Max acceleration line out of a corner
07-08-2018, 07:08 AM
#11
Former Moderator
What you describe is the classic "late apex" which allows earlier and harder application of throttle. The more powerful the car the later the apex. So yes, you are on to something 
07-08-2018, 05:09 PM
#12
A couple of observations.
-The objective, irrespective of power, weight, aero, is have the highest corner exit speed. There probably aren't any cars regularly used on road racing tracks that accelerate as hard as they brake, at least over 30mph or 40mph, speeds they wouldn't be at on a road racing track,
-An important part of turning is that the car yaws around its axis. I often read about this, but it wasn't until I took the time to work my super late model that I really understood. I just kept on making changes--smaller front bar, softer front springs, stiffer rear springs, lower front roll center (by changing the upper control arms to longer ones), higher rear roll center (by raising the panhard bar) that I got control of the problem.
When the car started rotating on entry the difference was obvious and made putting the power down on exit different. Because the car was pointing further down the track the apex was actually a bit earlier. The focus changed to working the balance on corner exist to get more power down.
The idea is not just a later or earlier apex, but being pointed down the track at that point. The goal is to get the most power down earlier to achieve the first point: highest exist speed.
-The line and braking are different in traffic where positions are being defended or gained, or when running in practice, qualifying, or time trials. In traffic the braking point may be later, the line chosen not to cede an advantage rather than maximize speed. Still, exit speed is important so as to not cede the advantage to a competitor on the next straight.
-Whether a faster car is a momentum car or not depends on the competition. A look at the racing of today's British Grand Prix shows a lot of action that looks pretty much like the cars in that Spec Miata race...just going faster.
-On the Schumacher video, note that he lifted earlier than Herbert, then balanced the car in heavy cornering where Herbert slowed then accelerated. Schumacher's trace was closer to a Spec Miata's or an S2000.
-In the Spec Miata video note that the driver of the camera car, Denny Steyn, is a long time Spec Miata racer, one of the fastest Spec Miata racers in the country, and regularly builds himself new cars. He also took a stab at running a version of his Miata in SCCA STL class.
-The objective, irrespective of power, weight, aero, is have the highest corner exit speed. There probably aren't any cars regularly used on road racing tracks that accelerate as hard as they brake, at least over 30mph or 40mph, speeds they wouldn't be at on a road racing track,
-An important part of turning is that the car yaws around its axis. I often read about this, but it wasn't until I took the time to work my super late model that I really understood. I just kept on making changes--smaller front bar, softer front springs, stiffer rear springs, lower front roll center (by changing the upper control arms to longer ones), higher rear roll center (by raising the panhard bar) that I got control of the problem.
When the car started rotating on entry the difference was obvious and made putting the power down on exit different. Because the car was pointing further down the track the apex was actually a bit earlier. The focus changed to working the balance on corner exist to get more power down.
The idea is not just a later or earlier apex, but being pointed down the track at that point. The goal is to get the most power down earlier to achieve the first point: highest exist speed.
-The line and braking are different in traffic where positions are being defended or gained, or when running in practice, qualifying, or time trials. In traffic the braking point may be later, the line chosen not to cede an advantage rather than maximize speed. Still, exit speed is important so as to not cede the advantage to a competitor on the next straight.
-Whether a faster car is a momentum car or not depends on the competition. A look at the racing of today's British Grand Prix shows a lot of action that looks pretty much like the cars in that Spec Miata race...just going faster.
-On the Schumacher video, note that he lifted earlier than Herbert, then balanced the car in heavy cornering where Herbert slowed then accelerated. Schumacher's trace was closer to a Spec Miata's or an S2000.
-In the Spec Miata video note that the driver of the camera car, Denny Steyn, is a long time Spec Miata racer, one of the fastest Spec Miata racers in the country, and regularly builds himself new cars. He also took a stab at running a version of his Miata in SCCA STL class.
07-08-2018, 05:54 PM
#13
Assuming corner entry speed is constant, drive the line that lets you open the throttle as early as possible. Do whatever you need to do with the steering to accommodate without having to countersteer more than a few degrees. I think you basically said this but just in a lot more words.
But if you're ever 'turning more slightly later' mid-corner, you're doing it wrong, assuming a standard single apex corner.
Also, if you've entered the corner correctly, you won't be at full throttle mid-corner. You're probably just too slow during corner entry if you can go full throttle mid-corner.
From around 2:50 in this video, see that I'm in 4th gear but still have enough torque mid-corner to not be able to go full throttle through the esses. This is because my corner entry speed is high enough. Also notice the sweet zero counter-steer while exiting the last S at around 3:05.
https://youtu.be/OljAWRi92tk?t=146
But if you're ever 'turning more slightly later' mid-corner, you're doing it wrong, assuming a standard single apex corner.
Also, if you've entered the corner correctly, you won't be at full throttle mid-corner. You're probably just too slow during corner entry if you can go full throttle mid-corner.
From around 2:50 in this video, see that I'm in 4th gear but still have enough torque mid-corner to not be able to go full throttle through the esses. This is because my corner entry speed is high enough. Also notice the sweet zero counter-steer while exiting the last S at around 3:05.
https://youtu.be/OljAWRi92tk?t=146
I had a sweet zero counter steer on that corner last weekend, dropped a wheel and spun across track into the guardrail
. I got a few solid laps in before that though, I really love that place!
07-08-2018, 08:51 PM
#14
I'm not sure I understand the counter steering mentioned. In the Spec Miata video, does Denny Steyn ever counter steer? In the video below of Louis Hamilton qualifying for the British GP at Silverstone on Saturday, does he ever counter steer? And that is one of the best drivers in the world effectively doing a time attack lap with no traffic under pressure from his major opponent and his teammate. He won the pole by less than 1/20th of a second.
07-08-2018, 09:42 PM
#15
If this is to me, I'm definitely not describing a classic late apex. In the OP I was asking about a minor edge case that would be an exception to the standard logic on apexing. I think in general it's not really going to be a thing though, aside from exceptions like a bit of countersteer when going over an apex curb or that sort of thing. What originally made me feel like I was doing as I described was a particular early apex corner where I found I was able to get on the throttle earlier than expected by straightening out somewhat a bit faster than I had been (but not all the way), and then using the large exit area on that particular corner to finish turning. So it was actually a classic early apex. It just felt like I was actually feeding in slightly more steering after the corner because I had been apexing that corner slightly later originally, so I was used to being straighter at that point in the corner. Hope that makes sense. At least it sparked a lively discussion though!
07-08-2018, 09:46 PM
#16
I'm not sure I understand the counter steering mentioned. In the Spec Miata video, does Denny Steyn ever counter steer? In the video below of Louis Hamilton qualifying for the British GP at Silverstone on Saturday, does he ever counter steer? And that is one of the best drivers in the world effectively doing a time attack lap with no traffic under pressure from his major opponent and his teammate. He won the pole by less than 1/20th of a second.
https://www.youtube.com/watch?v=heKgXtigPhs
https://www.youtube.com/watch?v=heKgXtigPhs
07-09-2018, 02:56 AM
#17
DavidNJ- if you watch Danny Steyn videos including this race, yes he will “unwind into the slide”. It’s not a turn and pause like a high hp car because these things kind of Wobble or dance at the limit. Drive one in the rain and it becomes a “turn and pause” steering input. He is not the only guy with non SM Miatas, I ran against Todd Burus (amazing driver!) 2 weeks ago at Sebring and he was driving a 1.6 built for PTD at NASA. Burus is in this video driving the silver/orange Krispy Kreme donut car that goes off. He had the same big off at Sebring in 15 and hept his foot in it and just regained the field. It must be a little frustrating to drive st that level and know the required SM suspension is not at all optimized for the car. Many of the top guys say the stock NB suspension would be better.
07-09-2018, 03:42 AM
#18
. Hopefully just cost me a couple of wheels and an alignment. I also had to sit on the sidelines the rest of my Sunday which sucked. I will be back in September though. I saw Shind’s 2:04.xx what are some other S2k times out there?
07-09-2018, 05:39 AM
#19
He is definitely pretty clean, but there is a bit of counter steer here and there. Exiting the chicane at 1:27 (of the video; 1:23 of the lap) is a good example. I don't think the argument is that counter steering makes you faster; it's more than in order to be fast you need to be driving right on the edge—and if you're right on the edge you're occasionally going to go just past it and need a bit of counter steer to catch that. (And if done right, lose little to no time doing so.)
the other worthy thing is how to define “the track” and how comfortable a driver is exceeding it. Places like COTA place suspension breaking bumps to real in drivers. Go to a place like Sebring and the pros are running 2 tires way off in turn 1. If you go stand inside turn 3-5 on the grass mound and watch the pros come around 1 ....it’s wild. So in the OP question , this is yet another factor to define the Apex and exit speed.
07-10-2018, 12:28 PM
#20
Former Moderator
For lower speed corners carrying extra speed into the corner and using that speed to brake deeper into the corner to get the rear end to slide around, rotate the car and counter any understeer worked for me in a lot of places.