4wd Vs Awd??

[cipher]

AWD, 4WD whatever is just a name that the manufacturers use and has nothing with the actual system on the vehicle. It used to be that AWD was for passenger cars and 4WD meant a truck with a transfer case. But these days it's all blurred with many trucks & SUVs getting similar systems as passenger cars.

[M-e-X-x]

for those that have ACTUALLY driven these 4WD and AWD, you have the right to comment... for all others, please refrain from replying...

with that said, i have driven 4WD and currently own an AWD car...

4WD can have a transfer case for manually controlling the torque split, but then there are the permanent 4WD systems (aka Jeep brand)... they are 4WD all the time, no matter slip or not... my family has a pathfinder with a shift-on-the-fly system (transfer case) that does a 50/50 split when the driver sets it... 4WD can do low range and high range, as is the nature of most transfer cases i've encountered... and yes, a lot of 4WD shift-on-the-fly systems are RWD when not engaged...

AWD is permanent split between front and rear, may it be 50/50, 40/60, etc. for subaru's 4EAT (aka automatic transmission), 1st and R are 50/50, 2nd i'm not sure is 50/50 or not, but as u go higher in gear, it's 90/10.. the 4EAT in a wrx is 45/55 as one other poster mentioned...

as well, those 'torque transfer when slippage is detected' ARE NOT true 4WD/AWD systems...

[achc]

I agree with almost everything you said other then this. You are generalizing AWD/4wd with respect to what cars they are usually on.
This has nothing to do with the actual AWD/4WD system.

AWD makes driving easy but extream offraod or hill climb, you need 4WD

I don't get your point. Yes I mention what cars have 4WD and what cars have AWD, but I did mention how AWD works (a computer sensor) vs 4WD works (drivers select which wheels to drive the car)

I even answered lesnar question directly about if this system can be turned off manually or automatic.

What's the difference?
Do you turn it ON/OFF with a switch in the car? or is it automatic?
And is there a major fuel efficiency between the two and compared to a traditional 2WD?

I wrote before:

If you car is AWD, it CANNOT BE TURN OFF. Its full time AWD. That means the computer checks the wheels like 200 times a second (depending on what car you have) to see if it slips or loose traction, etc. It then transfer power to wheels to keep the car going at where the driver wants it to. Most SUV now a days are AWD. Most sports car that runs on more then 2 wheels are AWD not 4WD.

4WD is you can manually adjust which wheels to drive the car. This is used for real offroad. You can set front wheels only, rear wheel only, or 4 wheels. In basic 4WD, it is usually rear wheel only or 4 wheels. But an expensive top line offroad vehicle that is 4WD lets you drive with front wheel power only as well.

There is an ON/OFF switch for 4WD but none for AWD.

This pretty much answer all lesnar questions besides the fuel efficiency part and I will state it here: Yes, 4WD/AWD will use more fuel then a 2WD car.

[baileyr]

I don't get your point. Yes I mention what cars have 4WD and what cars have AWD, but I did mention how AWD works (a computer sensor) vs 4WD works (drivers select which wheels to drive the car)

Bumping an old thread...

AWD does NOT mean that there are "computer sensors" involved.

The most basic AWD system would have three open differentials (front, centre and rear) and no computer involved or needed. Most early systems like this have some method of locking the centre diff, since it is quite easy to get stuck if you can't lock the centre. The early quattro systems also had a manually engaged solid lock for the rear diff as well, essentially becoming a "true" 3 wheel drive (both rear wheels and one front) when locked.

[kdholdom]

Just to clarify the Part Time 4 Wheel Drive System:

Part Time 4 Wheel Drive
This is the oldest system which the settings can be changed depending on your driving situation. With this system the four wheel drive CAN NOT be left engaged on pavement. The result will be necessary wear on mechanical parts. It costs quite a lot to replace your transfer case after it snaps because of Pavement four wheel driving. You have three settings 2WD, 4WD High, and 4WD Low. In 2WD it usually is the rear wheels that are working. In 4WD the torque gets distributed 25% to each wheel. When traveling around a corner the wheels have to travel different speeds but are linked together and forced to spin at the same speeds. As mentioned abve this puts a rather large strain on the transfer case. This type of system is best for people who go off-roading which is the reason this is the system of my choice.

[lh0628]

Subaru cars probably have way above average low end torques.

Most manual subaru cars have 50/50 F/R power split, some autos have 90/10 F/R power split, this changes when F/R tires spin at different rates, at which time the center differential comes in to work and changes the ratio.