JP66

So recently I started a thread discussing how to over come "self preservation" in difficult corners and get that last mph out of your performance. That discussion was all based on a graph I had comparing my best lap with the best lap of the previous owner of the same car. Yesterday Spencer of Speed Sport Tuning drove my car and when I compared his data to mine and Jim's I realized it just didn't look right.

So . . .

I read a few threads on GPS misalignment and came across the suggestion that aligning based on Lateral G's might be one way to get a better comparison. I ended up using the Beacon adjustment to move Jim's data 100 feet and now the Lateral G's align better.

Questions:

1) Is what I did logical?
2) Jim's data seems permanently altered. Is the original data stored somewhere?
EDIT: 3) Was there a better way to achieve the same result?


What is, to me, most fascinating about this exercise is that the new comparison changes the analysis significantly. When improperly aligned, it appeared I was faster in the beginning, but with the new alignment it appears my entry into Big Bend is my single biggest slow point, and THAT makes a lot of sense to me. My second biggest time loss is still on the Uphill, but Jim drives a very different line into Big Bend and now I am eager to try that line next time at LRP and see if I can't chop off a large chunk of time.


Anyways, the first graph below is the newly aligned data. Jim is red (1:00.7), I am blue (1:02.0), and Spencer is black (1:02.1).

Thundermoose

Don't use beacon shift. Use GPS Lap Insert instead. I'll post a link to how to if Matt or Peter don't beat me to it.

Frank 993 C4S

Correct - use GPS lap insert. Open the tests and then for each test in "Lap Manager" tab click on "GPS Lap Insert" on the top right of the page.

Click on "Use Start/Finish" from track database and select the appropriate track from the tracks that come up.

Thundermoose

That being said if someone drove your car with your AIM the data should be aligned. I'd go ahead though and use GPS lap insert on both data sets and see how they compare.

JP66

Done. Now looking at the Uphill and seeing the alignment of what must be the crest of the hill makes perfect sense. Still losing the most time in Big Bend and the Uphill although I'm seeing that my Left Hander could use work as well. I'm pretty happy about that because I consider those areas easy to adjust. Can't wait for my next practice!

Thanks guys!!

linzman

I don't know, if those graphs are really aligned properly, it looks like you do a better job trailbraking into Big Bend, and the time difference is a pretty steady slope up from the left hander through the downhill, with the uphill being the biggest jump. But I'll defer to the experts.

ProCoach

This is correct.

Uphill brake release and MUCH more importantly, throttle app, is NUMBER ONE.

JP66

Interesting. After closer examination I think you are right. I've discussed the different entry with Simon and he has always contended that the straight line entry into Big Bend is initially faster, but then loses time as the line becomes tighter faster whereas the line I take is more of a broad arc, but I can keep a higher speed deeper so probably changing the line would gain initially, but it wouldn't change the lap time.

Hmmm.



Yesterday all was well with my Solo DL and so I finally have throttle data. Here's a blow up of Jim (red) me (blue) and Spencer (black) just on the uphill. Clearly Jim's throttle application is key!

ProCoach

The key is BOTH, and I've seen people do it. You, for sure, benefit from carrying more speed deeper into BB.

You should add a third graph, gSum, to determine how much unrealized friction circle area there is in the transition between end of braking and early part of BB.

Spence's late brake into the Uphill, along with premature release (you have some of this, too) is a component in late throttle application.

JP66

Gotta love the internet! Just found this video from the 2016 Lime Rock Park PCA Sprint race. It's Matt behind my car. Lap 2 is the lap in the graph above. I REALLY am having fun with this car!

Matt Romanowski

Great your using your data like this to get quicker and finding the old video is terrific too.

GPS insert, like you found, is the permanent way to align two laps. The other fast and dirty way is to use the snap button. Then you can drag the distance meters at the bottom of the graphs to align the laps. When aligning, Lat G can work along with speed. One thing to look for is the time compare graph. If it has large variations at each corner, then it's probably still not quiet right. You can see this in the second example. It's the same data as the first image.

Also, make sure you don't lose alignment mid lap. That can happen when someone takes a different line later in the lap. The laps will start out aligned and then go out. This is the perfect time to use the snap function to be able to compare the parts of a lap, even in separately.

JP66

Thanks Matt! You were the one who made the comment on aligning LatG that got me started. I really feel like this is becoming Rookie 2.0 for me. I think that the SP2 car was just bad in terms of timing. I never had time to get practice before my first races, and the SP2 car had no ABS which is really a bigger change than folks realize when you are 50 years old and learning to push cars to the edge of performance. I have really high hopes for next Spring, and I hope and believe data will definitely play a role in getting me closer! The caveat is that data has limits and at the end of the day it will come down to "seat time" and whether or not I can learn the lessons of car control that my coaches are trying to impart.


But,

you guys are great here on RL, and I believe beyond a shadow of a doubt that the lessons I learned here - online - have advanced my learning by years. Thanks for all the great advice!!