My '86 GTI build

[sachilles]

The gps data logging I've done tends to be real interesting to look at, but I haven't really been able to put to good use to improve at a particular event as the conditions change somewhat on the next visit to the venue(or an autox course which isn't repeatable).
Now if I can actually keep my car on the road for a full season, I might have a better data set to work with. What I find the most useful at non autox/rallyx venues is breaking up the course into smaller segments; Hopefully finding when I get a particularly good segment time that I can look at the data and see what I did right(along with the video).
What I find is that when I drive one segment better than I had previously, I end up screwing up the following segment negating any time savings overall....so without the segment timing if I just looked at my run time, I get frustrated by the lack of overall improvement and may abandon what may have been a quicker strategy.
The biggest thing for me is to get a better idea on the difference between what feels fast and what IS fast. So for me, I tend to use the data logging to see that there is a difference in time, rather than to dissect why that time is better.
This is a sample from my old data logger.
I have a new android based one this year, that should give me better feedback in a more timely manner, that I'm eager to use, providing I keep my car in one piece this year.

[sachilles]

oh....forgot to mention that grassroots motorsports mag is doing a series on datalogging etc. I'm not sure if that is among your reading list or not, but it's worth a read.

[walterclark]

oh....forgot to mention that grassroots motorsports mag is doing a series on datalogging etc. I'm not sure if that is among your reading list or not, but it's worth a read.

In fact that is what got me thinking. In particular how I handle coming into braking, carry speed and accelerate out of it at corners. The speedo log (versus time) should give me a good picture of what I am doing at various places on the hill and I can work to waste less time in critical spots.

[walterclark]

I can't follow the link to the camera from work.... what is the FPS at 1080?

30 fps at 1080p. It also has 30 and 60 fps at 720P plus a 960P and WVGA (60 fps). Its obsoleted all my mid-2000 home computers and laptop with XP - none can play the 1080P or 720P/60 in the native .mov without lots of skips and jerking.

[Rabbit Farmer]

So that is pretty much the same as the gopro. I run the wide 720 at 60 fps. I tried the 1080 at 30 and it was jerky on one of the runs (missed a lot).

[walterclark]

This is an example of the data I currently log. This is the Start into turn 1 at Okemo.


I know its a little hard to decipher in this small size, but if you look at the blue line (coolant temp) you can see that unless I make some cooling system change or start having heating issues, the data isnt interesting. I can do a good bit with what I collect. For instance I can filter the data (smoothing), hide any traces I want to focus on certain things, and even add a math operation to the data and display the result. So I think capturing vehicle speed is going to much more useful to me. While I dont have a parallel GPS log to be able to do the kind of (where was I on the road and what were the G forces) analysis one can clearly see with loggers like Traqmate or the MaxQdata, by applying the speed analysis techniques discussed in the GRM article I think I can identify places where I am braking early, not fully or too much, and where I am not committed enough to the throttle in short turns. I have already used the CTS drive voltage (yellow trace), for driving performance purposes it indicates when I am below WOT (trace drops to the straight horizontal line) to identify where I am lifting and probably dont need to - my in-car camera also picks up WOT on/off and is a big help.

[walterclark]

You know it just occurred to me that we dont have a topic anywhere dedicated to capturing and analyzing performance data as it relates to opportunities for improving our times.

I know I watched James M. upload and analyze his onboard data a number of times in the past. And I regularly study my in-car video looking for opportunities and mistakes (I have a small panel visible to the camera that has a WOT light, shift light and brake light).

I would bet there are a number of folks who have data gathering ability, have done analysis and learned from it. Maybe we should have a thread for people to share and learn from this stuff...

[STI NICK]

I was planning on ordering the Contour camera before Ascutney. Seemed like a good deal. I thought about getting the gps version, but wasnt all that crazy about the limitations of it.

[walterclark]

I was planning on ordering the Contour camera before Ascutney. Seemed like a good deal. I thought about getting the gps version, but wasnt all that crazy about the limitations of it.

Yes, I read some comments and of some in use issues with the GPS version on the Contour forums. It was also outside my target price range (I would have been happy with the even cheaper non-1080p version of the ContourHD but they were all gone before I ordered). It also occurred to me that the GPS might not work very well mounted inside the car behind and centered between the front seats. There are enough GPS issues at a mountain (with half of the prime sky for satellites blocked by the mountain itself) already. And there is no provision on the camera for an external antenna if that wer needed.

The camera part is void of some things that at first seem like a problem but in my use are not.

- It has no viewfinder or monitor screen so setting the camera up could be an issue. Since it will sit in the same spot in my car all the time and doesnt need to be removed for anything, that is not a problem for me.

- The only way to provide external power to the camera while in use is with the water resistant rear cover opened. I addressed this by cutting a square port in that cover to permit a custom mini-B plug to be plugged in with the cover in place. Contour sells a spare rear cover for anyone doing this and wanting to still have a bone stock camera to use for other things where a hole might be a problem. Note that a regular USB mini-B cable will not let you power and record (power to charge or power and download, yes). Contour uses a jumper between the unused mini-B pin 4 and the standard 5V pin 1 to tell the camera it is connected to a "power only" cord and it is OK to record. The Contour DC power cable comes with a cigarette lighter plug on one end and the mini-B on the other and is fine except the mini-B plug has the typical large over-moulding on the connector body and the hole cut in the back cover needs to be quite large to fit this with the back in place. I made up a power cable using a new mini-B plug which I covered only using shrink tubing so the hole is much smaller. Why would this matter? Well you have to look at the camera to see this but the mini-B jack isnt very far from the power on/off switch and when using the Contour cable it is almost covered by the connector over-mould. Worse yet, most of the rubber "power on button" on the back cover has to be cut away if you want to use it with that cover in place. My version does not interfere with the rubber "power on button" on the rear cover.

- The camera comes with a couple mounts that are intended for helmets, goggle straps and the like but arent really rigid enough for motorsports. They sell a tripod adapter which I also got - it is sometimes included in retail packages aimed at motorsports by places like IO Port Racing. The tripod adapter allows the camera to be mounted so that it is quite solid.

I havent really "used" it yet for racing so how it works for me is still TBD but I really love a few things about it.

- The large record switch is very easy to use even with gloves and no ability to look directly at the camera. It has a front mounted ON/Record light to confirm it is really on and running from the rear view mirror.

- The little micro-SC card can be removed without removing the camera from its tripod mount to download or swap and it offers that mini-B connection to download without removing the card or for changing camera settings.

- It supports up to 32GB micro-SDHC cards (though I settled on 16GB because they are a better deal right now) which gives lots of record time.

[sachilles]

My suggestion is to go with a stand alone bluetooth gps, that has the datalogging/recording ability in it. They can be had for less than $100, you can then mount it anywhere you like to get a clear view of the sky.
Something like this http://cgi.ebay.com/ebaymotors/GPS-Lap- ... arQ5fParts
It allows you to log the data an analyze after the fact, but the bluetooth will allow you to connect with something like maxqdata and trackmaster that supports bluetooth gps. So you can mount the gps where ever works best. Download the data after the fact, or integrate it with a smartphone app for realtime display.

I think a big key is looking at the data while the run is fresh in your mind.