SundayDriver

Opinions vary as to what is important, so here is mine. First comment, however, is that your results are no better than your sensors. If you have junk coming in, the data and results will be junk.
Personally, I would not trust such basic items as G's if they are calculated rather than measured. I have concerns about speed from GPS - I don't know the answer but the question is just how accurate and repeatable this is. Can it measure (and repeat) to less than 1mph? I also do not trust any lap times that come from trying to figure out where you are on the track rather than using a beacon. That said, here is my ranking and comments:

1) Lap Time. Nothing else matters if you can not relate it to lap time.
2) Segment time. Not much matters in terms of trying to improve if you can not determine segment times.
3) RPM - What am I doing to the car?
4) Various Temps, pressures, voltages, etc. Highly valuable when you are troubleshooting and if the car is broken, you can't run laps.
5) G's - Both lat and long
6) Throttle - One of the most important things for fast laps.
7) Brakes - not from the brake light, but brake pressure. I can see from speed when I got on and off the brakes - I don't need another on/off indicator. I do care about how quickly I build brake pressure and it is really nice to see bias.
8) Steering - While useful for calculation of oeversteer/understeer, I have not yet seen anything on a steering trace that I hadn't already felt in the car.
9) Shock positions. Get position, velocity and calculate height and downforce.

I probably forgot some stuff.

95m3racer

Just a note, the MXL pro (approx $2300 base) has 12 channels (thats in addition to rpm, speed,lateral g's, and lap time).

As for the difficulty of wiring...I spent 3 hours today in the garage, and I made a complete sensor harness for the Aim Xg log that i have coming. I have 6 sensors on 5 channels I combined water and oil temp, and wired in a standard toggle switch so i can select which one I want to seeon the Dash. This way I can have an extra channel open...in this case I am putting in a steering String pot in. I also spliced into the TPS, so i now have throttle position as well. Oil pre, fuel pres, water/oil temp, speed, rpm, lap time, tps, steering pot, lat g,long g,....with 8mb, even with a high sampling rate, its hours and hours and hours of data logging...plus a really slick dash. LED's are very bright, and individual alarm lights are key. I have the configuration setup for low fuel pressure, low oil pressure, low oil/water temp (so i know when its warmed up). Should be pretty slick, and it only took half an afternoon to wire up all the engine sensors.

For the speed I made an adapter to fit a hall effect speed sensor to fit into the stock ABS location and readoff the ABS toothed wheel (since i dont have abs anymore its not a problem).

FormulaOne10

In regards to the value of sensors in a particular order I think you have to prioritize them based on their relevence in a particular action.

For instance if I am troubleshooting something on my car setup (say brake temperature). I would want temp sensor on the caliper, temp on the rotor, lat g sensor, brake pressure sensor, and wheel speed sensor. On the other hand, if I was determining the fastest way thorough a couple of high-speed sweepers I want wheel speed, lat and long g (using these you can calculate a segment time fairly accurately), GPS (to determine line), RPM and all of my driving inputs. However, if I wanted to find out how shock adjustments affected transitions that same section, potentiometers on the shocks and lasers sensors for car height would also be very effective.

Sometimes a certain sensor does absolutely no good for me, other times that same sensor is indispensible for the application. It all depends.

Just my $.02

Geoffrey

I would agree with that. My priortization was based on the premise that DAS in this discussion was being used to help improve driver skill and was being used by people who have had no prior DAS analysis skills. It takes time to a) understand the software, b) understand the data, c) put together the templates and graphs that are most useful in displaying the data into useful information. Once you are able to do that, it takes additional time to understand how to improve or change driving habits.

RJay

I think Sunday is pointing out the relative priority of what do to achieve a particular action, that action being to go faster. It may be the general case, but its why we install these systems in the first place.

We of mortal means will never do this. First, you persumably have followed, to some extent Sundays hierarchical guide to sensor non-deprevation. An MXL Pista has 8 analog channels available out of the box. This means you can measure 8 individual devices (beyond the MXLs speed and ecu data acquition stuff). Decent IR sensors are $200-$300 a whack. At this level, a brake pressure sensor doesn't measure pneumatic pressure, it simply looks at the linear range of travel of the pedal and logs it. To set something this sophisticated up would likely cost as much a new set of Big Reds (possibly with can bus integration you might be able to read individual slave cylinder pressure data out of a modern PASM/ABS system, I have no idea). In F1 they may have this sort of thing, but it will be a long time before we have it at the amatuer level.

Its important to remember, as some have pointed out, that the purpose of having this data is to improve the driver and the car. If you don't understand what the numbers mean, its worse than useless, it may in fact be harmful, leading you to expensive mistakes on setup or driving style. I am nearly certain that I'll never put in shock sensors as I have no notion of what they're trying to tell me. I ultimately desire throttle, brake, steering because these are the only inputs I use to interact with the car. If I log these, I can correlate my actions with what the car was doing. I can reinforce good results and try to avoid bad ones.

I believe Sundays list, with the exception of the oil/water/etc which are important for diagnostic, not performance reasons, is extremely well ordered if you want to use these tools to go faster. Any numbskull such as myself can get something out of segment and lap times, can maybe figure out that the reason I was 3MPH faster at the end of the front straight on lap 6 was because I was 200 RPM higher at corner exit. My install is going in initially with speed (add a sensor), throttle (from the ecu's existing sensor), tach, oil temp, press (tapping the existing wiring) and a single EGT sensor (hey it was free, so we're putting it in for those rare happy moments known as free dyno days). Thats it. As I become more familiar with the system and what its telling me, if I find myself saying 'geez, I wonder what my braking or steering technique looks like, I might add them.

CCs suggestion that started this thread is about a far cheaper way to take advantage of all the sensors that pre-exist on a modern Porsche, it would be great from a cost perspective, but you certainly wouldn't be looking at every bit of data all the time. It would just be nice and cheap if it were available so you could, if the need arises.