BrianKeithSmith

In the case of 4 wheel speed sensors, how does it calculate speed? Average? Highest? Lowest? I'd almost need 4 because many times I only have 2 or 3 on the ground at once...

Brian

Larry Herman

Now that would be a cool way to enforce PCA rules. No chip checks, no teardowns, no nothing. If your car accelerates at better than a predetermined G load for a specified time period, you are cheating. I would think that a fairly good formula based upon weight and factory HP could be derived for each car. With a readout you could even see how close you were getting to the "bracket".

Tom W

So, if someone already had a MoTeC system running the car, what sort of ballpark money is it to add 4 wheel sensors, 4 shock sensors and the other standard package (rpm, gear, oil temp, oil pressure, etc) to replace all the stock Porsche gauges (and use the MoTeC dash)?

What would the equivalent cost for the AIM Pista Pro?

I'm looking to what the "added" up front cost of the MoTeC is to allow more expansion possibilities later.

Adam M

I crew for a friend who has a 997 in the Grand-Am series and we have on in his car. The good thing about the MXL is that it is far cheaper than anything else out there. That is the one thing I'd say that is 'good' about it. We have 1 wheel sensor hooked up to get the speed, we get most stuff from the ODBII, but unfortunately they don't have many of the 'codes' figured out, so it is very basic (rpm, water temp, and oil pressure). We had to add a few external sensors to it. We *never* got the shift lights to work. We even had the 'pros' (guys who import them into the US try and they couldn't get it to work). The firmware on the unit is buggy. We had many sessions that we never got logs for because the unit didn't work. They put out updates at least once or twice a month. The PC software is *very* convoluted and hard to figure out (they should hire Apple to re-write it ;-). Plan on spending tons of time trying to figure out how it works. I would really love to like this unit, but at this point I would not get one for my car. Sounds like some others here had better luck. Maybe we got a bad unit too?!?!? I believe it got swapped last month for a another one, but we won't know if it's any better until it's on the track again...

My 2 cents.

Nordschleife

On the 996 Cup cars, the Bosch ABS sensors are used by the Motec ADL. However only three are hooked up, hook the fourth and Bosch invalidates your warranty.

Motec have an extensive catalogue in PDF format. The ADL is capable of reading data from the Motronics unit.

It really is worth reading up on the system capabilities before rushing out and spending money.

R+C

SundayDriver

Geoffrey explained how they do this. All of the systems I have used (MoTeC, Pi and Stack) were very consistent with official lap times (generally +/- 0.001 sec) and sector times repeat withing a few thousandths when running consistent laps.

Geoffrey

Watkins Glen lists the track length as 3.45 miles (I have also seen the track listed at 3.5 miles with the difference being 264 feet) when converted to feet and compared against my MoTeC "lap distance" channel, the MoTeC was 100ft different from what WGI lists as the track distance. There can be many reasons for this including the line that was driven and the accuracy and location at which the track was measured. Even with the 100ft difference, that is near .05% error.

To add 4 wheel speed sensors will depend on the car and how it is configured. I have used the 4 ABS wheel speed outputs as R+C mentioned and fed them into the MoTeC. I have also use stand alone sensors on cars where ABS was not available and I have used factory wheel speed sensors with factory ABS rings on cars where ABS was removed. Sensors are about $150 each + wiring. The MoTeC can use either square wave (hall effect digital) or sine wave (magnetic analog) inputs to determine wheel speed.

To add 4 shock position sensors you need to buy 4 linear potentiometers at about $225-275 each depending on length + mounting design and wiring.

To obtain engine RPM you should be able to tap into the engine ECU or ignition system. From engine RPM and wheel speed you can calculate gear position. To put oil temp and oil pressure you would most likely want to use separate sensors, or if you are replacing the 911 gauge cluster you can use the factory temp sensors but would need to remove the idiot light and replace it with a 150psi pressure transducer at $85-$225 depending on brand.

I would not pull anything other than temps from the OBD2 port, it does not have a high enough sampling frequency.

The MoTeC ADL and SDL both have 5v pull up circuts on all temp inputs which means you don't have to make your own. AIM MXL requires you to build a 5v pullup on an analog voltage channel when used with a resistive device such as fuel level sender or temp sensor. The main differences between the MoTeC ADL/SDL in terms of included components is that the AIM comes with the beacon transmitter and receiver and some wiring cables (depending on model). The MoTeC comes with the unit only which gives you the flexibility to build your own proper wire harness from lightweight aircraft wiring and connectors.

MoTeC also offers and ACL which is an even more advanced data logger and utilizes the compact flash card technology with unlimited channels and advanced CAN bus technology/capability. This will be the future for MoTeC in my opinion.

jrotsaert

The European Endurance Racing Championship has something similar. They put a GPS based box in the car and weigh the car before the race and after the race. They then check every box for acceleration between straights and torque out of corners to see if you're cheating for your series or not. The only rule is power to weight to define class and max rim and tire width which is pretty to see at scrutineering and at tyre mounting since it's a one make (Dunlop) championship. Not sure it will be panacea to fix the categories though because it' possible, by adding weights to an RS like mine, to run with cup cars... and I'm nost sure that's very fair because of cornering speed differences
JM

jlucas

As an RT dealer, I know that:
SCCA Club Racing office is now using Race Technology DL1 units to gather data for competition monitoring and fact based adjustments.
IMSA is using the DL2 for their competition monitoring.

Is PCA next.....

Jeremy Lucas
FastTechLimited.com

SundayDriver

That is interesting. How is SCCA managing to do this at the club level as I do not see anything in the GCR that allows them to do this kind of monitoring.

Regardless, I think your statements bring up two observations or questions:
1) If they are doing performance monitoring, that seems to be a very simple data set so I am not clear what your point is.
2) Do you have some vested interest in the DL1/DL2 series vs. other options?

jlucas

If you get SportsCar (the SCCA member magazine) there was a write up about it a couple of issues ago that covered the Runoffs. It's not a competitor requirement, rather the SCCA owns like 10 units and they place them in cars they want to monitor. AFAIK, there is no GCR rule yet so I don't think they can make you carry one at this point.
1) Just pointing out another couple of examples to add on jrotsaert's comment of GPS & accelerometer based D/A being used by sanctioning bodies for monitoring.
2) I sell and support RT as well as AIM products, no secret there as my website is listed with my name.

I would like to understand in more detail how these sanctioning bodies are using the data that they gather. I read in Race Car Engineering (IIRC), that a rather elaborate simulation system was developed for the FIA GT series to aid in monitoring competitiveness and judge potential comp adjustments. Does anyone know more about it? Are they using d/a output from entrants to feed the simulation?

Jeremy Lucas
FastTechLimited.com

SundayDriver

Thanks. As far as your sales status, I did not notice the website and it is not a link. Many (including myself) consider it very bad form to promote any product that you have a financial interest in without clearly identifying that interest. Obviously you can choose to do that or not, but it does impact you credibility a great deal.

PedroNole

I have the MXL Pro unit and, although I haven't used anything else, I really like it. The only thing that I don't like is the track mapping. It doesn't map "lesser" corners that well. For example, although Sebring is 17 turns, the MXL maps it at 13. Does it on all tracks....

I have the RPM, Speed, oil temp, oil pressure and voltage sensors. I have had the oil temp sensor freeze on me a couple of times. Going to change the sensor. Never had a memory issue. I did a 3 hour enduro race and it logged it all.

I download and clear after every weekend.

Caddell

I am a AiM dealer but we are also big users of the AiM product. We run a MXL Pro on a Spec Miata and I thought I could add a few things to the discussion on the memory issue.

We run these sensors: oil press, water temp, long g's, all 4 corner suspension linear pots, steering pos, brake pressure, Lambda. Plus the normal sensors: Speed, RPM, lateral g's, laptimes, battery voltage, calculated gear.

We do not gather any of the ECU data... '91 Miata!

With all of these channels set to record at 50hz (the data overlays onto the AiM DaVid system better) on the 16mb onboard memory, we have room for 5hrs 01min of data storage.

Also worth noting is that AiM just recently went to "Circular Memory" with their latest firmware upgrade so when I have used up the 5hrs of memory available to me, the oldest data just starts to be overwritten so I would always have the newest 5hrs of data.

It is also being talked about to have external data keys available to allow for more data storage but even more important to allow each drivers data to be quickly gathered during a driver change in a endurance race.

Hope that answers the memory question.

Roger Caddell

Geoffrey

Roger, did I read you right that you are sampling shock position at a mere 50hz? I can't believe that provides any good information at all. At 100mph, the car would have traveled 35.2 inches. Similarly, logging battery voltage at 50hz is probably unnecessary unless you were using it to identify an issue.