How to find your (and your cars) limit?
08-25-2017, 07:11 PM
#121
I've driven a lot of different types of cars over the last few years and I honestly can't think of a single time where I used a different "line" because of what chassis I was driving at the time. With the exception of avoiding some curbs in prototypes where you jump them in GT's... but it didn't really change my "line".
The things that change are:
* initial brake zone (some cars get much deeper than others).
* attitude of the car at entry/mid corner (rotation, some need more than others).
* initial throttle point and application curve (ie: the McLaren GT3 you have to get to power way early because of turbo lag.)
** hint, the last 2 are heavily dictated by the differential setup in the car....
The things that don't change are:
* turn in point.
* apex.
* track out.
While I may not be super fast, I've driven with plenty of co-drivers who are and who's results are directly effected by how fast I am. If they could tell me or show me a faster way, they would have by now.
IMO, what holds a lot of people back is overanalyzing things that don't matter. Again, which is why a good coach is super critical if you want to improve quickly and go fast. If you just want to have fun goofing around with your friends or bench racing on the internet, that's a different hobby...
-mike
The things that change are:
* initial brake zone (some cars get much deeper than others).
* attitude of the car at entry/mid corner (rotation, some need more than others).
* initial throttle point and application curve (ie: the McLaren GT3 you have to get to power way early because of turbo lag.)
** hint, the last 2 are heavily dictated by the differential setup in the car....
The things that don't change are:
* turn in point.
* apex.
* track out.
While I may not be super fast, I've driven with plenty of co-drivers who are and who's results are directly effected by how fast I am. If they could tell me or show me a faster way, they would have by now.
IMO, what holds a lot of people back is overanalyzing things that don't matter. Again, which is why a good coach is super critical if you want to improve quickly and go fast. If you just want to have fun goofing around with your friends or bench racing on the internet, that's a different hobby...
-mike
08-25-2017, 07:48 PM
#122
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^ Great summary diagram!
I know the lines shown are meant to be illustrative, but interesting to see that the trajectories (lines) can be noticeably different even when the turn-in, apex, and track-out points look almost the same, due to the differences in radii through the corner - we need to remember that the radius through a corner is never constant in any vehicle.
That may reconcile some of the seemingly different perspectives in this thread.
I know the lines shown are meant to be illustrative, but interesting to see that the trajectories (lines) can be noticeably different even when the turn-in, apex, and track-out points look almost the same, due to the differences in radii through the corner - we need to remember that the radius through a corner is never constant in any vehicle.
That may reconcile some of the seemingly different perspectives in this thread.
08-25-2017, 07:54 PM
#123
^ Great summary diagram!
I know the lines shown are meant to be illustrative, but interesting to see that the trajectories (lines) can be noticeably different even when the turn-in, apex, and track-out points look almost the same, due to the differences in radii through the corner - we need to remember that the radius through a corner is never constant in any vehicle.
That may reconcile some of the seemingly different perspectives in this thread.
I know the lines shown are meant to be illustrative, but interesting to see that the trajectories (lines) can be noticeably different even when the turn-in, apex, and track-out points look almost the same, due to the differences in radii through the corner - we need to remember that the radius through a corner is never constant in any vehicle.
That may reconcile some of the seemingly different perspectives in this thread.
08-26-2017, 12:01 AM
#124
Drifting
+1 but of course the track out or at least the extent of tracking out necessary is less if your car can't get enough power down to reach the tire limits on some combination corners. That can lead to different entry trajectory for the next corner that can sometimes be more advantageous.
08-26-2017, 12:12 AM
#125
I'm in....
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08-26-2017, 08:45 AM
#126
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It may be that I can go faster through this segment though and my ability to take the short way would reduce with increasing pace.
08-26-2017, 08:49 AM
#127
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Also, the idea would be to get straight as you can, as soon as you can, so that you aren't "pinching" the exit and scrub speed with steering input any longer than need be. Especially in a lower powered car. To watch SRF, Formula Vee and top Formula Ford drivers is a lesson in this.
You could do this several ways, but with additional yaw introduced at turn-in, sustained in such a way that you reduce the steered angle (WOT, all the while) finishing that yaw precisely at the exit point near the end of the concrete gaiters at the exit, but parallel with them and before the skid pad return road begins, would be the most efficient way of preserving elevated speed, selected AT turn-in...
Having driven, raced and won in a 70 hp FIAT 850 Spider at 1:39, a 165 hp FIAT 124 Spider at 1:25 and a 300 bhp Lola Sports Prototype at 1:12, the goal and the line through T1 and T2 are the same... Yaw generation and sustained yaw duration was greater in the lower horsepower car, however.
Power to grip ratio were a little different though...
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08-26-2017, 09:09 AM
#128
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I have found (with Manifold's help) places where I don't track out specifically to cut down on distance because the balance of distance traveled and speed results in a lower lap time. Summit Point turns 1-2 for example.
It may be that I can go faster through this segment though and my ability to take the short way would reduce with increasing pace.
It may be that I can go faster through this segment though and my ability to take the short way would reduce with increasing pace.
) The debate about whether "the line" is the same or not is unproductive. The answer is not binary. Optimal spots could shift by a foot, two, even a few feet depending on the car, set-up, conditions, temps, tires, etc. That's why the most-used black "line" on most tracks is a single fat line (instead of two thin lines) and is much wider than a car's width -- even for F1 tracks/races.
08-26-2017, 09:27 AM
#129
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Great point on the predictive lap timing indicator. Perhaps the most valuable real-time tool for ANY driver, in ANY venue.
Brian Redman told me that; "the only data worth looking at was the stopwatch." He's got a point!
Where discussion of "the line," or rather "the desired trajectory" IS important is to give a driver SO complete a vision of what they want to do, how much and when, before they GET there, that they are able (or more able) to FULLY commit to SOMETHING.
The path of the car through a corner can vary quite widely and the sector time not change, IF the grip capability (in all axis and in transition) of the car is underutilized, due to a lack of commitment.
DTMiller pointed out the goal in a very succinct manner when he said that he might not be able to take a tight, shorter distance covered exit, IF he went through the first portion of the corner quicker.
And that is the goal, to enter into a conversation with the car where, at the proper speed, and at the proper skip angle, the car DOESN'T follow EXACTLY your commands... You "guide" it, rather than drive it. Hence Mario's famous quote...
The big black line? That's "crisis management!"
Brian Redman told me that; "the only data worth looking at was the stopwatch." He's got a point!
Where discussion of "the line," or rather "the desired trajectory" IS important is to give a driver SO complete a vision of what they want to do, how much and when, before they GET there, that they are able (or more able) to FULLY commit to SOMETHING.
The path of the car through a corner can vary quite widely and the sector time not change, IF the grip capability (in all axis and in transition) of the car is underutilized, due to a lack of commitment.
DTMiller pointed out the goal in a very succinct manner when he said that he might not be able to take a tight, shorter distance covered exit, IF he went through the first portion of the corner quicker.
And that is the goal, to enter into a conversation with the car where, at the proper speed, and at the proper skip angle, the car DOESN'T follow EXACTLY your commands... You "guide" it, rather than drive it. Hence Mario's famous quote...
The big black line? That's "crisis management!"
08-26-2017, 09:52 AM
#130
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When the goal is to maximize the radius, the speed, the throttle application, while straddling the grip peak at all times, you can't really "drive" the car where ever you feel like. You can only "guide" it with your controls. It's physics that determines the line.
08-26-2017, 09:59 AM
#131
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Qualy up next here at VIR and we're not talking about line, we're talking about steered angle, throttle acceptance and front/rear slip ratios!
I've been super spoiled learning on and racing low-grip historic cars for decades. Stuff happens slow enough you can feel it, see it, and do something about it. In Cup, LBST, GTD and LMP3 cars, the slip angle window is narrower, the response quicker, but the thought process, execution and physics influence I've found to be the same.
At the level I race, if you fall too far away from that desired slip angle window (not enough or too much, delaying throttle), or hang on the brake too long, or are tardy in throttle application in comparison to the others, you're TOAST!
Sheesh! Sounds like an SPB love-fest!
Last edited by ProCoach; 08-26-2017 at 10:23 AM.
08-26-2017, 01:21 PM
#132
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I must say dancing on that limit is a blast. I am still working on the fundamentals but now and then I'll run a short string of corners right at the limit of the car. I just love the feel of the car gliding on the road with all the tires slipping and right at the edge... makes the whole car feel alive!
08-26-2017, 01:33 PM
#133
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Bingo! The variability gets less and less... And the curb use gets more and more...
Qualy up next here at VIR and we're not talking about line, we're talking about steered angle, throttle acceptance and front/rear slip ratios!
I've been super spoiled learning on and racing low-grip historic cars for decades. Stuff happens slow enough you can feel it, see it, and do something about it. In Cup, LBST, GTD and LMP3 cars, the slip angle window is narrower, the response quicker, but the thought process, execution and physics influence I've found to be the same.
At the level I race, if you fall too far away from that desired slip angle window (not enough or too much, delaying throttle), or hang on the brake too long, or are tardy in throttle application in comparison to the others, you're TOAST!
Sheesh! Sounds like an SPB love-fest!
Qualy up next here at VIR and we're not talking about line, we're talking about steered angle, throttle acceptance and front/rear slip ratios!
I've been super spoiled learning on and racing low-grip historic cars for decades. Stuff happens slow enough you can feel it, see it, and do something about it. In Cup, LBST, GTD and LMP3 cars, the slip angle window is narrower, the response quicker, but the thought process, execution and physics influence I've found to be the same.
At the level I race, if you fall too far away from that desired slip angle window (not enough or too much, delaying throttle), or hang on the brake too long, or are tardy in throttle application in comparison to the others, you're TOAST!
Sheesh! Sounds like an SPB love-fest!
Also, Peter Argetsinger teaches corner early turn in and and increasing rate of spiral towards the apex so the heading of the car at apex is such that you can go to go to full throttle at the apex with a circular constant radius line as seen from the steering input from apex to exit but not from the use angle of the car. My car is a Porsche 994 2.5L NA, 160hp
Driving a 1977 Chevy Agor Monza, my experience was turning in a little later, a little later apex, and full throttle after the apex. This is a race a 500hp race car with rear 17 in wide slicks and front 14 in front slicks.
My experience supports Adam Brouillard remarks of some where in between.
08-26-2017, 02:27 PM
#134
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The debate about whether "the line" is the same or not is unproductive. The answer is not binary. Optimal spots could shift by a foot, two, even a few feet depending on the car, set-up, conditions, temps, tires, etc. That's why the most-used black "line" on most tracks is a single fat line (instead of two thin lines) and is much wider than a car's width -- even for F1 tracks/races.
Moreover, you can have different lines through a corner for a given car, all of which are on the limit, but only one of them gives the lowest lap time (accounting for how corners are connected together). Adam's books and video give useful concepts and heuristics for generating that optimal line, based on a solid grasp of the physics and consistent with what top pros are doing.
All of that said, I'm not suggesting that drivers should be focused on the line (especially experienced drivers), since that alone certainly won't do the trick, and experience shows that other things need to be focused on in order to be fast (car control and vision being among the most important).
08-26-2017, 02:40 PM
#135
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I don't think anyone said it's binary. There are extremes, and everything in between. Most cars will be closer to the middle than the extremes. The point is that the optimal line can vary somewhat between cars, even if the turn-in, apex, and track-out points look about the same (since the trajectories between those points have varying radii, rather than being constant-radius arcs between the three points).
Moreover, you can have different lines through a corner for a given car, all of which are on the limit, but only one of them gives the lowest lap time (accounting for how corners are connected together). Adam's books and video give useful concepts and heuristics for generating that optimal line, based on a solid grasp of the physics and consistent with what top pros are doing.
All of that said, I'm not suggesting that drivers should be focused on the line (especially experienced drivers), since that alone certainly won't do the trick, and experience shows that other things need to be focused on in order to be fast (car control and vision being among the most important).
Moreover, you can have different lines through a corner for a given car, all of which are on the limit, but only one of them gives the lowest lap time (accounting for how corners are connected together). Adam's books and video give useful concepts and heuristics for generating that optimal line, based on a solid grasp of the physics and consistent with what top pros are doing.
All of that said, I'm not suggesting that drivers should be focused on the line (especially experienced drivers), since that alone certainly won't do the trick, and experience shows that other things need to be focused on in order to be fast (car control and vision being among the most important).
As far as the second, THIS is why concerted and careful examination (with validation from multiple measures) of collected data and video are SO important. That's why the more I do this, the less I know for sure...
Let the objective measure show you.Do a prime and alternate (no more than two at a time), then SEE which is the quickest, then do it again, then hone the final solution...
It's shocking the variation in execution points, amplitude and rate of control inputs, brake points, brake release and throttle application, not to mention the number one measure, SPEED at a GIVEN point there is between laps/sessions/days of the SAME (even accomplished) driver's performance...