20-09-2013, 03:02 PM
Best Answer - Chosen by Asker
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INTRODUCTION
The difference subaru's symmetrical AWD and a standard AWD system is that it will always be in AWD so traction is constant. For example a Nissan GTR's (CBA-R35) RWD-based AWD system will send power to the front wheels if the computer detects a slip by constantly monitoring all four wheels it give you as much traction as possible by sending up to 50% of its driveline torque to the front wheels making it 50/50 torque distribution to all four wheels but the downside is that the car mostly runs in rear wheel drive so it only switches to AWD if the rear wheels slip to prevent oversteer while corning and some cases can create understeer due to the computer not responding quick enough to send power to the front wheels, most sports car manufactures uses this setup because its more sport oriented and puts less stress on the front tires can increase front end grip. Next we have FWD-base AWD, this system will send power to the rear wheels to increase traction. A good example is the Acura TSX, most of the torque goes to the front and uses it to increase throttle-on direction changing speed (quickly turning left or right) and adds agility while rear wheels receive 25 to 50% of the available torque and increases rear end stability by preventing turn in oversteer because a normal front wheel drive (FWD) will have some sort of rear stability problems due to the lack of drive-line and because most of the weight is at the front of the vehicle. This can put a lot of stress on the front tires and brakes, so a FWD-based AWD system is designed to take away some of the stress and put on of it on the rear wheels as well. The downside of the system is that is only good when the car is with in its grip capacity, going over the vehicle's limit of grip can increase understeer due the fact that the system sends most of the torque (60 to 100 %) to the front wheels which can overload the tires making it difficult to gain control. Depending on the car the system only sends 50% of the torque to the rear wheels if the front wheels slip on acceleration. Last but no lease is Subaru's symmetrical all-wheel drive. This system gives you the best of both worlds by, in other words your not exactly full time AWD like 50/50 because the AWD systems i just mentioned have this thing called a transfer case, Subaru does not have one, instead they have what they call a center locking differential which is similar only that is clutch based center diff and not lock in gear type. The system is controlled via computer and monitors wheel slippage on all four wheels and can send up to 75% of the torque to the front or rear wheels, so no matter what there is going to be at lease 25% percent of power to the front or rear wheel which can increase respond time when the computer detects a wheel spin and can send the power to each wheel faster and more efficiently. An example it could send 75 % to the rear for acceleration and 75 % to the front for direction changing agility or 50/50 for cruising or on loose terrain. The only down side is that it can put stress on the drive-line components due to the constant torque distribution to the wheels and can also put stress on the tires as well. In the end they all have there pro and cons so it really depends on your driving style I personally prefer rear-wheel drive based all-wheel drive because the handling characteristics are more predictable. i hope you understand because i think i went a little overboard with explanationtion lol.