Good question. My take away thus far, although seems obvious in some ways, is both braking techniques are valid and dependent on the corner.
For T3 @ VIR (IMHO):
- it is more important to use the brakes to gracefully change the attitude of the car going into the turn until such time that you can see the exit point as early as possible. So, for this turn, the purpose of the brakes is not to slow down to a certain speed, but to settle the the car on its suspension in such a way that the fluidity of the transitions results in maximum acceleration as early as possible.
- Once the exit is in sight, powering out will not only increase the exit speed, but also tighten the turning radius ensuring proper arc; remember, T3 is a decreasing radius turn, which is the main difference of it compared to T10 and T3 at Summit.
- The faster the entry speed (less brake pressure), the earlier the turn-in, the more agressiveness needed with the throttle, and the faster slip times. Of course there is a limit to this
A way to clarify the differences in braking techniques required think about the entry to T4 as it relates to bullet #1 above. For that turn, the priority is actually to get down to a certain speed, hence braking abruptly initially then easing off the brakes on a straight line is the proper approach IMO, at least for approach to the turn. As you are down to a reasonable speed to have enough lateral speed, then we use the brakes/throttle to adjust the attitude of the car, sometime trailing the brakes and sometime throttle oversteer to go through the turn.
Same also applies to T10 from what I can see in the data, but it is less conclusive, I will keep looking at it though. However, Scott, you should see the T16-17a data, which was a surprise to me as it was not a section I was particularly working on. I had better slip times there as well, although my entry speeds were actually lower by 3-4 mph.