Well, the enduro didn't go off as planned; we didn't have more than 30 minutes between practice and race, and due to other issues didn't get the data downloaded in time to review beforehand. We also had major issues during the race leading to an eventual retirement, preventing us from getting much good data. Much work remains to be done on both of those cars.
Anyway. I do have some of the data from that enduro on my website:
http://www.vaughanscott.com/AIM/aim_tracks.htm
I also have some pics of the unit installed in my own car (just used velcro to pop it into the enduro car):
http://www.vaughanscott.com/construction.htm#MYCHRON3
I don't have handy any snapshots of data analysis, but you can download the software for free, grab my data, and play with it to your heart's content.
The system I use is the AIM Mychron3 Gold XG Auto. It records speed, RPM, computed gear, lap time, and lateral g's, plus 4 analog inputs your choice. It also has the realtime display (unlike some units, I guess) of rpm (by bar graph and programmable shift lights), previous lap time, 2 analogs, and your choice of battery voltage, rpm (digital #), best lap time, or vehicle speed. Comes with lap beacon and receiver, speed sensor, and two analog sensors.
I've chosen to use my own (stock) sensors; for now I have oil pressure, water temp, longitudinal G's, and yaw rate logged. For engine tuning I'll switch over to from 1 to 4 EGT probes; maybe all 4 on the dyno, just 1 on the track at most.
I agree it's best value, at this level, is for driver training; for this reason I expect to add a steering angle sensor at some point and run that with yaw rate, oil pressure, and either EGT or decel. I don't find the decel and lateral g's that useful except to show a major glaring issue (would be useful for driver comparisons, though). I find yaw rate smoothness is more meaningful, though of course nothing is ever more important than speed.
The best part is to be able to pair it up with the track map and analyze the incremental gains and losses around the track for specific laps by segment. The best tool by far for finding speed.
I can echo GregA's comments about finding speed. The most telling for me was that over 2 consecutive weekends on my home track (where I've been racing for 5 years), I was able to rip well over 3 seconds off my best previous ever laptimes after I started using the data system - this where I'd already pretty much plateaued. Not quite as earth-shattering as having someone else get in and drive, but still amazing to me.
Considering the cost required to get similar amount of time out of, say, the motor, tires, or suspension (if they were even allowed), the data systems suddenly become VERY affordable!!!
Less than a grand for multiple seconds? Portable between cars? More durable than NOS?
Plus, it's really fun to be able to say, without guessing or exaggeration, just how fast you were going!
Oh, yeah - wheel speed sensors, just the one on the rear axle for vehicle speed. You wouldn't know what to do with the rest, unless you're trying to perfect your threshold braking. I would also stay away from the linear potentiometers for suspension tuning, unless you have high-end shocks (like the ones we can't run), to tune them. For driver development, you need to know what the driver and car are doing. For the former, the most useful is steering angle; brake and throttle less so. For the latter, lateral and long. g's are a start, yaw rate will really get you there.
Since you're gonna ask (yaw rate is not readily available for these systems) - we're using a production yaw rate sensor from a car equipped with ESP (stability control) - specifically a 2000 Olds Intrigue. You give it power and ground, and it spits out a yaw rate signal and linear accelerometer (long. or lateral, depending on how you mount it). If you really wanted to be a jerque, you could get a couple and use them to try to look at pitch rate and roll rate, along with acceleration in all 3 directions. But that would be the less useful info. As I believe it may have been Carrol Smith once said, "Nothing good has ever been written about the rotation of a car about its pitch or roll axes."
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Vaughan Scott
Detroit Region #280052
'79 924 #77 ITA/GTS1
www.vaughanscott.com