Continued from Cresson CW Analysis
Looking at the data, I was much less consistent in the braking zone than I thought. The two laps shown below represent my two fastest laps, and my two fastest passes through this turn and the following straight. However, they are much different. The top lines are accel-G, RED is “main lap”, YELLOW is “ref lap”. The purple line in the middle is the lap time difference between the two laps. The bottom lines are GPS_MPH, pink = main lap, orange = ref lap.
Main Lap: Red, pink (hereafter the “red” lap)
Ref Lap: Yellow, Orange (hereafter the “yellow” lap)
As you can see there is a big difference between the two approaches to the corner, by the end of the straight “red” gained 1/2 second. Interestingly, combining the two turns there was another 0.05 to 0.1 available between them…without doing anything different than what I’ve already done on the track at one time or another. Just need to figure out how to string it all together.
Note that the above graph is vs. DISTANCE….not time.
In the red lap I got onto the brakes much earlier (100 feet earlier!). I was quicker to get to max braking, but I didn’t stay there very long…I modulated back to about 0.4g. Then I begin releasing the brake pedal, until I finally got back to full throttle.
In the yellow lap, I actually managed to brake much later gaining about 0.05 seconds over the red lap. The initial application to 0.4g was faster than the red lap, but then I kind of daudled around, taking another 50 feet to get to 0.6g. Then I released the brake pretty quickly until I got to about 0.05g. At this level I may have just been coasting. I can’t tell from the video. Its during this time that I killed this segment.
While the red lap is releasing the brake and working back to throttle, the yellow lap is still under heavy braking. Initially, this makes sense because the yellow lap is several mph faster than the red. But, at the 750 ft mark the speeds have equalized. However, the yellow lap continues to coast for 75 feet while red is full throttle. Additionally, yellow stabs the brakes hard at the 900 ft mark dropping another mph.
Finally, at the tail end of the yellow segment I elected to upshift, when clearly it wasn’t necessary as I didn’t shift on the red lap. RPM at this shift were 6700.
What follows is a point by point snapshot of the line through the corner at the points discussed above. YELLOW lap on the left, RED lap on the right.
Brakes On
Its hard to see the difference at this point on the track.  I think that is mostly because of the crappy video quality. As I said above, the left hand video is braking a full cone further into the corner. The other point that IS noticable is that I’m about a 1/2 lane inside in the left picture vs. full track-left in the right picture.
Max Brake
Its much easier to see the differences between the braking zones here. The dark cone visible in the left lap, is hidden by the red RX-8 in the right-lap. Again, I’m mid track on the left, and 1/2 width from the left on the right pic.
Brakes Off
In the right hand video, the last entry cone is about 2 car lengths behind me. In the left video I’m so much farther around the turn that my nose is actually aime at the red/yellow truck next to the house on the right, instead of still aimed LEFT of both houses. This corresponds to 130 ft of track distance.
Full Throttle
There isn’t much difference between these and the last set. In both cases I got right back on the throttle.
Apex
Trackout
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