Lap Data Analysis

Pacific Raceways (Kent, WA)

July 11, 2004

Mid-Day Lap

117Full.gif (KB)

This was my 5th lap of the third session of the day. There was no traffic in front of me, so this is more or less what I was comfortable with at the time, driving the line as best I knew it then. By this time, I'd memorized the track layout and was getting smoother and more consistent. I was still over 5.5 seconds off of my fastest lap of the day, so obviously I had room for improvement. Some interesting things to note: I carried about 93mph around the apex of Turn 1. I dropped to 55-56mph around turn 2, and I was only at 40% throttle as I touched the apex. Full throttle didn't come for a couple seconds after the apex. I dropped to about 35mph around Turn 3A and about 34mph around Turn 3B. I hit a peak of 47mph between 3A and 3B. I was on the throttle slightly before the apex of 3A and I was at WOT well before the exit of 3B. I capped my speed at 87mph between 3B and 4. I used the throttle to stabilize the car at 5A. I didn't get into the throttle until after the apex of Turn 6; definitely room for improvement there. I carried about 80mph past the apex of 7, dropping to about 75 to finish the corner. I went only 45mph upon entering Turn 8, crossing the apex around 47mph. From the entry to Turn 8 until I voluntarily lifted to limit my max speed after Turn 10, I never was completely off of the throttle. I topped out at about 113mph between 10 and 1, limited by my comfort level at those speeds.

Late-Day Lap

113Full.gif (KB)

This was my 6th lap of the fifth (and last) session of the day. There was no traffic in front of me, so this is more or less what I was comfortable with at the time, driving the line as best I knew it then. By this time, I was getting into a groove and being much more consistent. Some interesting things to note: I carried about 98mph around the apex of Turn 1, which was 5mph faster than the 1:57 lap shown above. I dropped to 57-58mph around turn 2, and I was only at 45% throttle as I touched the apex. Full throttle didn't come for a couple seconds after the apex, but I was feeding in throttle gradually, starting before the apex.. I dropped to about 37mph around Turn 3A and about 35mph around Turn 3B. I hit a peak of 46mph between 3A and 3B. I was on the throttle slightly before the apex of 3A and I was at WOT well before the exit of 3B. I capped my speed at 92mph between 3B and 4. I used the throttle to stabilize the car at 5A. Based on speed and throttle position around the apex of Turn 6, I didn't do things a whole lot better than on my 117-second lap. I carried about 5mph less speed through Turn 7 than I did on my slower lap... so there should be more time to pick up there. I dropped to a minimum of 50mph around turn8, which seems consistent with my much faster laps later in the day. I topped out at about 120mph between 10 and 1, limited by my comfort level at those speeds. That was 7mph faster than the above lap, though.

Fastest Lap

112Full.gif (KB)

This was my 7th lap of the fifth (and last) session of the day. This is the lap immediately after the lap shown above. Some interesting things to note: I carried about 100mph around the apex of Turn 1, which was 2mph faster than the 1:53 lap shown above. I dropped to 59mph around turn 2, and I was in the process of flooring the throttle as I passed the apex. As I understand it, carrying more speed through a corner and being able to get into the throttle sooner is the right direction to be heading... I dropped to about 37mph around Turn 3A and about 33mph around Turn 3B. I hit a peak of 49mph between 3A and 3B. This was pretty much consistent with what I'd been doing most of the day once I got comfortable with the lines in this part of the track. I capped my speed at 93mph between 3B and 4, which was consistent with my other fast laps. The section from the apex of 4 to the entry to 5B looks a little weird. It's possible that my apex points were a little off from the data in this section, but I think they're right. I'll have to go back and look at the video to see if indeed they're right. It looks like I accelerated in the first half of 5A, then hit the brakes between 5A and 5B, and then got back on the throttle around the entry to 5B. I then accelerated mildly through 5B. It looks like I got Turn 6 a little better this time - I was at WOT before the apex and accelerated nicely up the hill to Turn 7. I was still a little conservative as I passed the apex of Turn 7, probably due to the weird pavement and the looming barriers on the right. I topped out at about 120mph between 10 and 1, limited by my comfort level at those speeds.

Comparison of 1:57 Lap with 1:52 Lap

Here is the data from the above laps overlaid on top of each other. These charts show a comparison of the slowest lap (1:57) with the fastest lap (1:52). The first chart shows the whole laps, synchronized at Turn1 on both laps. The following three charts show close-ups of the first, middle, and last thirds of the laps, with synchronization occurring at Turn 1, Turn 3B, and Turn 8 respectively. What this means is that the data for the slower lap is time-adjusted so that the position of the car at the turn in question is identical for both sets of data. This more effectively shows where time is lost or gained between the two laps for this section of the track.
117vs112Full.gif (KB)	117vs112Sub1.gif (KB)
117vs112Sub2.gif (KB)	117vs112Sub3.gif (KB)

Comparison of 1:53 Lap with 1:52 Lap

Here is the data from the above laps overlaid on top of each other. These charts show a comparison of the late-day lap (1:53) with the fastest lap (1:52). The first chart shows the whole laps, synchronized at Turn1 on both laps. The following three charts show close-ups of the first, middle, and last thirds of the laps, with synchronization occurring at Turn 1, Turn 3B, and Turn 8 respectively. What this means is that the data for the slower lap is time-adjusted so that the position of the car at the turn in question is identical for both sets of data. This more effectively shows where time is lost or gained between the two laps for this section of the track.
113vs112Full.gif (KB)	113vs112Sub1.gif (KB)
113vs112Sub2.gif (KB)	113vs112Sub3.gif (KB)

Time Improvements In Session 3, Session 4, and Session 5

Note that there were ten laps in session 3, eleven laps in session 4, and eight laps in session 5. This makes for a total of 29 laps logged that day Here you can see data showing the time it took me to traverse sections of the track over the course of the day. I threw out any data points where I was being impeded by other traffic, as these are not a true representation of any improvements in my driving ability. Times are measured from apex to apex, with the exception of 3B, which uses the exit cone. The time listed is the time it took to get to the indicated turn from the previous turn marker. For example, the split time for "Turn 2" would be the time it took to get from the apex of the previous corner (Turn 1) to the apex of Turn 2. Interesting to note is that while most of the individual split time data did not closely match a linear regression (R2 <0.500), my overall lap time data did get close to a linear regression (R2 == 0.734) with the slope being 0.177 seconds.
Complete Laps (Turn1 to Turn1) Times-Full.gif (KB)
Split Time (Turn2 to Turn4) Times-2to4.gif (KB)	Split Time (Turn5 to Turn6) Times-5to6.gif (KB)
Split Time (Turn7 to Turn8) Times-7to8.gif (KB)	Split Time (Turn9 to Turn1) Times-9to1.gif (KB)