AWD help in all driving situations. But these systems provide added traction only when accelerating. They do not help in braking or cornering. "


:rolleyes:




I always thought AWD helps in cornering. Like Acuras new RL, their whole thing is SH AWD...It supposedly helps the car corner better. And even the sti's and evo's ...You think they would handle as well without AWD?...i doubt it....


Consumer reports don't sound like they know too much about cars...
 

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Under conditions where traction is good, full time AWD can conceivably help cornering. In the snow/ice, where traction is poor, it probably doesn't do much.

I absolutely agree with the notion that AWD mainly benefits straight line grip when first accelerating. CR is correct in this matter.

The Murano's AWD system is mainly FWD. I cannot see it benefiting in dry road cornering before the stability control kicks in.
 

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The RL's AWD system is rather advanced beyond tradional AWD, also. It helps cornering because the computer evaluates cornering dynamics and actually accelerates the outside wheel slightly.
 

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It's cornering under power, in dry, wet or ice, that it helps with. What it does is distribute the force on the wheels from the engine. Less force on an individual wheel, means it's less likely to break free, so you can corner better.

The Murano's AWD is more like FWD with RWD assist, in it's default condition.

It does make a difference in ice, as you're less likely to break your front wheels loose by distributing the engine power. Of course, this is with the AWD switch on, forcing it to engage. (I've found this out first hand.)

Similarly, since the CVT will do some engine braking, this too gets distributed.

So it doesn't make the tires stick better, it just distributes the forces they're under from the drivetrain, so you can use up more of that tire adhesion budget on cornering.

I'd say an old original Quattro is probably better at it, than the Murano is... Anyone looked at the G35x's system yet? Maybe they'll put that in the Murano!
:22:
 

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Quattros use Torsen differentials (center, and rear in the more upscale models), which direct power to the wheel that is NOT spinning. They are also full time - all wheels always connected.
Far superior to the part time, totally unlocked MO.
 

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My MO's faster than yours
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Discussion Starter #6
The g35x AWD is Identical to the fx's AWD and sylines. The reverse of our's.


jaak said:
It's cornering under power, in dry, wet or ice, that it helps with. What it does is distribute the force on the wheels from the engine. Less force on an individual wheel, means it's less likely to break free, so you can corner better.

The Murano's AWD is more like FWD with RWD assist, in it's default condition.

It does make a difference in ice, as you're less likely to break your front wheels loose by distributing the engine power. Of course, this is with the AWD switch on, forcing it to engage. (I've found this out first hand.)

Similarly, since the CVT will do some engine braking, this too gets distributed.

So it doesn't make the tires stick better, it just distributes the forces they're under from the drivetrain, so you can use up more of that tire adhesion budget on cornering.

I'd say an old original Quattro is probably better at it, than the Murano is... Anyone looked at the G35x's system yet? Maybe they'll put that in the Murano!
:22:
 

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b0xdesigns said:
The g35x AWD is Identical to the fx's AWD and sylines. The reverse of our's.



The ATTESA E-TS™ (Advanced Total Traction Engineering System for All Electronic Torque Split) AWD system on the FX and G35 AWD models default to a 25/75 F/R torque split upon acceleration from a stop. The system then routes the power to 100% RWD if slippage is not detected. Like the Murano, the system can vary F/R torque up to 50/50.

In contrast, the Murano's system defaults to 100% FWD, unless slippage is detected, and it can split the torque up to 50/50 FR. Even though it would decrease fuel economy, I would not mind if the Murano's system defaulted to 50/50 on initial acceleration. Nissan would have had to put in a beefier transfer case though, since it is clear from recent failures reported here that the system isn't really up to full time AWD duty.
 

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CU is right on the money. Their point as I see it is that people buy into the marketing hype of AWD (and 4WD) vehicles going way faster than is safe in poor traction conditions. As if somehow, giving power to all 4 wheels will help you in a panic stop.
 

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Truth of the matter in this area (NE) 99% of the time the road are completely drivable and AWD/4x is not needed.

I got my MO with AWD but at times I regreat the extra expense of it... at least where I am its just not necessary. Such a marketing ploy.

FWD is just fine.... now AWD/FWD vs RWD is a different story.
 

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hmmm RWD...

AWD/FWD vs RWD is a different story.
I agree with that!

I always like a rwd car, especially if it is a sport car. Recent development in traction/stability control does help in driving a RWD car with proper snow tire under light snow condition. On the other hand, knowing that murano is FWD most of the time, i never expect it to perform like a rwd.

Mo's AWD may be inferior to audi's quattro, but it sure has helped during my driving this past winter. I never plan to bring this $30K suv off road anyway, so i dont need the JEEP / TOUAREG 4x4 please. If the snows gets really bad, I stop/willnot drive.

It is all about what you expect and knowing what you need .:4:
 

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Eric, is it 50/50 with the switch on? Sure seems it...
 

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jaak said:
Eric, is it 50/50 with the switch on? Sure seems it...
Problem is, there are rarely any conditions where the switch can be turned on, given the instructions in the owners manual. From what I understand, the AWD lock is meant only to be operated on "rough roads" Even though I get snow and ice where I live, I wouldn't say the roads are rough when they are covered with powder, or ice for that matter. Given the numerous incidents of transfer case failure reported here and on FA, I would be cautious to use AWD lock frequently unless I was really stuck.

So, I am left with AUTO mode, which functions well most of the time, but is decided slow in responding to diminishing traction, particularly during a turn, when the AWD kicks in abruptly during acceleration, swinging the tail out. Normally if all four wheels were bring driven before entering the turn, this would be less of an issue. But in AUTO mode, its FWD into the turn, and when you accelerate out of the turn AWD kicks in, and you get some VDC theatrics. This is why I see the benefit of Infiniti's always on 25/75 split from initial acceleration.

I confess though, that the Murano's AWD may not be that bad at all, and its the decidedly average Goodyear LS's that lend themselves to the Murano's less than stellar handling on snow.
 

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So does that mean you don't know if it's 50/50 with the switch on?


:p


I turn it on and use it in the snow a lot... No problems. If you have good traction, you don't need it, and that's the condition the transfer case will suffer under.

If the front wheels can slip when you gas it, turn it on and it makes a big difference.

I don't baby it either... My neighbours have seen my Murano in four wheel drifts going around corners in the snow, with all four wheels spitting out snow under power.

Three winters, still not broken.
 

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jaak said:
So does that mean you don't know if it's 50/50 with the switch on?


:p


I turn it on and use it in the snow a lot... No problems. If you have good traction, you don't need it, and that's the condition the transfer case will suffer under.

If the front wheels can slip when you gas it, turn it on and it makes a big difference.

I don't baby it either... My neighbours have seen my Murano in four wheel drifts going around corners in the snow, with all four wheels spitting out snow under power.

Three winters, still not broken.
Yeah but you should know by now you got one of those bulletproof Muranos. With a GOOD alternator, a GOOD transfer case, etc...

:D
 

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You forgot the CV joint that goes clunk...:D
 

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I can't even tell from the SM if it locks it in 50/50.
 

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You are right! I guess I got the idea of 50:50 from the car mags.
 

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Actually it does say it on the previous page:

"AWD CONTROL UNIT
 Controls distribution of drive power between front-wheel drive
(100:0) and AWD (50:50) conditions according to signals from
sensors."

But I was wondering specifically what the lock button does... Hmm.. I'll look some more.
 

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System Description
ELECTRIC CONTROLLED COUPLING
Operation principle
1. AWD control unit supplies command current to electric controlled
coupling (AWD solenoid).
2. Control clutch is engaged by electromagnet and torque is
detected in control clutch.
3. The cam operates in response to control clutch torque and
applies pressure to main clutch.
4. Main clutch transmits torque to front wheels according to pressing
power.
 Transmission torque to rear wheels is determined according
to command current.

So even if the switch doesn't do this, it would be possible to force it on full manually. Imagine, dial your own configuration. (Void the warranty too, but what the heck...)
 
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