Throttle Steering and Trail Braking the TT
#2
10-17-2007, 09:06 AM
It's not possible to normally trail-brake with the 996tt because of
PSM which is on during braking, regardless of the dash switch.
PSM which is on during braking, regardless of the dash switch.
#4
10-17-2007, 11:04 AM
depends on what you mean and use trail braking for.
usually it is to rotate the car to turn in better, in mine I need to trail brake sometimes and I will get some rotation and some 4 wheel drift.
I drive at the track with the PSM off (as opposed to what I would recommend)
this may help some.....
The Physics of Racing,
Part 23: Trail Braking
the comments on these techniques being immediately obvious in wheel to wheel situations is what I experienced this past weekend while racing. Unless you are racing or timing you may never notice the actual difference is some of the more subtle driving techniques, just my 2 cents.
When I was taught to drive in the '80s, not all the fast drivers used trail braking and instructors usually gave it at most a passing mention as an optional, advanced technique. The reason was probably a risk-benefit analysis:
Nowadays, however, the general level of driving skill has increased to the point where it's no longer optional, unless you're content with fourth place.
As with most driving skills, it's difficult to get a feel for the limits without exceeding them from time to time. However, exceeding the limits at trail braking has some of the worst consequences one can invite on a race track, typically worse than those from mistakes at corner exit. It's definitely a big risk for a small effect, justified only because it accumulates. Blowing it results in too high an entry speed. You get:
However, when the cars are equalized, as in spec races, showroom stock, or in a lot of Solo II car classes, trail braking takes a prominent role. It can be difficult to spot it as an issue in Solo II, where drivers are alone against the clock. All else being equal, a Solo II driver without trail braking may just find himself scratching his head wondering how in blazes the other drivers can be so much faster. Go wheel-to-wheel on the track with equal cars, though, and the issue becomes instantly and visually obvious. You may be just as fast in the corner, coming out of the corner, down the straight. You may have perfect threshold braking. You may have perfect turn-in, apex and track out points. But that little extra later braking and entry speed will allow the trail-braker to take away several feet every corner. Corner after corner, lap after lap, he will gobble you up.
I recently completed a road-racing school at Sebring International Raceway where this is precisely what I saw. In identical Panoz school cars, the drivers who were faster than I were doing it right there and nowhere else. My ingrained, outdated style did me in, and even though I had much, much more on-track experience than the rest of the students, and even though they weren't faster in top speed than I, and even though their cornering technique was not nearly as polished as mine, three (out of twelve) of them had better lap times than I.
The instructors were as surprised as I. One even said he would have bet money that I was the quickest from watching me and riding with me (instructors sis not ride in the wheel-to-wheel sessions). The clock doesn't lie though, and we were scratching our heads and I started swapping cars. Once we went wheel-to-wheel on the third day of the program, I spotted it, right there the first time into turn 2: the three quicker drivers took a car length from me on the corner entry. They did it again in turn 10 (Cunningham), at the Tower turn, and turn 15 approaching the back stretch: all the turns requiring full braking and downshifts. I made up a bit at the hairpin, which is an autocrosser's corner if there ever was one, and I knew the importance of not missing the apex by more than an inch or two if possible. They also couldn't beat me entering turn 17, which has no straight braking zone: instead, the best technique is to brake partially after turn in (at 115 mph, this is big-time, serious fun). Thus, turn 17 did not trigger my old-fashioned "braking-zone" program, and I was able to use my high-speed experience to coax a bit more than average grip through it. So, in sum, my conservative turn-ins on the slow corners added up to about half a second per lap, which is about 65 feet at the start-finish line where we're going about 90 mph =132 fps (90 x 22 / 15). Ugly.
I was doing it the old-fashioned way: get the braking done in the braking zone and get your foot back on the gas pedal and up to neutral throttle before turn-in. That little tenth of a second or so where I'm coasting and they're still braking is the car-length they were taking out on me. It was small enough that the instructors couldn't feel it or see it. But electronic instrumentation would have picked it up. When I go back to the Panoz Sebring school next year, I will take advanced sessions in fully instrumented cars, where the instructors go out for some laps at 10/10s, then the students go out in the same car and take data. Back in the pits, the charts are differenced and the student can see precisely what he needs to do to come up to the instructor's level (most of the instructors have years of experience on the track, and hold current or former lap records in various cars on the course, so it's quite unlikely that a student will be as quick out of the box).
The following is a picture of the course snipped from the web site at http://www.sebringraceway.com, so you can see the bits of the course I'm talking about:
Let me say a few things about the school. The three-day program consisted of
Sebring is large, exciting, lovely, complex course with a deep history of sports-car racing. It is currently 3.70 miles in length, though it has been as long as 5.7 miles in its history. Let's do some dead reckoning, that is, math in our heads without even envelopes to write on. We'll see if we can cook up some data, from memory, to justify the intuitions and explain the results above.
There are 2.54 centimetres per inch: that's an exact number. Therefore, there are 2.54 x 12 = 30.48 centimetres per foot. The number of centimetres per mile, then are 30.48 x 5280 = 30 x 52 x 100 + 30 x 80 + 48 x 52 + 48 x 80 / 100 = 156000 + 2400 + (50 - 2)(50 + 2) + 3840 / 100 = 158400 + 2500 - 4 + 38.40 = 160,934.4. Thus, a mile contains 1.609344 kilometres, which we can round to 1.61, which is, conveniently, 8/5 + 1/100. So 3.70 miles is 29.637 / 5 = 5.927 kilometres or just about 6. Now, there are 5280 / 3 = 1760 yards in a mile, so we have 3700 + 2590 + 222 = 6,512 yards, which is consistent with 6 kilometres, so we've got a check on our math. In fact, we can be a little more sanguine about it. Another number we remember is that there are about 39 inches per metre; that's a yard and three inches, or 13/12 yard. So, if we have about 6,000 metres, that's going to be about 6,000 + 6,000 / 12 = 6,500 yards. Amazing, isn't it? Finally, this is 6,512 x 3 = 13,036 + 6,512 = 19,048 feet.
Big Track. Nice.
A record time around the course in the Panoz school cars is 2 min 28 seconds. The students were doing 2:40 to 2:45. I believe I uncorked a 2:36 somewhere along the way, but my typical lap was 2:40 and the quicker guys pulled about 65 feet on me at the start-finish every lap, which I reckoned before to be worth half a second. What's the average speed at 2:40? That's 3.70 miles in 160 seconds. The average speed is 19,048 / 160 fps ~ 1905 / 16 ~ 476 / 4 ~ 119 fps, which is 119 x 15 / 22 mph, and that is (1190 + 595 ~ 1785) / 22 = 892.5 / 11. It's hard to divide by 11, so lets multiply instead. 80 mph by 11 would be 880, and that's not enough by 12.5. So, if we go with 81 mph by 11, namely 891, we're short by 1.5. A tenth of 11 will take care of some of that, so 81.1 by 11, namely 892.1, leaves us close enough. Now, doing the same distance in 2:28, or 148 seconds, yields an average speed of 19,048 / 148 ~ 4,762 / 37. Another tough divisor. Let's try 130 x 37 = 3700 + 1110 = 4810, too much by 48. But, we lucked out, it's obvious that 48 is about 1.30 x 37, so we get 130 - 1.30 = 128.7 fps. Now multiply that by 15 / 22: (1287 + 643.5) / 22 ~ 1930 / 22 = 965 / 11. 90 x 11 would be 990, too much by 25, which is a little more than 2 x 11. So 90 - 2 = 88 x 11 would be 880 + 88 = 968, too much by 3, so we'll reduce 88 by 0.3 x 11 to get 87.7. The average speed of a record-setting lap is 6.6 mph faster than our pitiful student laps! The difference is 12 seconds, so, as a rule of thumb, a second at 85 mph average is worth a little more than 1/2 an mph.
But, before we wander too far off topic, let's compare 2:40 to 2:40.5, since my contention from the beginning of this note is THAT difference can be accounted entirely to trail braking in four corners of this course: 2, 10, 13, and 15. Well, at 119 fps, average speed, half a second is about 60 feet, which is about 4 car lengths. Yep, there you have it: one car length per significant corner due to trail braking. Darn it, looks like I'll just have to go back there and keep trying, over and over again.
P.O. Box 662
Burbank, CA 91503
usually it is to rotate the car to turn in better, in mine I need to trail brake sometimes and I will get some rotation and some 4 wheel drift.
I drive at the track with the PSM off (as opposed to what I would recommend)
this may help some.....
The Physics of Racing,
Part 23: Trail Braking
the comments on these techniques being immediately obvious in wheel to wheel situations is what I experienced this past weekend while racing. Unless you are racing or timing you may never notice the actual difference is some of the more subtle driving techniques, just my 2 cents.
Brian Beckman, PhD
©Copyright March 2001
Trail-braking is a subtle driving technique that allows for later braking and increased corner entry speed. The classical technique is to complete braking before turn-in. This is a safer, easier technique for the driver because it separates traction management into two phases, braking and cornering, so the driver doesn't have to chew gum and walk at the same time, as it were. With the trail-braking technique, the driver carries braking into the corner, gradually trailing off the brakes while winding in the steering. Since braking continues in the corner, it's possible to delay its onset in the preceding straight braking zone. Since it eliminates the sub-optimal moments between the ramp-down from braking and the ramp-up to limit cornering by overlapping them, entry speeds can be higher. The combination of these two effects means that the advantage of later braking is carried through the first part of the corner. In many ways, this is the flip side to corner exit, where any speed advantage due to superior technique gets carried all the way down the ensuing straight. The magnitude of the trail-braking effect is much smaller, though: perhaps a car length or two for a typical corner. Done consistently, though, it can accumulate to whole seconds over a course.When I was taught to drive in the '80s, not all the fast drivers used trail braking and instructors usually gave it at most a passing mention as an optional, advanced technique. The reason was probably a risk-benefit analysis:
- it's a small effect compared to the big-picture basics, like carrying speed out of a corner, that everyone must learn early on
- it's difficult to learn, so why burden new students with it?
- mistakes with it are ugly
Nowadays, however, the general level of driving skill has increased to the point where it's no longer optional, unless you're content with fourth place.
As with most driving skills, it's difficult to get a feel for the limits without exceeding them from time to time. However, exceeding the limits at trail braking has some of the worst consequences one can invite on a race track, typically worse than those from mistakes at corner exit. It's definitely a big risk for a small effect, justified only because it accumulates. Blowing it results in too high an entry speed. You get:
- inappropriate angular attitude in the corner
- immediate probing of the understeer or oversteer characteristics of the car
- surprise, pop quiz on the driver's car-control skills
- missed apex and track-out points
- a looming penalty cone, gravel trap, tyre barrier, concrete wall, tree, etc.
- when you bounce back from that impact, you can hit other cars, spectators, corner marshals, berms, etc.
- anything else that can go wrong in a blown corner
However, when the cars are equalized, as in spec races, showroom stock, or in a lot of Solo II car classes, trail braking takes a prominent role. It can be difficult to spot it as an issue in Solo II, where drivers are alone against the clock. All else being equal, a Solo II driver without trail braking may just find himself scratching his head wondering how in blazes the other drivers can be so much faster. Go wheel-to-wheel on the track with equal cars, though, and the issue becomes instantly and visually obvious. You may be just as fast in the corner, coming out of the corner, down the straight. You may have perfect threshold braking. You may have perfect turn-in, apex and track out points. But that little extra later braking and entry speed will allow the trail-braker to take away several feet every corner. Corner after corner, lap after lap, he will gobble you up.
I recently completed a road-racing school at Sebring International Raceway where this is precisely what I saw. In identical Panoz school cars, the drivers who were faster than I were doing it right there and nowhere else. My ingrained, outdated style did me in, and even though I had much, much more on-track experience than the rest of the students, and even though they weren't faster in top speed than I, and even though their cornering technique was not nearly as polished as mine, three (out of twelve) of them had better lap times than I.
The instructors were as surprised as I. One even said he would have bet money that I was the quickest from watching me and riding with me (instructors sis not ride in the wheel-to-wheel sessions). The clock doesn't lie though, and we were scratching our heads and I started swapping cars. Once we went wheel-to-wheel on the third day of the program, I spotted it, right there the first time into turn 2: the three quicker drivers took a car length from me on the corner entry. They did it again in turn 10 (Cunningham), at the Tower turn, and turn 15 approaching the back stretch: all the turns requiring full braking and downshifts. I made up a bit at the hairpin, which is an autocrosser's corner if there ever was one, and I knew the importance of not missing the apex by more than an inch or two if possible. They also couldn't beat me entering turn 17, which has no straight braking zone: instead, the best technique is to brake partially after turn in (at 115 mph, this is big-time, serious fun). Thus, turn 17 did not trigger my old-fashioned "braking-zone" program, and I was able to use my high-speed experience to coax a bit more than average grip through it. So, in sum, my conservative turn-ins on the slow corners added up to about half a second per lap, which is about 65 feet at the start-finish line where we're going about 90 mph =132 fps (90 x 22 / 15). Ugly.
I was doing it the old-fashioned way: get the braking done in the braking zone and get your foot back on the gas pedal and up to neutral throttle before turn-in. That little tenth of a second or so where I'm coasting and they're still braking is the car-length they were taking out on me. It was small enough that the instructors couldn't feel it or see it. But electronic instrumentation would have picked it up. When I go back to the Panoz Sebring school next year, I will take advanced sessions in fully instrumented cars, where the instructors go out for some laps at 10/10s, then the students go out in the same car and take data. Back in the pits, the charts are differenced and the student can see precisely what he needs to do to come up to the instructor's level (most of the instructors have years of experience on the track, and hold current or former lap records in various cars on the course, so it's quite unlikely that a student will be as quick out of the box).
The following is a picture of the course snipped from the web site at http://www.sebringraceway.com, so you can see the bits of the course I'm talking about:
- solo exercises in braking, skid recovery, and autocrossing
- detailed in-car instruction as driver and passenger over several lapping sessions
- racecraft including passing and rolling starts
- wheel-to-wheel sessions on the full open course
Sebring is large, exciting, lovely, complex course with a deep history of sports-car racing. It is currently 3.70 miles in length, though it has been as long as 5.7 miles in its history. Let's do some dead reckoning, that is, math in our heads without even envelopes to write on. We'll see if we can cook up some data, from memory, to justify the intuitions and explain the results above.
There are 2.54 centimetres per inch: that's an exact number. Therefore, there are 2.54 x 12 = 30.48 centimetres per foot. The number of centimetres per mile, then are 30.48 x 5280 = 30 x 52 x 100 + 30 x 80 + 48 x 52 + 48 x 80 / 100 = 156000 + 2400 + (50 - 2)(50 + 2) + 3840 / 100 = 158400 + 2500 - 4 + 38.40 = 160,934.4. Thus, a mile contains 1.609344 kilometres, which we can round to 1.61, which is, conveniently, 8/5 + 1/100. So 3.70 miles is 29.637 / 5 = 5.927 kilometres or just about 6. Now, there are 5280 / 3 = 1760 yards in a mile, so we have 3700 + 2590 + 222 = 6,512 yards, which is consistent with 6 kilometres, so we've got a check on our math. In fact, we can be a little more sanguine about it. Another number we remember is that there are about 39 inches per metre; that's a yard and three inches, or 13/12 yard. So, if we have about 6,000 metres, that's going to be about 6,000 + 6,000 / 12 = 6,500 yards. Amazing, isn't it? Finally, this is 6,512 x 3 = 13,036 + 6,512 = 19,048 feet.
Big Track. Nice.
A record time around the course in the Panoz school cars is 2 min 28 seconds. The students were doing 2:40 to 2:45. I believe I uncorked a 2:36 somewhere along the way, but my typical lap was 2:40 and the quicker guys pulled about 65 feet on me at the start-finish every lap, which I reckoned before to be worth half a second. What's the average speed at 2:40? That's 3.70 miles in 160 seconds. The average speed is 19,048 / 160 fps ~ 1905 / 16 ~ 476 / 4 ~ 119 fps, which is 119 x 15 / 22 mph, and that is (1190 + 595 ~ 1785) / 22 = 892.5 / 11. It's hard to divide by 11, so lets multiply instead. 80 mph by 11 would be 880, and that's not enough by 12.5. So, if we go with 81 mph by 11, namely 891, we're short by 1.5. A tenth of 11 will take care of some of that, so 81.1 by 11, namely 892.1, leaves us close enough. Now, doing the same distance in 2:28, or 148 seconds, yields an average speed of 19,048 / 148 ~ 4,762 / 37. Another tough divisor. Let's try 130 x 37 = 3700 + 1110 = 4810, too much by 48. But, we lucked out, it's obvious that 48 is about 1.30 x 37, so we get 130 - 1.30 = 128.7 fps. Now multiply that by 15 / 22: (1287 + 643.5) / 22 ~ 1930 / 22 = 965 / 11. 90 x 11 would be 990, too much by 25, which is a little more than 2 x 11. So 90 - 2 = 88 x 11 would be 880 + 88 = 968, too much by 3, so we'll reduce 88 by 0.3 x 11 to get 87.7. The average speed of a record-setting lap is 6.6 mph faster than our pitiful student laps! The difference is 12 seconds, so, as a rule of thumb, a second at 85 mph average is worth a little more than 1/2 an mph.
But, before we wander too far off topic, let's compare 2:40 to 2:40.5, since my contention from the beginning of this note is THAT difference can be accounted entirely to trail braking in four corners of this course: 2, 10, 13, and 15. Well, at 119 fps, average speed, half a second is about 60 feet, which is about 4 car lengths. Yep, there you have it: one car length per significant corner due to trail braking. Darn it, looks like I'll just have to go back there and keep trying, over and over again.
About the author:
Brian Beckman is a physicist and member of the No Bucks Racing Club. He my be contacted at the following site: Physics of Racing SeriesP.O. Box 662
Burbank, CA 91503
Last edited by tom kerr; 10-17-2007 at 11:34 AM.
#5
10-17-2007, 11:10 AM
depends on what you mean and use trail braking for.
usually it is to rotate the car to turn in better, in mine I need to trail brake sometimes and I will get some rotation and some 4 wheel drift.
I drive at the track with the PSM off (as opposed to what I would recommend)
usually it is to rotate the car to turn in better, in mine I need to trail brake sometimes and I will get some rotation and some 4 wheel drift.
I drive at the track with the PSM off (as opposed to what I would recommend)
Well the technique is perfect for the TT, if you are turning while braking, you are loading the front tires, which counters the rear weight bias that doesnt put enough weight over the front wheels, thereby making turn-in a lot easier.
You then use throttle steer, mid corner to get the car pointed where you want to go before you go full throttle to reduce the power understeer at track out.
I used it effectively in my TT, I dont see how you cant use it in a TT normally, I need explanation. Because I havent tried it in another car to know if it made be made better, but it CERTAINLY can be effective in the TT.
#6
10-17-2007, 11:43 AM
I too have wondered - "What is the fast way around this track?"
I too have stood the Turbo on it's nose at apex for rotation, catching it and squirting toward exit, I've gone into braking duels with my "self-preservation" alter-ego... Only to wonder...
Read this and wonder with me...
The Rocking Chair - We would be back of packers
I'd love to see a Supercup driver in my car at Mid-OH and see what the car is really capable of... Humbling I would have to believe - just plain humbling.
Deetz
I too have stood the Turbo on it's nose at apex for rotation, catching it and squirting toward exit, I've gone into braking duels with my "self-preservation" alter-ego... Only to wonder...
Read this and wonder with me...
The Rocking Chair - We would be back of packers
I'd love to see a Supercup driver in my car at Mid-OH and see what the car is really capable of... Humbling I would have to believe - just plain humbling.
Deetz
#7
10-17-2007, 12:01 PM
"surprise, pop quiz on the driver's car-control skills "
This is very true, and applies to throttle steering as well.
This is very true, and applies to throttle steering as well.
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#8
10-17-2007, 12:07 PM
Registered User
Join Date: Sep 2004
Location: Murrieta, Southern California
Age: 39
Posts: 1,489
Rep Power: 80 
I too have wondered - "What is the fast way around this track?"
I too have stood the Turbo on it's nose at apex for rotation, catching it and squirting toward exit, I've gone into braking duels with my "self-preservation" alter-ego... Only to wonder...
Read this and wonder with me...
The Rocking Chair - We would be back of packers
I'd love to see a Supercup driver in my car at Mid-OH and see what the car is really capable of... Humbling I would have to believe - just plain humbling.
Deetz
I too have stood the Turbo on it's nose at apex for rotation, catching it and squirting toward exit, I've gone into braking duels with my "self-preservation" alter-ego... Only to wonder...
Read this and wonder with me...
The Rocking Chair - We would be back of packers
I'd love to see a Supercup driver in my car at Mid-OH and see what the car is really capable of... Humbling I would have to believe - just plain humbling.
Deetz
#9
10-17-2007, 03:13 PM
I am revealing my autocross bias, and retract my comment for road-race.
The type of severe loose rotation you may want in autocross is not possible
with PSM, but on a road course there is no reason why you cannot start your
turn-in while still on the brakes some.
Joe
The type of severe loose rotation you may want in autocross is not possible
with PSM, but on a road course there is no reason why you cannot start your
turn-in while still on the brakes some.
Joe
#10
10-17-2007, 03:30 PM
If I'm on the gas while you're still on the brakes, who's
gonna be faster down the straight?
Deetz
#11
10-17-2007, 05:35 PM
Registered User
Join Date: Mar 2007
Location: VANCOUVER, BC, CANADA
Posts: 489
Rep Power: 37 trailbraking is used so that you can brake as LATE as possible...and carry very minimal braking to or just before the apex... this SHOULD give you MAX traction through the corner..which will allow for higher corner speeds...and higher retention of momentum through the corner...
the fact that you are throttling sooner might possibly mean that you are not going fast enough through the corner to begin with.
THERE ARE some corners where early throttle applicaton will help you exit the corner faster....but usually on very late apex situations where you are already going pretty much straight at the apex
#12
10-17-2007, 05:43 PM
If I'm on a road course, and do trail braking, I enter the corner
faster than someone who slows down enough to need zero braking
at his turn-in point. Presumably the corner is long enough to have
a stretch of it where we have to be on an even throttle. As long
as I get to the same line as this other person, and I'm pointing the
same way, before either of us can accelerate out of the corner I
may have won something with my extra speed before our lines
converge. And if the corner is too tight/short to need any constant
throttle, if trail-braking brings the tail around controllably so the car
is pointed better at the apex, you may be able to put on more power
and drift out, where a non-trail-braker might still be pointing too
much to the outside to be able to put the power on as much.
#13
10-17-2007, 06:37 PM
I don't think you (silver and joe) are getting it...
It's about the weight transfer.
Let's all assume that we are competent drivers - none of this "if you nail the exit" If you aren't absolutley nailing your marks, you shouldn't even be attempting trail braking. Lets also assume that we are on line (yes there is only one line) and that we are consistent.
What the article is saying (these are PROs running SUPERCUP hint hint) is that braking early (and not standing the car on it's nose) then back *on the gas* throughout the corner is gonna win in a Porsche.
I'm just throwing it out there for discussion. I know what I do, and I know what everybody says - but these guys are faster than me, and what they say is "Rock the chair back a bit - early - and that supports the fact that Porsches stick better *all the way through the corner* with positive throttle.
Another point - How good (consistent) are you with trailbraking? I don't know about you - I think I'm pretty fast, but if I'm haulin down Mid-OH at 155 to a 70 mph corner - it is damn'd hard to nail braking point, turn in, entry speed, amount of rotation, smooth brake release, etc in a consistent, repeatable manner.
Remember - what trailbraking really is -
We are inducing a spin intentionally that we intend to catch in the middle of the corner with throttle application to then stick the rear and abate the spin.
Thank you very much, but I know I practice, but I can't get it to where I'm anywhere near the limit when I do it, and if I don't get it, I'm way *over* the limit, and have to mitigate to recover and lose all the advantage I was trying to gain with the technique.
And I'm not saying I go through a corner slower - I think I'm just a fraction *faster* because I have much higher control over precise entry and corner speeds.
FWIW - YMMV
Deetz.
It's about the weight transfer.
Let's all assume that we are competent drivers - none of this "if you nail the exit" If you aren't absolutley nailing your marks, you shouldn't even be attempting trail braking. Lets also assume that we are on line (yes there is only one line) and that we are consistent.
What the article is saying (these are PROs running SUPERCUP hint hint) is that braking early (and not standing the car on it's nose) then back *on the gas* throughout the corner is gonna win in a Porsche.
I'm just throwing it out there for discussion. I know what I do, and I know what everybody says - but these guys are faster than me, and what they say is "Rock the chair back a bit - early - and that supports the fact that Porsches stick better *all the way through the corner* with positive throttle.
Another point - How good (consistent) are you with trailbraking? I don't know about you - I think I'm pretty fast, but if I'm haulin down Mid-OH at 155 to a 70 mph corner - it is damn'd hard to nail braking point, turn in, entry speed, amount of rotation, smooth brake release, etc in a consistent, repeatable manner.
Remember - what trailbraking really is -
We are inducing a spin intentionally that we intend to catch in the middle of the corner with throttle application to then stick the rear and abate the spin.
Thank you very much, but I know I practice, but I can't get it to where I'm anywhere near the limit when I do it, and if I don't get it, I'm way *over* the limit, and have to mitigate to recover and lose all the advantage I was trying to gain with the technique.
And I'm not saying I go through a corner slower - I think I'm just a fraction *faster* because I have much higher control over precise entry and corner speeds.
FWIW - YMMV
Deetz.
#14
10-17-2007, 08:09 PM
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Join Date: Mar 2007
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well, i think in your case if doing things with a high level of efficacy and consistancy at the track at the limit is an issue more practice may be necessary. i dont know you so i wont comment on your particular level of skill, however, based on your own comments this may be a problem for you.
and i am fully aware about weight transfer and the physics implied by it with respect to driving and controlling car. trailbraking is used by all racers to get the best use of the available energy in the car to load up or unload a particular corner of a the car.... with the end result be ideal rotation of the car. for the specific corner.
YES Porsche's do have amazing grip, especially on the rear, once the throttle is applied...but this is only usefull if you are already pointed inthe right direction... trailbraking, as i said before, will also allow for the fastest possible entry speed at the absolute limits of the car and also stabalize the suspension at entry and through the corner...
if you still dont think trailbraking is faster than not...then good for you.
and without throwing names, my best friend runs the michelin supercup and is also a Porsche cup champion...and he has taught me quite a bit.... you can argue with him that trailbraking is slow
and i am fully aware about weight transfer and the physics implied by it with respect to driving and controlling car. trailbraking is used by all racers to get the best use of the available energy in the car to load up or unload a particular corner of a the car.... with the end result be ideal rotation of the car. for the specific corner.
YES Porsche's do have amazing grip, especially on the rear, once the throttle is applied...but this is only usefull if you are already pointed inthe right direction... trailbraking, as i said before, will also allow for the fastest possible entry speed at the absolute limits of the car and also stabalize the suspension at entry and through the corner...
if you still dont think trailbraking is faster than not...then good for you.
and without throwing names, my best friend runs the michelin supercup and is also a Porsche cup champion...and he has taught me quite a bit.... you can argue with him that trailbraking is slow
#15
10-17-2007, 10:03 PM
For my 2 cents worth I race a GT3RS and a track a modded road registered 996TT in club days and the techniques are quite different.
The race car is much lighter, set up with very stiff suspension (1500lb springs and 4 way afjustable shocks), slicks etc. and can readilly take light trail braking to counter turn in understeer. The key with a 911 is to concentrate on earliest possible application of the throttle and not mid corner speed so the apex is going to be later than that for a front or mid engine car so as to allow for the straighter exit line/earlier throttle.
The TT is comparatively heavy and soft and I find trail braking more difficult in that it is easier to upset the balance. Maybe some more practice would help but I suspect the key is "smooth is fast" which is hard to do if you are effectively forcing turn in oversteer to combat the understeer. IMHO it requires a smoother application of everthing but the concentration is still on the early power.
Any 911 in a mixed field is at a disadvantage from turn in to apex but comes into it's own with all that weight over the rear wheels allowing much earlier application of the throttle.
The race car is much lighter, set up with very stiff suspension (1500lb springs and 4 way afjustable shocks), slicks etc. and can readilly take light trail braking to counter turn in understeer. The key with a 911 is to concentrate on earliest possible application of the throttle and not mid corner speed so the apex is going to be later than that for a front or mid engine car so as to allow for the straighter exit line/earlier throttle.
The TT is comparatively heavy and soft and I find trail braking more difficult in that it is easier to upset the balance. Maybe some more practice would help but I suspect the key is "smooth is fast" which is hard to do if you are effectively forcing turn in oversteer to combat the understeer. IMHO it requires a smoother application of everthing but the concentration is still on the early power.
Any 911 in a mixed field is at a disadvantage from turn in to apex but comes into it's own with all that weight over the rear wheels allowing much earlier application of the throttle.