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How a Coach uses Data

1/11/2012

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This contribution comes from Dave Scott, Lead Instructor at RaceCoach.Net. Dave has experience working with many drivers across all levels of driving and has helped a lot of people learn to drive faster. Check out what is important to him in teaching folks to go faster.

I coach a lot of drivers. A majority are racers (from rookies to very experienced) or folks actively preparing themselves to race. The rest are experienced track day instructors and drivers looking to improve their skills.

In all cases, using a basic data acquisition system can be a real productivity tool, and also especially a tool for the client to use for continued learning and improvement on their own, when I am not in their car. It is very easy to get overwhelmed by data acquisition, and succumb to paralysis by analysis, which frustration usually presages the data system being only used as a glorified expensive lap timer. However, by being selective about what data to use and what data may be a lesser priority, I am able to help the client rapidly improve without wasting a lot of time or energy.

What I would like to do here is share some of the things I look for in clients’ data when I coach, and why, as well as how I use this data to make them faster, safer, more consistent drivers. The following paragraphs will not contain evaluations of various data systems; that is not my intent or goal in life. I will use terminology from TraqMate, but the basic concepts apply to any system. Regardless of the system, I strongly encourage clients to always run video, with decent sound, alongside their data, and integrate them if possible, especially since integrated data/video is fully mainstream now and very easy to implement.

In coaching, the key information I look for are:
  • lap times (obviously)
  • longitudinal G’s over distance (which approximate acceleration, coasting, and braking) 
  • lateral G’s (which approximate cornering forces & an indication of comparative steering angle)
  • turn radius over distance (which approximates how smooth an arc is being used in cornering)
  • segment times (selecting segments is critical, and will be the subject of a separate article)
  • velocity over distance
  • time gap over distance (which allows comparisons between different drivers or different laps by the same driver)
There are many other data points, but to me these are the most fruitful for most clients. If we have the luxury of the following, all the better:
  • throttle position
  • brake position
  • steering inputs
Using longitudinal G’s (and throttle & brake positions, if they are available), I can quickly analyze how smoothly the client is loading the front suspension under braking, how smoothly brakes are released in order to reload the rear suspension, and the correlation between the end of braking and the beginning of turn in (trail braking). All of these go to coaching towards “surprising” the car less, and better managing the distribution of the mass of the vehicle during transitions in order to reduce the drama of these transitions. The more smoothly the car is loaded on braking, getting it to “squat” rather than “dive”, and especially the more gracefully it is unloaded on brake release, the more grip and stability the car will have from all 4 contact patches on turn in and through the corner. This, quite simply, means more grip and more speed in the corners, and less fighting the car to make it turn.

The same principle holds when we look at lateral G’s (and steering input, if available). Not only does this show the obvious: how much lateral load the car is withstanding. But more importantly, it can show whether the client tends to turn in late, with a lot of steering input (thus necessitating more braking for a slower, more squared off entry), or whether they turn in sooner, with less steering angle, loading the car much more gently and gracefully, which again leads to less braking and more cornering speed with more stability. I use this lateral G analysis especially to augment the observations I note on my little yellow note pad while in the right seat.

Both of the above data sets are very useful, along with video and in car instruction, to get the client to be smoother and more graceful all through the braking/cornering/acceleration cycle….to flow the car more and do much less work behind the wheel. And both data sets can be especially illuminating when we overlay the data of a faster driver, such as when I drive their car for a few laps to set an approximate baseline.

I use segment times in a couple of ways. First, since traffic can play a big role in lap times in race sessions and even during a practice day or DE, using segment times is often a much better predictor of true lap times, and allows me to coach them a little bit at a time all the way around the track, without focusing on overall lap times. Second, in many cases, the client has difficulty or bad habits related to a particular corner or type of corner. I will create a segment that incorporates this trouble area, and just work on that until they reach a breakthrough. I will augment this with their video and my in-car observations. Then, we will work on a different segment that may also have the same type of corner. The objective here is to make the client a faster, better driver wherever they drive or race, not just on the specific track we are working on that day.

Velocity over distance can show us the effects of traffic, or, more usefully, can show us how gear selection or losing entry speed on a previous corner due to a mistake or an incorrect analysis of that corner can have a far-reaching impact into the next corner, affecting segment & lap times. In addition it can be very useful when comparing overlaid laps, which we will cover next.

Which brings us to time gap over distance (Time . This (in TraqMate lingo) is a relative comparison all across a full circuit of the track, showing where one lap/driver/car/etc is faster and slower than the other used for comparison. And in fact, more than 2 laps/drivers/etc can be compared (but beware comparing too much data, since it makes the graphs visually confusing and hard to decipher in all but experienced hands). I will use this to show various places where, for example, my baseline lap in the client’s car is faster than theirs. Then, we go to the raw data as explained above to understand why. If there is video of the laps or sessions being compared, all the better, since it allows me to illustrate visually what different drivers are doing in the car, and how the car is reacting to them. We then build a brief action plan for our next on track session to shrink this gap. Presuming we execute properly, when we pull back into the pits and look at that session’s data, we should see the time gap shrink considerably in that segment. And we do this over and over with different segments to get the client where she/he needs to be.

In my experience, there is no substitute for a coach riding in the car with the client. There is so much nuance, body language, and car positioning/attitude that cannot be discerned outside the car. Clients who use coaches who do not get in the passenger seat are giving up so much value. And data, properly distilled and sifted, is the best, most truthful, accentuation to in car coaching there is. Video with sound is an 70% solution, but data is the real deal, and tells me what the car is doing every foot of very lap. And this has been an invaluable tool in making marked improvements in clients’ performance.

RaceCoach.net’s founder and chief instructor, Dave Scott, spent many years racing professionally in Grand Am, World Challenge, and ALMS, in addition to a variety of amateur and club racing organizations. He watched as a few racers seemed to prevail in any car, on any track, and in any weather, and distilled many of their secrets into a detailed, organized coaching program.

RaceCoach.net has grown into a group of affiliated top-tier professional racing and driving coaches who work one on one with clients and also as a focused team, anywhere in the world. Some of the coaches Dave has teamed with to deliver high level race coaching include Seth Thomas, Tommy Archer, Patrick Long, Kuno Wittmer, Cory Friedman, Larry Herman and Chris Cervelli.

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