RJay

I don't think the little guys have track mapping capability and they are only 512k as opposed to 8 Meg of logging memory, but they're still pretty useful. There is a version below the XG Log that deletes the can bus and retains the track mapping capability for less $$$ (is this the gold, I thought it was closer to $800 could be wrong), but you lose the steering wheel mounting. The other thing that should be pointed out is that all these mid range Aim units come with a track beacon and will display laps times (and best lap time) on the logger while your on track. So no need to buy that hot-lap unit for in-car info. Don't believe the DL-1 can do this stuff. Another cool feature, at least in the Kart version, not sure if it carries over to the auto stuff is that you can play back your session on the display itself. Not sure how useful this is, but its sure to impress your friends (assuming you really did hit 145 down the back straight!).

mpaton

I think you're correct about the track map capability of the lesser AIM units. If AIM USA had had their "almost there" website finished, I would likely have been unable to resist buying an MXL in the past 6 months. Even though the Italian website did seem to have all the data. By the time I was ready to do it anyway, the MXL had got a big price increase, and the ease of installation of the DL-1 seemed more attractive.

The DL-1 has 7 analog inputs (maybe I'll get steering input one day) and 4 frequency inputs, and although I've only done a few trips round the block, the data seems interesting. No testing of my max g-sum yet, let alone on the correct line. :-)

The DL-1 can accept a lap beacon input also, although it doesn't come with a lap beacon. They do suggest that the analysis program's capability of accepting lap markers compensates for this, and it may well be enough if you don't need an accurate lap time. It has to depend on accelerometer corrected GPS position though, and I'm not sure how consistent that's going to be. Seeing I'm not racing, it's not my primary interest, but if it was, I guess I could get a beacon and use it with the DL-1.

I agree that the AIM softare seems to be a little more useful than the Race Technology, so I hope that continues to improve. I got the cable from cb-racing that reads RPM and supplies power from the OBD-II socket, so I have that 1 connection and the GPS antenna for connections. I wasn't looking forward to getting good sensor connections on the 2002 911. Apparently 2003 is the first year of CANBUS, so I didn't need that. I think I'm going to prefer the data storage to Compact Flash over needing to plug a laptop into the data logger, but I'll reserve judgement until really use it. I also didn't especially want a dash display unit, although it seems that Race Technology may have these soon if Google searching is accurate.

I too have the McBeath book, and I'm glad I got it and read it before buying a logger. I understand your opinions about it, but the message I got is that you can still learn alot even if you only have rpm input. So we'll soo how I feel after some months of use.

Now I need to see if my track junkie friends will get one too. The AX-22 with its rubber suction mount seems attractive enough to be shared among a few people.

For those of you using data loggers, is it possible to convert data files from one vendor's format to another, either to use different analysis programs, or to compare with data from another car with a different make of data logger.

Given the need to set/calibrate/zero accelerometers or adjust for installation angles, how reasonable is it to compare data from different installations in different cars?

Anyone got a DL-1 data file from TWS or MSR in Texas?

Michael Paton

95m3racer

Whats the big hub-bub about installing these systems?

They are all standard sensors...we're not talking any shock pot's or strain guages here, they are just temp,sensor, rotary/linearpotentiomets (steering/pedals).

Grab a soldering iron, heat shrink, some nice connectors, and a bunch of wire and loom to bundle it. Wiring is very easy you just have to take it slow and not screw up.

DL is nice, but in my opinion does not come closeto comparing with an Xg-log or MXL Pista/Pro.

FixedWing

It would be very useful if someone were to create a central database where we could all share data log files.

I am aware of such a web page recently set up for the Nürburgring but it is not accessible to the general public.

Stephen

FixedWing

The DL1 is definately accurate enough so that no lap beacon is necessary.

Stephen

RJay

Its software, anythings possible, but I doubt it would be trivial, i.e. if the formats are unpublished you'd have to reverse engineer the data files and build a conversion program, not a big deal, but certainly beyond most mortals. There might be some way around Excel spread sheets to export data and compare it at least under Excel. One other issue, oft times overlooked is that Macs and Linux are, as yet largely unsupported in this world as far as I know.


BTW, I had forgotten about the CF memory on the DL, that is a really nice feature! So this brings up an interesting notion. Has anyone tried to hook up a portable USB drive to an AIM? Would be nice, and probably more convenient to be able to offload onto one of these so I can leave the laptop in the truck. A a half gig could probably store the entire season and then some, plus they're cheap as spit.

mpaton

i agree it's not hard in theory. In practice to do a nice job on a modern plastic dashboard car that I don't especialy want to drill extra holes in is going to take a little longer.

And I'm not challenging your opinion, but why do you think it doesn't come close. If you wanted a dash display, I'd agree with you. I'll be upgrading the Mychron light in my shifter kart to a Mychron 3 later this year.

Michael

Geoffrey

As a MoTeC dealer, I've worked on a number of ADL configurations and installations in a wide variety of cars. While this particular device is targeted at the professional level, we are seeing a number of older Cup cars delivered to customers who want to take advantage of its capability. For many of the users, they are basically using it as an expensive lap timer with pretty pictures because there has been no one to educate them on how to organize the logged data and analyze what is happening. I've also been working with AIM and they've given me a dash and for the price it is an excellent value. It is much more useful than the DL-1/90 because it can a) connect with a wide variety of ECUs to obtain engine data, b) has 8 user defined channels, c) has substantial memory capability, and d) software that is easy to use, powerful enough to give the novice the ability and confidence to look at the data without overpowering them.

It is my opinon that the sensors to read in order of priority are:

RPM and Throttle position. With these you can get an idea of where the engine is operating in the RPM range and where and how long the driver is at each throttle position. You can also use a gear chart to plot maximum speed.

Speed, lat & long 'G' force and lap beacon. With these you can spend as much or as little time as you want analyzing corner entry, brake effectiveness, straight entry speed, corner exit speed, lap time, driver smoothness, etc.

These 2 groups combined with good analysis software (some may even give you gear selection based on RPM, Speed, Gear ratio) will give you enough data to compare against another driver (in your car), segment (corner, straight, corner, etc.) breakdown by lap, predictive lap timing, segments within a 5% variance, etc. which will help you understand what you are doing with the car and then you can begin to use it to improve your driving skills.

You can then add:
Steering input - when plotted against lat 'G' will tell you over/understeer, will show smoothness
Brake force - will show when and how hard the brakes are used
Shock position - will help identify vehicle dynamics, high speed vs low speed compression and rebound effectiveness for example

If it were me and I was serious about using DAS to improve my driving, especially if I had a coach, I'd recommend spending the extra money for a MXL Pista (list about $1700) because a) the software is so much more useful than the DL-1/90, b) there is a larger upside potential as you grow in DAS understanding.

PS I too can sell the MXL series, sensors and help set up the software.

924RACR

I still would personally put steering angle over lateral and long. G's, but that's just me. Certainly you've got to have speed, RPM, lap marker first...

But back to what RJay was saying... yes, I've got the 8Mb memork, track mapping, steering wheel display (if I wanted it, dash works better for me), etc. And yes, the heads-up display of lap time is very nice too - that is the second most important thing I get out of mine while on-track, after the integrated shift lights.

As for install - for me, the biggest PITA is the bracketry, since I don't have the ability to do such simple little fab jobs myself. At very least, I have to call in my fabricator, which takes time and adds complexity. So installing the speed sensor took a few, and I still haven't added (as mentioned) the steering angle. That'll even be more of a PITA due to the need to not only mount the string pot but to also add a spool on the shaft. BTW, M3racer - got any connections/recommendations for getting that string-pot? We use them all the time at work for steering and brake, but can't get my hands on the bits...

Geoffrey

For steering angle, you have 2 options, one is to put a linear potentometer on the steering rack, or to use the string pot on the shaft. I can get either. email me for prices

Shpeyeda

Umm, yeah, right. Maybe after doing a few it gets easy, but I couldn't begin to figure out how to find and tap an RPM signal or install wheel speed sensors or steering angle sensors. Give me a break.

Now, the on/off brake light signal, I'll give you that. It was pretty easy. If you have a suggestion on which wire to splice into for the RPMs on a 993 then I'm all ears and will thank you profusely.

My buddy paid several hundred $$ to get his $1300 AIM system installed and most of us would have to do the same. Like I said, it all wasn't worth it to me, but I can see the opposing viewpoint obviously.

RJay

I think the point was that it ain't any easier (or harder) with any other system. The procedure is the same. If you want tach, or throttle or what have you with your DL-1, you have precisely the same issue. You don't have to hook up a tach etc to the AIM to get the track mapping etc , but it certainly lessens the value of the display and limits the usefulness of the software. I surmise one key difference and that is that with the GPS of the DL-1 you don't have to install a wheel speed sensor, which I assume you must do with the AIM otherwise you get no useful timing and speed data.

FixedWing

Doesn't the OBD-ii port have a pin which carries an RPM signal? So on a modern car that would be pretty straightforward. Now .. throttle position could be a little more interesting...

Stephen

ColorChange

Geoffrey:

I agree with most of what you said but the order of sensor importance. Here is my ranking.

1. Speed. You can not only calculate rpm and gear from this, but long g as well.
2. Lateral g. With this you now have the all important G-SUM.
3. Track Map or Position. This allows you to calculate segment times and easy lap comparisons.
4. Throttle Position. This shows car handling and set-up like steering
5. Steering Angle. This shows car handling and set-up.
6. Brake Pressure. How are you using the brakes, detailed -long g analysis

I used a rotary encoder coming from a belt on my steering shaft spline on my Lambo.

Vaughan, boy g-sum is way more important than steering angle IMO.

The Aim has RS-233 input and it is easy to get rpm from the OBDII.

FixedWing

I still don't buy that G-sum is "all important". To me, it is just a surrogate for lap-times (and a poor one at that). It is, by definition, a macro indicator. It lacks the detail to tell you anything interesting. Wouldn't a racer have a pretty good G-sum on the warm-up lap when he is swinging his car back and forth behind the pace car to warm the tyres? That's hardly going to be his quickest lap!

I think that the reason that G-sum works at all is that many tracks it is being used on have pretty clear lines so everyone is sticking closely to the same line. But I can’t see it being useful at all at a track like the Nürburgring where lines are absolutely critical and not easy to figure out or stick to.

As for the rest, with the exception of steering angle, I believe that they could all be derived from position and time information (assuming that the driver isn't doing stupidly inefficient things).

Stephen