Data Aquisition Question
12-26-2006, 01:50 PM
#31
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LOL... of course then, after complaining about resolution... I realize I can just zoom in Word! Duh.
Thanks for the added detail - sounds like rovals can be a whole lot more technical than I'd imagine! (confession time, I've never run one)
Yeah, that last complex is rather... well, complex! It's pretty tough to make any further statements about line or technique beyond that already discussed - without having seen the lay of the land. The things in your trace that do appear perplexing to me are the additional speed loss on the first LH turn there - but that may be a case of trying to optimize entry speed (since it's at the end of the straight) rather than exit speed - and the reduced lateral on the 2nd RH turn... it's not so low as to suggest a kink during an acceleration run, yet it's not quite max-lat as capable/shown for the tires. OTOH, since you're transitioning from WOT accel on a RH turn to braking corner entry for a LH turn - you may be all used-up there!
I guess the only thing I might wonder about trying would be a softer/lazier approach through that RH'er that would allow a faster line through the two LH-ers subsequent. All with the goal of getting on the gas sooner for the two LH turns. Though it seems that you don't have any need to lift to make the second one?
Hmmm... Here's another question. Exiting 10 you're up on the banking... I see a slight loss of speed, such as might be associated with a shift. Yet accel before and after seems about the same, and I also see a late simultaneous blip of lateral. Is this another, more subtle example of a slight oversteer, or is there something else going on with the car here, like loading/unloading on the banking?
Thanks for the added detail - sounds like rovals can be a whole lot more technical than I'd imagine! (confession time, I've never run one)
Yeah, that last complex is rather... well, complex! It's pretty tough to make any further statements about line or technique beyond that already discussed - without having seen the lay of the land. The things in your trace that do appear perplexing to me are the additional speed loss on the first LH turn there - but that may be a case of trying to optimize entry speed (since it's at the end of the straight) rather than exit speed - and the reduced lateral on the 2nd RH turn... it's not so low as to suggest a kink during an acceleration run, yet it's not quite max-lat as capable/shown for the tires. OTOH, since you're transitioning from WOT accel on a RH turn to braking corner entry for a LH turn - you may be all used-up there!
I guess the only thing I might wonder about trying would be a softer/lazier approach through that RH'er that would allow a faster line through the two LH-ers subsequent. All with the goal of getting on the gas sooner for the two LH turns. Though it seems that you don't have any need to lift to make the second one?
Hmmm... Here's another question. Exiting 10 you're up on the banking... I see a slight loss of speed, such as might be associated with a shift. Yet accel before and after seems about the same, and I also see a late simultaneous blip of lateral. Is this another, more subtle example of a slight oversteer, or is there something else going on with the car here, like loading/unloading on the banking?
12-26-2006, 02:20 PM
#32
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Hmmm... Here's another question. Exiting 10 you're up on the banking... I see a slight loss of speed, such as might be associated with a shift. Yet accel before and after seems about the same, and I also see a late simultaneous blip of lateral. Is this another, more subtle example of a slight oversteer, or is there something else going on with the car here, like loading/unloading on the banking?
Thanks for the analysis!
12-26-2006, 02:26 PM
#33
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The #1 reason I don't ever want to run on a roval! 
Cheers, hope you can return the favour... wink wink...
Cheers, hope you can return the favour... wink wink...
12-26-2006, 03:38 PM
#34
Drifting
For those interested, the last 3 issues of RaceTech magazine have featured a series of articles on affordable DA systems for club racers (racetechmag.com). They compared many of the popular options and chose the DL1 for the series but the info in the articles can be applied to virtually any system.
Another consideration when comparing DA units is the cost of the sensors, they vary greatly depending on which system you buy and on some systems adding TPS, steering, and brake pressure nearly doubles the cost. I'm looking forward to seeing the AIM GPS based system and how it compares to their current products.
Another consideration when comparing DA units is the cost of the sensors, they vary greatly depending on which system you buy and on some systems adding TPS, steering, and brake pressure nearly doubles the cost. I'm looking forward to seeing the AIM GPS based system and how it compares to their current products.
12-26-2006, 06:18 PM
#35
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Originally Posted by kary993
Your last sentence could be interpreted a few different ways though my initial thought was you are having difficulty with your stack system, is that what you are saying?
In terms of what I was trying to show folks here is that an oversteer condition shows itself with a GPS based system. The upper graph showing lateral G load and MPH shows an increase in G's and a lose of MPH at the point where the cursor is. The lower right graph which is magnified shows the driving line which takes an abrupt right turn not because it is a turn but because the car is over steering. Drinving line and car attitude change which is picked up bythe GPS based unit. The graph on the lower left shows the overall track position.
While this is not a definitive method to tell when a car is over or under steering all the time (smaller correction of the chassis) it does show that these "less expesnive" units can display some of the characteristics of the much more expensive units.
I know that the resolution of the pic I posted might be hard to see though it is easily seen when using the analysis software directly.
In terms of what I was trying to show folks here is that an oversteer condition shows itself with a GPS based system. The upper graph showing lateral G load and MPH shows an increase in G's and a lose of MPH at the point where the cursor is. The lower right graph which is magnified shows the driving line which takes an abrupt right turn not because it is a turn but because the car is over steering. Drinving line and car attitude change which is picked up bythe GPS based unit. The graph on the lower left shows the overall track position.
While this is not a definitive method to tell when a car is over or under steering all the time (smaller correction of the chassis) it does show that these "less expesnive" units can display some of the characteristics of the much more expensive units.
I know that the resolution of the pic I posted might be hard to see though it is easily seen when using the analysis software directly.
The resolution on your pic is probably the issue for me to see it on your chart. anyway, i don't have gps on the stack. all the best
HA HA HA
12-26-2006, 08:15 PM
#37
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Thanks to everyone who responded so far. Looking at all of the systems available is making my head spin. 
I want to cut to the chase and that is simply that I feel that my car is well setup, and for the most part, more speed is to be found behind the wheel. Here are 2 examples of what I want to learn:
1) Entering a midspeed corner, would it be better to carry a little more speed into the corner with an earlier line, hug the apex a little (later braking with better early corner speed) and then get back on the gas carrying the same exit speed, or brake a little more and turn the car in a little harder and later, getting on the throttle much sooner and accelerating harder through the turn?
2) Entering a high speed corner, would it be better to brake briefly, downshift and accelerate throught the corner, or braker longer and more gently, floating the car through in a higher gear, but with less acceleration?
The only way I can truely analyse these scenarios is with accurate sector times. Exit RPMs only tell half the story. Plus, it would be of great benefit to see what I am doing, i.e. video, and to be able to narrate as I go along. The only caveate is that I don't want to sell myself short; that I am able to really get on top of the equipment only to find that it is too limiting.
I want to cut to the chase and that is simply that I feel that my car is well setup, and for the most part, more speed is to be found behind the wheel. Here are 2 examples of what I want to learn:
1) Entering a midspeed corner, would it be better to carry a little more speed into the corner with an earlier line, hug the apex a little (later braking with better early corner speed) and then get back on the gas carrying the same exit speed, or brake a little more and turn the car in a little harder and later, getting on the throttle much sooner and accelerating harder through the turn?
2) Entering a high speed corner, would it be better to brake briefly, downshift and accelerate throught the corner, or braker longer and more gently, floating the car through in a higher gear, but with less acceleration?
The only way I can truely analyse these scenarios is with accurate sector times. Exit RPMs only tell half the story. Plus, it would be of great benefit to see what I am doing, i.e. video, and to be able to narrate as I go along. The only caveate is that I don't want to sell myself short; that I am able to really get on top of the equipment only to find that it is too limiting.
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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.
12-26-2006, 09:14 PM
#38
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Larry,
A GPS based system can do what you want to do. The G2X or the G2XPro can accomplish this. Depends upon how much you want to spend up front and how far you really want to go. There is a lot to learn with a basic unit like the G2X. What you outlined the basic G2X can accomplish.
Want more, try a G2XPro with higher sampling rates and more sensor capability. Not sure you want to go that far, that is the beauty of the G2X. Most folks just stay at the G2X basic that I have seen. Takes a lot of time, money, and energy to go past the basics. Just depends upon what you want.
You know where I am if you want a G2X or G2XPro......
A GPS based system can do what you want to do. The G2X or the G2XPro can accomplish this. Depends upon how much you want to spend up front and how far you really want to go. There is a lot to learn with a basic unit like the G2X. What you outlined the basic G2X can accomplish.
Want more, try a G2XPro with higher sampling rates and more sensor capability. Not sure you want to go that far, that is the beauty of the G2X. Most folks just stay at the G2X basic that I have seen. Takes a lot of time, money, and energy to go past the basics. Just depends upon what you want.
You know where I am if you want a G2X or G2XPro......
12-26-2006, 10:22 PM
#39
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Larry,
I you want some highly experienced and unbiased opinions about systems, I suggest you call Ellen or Dave Ferguson at Veracity Racing Data (408) 732-6606. They have been doing data aq systems for some years and are the only dealer I know who sell almost all systems (AIM, MoTeC, Pi, SPA, Stack, Race Technology and others). Since they represent so many different brands, they do not have the agenda of selling only the one brand they offer.
I you want some highly experienced and unbiased opinions about systems, I suggest you call Ellen or Dave Ferguson at Veracity Racing Data (408) 732-6606. They have been doing data aq systems for some years and are the only dealer I know who sell almost all systems (AIM, MoTeC, Pi, SPA, Stack, Race Technology and others). Since they represent so many different brands, they do not have the agenda of selling only the one brand they offer.
12-27-2006, 04:01 AM
#40
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Larry, there are 3 ways to to best answer your two questions.
1) I would suggest looking at section times of the corner in question and the straight after to corner combined. This should tell you which method is faster. This might be the fastest sure way to accomplish your task.
2) If you had a system that did a time/distance variance you could graph the speed of each method and see where exactly the time is gained or lost. This would give you the most information about where, how and why one is faster.
3) You could log and look at lap gain/loss otherwise known as a predicted lap timer, this would tell you which line is faster or slower. This has the advantage of being able to tell you while you're driving for instant feedback.
But to be correct in your analysis, you must test the test as Claude Roulle would say. That is you must do multiple laps with each method, not just one lap for each line. I recommend doing 5 laps one way, then 5 laps the other.
As far as what the best system is for you? Whatever you can afford. If cost is the biggest concern, then I would recommend a proper racing school like Russel or something. If you've never been, then that's the biggest bang for your buck in trying to lower your lap time. Get used to driving a formula car, then when you go back into a production car you'll be twiddling your thumbs with so much spare time to think while driving
1) I would suggest looking at section times of the corner in question and the straight after to corner combined. This should tell you which method is faster. This might be the fastest sure way to accomplish your task.
2) If you had a system that did a time/distance variance you could graph the speed of each method and see where exactly the time is gained or lost. This would give you the most information about where, how and why one is faster.
3) You could log and look at lap gain/loss otherwise known as a predicted lap timer, this would tell you which line is faster or slower. This has the advantage of being able to tell you while you're driving for instant feedback.
But to be correct in your analysis, you must test the test as Claude Roulle would say. That is you must do multiple laps with each method, not just one lap for each line. I recommend doing 5 laps one way, then 5 laps the other.
As far as what the best system is for you? Whatever you can afford. If cost is the biggest concern, then I would recommend a proper racing school like Russel or something. If you've never been, then that's the biggest bang for your buck in trying to lower your lap time. Get used to driving a formula car, then when you go back into a production car you'll be twiddling your thumbs with so much spare time to think while driving
12-27-2006, 09:15 AM
#41
Nordschleife Master
You'll need to look a why a section was faster, and for that you'd need a fairly high sampling rate to see what you are doing with the brakes, steering, accelerator, and what the car is doing wheel speed, lat/long acceleration. With that data, you can see if you are maximizing your braking, to see if your reaction time is fast (in the .2sec range), etc.
12-27-2006, 09:44 AM
#42
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Originally Posted by cbracer
2) If you had a system that did a time/distance variance you could graph the speed of each method and see where exactly the time is gained or lost. This would give you the most information about where, how and why one is faster.
As far as what the best system is for you? Whatever you can afford. If cost is the biggest concern, then I would recommend a proper racing school like Russel or something. If you've never been, then that's the biggest bang for your buck in trying to lower your lap time.
12-27-2006, 09:50 AM
#43
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Originally Posted by cbracer
Larry, there are 3 ways to to best answer your two questions.
1) I would suggest looking at section times of the corner in question and the straight after to corner combined. This should tell you which method is faster. This might be the fastest sure way to accomplish your task.
2) If you had a system that did a time/distance variance you could graph the speed of each method and see where exactly the time is gained or lost. This would give you the most information about where, how and why one is faster.
3) You could log and look at lap gain/loss otherwise known as a predicted lap timer, this would tell you which line is faster or slower. This has the advantage of being able to tell you while you're driving for instant feedback.
But to be correct in your analysis, you must test the test as Claude Roulle would say. That is you must do multiple laps with each method, not just one lap for each line. I recommend doing 5 laps one way, then 5 laps the other.
As far as what the best system is for you? Whatever you can afford. If cost is the biggest concern, then I would recommend a proper racing school like Russel or something. If you've never been, then that's the biggest bang for your buck in trying to lower your lap time. Get used to driving a formula car, then when you go back into a production car you'll be twiddling your thumbs with so much spare time to think while driving
1) I would suggest looking at section times of the corner in question and the straight after to corner combined. This should tell you which method is faster. This might be the fastest sure way to accomplish your task.
2) If you had a system that did a time/distance variance you could graph the speed of each method and see where exactly the time is gained or lost. This would give you the most information about where, how and why one is faster.
3) You could log and look at lap gain/loss otherwise known as a predicted lap timer, this would tell you which line is faster or slower. This has the advantage of being able to tell you while you're driving for instant feedback.
But to be correct in your analysis, you must test the test as Claude Roulle would say. That is you must do multiple laps with each method, not just one lap for each line. I recommend doing 5 laps one way, then 5 laps the other.
As far as what the best system is for you? Whatever you can afford. If cost is the biggest concern, then I would recommend a proper racing school like Russel or something. If you've never been, then that's the biggest bang for your buck in trying to lower your lap time. Get used to driving a formula car, then when you go back into a production car you'll be twiddling your thumbs with so much spare time to think while driving
It was good to see you and I am glad to see an expert like you chime in on the data aq discussions here.
12-27-2006, 09:51 AM
#44
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Originally Posted by Larry Herman
I think that's pretty much what I am looking for. I think that at my point now, I am looking for a tenth or 2 in a corner.
Thanks, but I think that I am beyond some of the instruction that is offered in those schools. Plus I want car specific knowledge. I went to the Akin-White school in 1990 in Sebring. I was the fastest one there; faster than the instructors and set the record for their school. Maybe some on-on-one with a pro would offer pointers, but I am not unwilling to try new lines, techniques, etc. on my own, I just need to know if they work.
Thanks, but I think that I am beyond some of the instruction that is offered in those schools. Plus I want car specific knowledge. I went to the Akin-White school in 1990 in Sebring. I was the fastest one there; faster than the instructors and set the record for their school. Maybe some on-on-one with a pro would offer pointers, but I am not unwilling to try new lines, techniques, etc. on my own, I just need to know if they work.
12-27-2006, 09:56 AM
#45
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Originally Posted by SundayDriver
You should consider the Mid Ohio competition school. Great coaches using your own car and they do not follow a structure in that class - they coach to individual needs.