In-car GPS monitoring units

[JoshC]

NASA is actively conducting research on the use of in-car GPS monitoring units as an alternate method of compliance testing of horsepower output. It is possible that GPS monitoring will be used at the 2010 NASA Championships, and that vehicles found to be out of compliance will be penalized without Dyno testing, based on the results of the GPS on-track monitoring. If NASA elects to begin compliance testing with GPS units, competitors will be given adequate notice prior to their use, including details of the units to be used, so that they may do their own testing if desired.

I read the above in the new rules that Greg posted. My experience with GPS devices that calculate horsepower is that they are not reliable. They don't account for elevation changes, wind, the use of draft, etc. They attempt to account for rolling resistance of the tires and aero drag but are really just estimates unless you have access to a wind tunnel. I would have no issue with using GPS to identify those that MAY be exceeding power to weight… but using it as an official HP reading without being backed up by a dyno creates a margin of error that could unfairly disqualify competitors that have done nothing wrong.

 

Maybe my Traqmate is just not high quality enough to provide accurate readings and I’m needlessly concerned. Anyone have better experience with these things?

[Greg G.]

Josh, our testing at Buttonwillow this past event was very accurate--margin of error was less than 2%. We will continue to do testing the first half of the season in 2010, and determine what allowance there will be for error (likely a % of the result). However, these units are now being used by multiple Pro series to help with compliance testing. The problem, as you may know, is that with the current (and upcoming) electronic technology built into modern cars and aftermarket computer systems, Dyno results are accurate for those that are not attempting to gain an illegal advantage but not those are. As well, the majority of regional events across the country do not have a Dyno available at the track. In the past, I have seen cars that were being monitored lose 1-2 seconds a lap compared to when they were not being monitored (probably due to the extra few ounces of weight added to the car by the GPS unit )

[Andrie]

In my experience gps based alone to determine HP is less than accurate. In the tune of 10-15%.

 

I also would like to hear what pro series uses gps based unit to determine HP compliance.

 

Speed world challenge uses gps traqmate system to do comparison between cars, but not hp numbers. They uses acceleration curve comparison and g among other things as tools for them to do further compliance check. But they do not use the logger for the sole purpose of determining compliance.

[DHarsay]

... our testing at Buttonwillow this past event was very accurate--margin of error was less than 2%. ...

 

Do you have any specifics and data available?

 

Thanks,

Dave

[L98Terror]

NASA is actively conducting research on the use of in-car GPS monitoring units as an alternate method of compliance testing of horsepower output. It is possible that GPS monitoring will be used at the 2010 NASA Championships, and that vehicles found to be out of compliance will be penalized without Dyno testing, based on the results of the GPS on-track monitoring. If NASA elects to begin compliance testing with GPS units, competitors will be given adequate notice prior to their use, including details of the units to be used, so that they may do their own testing if desired.

I read the above in the new rules that Greg posted. My experience with GPS devices that calculate horsepower is that they are not reliable. They don't account for elevation changes, wind, the use of draft, etc. They attempt to account for rolling resistance of the tires and aero drag but are really just estimates unless you have access to a wind tunnel. I would have no issue with using GPS to identify those that MAY be exceeding power to weight… but using it as an official HP reading without being backed up by a dyno creates a margin of error that could unfairly disqualify competitors that have done nothing wrong.

 

 

There is no system that is 100%, it would be nice if there were enough of these to cover all the front runners & we had access to them ahead of time to see where we stand.

 

As for accuracy I was dynoed at Nationals many, many times and at one point I got dynoed at 9 AM (my Dime) and ran one TT session and was pulled back to the dyno (NASA Dime) and dynoed about 12 HP less. Same day, same dyno, same tune, same car. I recommend you alway give yourself a margin for error. I do but one of these day I have a feeling I'll be on the other side./

[JoshC]

My experience has been 10 to 15% variation with GPS as well. I wasn't at nationals but did hear that there was quite a bit of variation from pull to pull on that dyno. You have to expect some variation in any case due to temperature, pressure, and humidity but I've only seen that variation to be < 3% on a shop dyno... not that I'm some kind of dyno expert.

 

Anyway, I do understand the problem, so rather than just complain I'll volunteer to participate in testing if that helps.

[ryan0]

I think the main point would be to catch guys with turbo cars from gaining 5-10% HP throughout the day.. or session.

 

I'm sure they can figure something out to catch obvious discrepancies.

[Greg G.]

Ryan, it is not just turbo and supercharged cars. There are big bore motors that can be significantly detuned using timing and fuel maps to run with lower hp on the Dyno as well. However, you are correct that we are looking for the bigger discrepancies in terms of using the GPS to actually D/Q someone. At the same time, the GPS units will also show us who needs to be put on the Dyno for the close calls.

[philstireservice]

Greg what unit are you testing with? Same as the World Challenge ? And what lee-way % would you call acceptable?

[Greg G.]

Phil, we are testing with more than one unit, and the testing is to determine what % range we will be using.

[Vettedoctor]

If it is decided that these units are going to be used at Nationals will someone who is planning on going to Nationals be granted the use of one of the units before Nationals at a Regional event. I would think there would be a lot of guys in the GL/Midwest that would like to have there cars tested to see what the results would be. Like at the September 11-12 Autobahn crossover event.

 

I would also assume that there will still be a chassis dyno at Nationals even if the GPS units are used so we compare the results.

 

Thanks, Joel

[L98Terror]

I would love to test one at Mid Ohio since I'm sure I will be one of the first ones to have one strapped on my car at Miller in 2010

[panozracing]

Anything that will give results that are consistent I am up for. We dyno'ed our car before leaving for nationals 2008 and then got checked at MO dyno and we had 30hp less or about 8%. That is ok except that we could have easily gone the other direction and then been illegal. Then what? Very hard to tune with variables like that.

[Greg G.]

If it is decided that these units are going to be used at Nationals will someone who is planning on going to Nationals be granted the use of one of the units before Nationals at a Regional event. I would think there would be a lot of guys in the GL/Midwest that would like to have there cars tested to see what the results would be. Like at the September 11-12 Autobahn crossover event.

 

I would also assume that there will still be a chassis dyno at Nationals even if the GPS units are used so we compare the results.

 

Thanks, Joel

Joel, we will still have a Dyno, and will certainly be looking at the comparison results (especially of our "known" test cars). However, the purpose of using the GPS is to ensure that there is no funny business going on with cars on the track vs their performance on the Dyno. Whether or not this has gone on in the past, there is a perception that it could be. We want to do whatever we can to make sure that it isn't.

 

While none of this is 100% certain (otherwise we would have put the specifics in the Rules), my guess is that if we end up using them as a true compliance tool (not just an aide) at the Championships, that we will give competitors at least a month or two notice of the brand and model we will be using, as well as any group buy/discount that we can arrange. These things generally cost less than two new tires, and again, my guess is that many competitors will want to purchase their own units for their own year-round testing, and to monitor themselves at the Championships. I know that many of the Regional Directors are interested in getting them for their regional compliance program. So, there may be some in your region by that time that your Race Director/Series Director will put on your car. Unfortunately, we do need this next 6 months to continue our testing so we don't put something into place that causes more problems than it solves.

[RAFTRACER]

How is the lack of monitoring torque going to play into the analysis of the GPS Data......I know for FACT that one of the units used @ RA last weekend was 18-20 rwhp off anyway on a car that I know.....I know it'll take some time to get this sorted out.

 

I think that the GPS is a good idea, but not sure if it should soley be used for compliance ....way,way to many variables.. It will however catch large errors at a regional level.

 

I think that my car may become a very-high downforce car....j/k...

[TexaST-1]

I think it has its place as a trigger point for potential creative rules interpretation.

[ryan0]

I think that the GPS is a good idea, but not sure if it should soley be used for compliance ....way,way to many variables.. It will however catch large errors at a regional level.

 

i think it's main use should be "you were at X HP this morning and you qualified 4th... but in the race you magically showed X+30 HP... CHEATER"

[DHarsay]

A dynojet dyno is I think 12% off from actual RWHP, it's a built in calculation error which came from their motorcycle roots... they kept it there because due to human nature and egos, higher dyno numbers sell more dynos.

 

Now to get to the point... are we expecting the GPS to indicate dead on with the Dynojet Dyno used for certification? Probably not, in fact it may potentially be more accurate.

 

Dave

[panozracing]

A dynojet dyno is I think 12% off from actual RWHP, it's a built in calculation error which came from their motorcycle roots... they kept it there because due to human nature and egos, higher dyno numbers sell more dynos.

 

Now to get to the point... are we expecting the GPS to indicate dead on with the Dynojet Dyno used for certification? Probably not, in fact it may potentially be more accurate.

 

Dave

 

how come one dyojet to another vary so much?

[Jaymz]

Maybe some dyno operators do not follow the maintenance schedule to the T...

[Jaymz]

Greg... Can you elaborate on how the testing will be done and with what product? Right now we can make sure that we are compliant by going to the closest dyno or the dyno at the track. If we will be tested with GPS I would like to know the method so I can test my car as I currently do on the dyno.

[DHarsay]

... how come one dyojet to another vary so much?

 

No no... all Dynojet Dynos indicate about 12% higher dyno numbers than reality. I re-read the sentence, still not sure why this was misunderstood.

[Jaymz]

I dont think he misuderstood.. He is wondering why one dynojet might show 450 on his car and another dynojet might only show 420.

 

I have seen 10 hp swings myself. which cost me a DQ at one of the races at the Championships in 2008.

[mrc24x]

I'm guessing the benefits of Ram Air are going to be a factor to add in if you are just using Dynojet data currently.

 

It would be nice if NASA comes up with a rule to use systems already installed. (Traqmate, G2X, DL1,etc...) Is it as simple as using Acceleration G's? (among similar shaped cars) and/or get rid of the hp advantage for sedans since the aero is already taken into consideration w/ the data aq.??

[vlamgat]

I think that the GPS is a good idea, but not sure if it should soley be used for compliance ....way,way to many variables.. It will however catch large errors at a regional level.

 

i think it's main use should be "you were at X HP this morning and you qualified 4th... but in the race you magically showed X+30 HP... CHEATER"

 

This sums up the problem IMO. If one looks at the history of t/c racing cars based on production platforms, there is a trail of sand bagging that extends from the lowest funded to the factory operations. The Group B cars of the 1980s were quite simply called "Too Fast to Race" because of the unlimited capabilities of 2 liter t/c motors in the hands of skilled technicians and drivers/pilots. Grand Am, NASA and SCCA are killing themselves trying to regulate this process. I think the only answer is for either a displacement limit and then allow whatever the owner wants or can afford with the tune as per Group B. This effectively means another class for t/c cars as n/a motors will have to be a lot larger than 3.5 liters to compete. Alternatively supply the ecu to every t/c car and withdraw it after every event...not going to happen!

 

The sport either has to accept that technology must and will progress and the spoils will go to the endowed or we must go to a NASCAR standard where the spectacle is more important. The middel ground requires a level of technical scrutineering that barely exisits at the regional NASA or SCCA level and IME taxes SCCA Pro and Grand-Am too.