Gary R.

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.

Larry Herman

Obviously not very.

AllanJ

You have to ignore the instantaneous spikes in G-forces. Go by the average over a short range for better accuracy.

Cheers,

Gary R.

Nice shot Larry!
Actually I was looking at segments and got the map twisted.. I corrected it above. In West bend it was a high of 1.3.

Tom W

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.

Circuit Motorsports

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.

Gary R.

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

Circuit Motorsports

The G sensor on the AIM MXL is in the dash unit itself. Part of the reason you want a good mouting system that is 'correct'.

Did you go with a brake pressure sensor or the on/off brake sensor?

Gary R.

Ahh, got it.. It is mounted on a very strong plate on the column, 0 movement. I have the pressure sensor, which currently has a baseline of 500 PSI and I have hit just under 2000 PSI under hard braking. My Gas pedal sensor also needs to be re-zero'd as it starts at 55% and tops at 100%.

Here is a picture of me playing around with it..

Geoffrey

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.

Gary R.

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..

Geoffrey

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.

Gary R.

I would use the Beacon but with each region having it's own policy on placing it out there it's a PITA.. I'll have to see if Potomac will allow one at Summit on 4/12, i'm assuming PDA will at Limerock on 4/19...

FredC

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.

Gary R.

Yep, at some events there is one out there already, even at DE's. There is no set rule on self-timing, but a DE can not be a "Timed Event", meaning the Region itself is forbidden to time it. Some regions forbid the placement of transmitters, some don't.. NNJR is one I know that won't let you put one up...