In the 90's we heard about (predominantly Formula 1) racing teams downloading telemetry down AND up to the race car, changing characteristics of the transmission's shifting, doing everything for the driver (launch control, anti-lock, traction control, auto shifting, even auto braking!) - we remember the Nigel Mansell quotes. All of this was only available at the highest levels of racing (and budgets) but never has the grassroots driver had the chance to record their skills with accuracy. Never have you been able to test new parts, log your mistakes and teach yourself and others how to go faster - until now. Fast forward to the 21st century and GPS for the data logger.

Author & Pictures:	Hanchey
Add'l Content:	Fair
Date Posted:	02.12.06
Last Edited:	08.27.06

So how did we arrive here? Fair and I participated in the SCCA Solo2 Nationals September 2005 in our STU classed E36 M3. We had won some preliminary events that made us feel like the car was a strong contender to win the STU class. Then we got to Nationals where, although the car was dominant in the rain, in the dry we could not make the car handle. We can go through the list of loser's excuses, or we can just say we lost; however, it was both of our opinions that something was very wrong with the car. By then, it was too late to determine what actually went wrong. Being an impatient person with limited access to track facilities, I wanted answers quickly. Were we both off that day? Were the tires dead? Was it down on power? How could it go from SO good to SO bad in just a few events??

This is the "poor man's" version of the modern racing data logger, but hey - we're poor. Instead of a 20Hz GPS signal, we get by with a 5 Hz antenna at less than half the price. Also, we can't read more than 2g's without another plug in, but we're on DOT racing tires that won't push that limit, so no big deal there. Certainly, this didn't fix the issues with our car by itself, but at least have data on it now!

Our DL-1 made its maiden voyage in January at the Vorshlag Motorsports Test N Tune. We had to learn everything that day, so we didn't get to put it in too many cars, but we did manage to test five different cars that day. We're learning as we go, but it was good to learn that simple masking tape will put the DL-1 nicely in the passenger side foot well. We'll probably make a heavy floor mat to mount it to more permanently. 3M is happy about us using tape, but the tape ball can get fairly large after one day.

Day of the event for the DL-1 is a fairly simple process. Get some tape, be careful not to close the door on the GPS antenna wire, plug it into the cigarette lighter and hit the big red button. You're logging! One thing I found out later was that you have to set the time to your time zone. We couldn't correlate data because it goes off GMT, after all it is made in the UK and we're talking about GPS. A few notes from the manual to remember; make sure the antenna has a really good view of the sky which means you must put it on the roof, some doors have frames all the way around the glass (I'll stop there to avoid ruining my warranty), and make sure the roof is steel (sorry Evo MR guys and M6 owners). The manual says you can tape the antenna but stay away from dark tapes which have too much carbon in them.

Loading the data of the CF card is where the easy part begins and ends. The program, DL-1 Analysis, has positives and negatives. The good news is that it is extremely flexible. The bad news is that it is extremely flexible. Being a former software developer, I don't mind the complexity and in fact I like it once you figure it out. I'm guessing I'd feel the same way about iDrive? I spent 8 hours playing with it to feel comfortable. The help menu is very good and I was able to learn just about everything I needed to know for my initial use of the program. I have only touched the surface though. There are performance tests and measurements and we haven't even considered running a lead to the RPM signal on the car much less OBD II information.

Once the data is loaded you'll see a map of where you've been. The data is almost worthless at this point. Almost all the calculations are done off of laps and sectors so the first thing you have to do is define a start/finish line. There are two ways to do this for autocrossing; one would be just don't define any sectors after the finish, or if possible you can draw the start/finish line across both paths. We were doing flying laps so we didn't have to bother. For the most part, the automatic marker and sector tool worked great. You let it create the sectors and it takes into account distances and sharp corners defining the gaps between markers. Once you've created sectors and a start/finish, you can see that you can turn off laps and show one run (lap) at a time. This is helpful so you can see your line for that particular lap and compare against another driver.

All of this matters with your typical calculations as well. I want to see lateral acceleration for a sector, not for all three laps. Also I want to see longitudinal acceleration for a lap, not the entire session. Then you have the options of showing more laps at the same time from different drivers. This is where it gets interesting. Each driver is color coded differently so you can read the track map, the XY graphs, sector times, summary statistics of each driver very easily.

The track map is great for showing your lines through a course as well as comparing your lap against another driver. You can color code your map with several factors like lateral/longitudinal acceleration. Your map comes back with a color scale from your minimum to maximum g's. Also, you can define a braking flag to show where you are braking on the course. The track map comes in handy later when you want to play your lap back with the lap player. As a side note, you can buy an add on device to correlate a video camera feed to your lap player!

Sector Times

The sector grid is very handy for analysis. A checkered flag appears by your fastest time. Click on a particular lap and it will be highlighted on the track map. Sector analysis, in my opinion, is the most important part of improving yourself. I ran Terry's lap and my lap in the same car and it is very apparent where each driver was faster. Having ridden with Terry on that lap, I knew exactly what I was doing wrong once I saw the sector times and the braking choices each of us made. Also, Terry could see where I wasn't braking and he was braking in another section. That section alone allowed me to pick up 0.4 seconds on him, huge time in a 24 second autocross.

XY Graphs

XY Graphs are my next favorite part of the DL-1. This allows you to show acceleration, heading changes, speed vs. time in a graph. Again you can use this to chart against another lap or another driver and instantly see how many g's you're pulling in a certain corner. Clicking on the line of the graph gives you the instantaneous data logged at that moment. You can even display the sectors on the graph. There is an option to do a "Quick Graph". I didn't find this very useful because as the name implies, it is just a quick representation of the data. Seeing the details is really where you see what is truly going on during the run.

Play Mode

Try this G Analyst! Play mode will play your run through the course and up to 4 other runs at the same time. Here you can see real time where you were fast or slow. Each run/driver is color coded so you can tell who is where on the course. Also, it will follow in any other windows open at the same time. For instance, you'll see the XY Graph and where you are on the course designated by a vertical line traversing the graph. There is a "dashboard" mode that will show you your run on standard dials like an instrument cluster in your car. I didn't find this very useful without having the RPM input set up. We'll be experimenting with that next.

	This window shows sector analysis of the 11 cone, 660' slalom from our Test N Tune. You can have the program set up sectors or create your own. I created my own here so it wouldn't count the return trip in the numbers. If you turned off the data logger at the end, it would solve that issue. The summary statistics will tell you things like max/min longitudinal and lateral acceleration. This was in the rain so the g's hover around 0.8. In the dry we were pulling 1.1g on street tires. The Quick Graph shows speed and lateral acceleration. As you can see, there is initial braking into the slalom then the driver gradually speeds up. This shows that if you keep ahead of the cones, you can go faster in the initial sections (assuming the cones are spaced the same).
	This graph is obviously from a skidpad (in this case one with a 200 ft. diameter). Summary Statistics is probably the most useful part of this chart. Really we're going for maximum lateral acceleration. We also used a pyrometer to check temps on the tires immediately after the run. Again, this was in the wet so the numbers are low. The DL-1 has the ability to take infrared sensor inputs so you could record the time temps real time with the data logger.
	At our Test N Tune we had an increasing/decreasing radius oval. Notice the comparison of the two runs and how different the lines are. The red lap was faster and had a wider line. Sometimes this works to your advantage in autocrossing, but some times it is best to keep a close line. Some of the other runs show an "off track" excursion; late braking a little too much. This oval is great for practicing late braking and shock tuning for corner entry and exit. You can easily find out the limits of your car in a matter of a few laps. Dividing the oval into sectors gives you time and speed at corner entry and exit.
	This longitudinal comparison is against two different drivers. Notice how smooth the red lines are versus the black. The red driver is steady on the gas around 5 seconds where the black driver is on and off the gas. The red driver also brakes earlier around 10.5 seconds. Taking this graph against playing the lap will show the red driver is faster.
	This is our mini course from the event. DL-1 Analysis automatically assigns sectors. Load several drivers at the same time to do comparisons. The sectors give incredible insight into your times; where are you fast versus the other guy.
	Playing the movie of the run here solidifies what the sector analysis already tells you, you got smoked! Check the lateral acceleration, braking, etc and you can see where you need to improve.
	The Track Map can be displayed as color coded. This map shows coloring by lateral acceleration red is max in right hand turns, blue in left hand turns.
	Another color coded track map, this time showing braking by color. You can setup a flag based on a longitudinal acceleration value and see where you're braking. Why is this driver braking three times in the turn around in Sector 4-5? Get your braking done at the beginning so you can accelerate early out of the corner.

While the software is not user friendly like a well developed Microsoft program, it is packed with data and can gets the job done. Please note, I don't expect a start-up company to have "Microsoft level" assets devoted to their software, but it would be nice to see future releases save the data to files easier and use wizards to walk you through some of the functions. Still, kudos to Race Technology for making such a powerful piece of hardware.

If you are analyzing DL-1 data be prepared to spend some time reading the Help menus. After you learn the software (figure a dozen hours for this), you'll be amazed at how quickly you can see where to improve. We hope this review demystified data acquisition systems a little, but analyzing the data is still is a bit daunting. You can ask about reserving our DL-1, including our data analysis assistance, on our services page.