forklift

P.S.

I don’t pretend to have all of the answers, but what I can say is that I have spent most of my weekends this spring and summer at the track driving. I have learned quite a bit from some knowledgeable instructors. I agree with Lothar, who I figured out is a good driver; I have never told anyone I am a good driver, I let them figure it out.

FWIW, I have found my best lap times are when I can brake as late as possible, yet more importantly, still have the car settled for throttle as early as possible. If I brake too late and the car is upset when I need to be transferring to throttle, my exit speed suffers. I have also found trail braking to be useful in some corners, but not all of them. I tend to trail brake at the end of long straights as to keep that straight as long as possible. If it is a fast corner, I will probably be on the throttle prior to the apex, and will brake in a straight line. For now my DAS is checking my exit speeds out of corners with different approaches and throttle applications. I am open minded and have taken different bits of information from my instructors and this board and applied it to my driving. Some techniques work well in some corners and in others they do not. Recently I have become an instructor at the local track and have been lucky enough to work with drivers who are themselves open minded and willing to learn. I have to say that I would be hesitant to “jump” in a 996 turbo with Moton’s and a driver who thinks he has all of the answers and so little seat time.

For me it’s not what you say, but how you say it. I know you are not here for a popularity contest, as I am not either. However, being civil with those who disagree and appreciative of those who are trying to help you is severing lacking IMO.

ColorChange

Lothar:
I still don’t understand how come you guys can’t separate correct theory from my personal ability to execute it or not. I was/am right on nearly all of my technical assertions. I cannot execute many of them particularly well or consistently, yet. The two are completely separate issues. If I do find myself on a slowed learning curve, you bet I will change my learning method.

M758
OK, I don’t recall you saying trail braking was the fastest, and that I was right, but you have been one of the more rational voices so you may have.

I’m sorry, but I still don’t see the need for an instructor to help me with consistency. I know when I make I make most mistakes, and I know how to correct them (the best line in much more subtle and complicated, and there I have already said I have sought and will seek additional help). I can feel the car as you discuss, but I am working on feeling it better, and making my corrections earlier/faster.

Well it can show that I am or am not consistant, but it can't say why I was or was not consistant.

Yes the DAS will not only show you where you were inconsistent, but why you were inconsistent. You could look at your g-sum, note any time it dropped below a certain level, and then analyze what you did wrong (turned in early or late, over slowed, entered too fast, pushed, etc.)

It can show that your CAR did one thing or another while on the track, but rarely does it have the capability to tell YOU what YOU did on the track.Who do you think is controlling the car? You are! The DAS will show what you did with the steering wheel, brake, clutch, and the throttle. Those are your controls and that is what controls the car (ABS and PSM aside).

Really fast drivers want to minimize their G-'s in each corner to mazimize speed.

This is absolutely wrong. The fastest drivers MAXIMIZE g-s along the best line, or maximize g’s in the appropriate direction (same thing). Please do whatever it takes to understand this. If you want help with specific links and references, I will relist them.

To the low character group that continues personal attacks instead of admitting their errors or apoligizing, you are wrong yet again. NOT defending yourself against a repeat slanderer is bad. If I do so too aggressively, too bad. The much greater assault is the repeated slander to begin with. You say nothing about the offender and try to attack the defender. What does that say about your character? Or should I better say your lack of character. Hmmm.

M758

Color,
I never said trail braking was the fastest. It is very corner and car dependant. That said those that never trail brake will most likly be slower than those that do trail brake in right places. The key is the right places. No I never said you are "Right". Simply the trouble that you get into is the absolutes. Trail brake every corner. MAX G-sum in every corner. Well it is trully not that simple. There are far too many variables to be calcuated to make those blanket statements. The theroical perfect line and g-sum through any corner is just theory. The reason is not that theory is wrong, but putting it into practice is extremly hard. Reason is that even in F1 where they use DAS and everything they can to get faster there are compromise and change. A cloud comes over the track during qualfying and changes track conditions thus they "perfect line and max G-sum" through turn 1 is not slighly altered. Well no time to change the car so the driver must be able to make up the differnce. Get the car close and driver will use feel to adjust for changing conditions at all times.

Sure the drivers want minimize g's in corners. Look at Indy for example. The oval. It is flat out all the way round. To be fast you need the car going straight. Cornering slows the car even at full throttle. So I'd want to see LOWER g's in the corners. In fact the lower the g's the straighter the path and high potential to speed. Now the what one must remember is that you cannot JUST minimze G's. I can do that by going slow. The end goal should low lap times. Measureing a g-sum is merely a tool to help you figure how you can reduce the lap times. By trying to lower the g-sum and lower lap times you will be working on the line and trying to optimize that. Once you find the optimal line you want to then achieve 100% g-sum potential in corners where that is limiting you speed. So in a way we are both right. The real key is that driving is really a system of equations. The goal in the engineerin sense is to minimize lap times. Maxing or Min G-sum is by themselves is irrelvant. They can however provide input as to how to minimize lap times. The real key is that this is an optimization problem in that even g-sum is too vague. You really need to look at max lateral loads where needed and then optimizing the trade between accel/decel loads and lateral loading. This is more complex optimization. Of couse also thrown in to this is that the MAX accel/decel and lateral loads are not constant. They are quite variable given a whole host of elements that are quite difficult to gather data for. This where even F1 team struggle. So while one can fight over the equations of speed all day long, there is still so much not captured that non-scientific elements such as "feel" and "balance" are still vastly important. Driving is simply too complicated to boil down to simple Y = f(x).

Lothar

CC,

DAS is clearly a tool that helps teams at the pinnacle of motorsports to make the incremental improvements in setup and, to some degree, technique. I'm not debating theory. I'm debating how one improves their driving.

DAS cannot teach you the driving techniques that make you smoother and faster, i.e. occular driving, braking and shifting techniques, etc. You say you can look at the data and establish how smooth you are driving. An instuctor could tell you imediately during the session if your inputs are smooth and consistent. Best of all, you can factor this information into your driving on the spot. DAS cannot do that for you.

You have repeated that your DAS cannot lead you to the perfect line. So, why not get several opinions? One of the advantages to runiing DE in a solo group is the ability to invite multiple instructors to ride with you. Or, you could ride along with instuctors to view their line and technique from the passenger seat.

I'm not attacking you. I just don't understand why you don't want to use all the tools available to you, specifically a driving instructor. It sounds like you believe you know what to do but need practice executing. There are always drills and training techniques that can be applied to improve your execution. Data can only show your progress but can't convey the techniques that will make you better.

Finally, your attitude is exactly opposite to mine when I go to the track. You seem to know it all, where I assume I know nothing. You disbelieve what an instructor might tell you, where I trust implicitly until I prove or disprove on the track. Am I a great driver? No. Am I progressing at a rate that I am happy with? Most certainly. Could I have gotten where I am now without the help of qualified instructors, including a successful professional race driver? No way!

I wish you luck and much fun. I mean that sincerely.

FORKLIFT: Thanks for the compliment. I was quite impressed with your driving too.

ColorChange

M758
I never said to trail brake all the time, all the way to the apex. This is wrong. So we are in general agreement on your description of tb. I may be al little stronger proponent, but we are in the same ballpark I think so no problem.

No, your analysis is still a little wrong but maybe I see what you’re getting at. First separate the two g’s, long and lat. You want to maximize the long g’s for sure. As the recent article in Race Car Engineering (I think) discussed, for a hairpin, you want to minimize the lat g’s, but you are still on the fc, it’s just that most all of the g-sum is coming from long g’s. Then as you don’t turn so sharply, lat g’s play a bigger and bigger role. You don’t want to use more lat g’s than is necessary, certainly long g’s are preferred normally, but they are still critical in most turn. Maybe what you are missing is there are two conditions; maximize g’s along the ideal line. The ideal line stops you from wasting too many lat g’s.

Lothar
Without being tricky, DAS cannot give real time feedback. Mind you, it can be done and I am happy to discuss how it could work, but in general, it is not used for real time feedback.

I agree with getting different line suggestions and already stated I do this and welcome this. I don’t feel attacked by you and I do try to use as many of the constructive tools that I can, just as you are suggesting. Please don’t assume from the confidence I have in basic vehicle dynamics/driving that I carry that over to my own capability on the track. I understand how you might think that from what I write here, but I do not drive with that kind of attitude. I’m just not that good. I can question some suggestions right on the spot because my theoretical understanding is fairly strong. Thanks, good wishes to you to. You and I can have civil disagreements and I can still respect you. Others take different approaches that canlead to "difficulties".

mitch236

WOW! This thread has grown so much. I was at Homestead this weekend and spent some time thinking about why your (Tim's) theory about DAS is flawed.

Here is my theory:

Assumptions:
-Driver is absolutely consistent.
-The line is absolutely correct.
-The track is absolutely consistent
(I'm sure there are more variables but let's say this removes most)

Now we are left with only two :
G-sum
Force vector direction

Question: which is most important of the two remaining variables? The vector direction. It doesn't matter how much force you generate if it is not going in the correct direction and the line and vector direction are absolutely not the same thing. Now you see why everyone is getting so bent out of shape, your g-sum is the least important variable of all.

In my opinion the order of importance of these variables would be:
1. The line
2. Driver consistency
3. Correct vector direction at all times
4. G-force

Sorry, but true.

ColorChange

Mitch, You're a little confused as mentioned in my other reply. After you specified the correct line, the g-sum and force vectors are exactly the same thing. That is exactly what keeps the car on the line.

DJ

1) You aren't driving an F1 car.
2) Your car is very softly sprung (compared to an F1 car).
3) Your car has a lot more weight transfer/pitch/roll than an F1 car.
4) Your car has vitually no downforce as opposed to an F1 car which literally has tons.
5) F1 cars have carbon brakes, and your doesn't (that's why they can withstand that abuse, and yours can't).
6) F1 cars don't have ABS, yours does. ABS in passenger cars lengthens stopping distances compared to proper threshold braking.
7) F1 drivers are F1 drivers, and have years of experience. You are not, and have not.

Should I continue?

Or, maybe--just maybe--you could admit for once that you were wrong? More likely you will play the victim, and screech about how my character is low, and whine that I have assaulted/insulted you...

Smoother is faster.

mitch236

I don't see your theory. Let's say that you take the line at 0.9g which is the g-max, are you saying that I couldn't take the same line at 0.8g but with a vector angle closer to the line? I'm sure you can get more lateral g-force than forward longitude. So if I get on the throttle sooner that you, on the same line, that would give me less g-sum but a faster exit.

Maybe I am missing something but from a theoretical point of view, this makes sense to me. I find that as I track out, there seems to be less total g-force (going by my butt meter) but more speed. I know this fits into the "no unnecessary g-force creation but I am still arguing your previous statement that the turn couldn't be taken faster. I think that figuring out which g-force is unnecessary is very difficult and no amount of DAS (except the timing values) will help.

What would be valuable would be segment times. You could break down the track to small sections and work on them individually. Much like many of us do.


Oh, and by the way, from a strict physics definition, the g-sum and force vector direction are not the same. I studied enough physics to know that. The g-sum is the size of the vector, the direction is the angle.

CMMTracknut

Color, I did not see you at my Gingerman event this past weekend, when we posted earlier you must have been thinking about another PCA event.

I have alomost 3000 laps at Gingerman, I have looked at your video very carefully, I would like to comment about it if I may. First of all, as a novice student, you have an incredible car! I think too much frankly. The first lap was the closest to an "ok" lap and as you continued to push it got worse. People who don't like Gingerman usually don't get it. The time is made or lost in turn 2 the 4-5-6 complex and 8-9. Not surprisingly I don't like your line in these areas. In your first lap you came out to the blend line turned into the "very late" apex area and let the car work its way out as you realxed the wheel, this was the best line out of all of the laps. In turn 3 you need to let the car out so the drivers side wheel just makes it onto the concrete. Turn 4 approach is fine remember it is not important to get all the way to the right you just need to set the car up for 5 you can carry lots of speed through this area. 5-6, come out a little widerlike a caraosel your entry is too much of a tight "V" is needs to be more of a "J", 6 has more grip than you think so you can let the hill pic u up. You are apexing 8 too soon. You need to stay out on the third section until you see the the asphalt patch and cut across it to be parallel with the curbing on the right side then follow that striaight into the middle portion of the track to then transition for 9. You are apexing 9 too early. the apex is much later and you are improperly set up for the track out and for the next corner. You are apexing 10 too early I see too many steering inputs. This corner obviously is very important with the big straight ahead and your line is not allowing you to get on the power soon enough. Turn 11 and 1 are great trail braking corners, you need to NOT pinch 11 DON'T PINCH 11, DON'T PINCH 11 you get the idea, let the car come out to the track out, you are loosing lots here too.
I hope this helps. If you had come to one of our event we would have gone over this in my car and in yours. I wish you the best of luck and perhaps I will see you at the track sometime.
C
PS Your car is tough to drive. It is so fast. You really need to slow down and build up consistenecy. I know that everyone has talked about that. Your lap times are pretty fast for a novice. It is really important to be smooth, controlled and consistent.

ColorChange

Mitch236:
I don't see your theory. Let's say that you take the line at 0.9g which is the g-max, are you saying that I couldn't take the same line at 0.8g but with a vector angle closer to the line? I'm sure you can get more lateral g-force than forward longitude. So if I get on the throttle sooner that you, on the same line, that would give me less g-sum but a faster exit.

Let me see if I understand. Same car on the same line, two different laps. First lap pulls a lat g max of .8 and second time through pulls lat g max of .9. The only way these two card can stay on the same line is if lap 2 was faster than lap 1, otherwise the higher lat g load would have tightened the turn and the lines would have changed. If this isn’t what your after, discuss long and lat g’s for the two different laps so I can follow you.

Maybe I am missing something but from a theoretical point of view, this makes sense to me. I find that as I track out, there seems to be less total g-force (going by my butt meter) but more speed.

NO! the g force available to the car is the about the same! Braking, turning, acell, is always about the same, fast or slow (unless elevation, camber, aero, or track surface changes).

I know this fits into the "no unnecessary g-force creation but I am still arguing your previous statement that the turn couldn't be taken faster. I think that figuring out which g-force is unnecessary is very difficult and no amount of DAS (except the timing values) will help.

The only way a turn cannot be taken faster is if you are on the ideal line and you max your g-sum through the whole turn. A line cannot be taken faster if you max your g-sum but someone could find a quicker line. Determining unnecessary g creation, or better put, applying max g’s in the optimal direction is difficult. That is selecting the line.

What would be valuable would be segment times. You could break down the track to small sections and work on them individually. Much like many of us do.

Sure, this is exactly what you do in your DAS analysis.

Oh, and by the way, from a strict physics definition, the g-sum and force vector direction are not the same. I studied enough physics to know that. The g-sum is the size of the vector, the direction is the angle.

The g-sum= sqr [ (lat g)^2 + (long g)^2 ]. So, the g-sum does take into account the vector components but I suppose if someone just gave you the raw number, you wouldn’t know the components. In reality, the g-sum is the resultant force vector of the two individual vectors and incorporates both magnitude and direction. Agreed?

mitch236

This is in response to the next point as well. In my car, I am sure I can brake at a higher g-force than I can accelerate. And I think I can apply higher g-forces laterally than I can accelerate, so what I am trying to say is that if I get on the throttle sooner and at a lesser steering angle, I would have a lower g-sum but possibly a better segment time.


I guess we are stating the same thing differently. Finding and being on the best line IS the hardest part. If you were driving a perfect lap then you would be on the optimal line with the correct vector angle g-sum.

Yes, the g-sum is the resultant number but one would need to know the components to determine the angle.

ColorChange

You are definitely correct that in your car you can accel probably 0.2 g's maybe 0.3 g's if you have a turbo. Braking will be at the limit of your tires, about 1.0 for streets, about 1.2 for r's, and probably a little higher for slicks. The long g and lat g maxes are about the same for our cars. This is what gives most g-g curves the heartish shape. With my power kit, I should be cloase to a circle as stock, I could pull 0.4 g's accel, hopefully 0.8 g's in lower gears with the kit.

We agree on the rest.

CMMTracknut

Color, do you even care that I took the time to review your video? Why are you so caught up with the g-sum bull crap, why don't you take a second and look at the non-mathematical side. Who cares what the charts and graphs say, this is driver's ed. You should be learning to drive the car. Studying that stuff is not going to help you to become a better driver. You are not going to hit the track and plot a course fot the highest g-loading. You can't measure that with you butt-o-meter or use keenly tuned eye sight to measure your skill. Everyone(well at least most) are trying to help you.

ColorChange

CMM, I apologize for not responding in detail. But until then, how do you know what will and will not make me a better driver when you don't know me? I can understand you saying you don't think so, but you state it as fact.

I was going to take your comments, view the video, and then compare that to the data. Am I wasting my time?