Brake-downshift-turn or Brake-turn-downshift
07-13-2006, 02:04 AM
#16
Nordschleife Master
If you can heel and toe perfectly you can downsift anywhere. Tha being said, most of use cannot, so best to do it in a mostly straight line.
07-13-2006, 11:40 AM
#17
Race Car
ok, I've instructed students to late downshift... mostly to fix a ealy downshift problem, later to be corrected to the brake-downshift-turn
if the student is going for the shifter early in the brake zone, or more importantly letting out the clutch early in the brake zone and transmission braking, I'll request them not to do that, and downshift late to get the braking down. (and I don't teach heel and toe or dbl cluthing to match rev's... at least not when braking is still an issue.)
for me is more of a hierarchary of problems, which is most critical driving problem... fix it and move on...
-this kinda goes back to the backwards braking thread last week...
So, imho, its not the correct, BUT can be used to fix a bigger problem... and easier to correct once you can scrub speed effectivly.
-no one else does this?
if the student is going for the shifter early in the brake zone, or more importantly letting out the clutch early in the brake zone and transmission braking, I'll request them not to do that, and downshift late to get the braking down. (and I don't teach heel and toe or dbl cluthing to match rev's... at least not when braking is still an issue.)
for me is more of a hierarchary of problems, which is most critical driving problem... fix it and move on...
-this kinda goes back to the backwards braking thread last week...
So, imho, its not the correct, BUT can be used to fix a bigger problem... and easier to correct once you can scrub speed effectivly.
-no one else does this?
07-13-2006, 11:43 AM
#18
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Let me try this again. If this is a duplicate post, I apologize...fat fingers.
I am an advocate for straight line shifting (up or down). I teach this at all times and it is, in addition to the points made already, potentially a problem for novice students because they have so much already on their plate. Keeping things simple is a plus: braking to slow down and downshifting (if the corner requires it) and then progressively accelerating through the apex, is a better method of driving the numbers for most drivers.
Having said that, I have shifted in certain turns when, for instance, there is a "straight" portion within the turn and there is a train of cars driving so slowly that the pace drops down considerably through the turn.
But, this kind of shifting has to be done with great care and smoothness and can't upset the car...or me.
I am an advocate for straight line shifting (up or down). I teach this at all times and it is, in addition to the points made already, potentially a problem for novice students because they have so much already on their plate. Keeping things simple is a plus: braking to slow down and downshifting (if the corner requires it) and then progressively accelerating through the apex, is a better method of driving the numbers for most drivers.
Having said that, I have shifted in certain turns when, for instance, there is a "straight" portion within the turn and there is a train of cars driving so slowly that the pace drops down considerably through the turn.
But, this kind of shifting has to be done with great care and smoothness and can't upset the car...or me.
07-13-2006, 11:47 AM
#19
Race Car
oh, one more thing is keeping the brake peddle pressed when going to the clutch... so many students give up on the brakes when down ****ing.
hard to get the feet moving independently. aka left foot braking....
(or... keeping at a '9' peddle (hard) when using the left foot for clutch work.)
I try to fix one at a time, then string them together.
line, brakes, then speed....
hard to get the feet moving independently. aka left foot braking....
(or... keeping at a '9' peddle (hard) when using the left foot for clutch work.)
I try to fix one at a time, then string them together.
line, brakes, then speed....
07-13-2006, 12:48 PM
#20
Race Director
Come to think of it, there is a corner where I do shift into a higher gear at the apex - Summit Point - Shenandoah circuit - Little Bend. It's either shift into third before the turn and bog down the motor, short shift into third at the apex, or rev it till kingdom come exiting that turn. I'd rather save my motor/tranny and short shift there. Little Bend isn't that sharp a turn - and the car is pretty straight at the apex.
But that's a specific corner / gear ratio issue, and I'm talking about an upshift, not a downshift.
I'd appreciate input from the NoVa folks as to how they deal with that turn...
- Zoltan.
But that's a specific corner / gear ratio issue, and I'm talking about an upshift, not a downshift.
I'd appreciate input from the NoVa folks as to how they deal with that turn...
- Zoltan.
07-13-2006, 12:50 PM
#21
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Originally Posted by mrbillfll
oh... so many students give up on the brakes when down ****ing.
sorry, can't resist.
07-13-2006, 06:05 PM
#22
Do whatever creates the smoothest transition... balance of the car is critical... eveything else should be subordinate to that.. there is no "right" way... there is the smooth way and the "wrong" way.
07-13-2006, 06:36 PM
#23
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If you don't have solid transmission and motor mounts and particularly with our wonderfully sloppy early 911 trannies, downshifting or upshifting in a turn or when pulling out to pass can result in rather costly engine repair. Ask me how I know 
Certainly shifing in turns seems to be a part of the F1 repertoire, but I think I'll wait until I get a sequential to consider it.
Certainly shifing in turns seems to be a part of the F1 repertoire, but I think I'll wait until I get a sequential to consider it.
08-01-2006, 10:43 AM
#24
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Originally Posted by GlenL
Probably beat to death but gotta ask:
When do you downshift in a corner?
To frame it up call it a 90 degree exit speed corner.
I'll downshift into the gear needed for exiting before turning in. This way the rears are helping to straighten the car (with a bit of clutch control) and I'm ready to apply power as soon as possible.
I've talked with guys who advocate downshifting right near the apex. They say it's hard on the clutch to downhift at higher speeds and that brief moment where they're shifting and I'm rolling on the power doesn't matter.
Aaargh! What say you?!
When do you downshift in a corner?
To frame it up call it a 90 degree exit speed corner.
I'll downshift into the gear needed for exiting before turning in. This way the rears are helping to straighten the car (with a bit of clutch control) and I'm ready to apply power as soon as possible.
I've talked with guys who advocate downshifting right near the apex. They say it's hard on the clutch to downhift at higher speeds and that brief moment where they're shifting and I'm rolling on the power doesn't matter.
Aaargh! What say you?!
About 60% to 70% through your brake zone, downshift.
Turn in.
Downshifting that late means you need a MUCH smaller throttle blip, and the engine speed/wheel speed differential will be much less, so if you mess up, you are much less likely to lock up the rear wheels. Plus, you put less wear & stress on clucth & all associated parts.
08-01-2006, 11:54 AM
#25
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A lot of comments and at least everybody is consistant nwith the fact that you shift while still in a straight lien, before turn in, unless it is an unusual corner. However, there are a few misnomers on this thread that I would like to challenge.
Firstly, although when teaching somebody, the concept of shifting at a certain % of the braking zone might be helpful, it doesn't get to the heart of the matter. On a forum we should be talking about when, mechanically, is the right time because people need to develop that mechanical sympathy. The person who commented on shifting whenever it was going to produce the smoothest shift is nearest the mark.
IMO, the point is detremined by a moment when it is no longer too early and at the same time, it's not too late!!! So, when is too early? Well, it is way too early if the shift will leave the engineat the top of the rev range. Then you are engine braking and this can be very unsettling. In addition, it gives you no ability to adjust through throttle inputs. Too late is the point where the engine doesn't have time to "settle" in the new gear before turn in and also there needs to be enough time to get back on the throttle as you don't want to be entering the corner on a totally trailing throttle.
Shifting too early can badly upset the back of the car (biggest cause of F1 back end break aways) while shifting too late destablises turn in.
Moving on, contrary to some of the comments, the later you leave the shift, the MORE the throttle needs to be blipped to match RPM. At first glance, it is tempting to believe that if there is a 750 rpm difference between gears, that remains constant and therefore it doesn't matter. Some (above) even suggest it is easier to match the rpm later in the braking. This is only true if you are right at the top end of the rev band.
The reason you need to blip more as the car slows is as follows. For any given braking effort, the car slows down quicker the slower it is going. It is an expinencial (sp) curve. The slower you are going, the greater the deceleration for any given effort. It is that rate of decelerration which determines how much you need to blip tghe throttle by so as to match. The total blip is the difference in revs + the amount the revs will have dropped in the time it takes to execute. The faster the deceleration the more drop during the execution. Sorry for accidentl;y posting this the wrong way around (see below)
I also believe that while your initial braking is not at full force and that you don't just lift off the brake at the end, you will be downshifting while braking at the maximum.
Another consideration is to ensure that at all times, the revs are kept in the power band or "on cam" or whatever you want to call it! My preference, if possible, is for the revs to fall no lower than about 200rpm from the bottom of the power band, giving room to scrub speed if a bit quick but also giving maximum amount of revs to go through, on exiting, without the need for a shift.
Contrary to some people's belief, it doesn't matter how well you can shift, if you do it mid corner you will unsettle the car.
All of the above is relatively basic and I have just been discussing this with a friend who raced F3000. He went one stage further, saying you can use the timing of a late shift to help the balance on turn in, allowing you to enter the corner faster although your exit speed will be down a bit. No use for sprints but for overtaking, it can be very good
All of this is a matter of feel and IMO, teaching people to feel their car is the way forward.
Firstly, although when teaching somebody, the concept of shifting at a certain % of the braking zone might be helpful, it doesn't get to the heart of the matter. On a forum we should be talking about when, mechanically, is the right time because people need to develop that mechanical sympathy. The person who commented on shifting whenever it was going to produce the smoothest shift is nearest the mark.
IMO, the point is detremined by a moment when it is no longer too early and at the same time, it's not too late!!! So, when is too early? Well, it is way too early if the shift will leave the engineat the top of the rev range. Then you are engine braking and this can be very unsettling. In addition, it gives you no ability to adjust through throttle inputs. Too late is the point where the engine doesn't have time to "settle" in the new gear before turn in and also there needs to be enough time to get back on the throttle as you don't want to be entering the corner on a totally trailing throttle.
Shifting too early can badly upset the back of the car (biggest cause of F1 back end break aways) while shifting too late destablises turn in.
Moving on, contrary to some of the comments, the later you leave the shift, the MORE the throttle needs to be blipped to match RPM. At first glance, it is tempting to believe that if there is a 750 rpm difference between gears, that remains constant and therefore it doesn't matter. Some (above) even suggest it is easier to match the rpm later in the braking. This is only true if you are right at the top end of the rev band.
The reason you need to blip more as the car slows is as follows. For any given braking effort, the car slows down quicker the slower it is going. It is an expinencial (sp) curve. The slower you are going, the greater the deceleration for any given effort. It is that rate of decelerration which determines how much you need to blip tghe throttle by so as to match. The total blip is the difference in revs + the amount the revs will have dropped in the time it takes to execute. The faster the deceleration the more drop during the execution. Sorry for accidentl;y posting this the wrong way around (see below)
I also believe that while your initial braking is not at full force and that you don't just lift off the brake at the end, you will be downshifting while braking at the maximum.
Another consideration is to ensure that at all times, the revs are kept in the power band or "on cam" or whatever you want to call it! My preference, if possible, is for the revs to fall no lower than about 200rpm from the bottom of the power band, giving room to scrub speed if a bit quick but also giving maximum amount of revs to go through, on exiting, without the need for a shift.
Contrary to some people's belief, it doesn't matter how well you can shift, if you do it mid corner you will unsettle the car.
All of the above is relatively basic and I have just been discussing this with a friend who raced F3000. He went one stage further, saying you can use the timing of a late shift to help the balance on turn in, allowing you to enter the corner faster although your exit speed will be down a bit. No use for sprints but for overtaking, it can be very good
All of this is a matter of feel and IMO, teaching people to feel their car is the way forward.
Last edited by SimonExtreme; 08-01-2006 at 03:09 PM.
08-01-2006, 12:18 PM
#27
Rennlist Member
downshift at the apex sure way to go for a off track excursion sooner or later ... get all the drama out of the way before.... tomany things can happen at an apex... think of a blown tire then throw torque to the rear wheel suddenly...hmmmmmmmm
slow in fast out
slow in fast out
08-01-2006, 12:23 PM
#29
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When I was down at Road Atlanta for a day driving the new Maserati with CambioCorse (single dry clutch) paddle shifters, I tried manual shifting at each and every apex, just to see how good the system really was.
OK, the system is really good, the car would never get upset at apex due to a rev mismatch.
That having been said, I would never do this with a manual transmission in my car.....too much opportunity for an 'off'.
OK, the system is really good, the car would never get upset at apex due to a rev mismatch.
That having been said, I would never do this with a manual transmission in my car.....too much opportunity for an 'off'.
08-01-2006, 01:10 PM
#30
Race Director
Originally Posted by ltc
When I was down at Road Atlanta for a day driving the new Maserati with CambioCorse (single dry clutch) paddle shifters, I tried manual shifting at each and every apex, just to see how good the system really was.
OK, the system is really good, the car would never get upset at apex due to a rev mismatch.
That having been said, I would never do this with a manual transmission in my car.....too much opportunity for an 'off'.
OK, the system is really good, the car would never get upset at apex due to a rev mismatch.
That having been said, I would never do this with a manual transmission in my car.....too much opportunity for an 'off'.
What's next? Drivers sitting in the bleachers operating their cars via remote control? Or robots actually using the remote controls to operate the cars?
I'll take a 5-speed manual tranny and a car without any ESP / PSM / E-I-E-I-O device that 'corrects' my faults. Thank you very much. (Ok, I don't mind having syncros, ABS, and power steering either!
)Ok, end rant...gotta go find my downshift point for T1 at The Glen...
-Z-man.