How accurate are these GPS G-Meters?
#1
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How accurate are these GPS G-Meters?
Edit - My AIM MXL is NOT GPS based, I was befuddled by the paperwork.. so solly.
I asked because my system shows me pulling up to 1.57 Lateral G's on top of the uphill and over 1.3G in most all the other corners at LRP, didn't think my car (or I) was capable of that? Funny how the left hander shows as negative G's.. just the opposite pull of course.
I asked because my system shows me pulling up to 1.57 Lateral G's on top of the uphill and over 1.3G in most all the other corners at LRP, didn't think my car (or I) was capable of that? Funny how the left hander shows as negative G's.. just the opposite pull of course.
Last edited by Gary R.; 04-07-2008 at 10:54 PM.
#2
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Larry Herman
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Larry Herman
2016 Ford Transit Connect Titanium LWB
2018 Tesla Model 3 - Electricity can be fun!
Retired Club Racer & National PCA Instructor
Past Flames:
1994 RS America Club Racer
2004 GT3 Track Car
1984 911 Carrera Club Racer
1974 914/4 2.0 Track Car
CLICK HERE to see some of my ancient racing videos.
#5
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Which GPS based data system?
I've been using a Traqmate for a year and it shows that I pull up to 2.0 g's in the high speed turns and less (about 1.5) in the slower turns. I don't doubt the numbers given I should be getting a lot more downforce at higher speeds and am running pretty wide slicks. Once I get the software sorted out from the MoTeC, I'll be able to directly compare the Traqmate and the MoTeC data that I acquired a week ago.
I've been using a Traqmate for a year and it shows that I pull up to 2.0 g's in the high speed turns and less (about 1.5) in the slower turns. I don't doubt the numbers given I should be getting a lot more downforce at higher speeds and am running pretty wide slicks. Once I get the software sorted out from the MoTeC, I'll be able to directly compare the Traqmate and the MoTeC data that I acquired a week ago.
#6
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G meters are accurate if your car has zero body roll and the road is perfectly flat.
For every degree of body roll you have to subtract .111 G's. It doesn't take much body roll to make a big difference in the reading. A mere 5 degrees in body roll can account for a LOT of inaccuracy. This is assuming that if you turned your G sensor on it's side it would read 1G (the reading that 'gravity' would be).
For changes in the angle of the track I don't have the mathematical patience to figure out what you need to subtract/add depending on the angle of the track.
The G meter in your AIM system is not GPS based.
For every degree of body roll you have to subtract .111 G's. It doesn't take much body roll to make a big difference in the reading. A mere 5 degrees in body roll can account for a LOT of inaccuracy. This is assuming that if you turned your G sensor on it's side it would read 1G (the reading that 'gravity' would be).
For changes in the angle of the track I don't have the mathematical patience to figure out what you need to subtract/add depending on the angle of the track.
The G meter in your AIM system is not GPS based.
#7
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Thread Starter
Of course you are correct Joe, it is just part of the AIM MXL and has nothing to do with the GPS itself, yes? I was just curious about it but it isn't one of the important data points for me to look at right now anyway. I'm more concerned with braking, throttle application, speed and RPM.. here is an article on braking data I was just directed to by Jerry Austin, good info.
http://www.optimumg.com/documents/te...e_tech_tip.pdf
http://www.optimumg.com/documents/te...e_tech_tip.pdf
Last edited by Gary R.; 04-07-2008 at 10:55 PM.
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#8
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Of course you are correct Joe, it is just part of the AIM GPS Module and has nothing to do with the GPS itself, yes? I was just curious about it but it isn't one of the important data points for me to look at right now anyway. I'm more concerned with braking, throttle application, speed and RPM.. here is an article on braking data I was just directed to by Jerry Austin, good info.
http://www.optimumg.com/documents/te...e_tech_tip.pdf
http://www.optimumg.com/documents/te...e_tech_tip.pdf
Did you go with a brake pressure sensor or the on/off brake sensor?
#9
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Thread Starter
Here is a picture of me playing around with it..
#10
Nordschleife Master
Gary, ideally, if you use 1 g-sensor, you will want to place it at the CG of the car. Since you have a built in unit, it will be a compromise, however, 1.3g is not unusual for West Bend. My car with slicks is 1.7g through West Bend. If you install 2 g-force sensors, you'll put them on the wheel centerlines.
#11
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Thread Starter
Thanks Geoffrey. I'm amazed at all the different ways there are to look at the data and just how much data there is to look at now! Hopefully by next week end at Summit i'll have it pretty well squared away and get some good stuff to study. Right now my biggest question, believe it or not, is how to set a virtual S/F Beacon in the GPS at the track to get lap times, Forecasts, etc.!! The runs at Limerock are porked, whole runs are counted as a "lap".. I plan on calling AIM today but Roger C. and Jerry A. have been extremely helpful..
#12
Nordschleife Master
I would use the beacon for lap timing. GPS is good for speed and relative position, but I think the beacon is more accurate for timing. Also, be aware of your GPS refresh rate, it can limit the sampling frequency and depending on what you are measuring may not show you the entire picture.
#13
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Thread Starter
I would use the beacon for lap timing. GPS is good for speed and relative position, but I think the beacon is more accurate for timing. Also, be aware of your GPS refresh rate, it can limit the sampling frequency and depending on what you are measuring may not show you the entire picture.
#14
Drifting
I thought DE events did not allow timing? That is what would compell me to purchase the GPS extension for my MXL Pista. You probably know this already, but at Club Races, you will definitely pick up signal from one of the 10+ beacons placed track-side - no need to bother setting up yours.
#15
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I thought DE events did not allow timing? That is what would compell me to purchase the GPS extension for my MXL Pista. You probably know this already, but at Club Races, you will definitely pick up signal from one of the 10+ beacons placed track-side - no need to bother setting up yours.