OK, I am posting this for two reasons, to show people how you can learn from a DAS and the power of g-sum, and secondly, to get some help or input (and preferably data from people who are familiar with Putnam). The graph is the turn 1-2 sequence at Putnam and is smoothed for clarity.



Turn 1 is a fairly flat 70 degree right hander, quite quick (has a little beneficial camber near the apex if I recall correctly). I approach at 140 mph and the maximum speed possible through the turn (for my car) is about 82 mph.*

*Race Data Power (from Precision AutoResearch) shows corner speeds for some tracks, including Putnam. According to their data through turn 1, a 1.0 g capable car should be at 78.5 max speed, a 1.2 g car will max at 85.9 mph. My car can pull maybe about 1.1 so I use the mid point, in this case 82 mph.

Here are my observations.

A.
It takes me 1.1 seconds to get from the gas to -1.0 g braking . This is brutal! I had new brakes on the car and was not used to entering at such high speeds. The new brakes require much more pressure than my old brakes so I am adjusting to that (yes, for now I am trying to modulate braking just below ABS). Secondly, it looks like I can just hit the brakes much harder than I am (downforce is probably helping me at these speeds). With my old brakes and in slower turns, I go from throttle lift to full braking in about 0.5 seconds, which I think is OK. I am probably a little scared to jam the pedal like I should at 140 mph and am squeezing it too much, as the g-sum curve should be much steeper.

B.
This still in the straight-line braking zone and is my downshifting (5th to 3rd). This also stinks! Just like in A, I am not maintaining enough pedal pressure while double clutch downshifting (I know it is not necessary but prefer to be gentle to my tranny and learn the skill). This took me over 1 second again. There is no need to downshift quickly but I should be maintaining threshold braking pedal pressure while downshifting. With my old brakes, I was fine so I am need to just correct my pressure modulation.

C.
At this point I am into the turn and simply overbraked the entry. Once the lat g’s build the g-sum comes back up, but I should have trail braked deeper so that I trade long g’s for lat g’s. This was 1.5 seconds below about 0.9 g sum. Bad!

OK, Turn 1 entry to mid summaryme self coaching): My slowest speed was about 77 and should have been closer to 82.
1. Hit the frikin brake pedal a little later!
2. Keep the pedal pressure up when you downshift!
3. Trail brake deeper so that you eliminate the dead time in B and properly trade long for lat g’s.

Turn 2 is a 93 degree right hander, again fairly flat. Max speed for me is 72.4 mph.

D.
Part of the drop here is that once you make the high speed turn, it straightens a little until you turn in for turn 2. Instead of squeezing the throttle while the lat g’s are down to only about 0.5 g’s, I maintained neutral throttle for about 1.5 seconds. Ughhhh! I should have squeezed the throttle before hitting the brakes before the entry to 2. The little dip after D is a slight over trail braking at turn in.

E.
The exit of 2 is a slowly turning section that only pulls about 0.5 lat g’s until you hit turn 3 where you max the lat g’s again, kind of like a mini kink. I was on the throttle near 100% near the bottom of the trough so I don’t think you can stop the bottom, but I could have delayed the size of the trough by being on the throttle harder and earlier.

Turn 2 summary. My lowest speed was 66 mph when I should be closer to 72.
4. Get on the throttle hard on the exit of 1/entry of 2 to avoid the D dip.
5. Get in the throttle earlier/stronger on the exit of 2 to reduce the early part of the trough E dip.

Do other people see the same g-sum dip at the exit of 2? Norm?

And for the record, this is pretty poor and that is why I am looking at it harder.

 

I have a few observations about your observations. My own opinions, which are offered up by another struggling amateur.

1) Stop beating yourself up. You're not going to F1 anytime soon, none of us are. To improve you need to build positive thoughts, not negative ones.

2) Okay your theoretical limit is 1.1-1.2G at what ambient temperature? At what tire pressures? At what tread temp? At what track temp? I really don't think you can extrapolate very much about your driving from a single pass, nor do I think you can infer much about how close to the limit you actually where as has been beaten to death here, there are too many variables involved.

3) I think you're thought process is going in the wrong direction. Phrases like "jamming on the brakes" & "braking later" suggest to me that you thinking you need to act more agressively. This is a dangerous line of thinking IMHO. Think back to the recent Schumacher DAS video. He broke earlier, possibly less agressively, was actually later to full throttle and yet was much faster than his team mate. This is in direct opposition to some of changes you're contemplating.

From where I sit, it would be more enlightening to look at a single corner on multiple laps. I'm certain you didn't brake, steer, shift throttle up at precisely the same points on each lap. Under which circumstances, earlier, later, harder longer, softer braking, throttle etc where you able to get through the segment the quickest? This should give you clue as to what works better where, and what direction you can go in to improve.

 

I agree with a lot of what Ray said. One thing I'd add about the braking comments: if you are approaching the turn-in at maximum braking, it's going to be real easy to overbrake the corner. Maybe the right answer for the perfect driver is to enter the corner at maximum braking, but you are not that perfect driver. You need to slowly build up your comfort level so you can take the corner at maximum speed. The best way to do that is to ease up on the braking so that you can better modulate your corner entry speed and so that your car is better balanced.

AFTER you have built up your entry speed and your comfort level, you should go back and examine your braking. Until then, pretend that you've overcooked your brakes and you need to brake a lot sooner and a lot lighter.

 

RJay: Thanks for the comments.

1. Yes I agree with you normally, my personality is somewhat perfectionist and tough so I talk directly and clearly (negative or positive as earned), and I will not get easily discouraged. This helps my concentration and focus but for many might be a distraction.
2. You would be quite surprised that the data is highly similar from Gingerman and Putnam, from 50F to 100F. Street tires are less variable here, but the data is all within about 0.1 g’s. Now, I will not beat myself up if I am at 1.1 instead of 1.2 on a particular turn due to many of the variables you correctly list, but not when I’m down to 0.9 on one lap and 1.1 on others.
3. I understand your concern and I agree in general. In this particular case, I really do need to smack the pedal hard as I was much to slow with my normal push. These brakes require much more force and I think I was probably a little tentative getting on them firmly from 140 mph. Finally, if I do really slam them too hard, the only thing that should happen is I engage the ABS (and this may be faster still but please, let’s not go there).
I learned in ski racing and jumping that when I tried to be physically aggressive I was always slower so I do understand your comments. I try to concentrate and if anything, respond quickly … not forcefully.

Your points on multiple laps are dead on! I have done this and sadly, when averaged over about 20 laps, similar problems appear and that I why I went into detail on this turn. Yes, sometimes I was much quicker, but I made the mistakes consitently enough to make sure I watch this for next year. I will take this summary and watch myself closely to make sure I don’t repeat the same mistakes.

BrianP: I agree. Threshold braking and then trail braking release to an exact maximum corner speed is extremely difficult … and extremely fun when done right. It is easier to overbrake and the higher the difference between entrance speed and corner speed, the easier it is to overbrake.

Please understand I am trying this only on “safe” turns, but it is still a safe technique IMO because if I blow it, I just stay on the brakes longer and lose my line. It is rare that I leave the track doing it.

 

CC , sounds like you know where you are having problems, and just how much faster you could be going. That is really the first step to going faster...convincing yourself you can. I think the biggest problem is your speed is too slow through the corner. I think you need to start to slowly push your cornering speed up and get used to that increase in speed. Once you are acclimated to the higher cornering speed and feel comfortable balancing the car, then I would start to worry about how to optimize braking. I think you are now overbraking and miss judging your entry speed, so the answer may be to actually brake with less force and see what happens. Once you are used to the higher entry speed and maintaining that speed through the corner, then you can start to optimize braking points and carrying max g-sum through the transition phase. I know "brake less" goes against the g-sum theory, but I think what you are battling here is self preservation instinct which is a good thing to have as well. You need to raise the bar, but it takes time and it should be done in slow increments. So in summary, brake less and scare yourself a little.

 

When I want to go faster in turn 1 at Putnam, I try to brake less and get on the throttle sooner. Force yourself to come off of the brake sooner, and get right back in the throttle aggressively. In my car I'm at full throttle as soon as I come off of the brake. Your car probably has too much power for that, but you get the idea. Your entry speed should be high enough that you hear your tires loud and clear through the apex. Street tires give great audible feedback. Take advantage of that. You should also feel the car flirting with limit of adhesion through the apex. If you're not hearing and sensing the limit through the apex, then try even less brake and more throttle the next time around.

Also consider the possibility that dropping down to 3rd is causing you to overslow the car. I'm not familiar with the gearing in your car, but turn one is definitely a 4th gear corner for my car. I have students change from using 3rd to 4th gear in turn one all the time, and it almost always speeds them up. You then grab 3rd gear between the exit of 1 and the entry for 2.

 

For a double apex turn like that, agreed! I haven't driven a car where that cannot be done, but my experience is limited to less than 500 hp. Jim, I agree with you here too. I would point out from my perspective is that being on the limit through and past the apex means controlling the back of the car; keeping it from stepping out.

Too many drivers do not make a proper transition (read full throttle) from the brake to the gas. And at that point in the turn, "C" if I read Tim's graph properly, he should be gaining speed until he hits that brakes again for the second apex for turn 2. This set of turns seems to be a lot like Big Bend at Lime Rock.

BTW, Tim, I think that I am starting to understand your graphs.

 

Hey Tim;

For what it is worth to you, I see a definite shift in your approach to this driving thing. Unlike at first, there seems now to be room for some "gray". I think all of this List stuff has made you much more open and less insular. I really think that this - more so than direct driving study - will be your greatest assett in breaking down the often counterintuitive barriers we all face as we move forward. You will not be the first person "humbled" - to whatever degree - by performance driving. I think it is all fitting you very well indeed these days.

I wish I could make heads or tails out of that data because I do find it interesting. Unfortunately, I have not been trained, and I'm not that smart on my own. However, I CAN tell you from experience that the others are right on track - as it were.

I have always felt that you (and many people) put too much emphasis on braking. My experience as a driver and instructor has shown me that braking is a distraction. It hypes you up and makes you jittery. Braking aggressively gets your brain out of kilter, takes concentration away from setup and transition, and unsettles the car. The old joke of "Accelerate till you see God, then Stand on the Brakes" is probably the WORST advice anyone ever got and is actually the kind of thinking that all we instructors must battle every time.

The boys are on the right track, in varying directions. For whatever reason your new brakes require more effort. I can only assume a non aggressive pad compound with low intitial bite. That is fine, and I think you can use it to your advantage. The way to increase your cornering speeds is to brake less. That sounds patently obvious until you try it and find that it is definitely not something easy to accomplish.

As you state, judging the point where you reach the right cornering speed and release the brake is tricky to find, and larger declerations exacerbate this. A very astute observation indeed. I would offer to you that one of the reasons for this is distraction. Braking very late sets up the feeling that you NEED to get that braking done NOW or you'll miss the corner. This anxiety clouds your judgement and distorts reality.

You can brake two ways. 1) The "normal" late brake and stand the car on its nose to reach a given speed and then release immediately and transition to accel. 2) Earlier and softer transition to full forward g-load with less overall pressure but ultimately the same amount of deceleration. The first feels fast. The second IS fast because it holds more potential for future increases in cornering speed.

The difference is in balance, both in the chassis and the cerebelum. The drastic compression of time that takes place in the first model will make it very hard to judge the speed at which you actually CAN transition. The 2nd model offers you more subconscious serenity, and allows you to remain more focussed on a point where you COULD transition.

Stepping up and going faster is about carefully approaching and then breaking down mental barriers. The 2nd model allows you to feel and assess the transition phase more intimately, and more easily approach, surpass, and enventually reset your comfort threshold. Since the car will be better balanced, the transition will be more manageable, and likely more effective as a result.

Let me quote Rick Bye from the December Pano. One of the best tips on driving that I have ever read. It is taken a bit out of context, but applies beautifully. Regarding ceramic brake wear, he stated;

... I find it common for DE drivers to think that whoever brakes last going into a corner is the fastest. When in racing, the really fast drivers rarely brake last because that leads to premature wear on, and failure of, the braking system. That's not what car control is about - we have to preserve our cars. (...) I believe that if all drivers adopted this point of view, ceramic brakes likely would last for most of a DE season"

I wrote Mr. Bye a letter thanking him for this tip, and inquiring as to whether he would apply that tip to ALL braking situations, not just in terms of component life. He most heartily agreed he would, and in subsequent e-mails we discussed at length how the Brake-till-you-see-God thing was so innappropriate and wrong-headed. A very enthusiastic and helpful fellow!

So, I would advise trying to shift your focus to lighter longer braking as a way to more effectively hit your entry speed target, and eventually increase it!

 

John that was well put and I agree completely. Ultimately, you want to get to where you optimize your braking point and match it to maximum entry speed, but first you need to re-program your brain's comfort zone entry speed by braking lighter and raising the bar.
Roebling Road has a turn 1 / 2 sequence that is very similar to this turn at Putnam where the turn 2 segment is a slightly tighter radius than turn 1. Most people brake lightly for the entry of 2, but I was taught to stop doing that and the result was I immediately got faster and found I could scrub the seemingly excess speed into turn 2 with a little balenced throttle entry slide. That really raised the bar for me and paid dividends everywhere else on the track. I re-programed myself by taking braking out of the equation.
CC, you could do the same thing by doing everything the same except when you come to point D, try just lifting a bit, then balencing the increased entry speed into 2 with throttle and steering modulation, rather than braking. That will get you faster and raise the entry speed bar everywhere else.

 

I've come to believe, perhaps mistakenly so, that the late braking thing only works in the AX type turns, the Oak tree at VIR comes to mind, where putting a lot of weight on the nose and getting the car to rotate rapidly seemed to work very well, at least for me. This is particulary so in a turn like this where I find it very difficult to look out the passenger window early enough.

I think that a key psychological problem with braking later is that as the stakes go up you start to really focus on the spot where you're trying to brake and you lose focus on the corner, which IMO is where it should always be. If instead you get the decel out of the way earlier, you can fully concentrate on maximizing your grip and focus your attention to the exit.

BTW, thanks for the great response Tim! I'd echo the comments of others and give you the big for your posts and community spirit. I am really lookng forward to posting some of my data so I can see if I'll take the advice and criticism of others as well as you have.

 

Thanks for the feedback everyone.

Carrera:
I agree, in turn 1 I am only pulling an average of 0.9 lat g’s, … can anyone say “Chicken Sh*t!”. In turn 2 I’m up to speed and pulling 1.0-1.1 lat g’s but I am leaving a lot on the table going through 1 and should be faster around the apex.

I also agree that until I can get the corner speed up I should skip the maximum anchor trail braking. I was doing part of this intentionally; part because I never entered turns at 140 before, but mostly because I suck. I can do it on other turns but until I can get through the corner as fast as I should, lay off the braking.

It’s kind of funny. I doubt that there is anywhere else in the country to blow a high speed turn safer as you have a ¼ mile grass field in front of you, but I was still a wuss.

Jim:
Yes, I could not go hard on the throttle early, but I am not getting on it hard enough or early enough as you point out. I was getting some squeal but only near the apex and I should have been on the throttle harder to keep the pig singing.

On this turn, I downshifted twice, once I blew and released too much pressure, the second one was fine and didn’t effect my braking. When I got into third, I was at 5500 rpm, 86 mph and don’t think I engine braked too much as I happened to rev match well (that time). I can show the data if you want to see it.

I will take a look at your data later (thanks), but you probably won’t have the answer to E as our cars are so different.

Larry:
Point C is just before turn in. I should have gotten off the brakes earlier to carry more speed, but I should not be on the throttle as I should be nearing my max lat g’s nearer the apex and if I am on the throttle (accelerating … not maintenance throttle), it would mean I overbraked (like I did on this lap). So, I shouldn’t be gaining speed at C, I just shouldn’t have lost so much. Now, at D, after the apex, I should have been accelerating harder into 2.

John:
Maybe. If it appears this way … good.

I agree with the tendencies of hard braking to hurt your judgment and the big tendency is to overbrake. Since I know this, I can fight it and do what Carrera says “scare myself a little more”. I should have been doing what you and others are saying, get the corner speeds down first before you worry about throwing out the anchor. My mistake and I agree. I can also see your point about saving brakes under race situations, but I will ignore that for now as I am restricted to DE’s for the foreseeable future.

Carrera:
I never hit the brakes at D, but I didn’t hit the throttle hard either: instead I nearly coasted UGHHHH. I even hate typing that word. I sped up a little, but not much. Squeeze the throttle. I do need to brake before the entry to 2 as I am approaching at 86 and you need to get down to around 67 mph and I don’t think I could scrub that much. Plus, I need some brakes in order ot get it to turn in. I was fighting push on this day still shaking down my new car). But, if that is what Norm does, I’ll sure try. Norm, where’s your data?

RJay: Thanks.

 

CC, maybe I'm reading the data wrong, but it looks like you are approaching T2 at 77mph ( green line) then drop down to 67mph mid corner. I think if you were going 87 then certainly you would have to brush the brakes, but 77 when you say the car can handle 72 should not be a problem to handle the scrub without braking. I think later on once your speed is maxed out in 1 you will have to use light braking into 2, but at those numbers I am seeing on the data coming out of 1, I would not think it would be necessary at this point...later probably and I bet Norm has to brush them just because he is going so much faster in 1. My point was you could use "not braking" into 2 as a intermediate step to get where you want to go everywhere else on the track.

I just reviewed the tape you posted of Norm at Putnam. It's hard to say for certain wheather he touches the brakes or not going into T2, maybe a brush. His entry speed seems much higher than mid corner in T2 and his speed did not change much at all in the short strait section between 1 and 2. Also Ron Fellows says nothing about braking into T2 in his blurb on the Putnam site, just that he downshifts from 4th to 3rd.

 

If you get all the speed you should out of turn one, I don't see how you could get through turn 2 without braking at least a little bit. I've done lots of laps at Putnam, and I don't think I've ever seen anyone do it. I know for a fact that nobody in F Class does.

 

Tim, you're an engineer, so you should be very comfortable with basic acceleration and deceleration equations. I strongly encourage you to put together a spreadsheet with several braking scenarios. The scenarios might include the following:

1) Perfect driver. Waits until last possible second, slams on brakes at 100% efficiency instantaneously, and then releases thems instanteously with no ill effects on the balance of the car. I think we can agree that there is no such driver alive.

2) Someone who is doing what we suggest. Brake earlier and lighter (80% for example) and then eases off the brakes.

I did the analysis for someone approaching turn 1 at Watkins Glen (a hard braking zone) and found that the difference between then two can be measured in hundredths of a second. Think about that. If you overbrake the turn, you are going to lose FAR more than those few hundredths of a second. When you are decelerating at about 22 MPH per second, it's incredibly easy to overbrake a turn and lose time.

 

CC,
Listen to redlineman. His advice is excellent.

Often, when trying to push harder and brake later, you
completely throw off the tempo of the turn. You end
up fighting the car through the turn because you've
tried too hard. The transition from braking to lateral g's to throttle should be as seemless as possible, and trying to maximize one part will through off your timing for everything else.

I would add a couple more points:
1) This is going to sound a little goofy. You are obviously very analytical. This can help with driving, but driving fast is a lot like any other athletic activity in that it is much more than the sum of little bitty parts of the corner. To go really fast, you have to get into that zone where it is more about feel and flow than staring at the next braking cone and trying to get to it. When we try to go faster, we think we need to brake a little later and carry more speed into the turn and get on the throttle sooner (all of which is very true), however if you concentrate on braking a little later you are going to throw off the smooth transition from braking to throttle. You are often going to carry too much speed into the turn and end up fighting the car with constant corrections because it is going to be understeering or oversteering from the excess speed (all those corrections slow you down).

Try this the next time you go to the track. Forget the data analysis, keep your eyes focused way down the road, slow down and use your natural ability to feel the car through the turn. Use your fingertips to control the steering wheel and concentrate on smooth, easy, flowing inputs. The more settled the car, the more grip available for turning, braking or gas.


I know this sounds like beginner student bull****, but the truth is that feel, flow, relaxation, slowing down and smooth, easy inputs are the secret to more speed at any level.

In shorter terms, if you want to brake later, don't focus on the braking point, focus on the trackout point and allow your natural feel for the car to sense the fact that you can wait a little longer to hit the brakes. You will see and feel the entire turn as one smooth transition of inputs, rather than pieces of braking, turning and accelerating.

Do you play golf? Remember trying to create a golf swing by building up all the individual mechanical pieces? It doesn't work worth a damn.

I'm very analytical too, so I have to constantly remind myself that driving is a sport and not portfolio analysis. I finally got a lot faster when I turned off the stopwatch and started focusing again on smoothness and flow (just like what I tell students at DEs at all levels).

2) Bag the double clutching. That's what synchros are for. You'll be MUCH faster. Your downshifts should be very, very quick. Obviously, you can't focus on threshhold braking while simultaneously taking a couple of seconds to shift. I would say this is a BIG part of your entry speed issue. You are wasting a bunch of time and thought on this superfluous excercise.

3) I don't know where you are getting the data to suggest what the theoretical maximum G force for your car is through turn 1 at Putnam, but it can't possibly be accurate. Your tyre compound, age of tires, heat cycles, amount of rubber/oil/debris on the track, temperature, etc. etc. all will have a significant impact here. I think you are putting yourself up against a false benchmark.

I hope I don't sound too much like some sort of trackman-zen-hippie and your mileage may vary.

Flow on...
-dc