32 replies to this topic

[Tom Hampton]

<br />55 to 73 is a huge delta. I can't see that just being a change in technique. Sounds more like you were not warmed up to the car/track in the morning more than any particular technique. I'd get warmed up in a session later in the day and then do a few flyers with hard braking, then a cool down, then a flyer or two with easier braking, then a cool down, and one last flyer with hard braking and then compare the speeds/times. If you start comparing your technique times from your first session to your last I think you'll draw some improper conclusions,. (IMHO of course.)<br />

I wouldn't have called it a "technique" change, but rather more of an epifany that the turn could handle more speed than I'd felt. That realization was precipitated by the earlier/lighter braking. I use the word FELT above, on purpose, as opposed to THOUGHT. Another change I made was to switch the secondary display on my G2X to MPH from some other random data channel. So, now I have "predictive lap time" and "MPH".

So, the evolution of the change was driven by:

1. A similar change I was already making in another corner for different reasons that gave me a better sense of what the car could handle.
2. Experimenting with applying that change to this corner
3. Having MPH available to see the immediate effect on speed, and predictive to see the ultimate benefit.

So, in essence I think you are right, it was more about warming up to the car/track. But, the warmup was more fundamental than limited to "that day"...but, was really me learning some new limits to the car that I previously didn't know.

I'm new. I've driven on a track at speed 5 times. Once in a 220HP turbo 1990 Miata; once in a rented SM; three times in my own car. This was my second time in my own car to drive this configuration. I still have lots of "fundamentals" to learn. Some come in great revalations like this one.

[Jim Boemler]

You're lucky you're getting this epiphany so early, Tom. I had much the same experience years after I was racing. I was leading a good friend into a corner, when he unexpectedly hit me -- hard. He just wasn't the sort to do such things, and I didn't understand. Back in impound he apologized, explaining that he just never expected me to slow so much for the corner! It was a huge wake-up call.

I too keep an eye on the speedo, out of most turns. It gives me an instant indicator of improvement. I did get an opportunity to use predictive lap time once, but I don't have it on my own car. Nice feature, but I never came to lean on it.

[Todd Green]

I'm new. I've driven on a track at speed 5 times.

Gotcha. A couple of ideas come to mind:

1) Work a corner backwards to learn it. Never start with late braking. Start by working out how to track out getting the line down to where you are getting on the throttle as early as possible without lifting or scrubbing speed with the wheel. (Assuming the typical corner leading on to a straight.) Then work on mid corner speed, then entry speed/line, and finally you work on braking.

2) Have you considered autoxing? It is a great way to learn the limits of your car with little commitment/risk. If you are in a smaller region where you can get a lot of runs and you have a large area to set a course, it is great. If you are in a large region where you only get 3 runs in a day or have a small lot where you cannot get high speeds, it might not be worth the time. Something to consider for "off" weekends.

[HoneyBadger - BrianW]

Tom, it would be helpful if you found someone that also ran SM and do some lead follow. If I am at an event with you, hit me up and I will hop into your group and we can work on ratching the speed up. I never learn better than when I am following someone just a little bit faster than me around.

[Keith Novak]

Sounds about right. On one corner of my home track, I've picked up significant speed going from about 85 to sometimes 95 at my fastest recorded (successful) laps. Some of that was just getting comfortable with the fact that it would seem a bit dicey but the tires and track would still be there at the exit.

Street tires also have a much wider range at the grip limit unlike R-compounds that build to higher grip but drop off more rapidly once past the limit. (One good reason to get on those RA-1s so you learn the behaviour difference.) Where the street tires start to slide and make angry sounds, there's still much more left over before they let go completely. If I can pick up 10+ mph on RA1s realizing the car could handle more than I thought, 18 on street tires isn't shocking.

As a ghetto example of smooth, comfortable and consistent = speed: during the final stint of a 24hr chump car race on awful street tires, my goal was to conserve fuel and drive the final 2 hours without stopping. After 3 long stints on the course, a long double yellow convinced me I had plenty of fuel left. I decided to step up the pace a bit. Not too fast but have fun and enjoy the end of the race. Next thing I know, I look down and I realize I have more than 40 min to go with less gas than I'd use for a 20 min SM session. I didn't realize I was setting very quick laps within a tenth or hundredth of one another sucking down gas like mad but since I had become smooth enough that there wasn't any drama occurring and comfortable at that speed, it didn't feel that fast. Even after backing way off to what seemed a painfully slow pace, less throttle on the straights meant less brake needed for the corners and I still didn't slow as much as I would have thought.

[Tom Hampton]

Brian - Yeah, I was over at chris's yesterday talking about paint. Got some takeoffs and a similar offer from him. It will be interesting to see how things look with similar rubber.

I'm planning to do every apex and ecr track day this year... business trips allowing... and, anything else local i can find, between now and superschool in December. until I sort out the tow rig its hard to get south to the other tracks.

Keith and todd and jim- thanks for the feedback. This Site gets most of the credit for any early learning i may demonstrate. All I can do is learn from the experience of others, and try and get up on the curve faster.

I mentioned this in another thread, but I took the time a few months ago to read the entire specmiata.com forum from day one to last December. It's amazing how much information is there. I wish there were a way to collate that into a more useful resource. Everything is there.

[Tom Hampton]

PS, i did consider autox, but around here you can get on a real racetrack almost every weekend if you have the time and money. Correct me if I'm wrong, but track time seems better than autox time. In other words i shouldn't sacrafice track time to go autox.

[Todd Green]

Correct me if I'm wrong, but track time seems better than autox time. In other words i shouldn't sacrafice track time to go autox.

If I could only do a few events a year, there's no doubt I'd hit the track. You are talking hours of seat time, versus minutes and you don't have to shag cones in the hot sun. I do think that autox is an excellent tool for learning to look ahead, car control, and how to learn a track quickly since you only get 3 runs/laps at National events. Plus it's cheap competition which most of us crave. But at your stage, I'd only do it if the choice was no driving at all vs autox.

[Tom Hampton]

Gotcha. A couple of ideas come to mind:

1) Work a corner backwards to learn it. Never start with late braking. Start by working out how to track out getting the line down to where you are getting on the throttle as early as possible without lifting or scrubbing speed with the wheel. (Assuming the typical corner leading on to a straight.) Then work on mid corner speed, then entry speed/line, and finally you work on braking.

Yes, I've read and been given that advice before. As with everything else, it takes a few times on the track to translate the compactness of that statement into the actual meaning while on the track. I've found my exit speeds to be very consistent: within 1/2 - 1 mph, even with the difference in entry speed. What I see in the slower entries is a droop in mph (55), and then acceleration through the corner (65 at apex). By the time the trackout point is reached both speeds have nearly equalized (7-72-73).

On the faster entry variant, speed falls to 72-73, and then is mostly maintained through the corner and essentially holds steady to trackout...still at about 72-73...even though I'm WOT the whole time.

I did learn that when my entry speed is that much closer to the grip limit, it does require more smoothness on turn-in. It feels more like setting the car down into the turn, instead of turning the wheel and actually turning the car. Almost the same mental "feel" of trying to set something down on a hard surface without making a noise.

Another suggestion that I got was to have Keith Verges drive my car in the last session (he owns the school, and teaches the advanced group). I was going to, but I couldn't find him (or my own instructor) before the session started. It would have been cool to have data from a pilot like that in my car. Maybe next time.


Enduro's sound pretty fun, and like a great way to get a LOT of track time.

[Randy Thieme]

Tom,

Back to your original questions. The noise does not seem that bad compared to what I've seen. When the Caddell's still had their VictoryLaneData.com website up they had some of Andrew's data freely available. I saw just as much noise in their data as what I'm seeing in yours. The higher the rate of sampling the more of the fine noise. If you've got the sampling rate up high (like 50 hz) you could experiment with a lower rate like 20 hz, or even 10 hz. Personally I don't like anything lower than 20 hz.

[Tom Hampton]

Thanks, Randy. I haven't changed the sample rate from the default. I'm not sure what that is, but I remember it being pretty high. Possibly 100Hz for the accelerometers.

Another instance where having data from a good pilot driving my car would be useful, to sort out normal from bad-habit.

[Todd Green]

Another suggestion that I got was to have Keith Verges drive my car in the last session (he owns the school, and teaches the advanced group).

Definitely get a hot shoe in the car if you can. Be sure to video as well as record the data and, if you can, talk to him in person about his comments on the car's setup etc.

[Keith Novak]

Worth noting since I brought it up earlier and found the answer... Turns out the data showing my car turned much better right than left was just the data.

I compared some data from last year to today and saw that in a straight line, one showed zero, the other a couple 10th of G's. Not sure but I suspect it's that I installed the logger with the car sitting on a sloped garage floor and a somewhat random suspension setup. After suspension tuning, it probably now thinks my car is slightly tipped when it's sitting flat which makes it think I'm going slightly sideways.

At least I know it's not the car.