In an all wheel drive car, power is sent to all four wheels through your drivetrain. Because you are sending driving force to all of your wheels, one of the main benefits of an all wheel drivetrain is that the car always feels like it has lots of grip, regardless of the driving surface.
If you have an all wheel drive Subaru like the WRX or STI, your car has 3 differentials that determine how your power is distributed to the wheels. There is a front differential that determines the split between the front two wheels, a center differential that determines the split between the front and rear axles, and a rear differential that determines the split between the rear wheels.
Even though the drivetrains are nearly the same between the WRX and the STI, but if you drive each of them, they feel different. The STI feels like it has a lot more grip and like the STI's drivetrain is able to distribute that driving force much more effectively than the WRX.
The reason for this is that the STI has much better differentials than the WRX.
There are a number of up-grade options for your WRX to improve your differentials, and there are options for the STI as well.
In this video we talk about the difference between gear type or torsen differentials and clutch type differentials (also known as limited slip differentials or LSD's), and where and when you would want to upgrade your stock differentials to improve your drivetrain.
Limited slip differentials can also be tuned to change their behavior and we have an initial discussion about how that works as well. For more information on this, be sure to watch our video on how limited slip differentials work. Here is a link to that:
https://youtu.be/pf-s0f2EL2g
Thanks very much for watching and Stay Tuned!
In this Video:
00:00 - Intro to Subaru Differentials
00:25 - What are your options to upgrade your differentials?
00:59 - Torque Biasing Differentials and Clutch Type Differentials
01:20 - So when would you want to upgrade your differential?
02:21 - What is the difference between a 1-Way, 1.5-Way, and 2-Way differential?
04:05 - How can you tune the clutch-type differential behavior?