rapid fire tap of brakes what's the use?
10-31-2004, 08:33 PM
#1
rapid fire tap of brakes what's the use?
Hi,
I saw this japanese jgtc driver going into a braking zone doing arapid fire tap of the brakes like 1 tap/ 1/4 second as he kept his foot on the gas and then trail braked into the apex. Can someone explain using a tap technique's value VS just a progressive squeeze to threshold then trail brake to the apex? Is it used for some kind of car settling issue?
I saw this japanese jgtc driver going into a braking zone doing arapid fire tap of the brakes like 1 tap/ 1/4 second as he kept his foot on the gas and then trail braked into the apex. Can someone explain using a tap technique's value VS just a progressive squeeze to threshold then trail brake to the apex? Is it used for some kind of car settling issue?
10-31-2004, 08:44 PM
#2
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Usually, you would do a quick "sqeeze" of the brake pedal approaching the braking zone at the end of a long straight. This is done to ensure that the caliper pistons have not retracted, therefore, when you do brake, you have a high, firm pedal.
There are few things in this world that will raise your heart rate more quickly than getting to the braking zone at 175 mph, apply the brakes, and have the pedal go to the floor....................
There are few things in this world that will raise your heart rate more quickly than getting to the braking zone at 175 mph, apply the brakes, and have the pedal go to the floor....................
10-31-2004, 09:07 PM
#3
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I have seen some pro drivers do this and I agree it is for the reason Gumball stated. It's never a bad idea to gently test the pedal with the left foot a few hundred feet prior to the point of no return. It's also a good idea to pre-plan your "out" should you experience a brake failure at the track. Never ignore a soft pedal as they usually only warn once before giving up entirely. I never want to experience that kind of terror. Some of the worst accidents I have seen were due to brake loss. Here is a clip of a Viper losing brakes at CMP, you can see what happens when it all goes bad
http://www.gvc-bmwcca.org/photos/red...ipercrash.mpeg
http://www.gvc-bmwcca.org/photos/red...ipercrash.mpeg
10-31-2004, 09:29 PM
#4
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Originally Posted by carreracup21
Here is a clip of a Viper losing brakes at CMP, you can see what happens when it all goes bad
http://www.gvc-bmwcca.org/photos/red...ipercrash.mpeg
http://www.gvc-bmwcca.org/photos/red...ipercrash.mpeg
10-31-2004, 09:38 PM
#5
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I wonder if they ever figured out why they failed......if you lost them going 170 on the back at VIR you would do a serious Dukes of Hazard jump and probably land at the bottom of Hogpen.
10-31-2004, 10:07 PM
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No idea why he had the problem. Many on another board with lots of professional drivers thought it may have not been a brake failure but a driver error (missed the brake pedal or something, I can't remember the alternative theories)
Either way the incident made me re-think some of my instructing and I have not been in a Viper more than a time or two since. It is one thing to have a OTE at 100mph but at 150mph+ you are going to get hurt most likely.
Either way the incident made me re-think some of my instructing and I have not been in a Viper more than a time or two since. It is one thing to have a OTE at 100mph but at 150mph+ you are going to get hurt most likely.
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11-01-2004, 12:49 AM
#8
Thanks guys...I learn something from you guys almost everyday. I like the idea of a little test before the end of the straight. I always took for granted my brakes would work. Ignorance is bliss....
11-01-2004, 12:42 PM
#9
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I thought of something else. If you are running on a track such as Elkhart Lake, or the road course at Charlotte (and a few others) - where the straight is long enough for the brakes to cool down, a 2 second "drag" on the pedal, just prior to the braking point, is a good idea.
If you do a hard brake from 160-200 mph on cold brakes, it is possible that you could lock a wheel........with negative results...................
Just a thought.....
If you do a hard brake from 160-200 mph on cold brakes, it is possible that you could lock a wheel........with negative results...................
Just a thought.....
11-01-2004, 03:05 PM
#10
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Originally Posted by carreracup21
I heard from the guy that runs the Viper Days DE's , that a loss of brakes there can lead to a serious airborn adventure ... like 60 feet up in the air, Yikes.
Yeeeeeee Yee-haw.
End music
IIRC, to get a FWD car to get more turn-in, often a driver will stab at the brakes mid corner to get the rear to rotate around. Not my idea of the smoothest way around a corner, but then again, FWD on the track isn't my idea of a good combo either!
-Z.
11-01-2004, 05:03 PM
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Just a thought, I think some cars have self bleeders that release a small bit of brake fluid from the caliper on every application. This keeps the fluid in the caliper cool(er). This might explain the rapid, repeated application of the brakes because one tap would suffice to know if the pedal is 'there' or not. What do you think? One thing is certain, at that level, nothing is by accident or for fun; there is a reason, whether we are clever enough to figure it out or not. lol
11-01-2004, 05:18 PM
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Regarding the viper crash, I try to learn as much as I can. Can you guys please comment on my thoughts?
It looks to me like the driver made a number of mistakes.
1. You should always study exit points on the track, especially at big braking zones, so that you know in advance what you should do and can therefore execute the exit plan faster.
2. He should have known he was having a brake problem fairly early and then gone both feet in and hit the e-brake, dealing with those consequences while traveling in a roughly (hopefully) straight line.
3. He should not have turned in until he reached his corner entry (turn in) speed. He had much more room (paved as well) going straight then he had after he turned in. He turned in when he was going WAY too fast. Bad move.
4. When you know you are going to biff, get your hands away from the wheel. This can save broken hands, arms, etc. He held on all the way to the bitter end.
Anything else or am I wrong about anything?
I love the coolness of the instructor. Just a walk in the park … “turn the ignition off” and get the hell out.
It looks to me like the driver made a number of mistakes.
1. You should always study exit points on the track, especially at big braking zones, so that you know in advance what you should do and can therefore execute the exit plan faster.
2. He should have known he was having a brake problem fairly early and then gone both feet in and hit the e-brake, dealing with those consequences while traveling in a roughly (hopefully) straight line.
3. He should not have turned in until he reached his corner entry (turn in) speed. He had much more room (paved as well) going straight then he had after he turned in. He turned in when he was going WAY too fast. Bad move.
4. When you know you are going to biff, get your hands away from the wheel. This can save broken hands, arms, etc. He held on all the way to the bitter end.
Anything else or am I wrong about anything?
I love the coolness of the instructor. Just a walk in the park … “turn the ignition off” and get the hell out.
Last edited by ColorChange; 11-01-2004 at 05:49 PM.
11-01-2004, 05:21 PM
#13
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dgaunt:
Self bleeders are for bleeding brakes only, and would have nothing to do with cooling.
You would NOT want to leave them open/in use when the car is being run..!!!!!
ColorChange:
I would have to agree with you, with a few exceptions:
if I was in the car, first I would have been SCREAMING ..."BRAKES...HARD"
or, if I could see that the pedal had gone soft or away, I would have , again, SCREAMED...."PUMP PEDAL", and if that was not working,
I would have pulled the handbrake
(is the handbrake lever reachable by the passenger in this car?? I would know before I got in.....)
or taken the wheel to spin the car......
ANYTHING to prevent a high speed crash......
and you are right about getting your hands off the wheel before you crash - in a 4 or 5 point harness, cross your arms and grab your shoulder belts....
in a "street belt" system, grab shoulder harness with both hands,,,,,
Self bleeders are for bleeding brakes only, and would have nothing to do with cooling.
You would NOT want to leave them open/in use when the car is being run..!!!!!
ColorChange:
I would have to agree with you, with a few exceptions:
if I was in the car, first I would have been SCREAMING ..."BRAKES...HARD"
or, if I could see that the pedal had gone soft or away, I would have , again, SCREAMED...."PUMP PEDAL", and if that was not working,
I would have pulled the handbrake
(is the handbrake lever reachable by the passenger in this car?? I would know before I got in.....)
or taken the wheel to spin the car......
ANYTHING to prevent a high speed crash......
and you are right about getting your hands off the wheel before you crash - in a 4 or 5 point harness, cross your arms and grab your shoulder belts....
in a "street belt" system, grab shoulder harness with both hands,,,,,
Last edited by GUMBALL; 11-01-2004 at 05:39 PM.
11-01-2004, 05:35 PM
#14
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I'm glad both driver & instructor made it out OK; hopefully there were no injuries.
Also, after seeing the video, it makes me wonder if airbags are a good thing when you have a 5/6 point harness setup. I noticed at the end the instructor was wearing a Teamtech Rampac harness (very popular with Viper owners and the same harnesses I wear).
If it were me, I think I'd rather not have to deal with an airbag going off in front of me.
Also, after seeing the video, it makes me wonder if airbags are a good thing when you have a 5/6 point harness setup. I noticed at the end the instructor was wearing a Teamtech Rampac harness (very popular with Viper owners and the same harnesses I wear).
If it were me, I think I'd rather not have to deal with an airbag going off in front of me.
11-01-2004, 06:04 PM
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Originally Posted by ColorChange
Regarding the viper crash, I try to learn as much as I can. Can you guys please comment on my thoughts?
It looks to me like the driver made a number of mistakes.
1. You should always study exit points on the track, especially at big braking zones, so that you know in advance what you should do and can therefore execute the exit plan faster.
2. He should have known he was having a brake problem fairly early and then gone both feet in and hit the e-brake, dealing with those consequences while traveling in a roughly (hopefully) straight line.
3. He should not have turned in until he reached his corner entry (turn in) speed. He had much more room (paved as well) going straight then he had after he turned in. He turned in when he was going WAY too fast. Bad move.
4. When you know you are going to biff, get your hands away from the wheel. This can save broken hands, arms, etc. He held on all the way to the bitter end.
Anything else or am I wrong about anything?
I love the coolness of the instructor. Just a walk in the park … “turn the ignition off” and get the hell out.
It looks to me like the driver made a number of mistakes.
1. You should always study exit points on the track, especially at big braking zones, so that you know in advance what you should do and can therefore execute the exit plan faster.
2. He should have known he was having a brake problem fairly early and then gone both feet in and hit the e-brake, dealing with those consequences while traveling in a roughly (hopefully) straight line.
3. He should not have turned in until he reached his corner entry (turn in) speed. He had much more room (paved as well) going straight then he had after he turned in. He turned in when he was going WAY too fast. Bad move.
4. When you know you are going to biff, get your hands away from the wheel. This can save broken hands, arms, etc. He held on all the way to the bitter end.
Anything else or am I wrong about anything?
I love the coolness of the instructor. Just a walk in the park … “turn the ignition off” and get the hell out.
I can't really disagree with anything you have written but I just don't know what caused the brake failure, neither did the owner. The insurance company towed the car off and he never had a chance to look at it again. A sudden failure is hard to predict and your instincts take over. Not sure about the track run off, but I agree you should look for a way out and ingrain it into your mind so if this happens you may find a way out.
The driver was a relative newbie with maybe a half dozen events under his belt. I don't imagine the thought of releasing the wheel even crossed his mind, it is just not something you teach students. Maybe it should be.