longitudinal acceleration

Wilmington Data Crunch Part 3: Killer Oversteer

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After the big error discussed in Part 2 of this series, I got mad, got fast and made up some time. Then, it happened again!

Recall that this is what the course looks like from the GPS data, with sectors designated by dots. Run 1 is in blue, Run 3, overall slightly faster, is in red.

Fig 1 Overall Course Day 1

Fig. 1 Overall Course Day 1

I want to focus now on the revised seventh segment from the start (green dot), which is the one preceding the cross-hairs, i.e. the last one before the finish segment.

A closeup of segment 7 looks like this. It contains three sweeping corners.

Fig. 2 Segment 7 Close-up

Fig. 2 Segment 7 Close-up

Right off we can see significant differences between the two tracks. There even appears to be a kink in the red path, Run 3. Uh-oh! That’s probably not good.

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Wilmington Data Crunch – Part 2: Showcase Turn

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The showcase turn was an increasing radius on Day 1, the way most people drove it .  I lost of lot of time in it on my third run. The data can tell us how much.

If you recall from Part 1 we are looking at 20Hz GPS data. I don’t have engine parameters, steering angle, brake pressure… just position, velocity and acceleration and what can be derived from those.  For Part 2 I’ve slightly redefined the segments as compared to Part 1. They look like this, with the start being the lower left green dot:

Full 1 Mile GPS Track In 7 Segments

Full 1 Mile GPS Track In 7 Segments

The cross-mark is in the middle of the showcase turn, which is Segment 5. Here’s the segment time data, with Run 3 set as the baseline:

Segment Times- Part 2

Segment Times- Part 2

The Run 1 S5 delta is -00.40, meaning 4 tenths of a second faster (less time) than in Run 3. What happened to lose so much time the third time through this corner?

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