The ResultsAs eye-opening as the driving impressions were, the heart of this extravagant experiment is the data we've collected and the depth of detail it shows. For each diff, we show the difference between inside and outside wheel speeds (in mph) for both front and rear wheels. The difference in front wheel speeds around the 200-degree, 100-foot radius turn shows how much faster the outer wheel is spinning. Disregarding slip angle, this is a reference for what the rear-wheel speed difference should look like if there was an open differential installed. The rear wheel speed difference shows how much the wheels are locking. With any LSD, the difference in rear wheel speed should always be less than the front while the car is under power. If it's zero, then the two axles are fully locked. Since there are some erratic changes due to imperfections in the asphalt, we also overlaid a filtered and slightly smoothed representation of the difference in rear wheel speed.
One thing to look for is the smoothness of engagement and disengagement of the diff as it locks when the car enters and exits a turn. We also overlaid the throttle position data on top of the wheel speed data to show the magnitude of throttle modulations required to keep the car in balance. Looking carefully, you can gauge not only how much throttle input is required, but also how long it takes to lock after power is applied.
Two additional graphs show the steering angle and vehicle yaw data for each differential. The steering angle (amount the wheel was turned) illustrates how much the car understeers or oversteers at each stage of the turn. The consistency of the yaw rate throughout the turn also shows how well the car stays balanced.
It's a long, drawn-out geeky rant, but the story is the data.