RedlineMan

Bob -

Of course you are correct in your assessment of modern P-cars, and drivers in general. I have not to date EVER had a student who was advanced enough to teach it to. Probably a good thing because I might not have when I should. Now, if I sense a student is not carrying as much speed into a corner as they might, I will!

I am soooo glad I have an old, archaic car with a throttle cable and DSM (DRIVER Stability Management).

Our little CNY track group tried to get in that event en masse, but sadly Michel was SWAMPED with apps and we were frozen out. Perhaps next year. And, we have met of course, at Zone Presidents Meetings. You are simply not connecting this persona with that one.



Skip -

The problem you have is not doing it much, not your shoe size. I wear size 12, and either wrestling shoes or my Simpsons. I then have custom gas and brake pedals to make the small shoe work for H&T. Even a 911 - with their "unconventional" pedal layout - is doable with our size feet, given the right shoe. A 944 is easy... once you get the hang of it.

ColorChange

John and Mark:

Please do not repeat Bob R’s error in taking that statement out of context. That was a theoretical argument (from the start I might add). John, while you might not have followed that, I believe Mark knows it quite well and may have repeated this in big quotes on purpose.

Yes, I did say if you have a good enough ABS system you should trail brake all the way to the apex. This is perfectly correct. I also said on most turns, you should trail brake (to be fastest). This is also true.

Brian:
I currently do my analysis normally after the day, occasionally between sessions if I am looking for something specific. I am looking into this idea currently. You could have your display present your g-sum on the LED’s instead of the common tach which you can hear. This way, the LED’s would light up when you were on the fc. It could be done, I’m just not sure how usable it would be. All of your questions are reasonable. To do it more accurately, you would have to preprogram in the g-sum max all the way around the track because it can change. But, even this would be wrong if someone kicks up a bunch of dirt or spills some fluids, etc.

Sjanes
I understand your warning and agree. I think I am careful and so far, I have been able to recognize fairly early when I have made an error. This is a huge are I am working on, recognizing the error earlier before it gets too bad.. I have a tequipment roll bar, fire extinguisher, nomex, (Isaac) HANS, …

Chris:
Agree 100% with your post again.

Brian
Yes, any decel after turn in is trail braking in my book. My unqualified opinion is that if the driver can demonstrate basic car control at the limit, he should be able to trail brake. But I agree with you, if your 10 seconds off the pace, tb is not the answer.

Sjanes:
I agree, releasing brake pressure is a critical skill, probably one of the most difficult and something the top drivers do extraordinarily well.

smokey

It seems there are two issues at play here: trail braking per se, and trail braking at threshold to the apex. There is consensus that trail braking, where appropriate, helps lap times, that all fast drivers use it, even though some of them may not be conscious of doing it. Trail braking is defined as follows in this context: continuing to use the brakes after turn in to load the front wheels, thereby speeding the transition from longitudinal deceleration (braking) to lateral acceleration (turning). The main advantage of trail braking is speeding up this transition, thereby minimizing the period when the car is unbalanced. Trail braking does not increase entry speed: at maximum entry speed, i.e. just short of a spin, appplying the brakes would spin the car, so the entry speed has to be reduced slightly to be able to trail brake.
After this transition to balance, continuing to apply the brakes adds a force vector pointing backward, and reduces the force available within the friction circle for lateral acceleration, i.e. reduces the cormering speed. The fastest route to the apex is the one where the car is balanced at maximum lateral acceleration. If you can still apply the brakes after achieving balance, the car is not going fast enough.
Conclusion: trail braking to rotate the car decreases lap times, but continuing to apply the brakes after balance is achieved increases them. QED.
Trail braking is less useful when the car is light at turn-in. e.g. Corner 2 at Mosport, or where the car is in compression at turn in (skiers will know what I mean) as in Turn 5a at Mosport or Turn 2 at Watkins Glen. All this considers only the segment time from turn in to apex, and assumes that the car must make the apex. All this is influenced by what is coming after the apex, but that's another story. However, exit speed is not always the holy grail; what counts is the segment time from one turn in to the next turn in.

Bob Rouleau

Smokey - While generalizations are usually dangerous, I agree with your summary above. I'd add a slight tweak to your comments - where it can be done, trail braking may allow you to hold a high speed longer because some of the braking is being done at corner entry instead of before. Consider a relatively tight corner at the end of a long straight for example. A car that trail brakes there will have maintained a high speed longer than one that does all the braking before initiating the turn. As you imply it's a question of trade offs - staying at top speed for a second longer might shorten segment times in spite of being slower at the apex of a 90 degree turn. I agree that Mosport T2 is not a good place for this trick nor is T1 (compression) or T7 (off camber down hill) at LCMT.

Rgds,

smokey

Bob, I agree. If the hairpin does not lead to another straight, using the turn in as a braking zone increases your average speed on the preceding straight. For T8 at Mosport, it's more a question of high entry speed/scrubbing it off versus balancing the car early and getting on the throttle. I have never tried the former, but watched with awe from behind as Sentras and Miatas enter T8 without braking. I'm tentatively using TB for T10 leading onto the front straight. I had a front seat view of someone trying to use TB entering T2, and my car was in the shop for two months.

M758

Guys,
Trail braking is in general a great skill and requied to be fast. However I do not feel that max trail braking in every corner on every track is always the fastest way around. I posted my description of one lap at a local track. I use trail braking in many places, but I use it as tool. It not my "goal" to trail brake, but it is my goal to find the shortest lap time. If I can reach into my driving tool bag and pull trail braking out and use it in some corners to make me faster then it is worth while. I don't go into a corner trying to trail brake to the apex, but often will trail brake if I perceve it making me faster.

This is why a driver that does not trail brake will be slower. They have one less tool in the tool bag to get faster. The application of that tool is very track, car and driver dependant. The question of if trail braking should be used in corner XX on track YY is an interesting one. The answer is what ever works for you to get around the track faster. The theory may be valid to trail brake to the apex, but in practice it is a much more compliacted exercise. Frankly there may be places were most would say.. "No never trail brake there." Then along comes some hot shoe who does it sucessfully and leaves every one in the dust with blank looks. This guys is now faster than everyone else and they need to reset their meters of what is practical and possible.

DE in general is very sheltered world. The line is defined and rarely changes. Skills are moderate and advance techniques are rare. For most part folks don't and are discouraged from trying new techniques and lines. The reasons are obvious for DE.

In racing the measure is winning and to some degree lap times. Lines are not fixed. They vary, trying new techniques and lines is advantagous. It can mean that you find something no one else has and that can be your edge. If fact if you are not willing to try new things you can't hope to get faster at any track. New things means lines, techniques and set-up (tire press, aligment, sway bar settings, etc) changes to the car. In racing is there is no "perfect" line. In fact the closest thing is the line the racer took in setting the lastest track record.

Personally I would avoid generalities like TB is good for XX corners or high or low HP cars. Trail Braking is key skill that a racer needs to posess to be fast. He also needs the skills to assess where he can best use it to his advantage to minimize his lap times and maintain or gain positions. G-sum is analysis tool that a racer may use. Here again he must be smart enough to know where and when to focus on it so that the ultimate goal of winning races can be achieved. To me maxing G-sum everywhere is a useless exercise. Minimizing lap times is valid goal and if to do that means I max g-sum on they entry to turn 2. Then I max g-sum on entry to turn 2. If in turn 4 I want minimize my g-load to minimize scrubbing effect of side load to a run a faster lap then I do that. Heck if come race time I purposely take a slower line in corner 6 just so that I am harder to pass then I do that too. Since even fast laps times are just a means to an end. That end is finishing in front of the next guy.

smokey

M758: well said and an excellent summary. There are no absolutes, and the fastest drivers are always pushing the envelope, and using every tool at their disposal. Drivers like me occasionally hope to see the edge of the envelope from a distance, and drive the car home - but it's still fun.

JC in NY

For what it's worth, a few years ago I took the Derek Daley racing school at Las Vegas and they teach trail braking from day one. It is taught on every corner and it is the basis for the whole curriculum. Also, they do use data aquisition and one of the focuses of the analysis is to see where the student is trail braking effectively. By the end of the school, the "fastest" students lap times were very close to the instructors but the tenths that they were losing was in the trail braking sections. The cars were Formula cars without ABS.

My conclusion from this is that one cannot get pole position in a competitive field without trail braking extensively and at every corner.

ColorChange

M578, I agree with everything you said except for the comment about not maxing g's. You try to maximize g's in the appropriate direction at all times. So if you need the g's, maximize them.

JC
tb is appropriate in the vast majority of corners but not all. At Daley, yes, tb them all. At Immola, Schumi tb's them all. But, contrary to what so many accuse me of, tb'ing on every turn is not the fastsest, just for most turns.

M758

Color,
To me a place where you don't want to max g's is the esses at the Glen, Both you and I have not driven that track, but from both John & Chris's description it seems clear that max g's here is wasted enery. Here you want minimize g's and actual are shooting for a very low g sum. Reason is generating lots of G's means you are scrubbing speed. This is of course assuming you are flat out through there.

ColorChange

Always maximize g's in the proper direction! This is absolute (subject to risk, driver skill, ...) If those g's aren't going in the proper direction at the esses, OK never use them, but always max when possible in the beneficial direction, that's all.

M758

Color, I believe Maxing G's in the esses will cause you slow down. It should run a "straight" as possible. If I run through there flat out with less g's that you do also runnng flat out who will be faster? (assuming the same car.)


Oh it is rell not good to state absolutes. They are rearly true motorsports. To many special cases caused peculatrities of tracks, cars, etc.

Jack667

M758 and CC -
Rather than talk about maxing G's, why not talk about maxing speed? I've driven at the Glen many times. (Just to note: Since we all know that you take the esses flat out, we know that you don't trail brake, which may simplify things)
If you define the line and the car, isn't maxing g's the same as maxing speed? (Why does this seem to simple - I'm not an engineer so maybe I'm wrong, really)
The esses at the Glen are probably a bad example, bc you are flat out. The other thing that was discussed as having been defined was entry speed. So - if you're in the same car, on the same line, with the same entry speed, and you take the esses flat out: ho-hum, what else is there?
But - who would argue that you'd want the max speed? It certainly sounds better than max G's in that case. I'm still thinking that its the same though...
This max-speed thing needs to be analyzed over a different example. For turn one at the Glen, if you define the line, what is thew goal? Probably exit speed first (after getting through safely!). How to ge there? Driving at the limit? G-limit, or max speed? Again - are they the same thing? This is where trail-braking, etc comes into play, but regarding the max-G theory, why can't we talk about max-speed?
Max G's would be better if there was a replicable model, which there is not. For example, if you took your car to a skip pad and could spend an hour testing and come away with a G limit for the car (we over-use the 1.0 G thing IMHO), then we could look at DAS results from our session at Turn 1 at the Glen and see if we were at the lmit. However, every turn is different, as stated many times - radius, camber, etc, plus other factors that make the limit different of the same turn - temps, tire wear, etc. So - you never really can predict max G for a given situation any better than you can discuss max speed.
In short, IMHO, max G would be good in a theoretical world where you could apply similar data to many situations (turns), but in the real world, every situation is different, so max speed could be easily substituted. I would say that max speed is a better parameter because most of us have speedo's in the car and we can get instant feedback! DAS can be used after the fact as well, bc we can be staring at our speedo's throught every turn.
Sorry for the ramble!