I just posted this, but the forums crapped out, so hopefully this won't be a repost.

Anyway, I was at an AutoX last weekend, and one of the guys had a G-Timer and a laptop. The G-Timer can record 5 minutes of data, so he'd hook up a car and then download the data after its run. I was one of the cars lucky enough to get logged, so here are my results.

The G-Timer will output the following:
Time (1/1000 sec in 0.025 sec increments)
Forward Acceleration
Lateral Acceleration
Velocity
Distance
HP

All that data was incorporated into Excel, and then you can do pretty much anything you want to it. Attached are some charts that the owner of the G-Timer made for my runs (two laps back to back, so you'll see the second lap start @ just befor the 60 second mark). I was running Kumho V700's 265/35-18 on 18x8" Enkei RPO2-J's. The rest of the car is stock. I was able to pull about 1.15G in steady state cornering, but peaked at about 1.29G in a quick switchback.

-D'oh!

 

Posting image separately this time so I don't have to type everything over....

D!

 

Close up of another chart showing combined forward and lateral acceleration (ForwardG^2+LatG^2)^1/2

-D'oh!

 

So now you have lots of charts... just like F1 team!
What the practical use?

 

With the mushroom'd shaped chart, one would look for equal symetry about the left and right axis (ie: possibiliy of corner balancing issues). It also helps to show where potential weaknesses are in the transition from one load to another. Smoothness of the lines (ie: no jerkyness) could also indicate better driving technique.

Of course, the conditions of the pavement and the actual layout of the course must be taken into consideration. It would be interesting to compare the same driver/car on different courses and venus.

Overall, it's one of the better charts I've seen out there D'oh! Good work.

 

sweet. that's really awesome!

 

Well, I was able to spend an hour or two @ work staring at the computer. I'd say that's practical, dammit!

I can't take credit for the charts, since the other guys made them and then sent out the spreadsheet. They are cetainly cool though.

Actually, here's some practical use for you:
1. In second gear the Z will accelerate @ about .4 G's
2. You can see that there are many instances where I am rolling into the throttle perhaps a little slowly, maybe because I did not set myself up properly in the previous corner. 74-78 seconds was a straight, and you can see that I was coming onto the throttle a bit slowly because I was still turning. Maybe if I had let off a bit earlier in the corner I could have hit the gas a bit sooner and had a bit more speed through the straight.
3. You can see that I am able to brake @ about .9g's or so, yet there are only a couple spots where I can reach those deceleration levelt. It's true that most of this track was curvy, so I couldn't brake while going straight, but at the same time it looks like even when I did hit peak decel I kinda crept up on it. Maybe hitting the brakes a bit harder would have made a difference.

Anyhow, here's a chart from a guy with a Gen1 rx-7 on street tires. I beat his time, but notice that he seems to be much more consistently at the limits. Might be partially the car, but probably also quite a bit because of the driver. Notice how rapid he transitioned from accel to braking. I'm not saying that slamming on the brakes is the way to go, just that I could probably transition a bit faster.

Really though, it's just another fun topic to discuss, and play around with. It's kinda cool for me because I can look at the graphs and know where that was on the track. Definitely not as fun for you guys I guess.

-D'oh!