IS ABS the definitive way to break at the end of a straight?
01-22-2004, 10:11 AM
#107
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After a good nights sleep, I am going to offer the following observations and change in my response stance. I will only reply to sincere specific questions where the poster indicates exactly what they don't understand.
I have a personal weakness that I find brazen stupidity, combined with an over inflated ego that a weak character cannot overcome to be a particularly offensive personality type. Sadly, this is commonplace around the race track. While I do not normally try to help these types of people (they rarely want the help because it points out that they have been wrong and they lack either the intelligence to recognize it or they lack the character to admit it [see this thread for an example]) I made an effort here and I am being attacked by some for it. Further, it really isn’t that fun, much like when a bully beats up on a weakling, yea … you did it, but you don’t feel good about it. Bob, I apologize for taking you behind the woodshed and giving you the biggest beating I have ever seen on any forum. Yes, you deserved it, but that still doesn’t make my actions right.
Just to summarize, the viewpoint I have expressed is that trail braking is the fastest (and smoothest when driving quickly) way around the track in almost all turns (to varying degrees of course, some well into the turn, some through turn initiation only). They people on the opposing view have offered NO FACTS and NO EXPLANATIONS (except one erroneous article and uninformed opinions) as to why everyone that I listed says trail braking is faster. You will also notice that they refuse to attack my arguments on a line by line basis … because they can’t! This trail braking isn’t new and it isn’t my idea, like I said earlier, it is an accepted fact by those who are informed on race car vehicle dynamics. If you don’t believe it, open your mind, read a book or two, or ask questions here. If I can’t answer the question, I know the people who can. Sorry, off my soap box now.
I have a personal weakness that I find brazen stupidity, combined with an over inflated ego that a weak character cannot overcome to be a particularly offensive personality type. Sadly, this is commonplace around the race track. While I do not normally try to help these types of people (they rarely want the help because it points out that they have been wrong and they lack either the intelligence to recognize it or they lack the character to admit it [see this thread for an example]) I made an effort here and I am being attacked by some for it. Further, it really isn’t that fun, much like when a bully beats up on a weakling, yea … you did it, but you don’t feel good about it. Bob, I apologize for taking you behind the woodshed and giving you the biggest beating I have ever seen on any forum. Yes, you deserved it, but that still doesn’t make my actions right.
Just to summarize, the viewpoint I have expressed is that trail braking is the fastest (and smoothest when driving quickly) way around the track in almost all turns (to varying degrees of course, some well into the turn, some through turn initiation only). They people on the opposing view have offered NO FACTS and NO EXPLANATIONS (except one erroneous article and uninformed opinions) as to why everyone that I listed says trail braking is faster. You will also notice that they refuse to attack my arguments on a line by line basis … because they can’t! This trail braking isn’t new and it isn’t my idea, like I said earlier, it is an accepted fact by those who are informed on race car vehicle dynamics. If you don’t believe it, open your mind, read a book or two, or ask questions here. If I can’t answer the question, I know the people who can. Sorry, off my soap box now.
Last edited by ColorChange; 01-22-2004 at 06:33 PM.
01-22-2004, 11:09 AM
#108
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Color I have only one suggestion. Print out this entire thread, take it to a competent mental health professional and ask for help.
01-22-2004, 11:18 AM
#109
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this is so blissful due to technology
"ColorChange
01-22-2004 09:11 AM This person is on your Ignore List. To view this post click [here] "
ah, yes. Uncle Bob, try ignore list, you'll like it
man on john: "ABS in the all new Icrap allows me to poop deeper and later.
Power, performance, the all new Icrap: Poop different"
01-22-2004 09:11 AM This person is on your Ignore List. To view this post click [here] "
ah, yes. Uncle Bob, try ignore list, you'll like it
man on john: "ABS in the all new Icrap allows me to poop deeper and later.
Power, performance, the all new Icrap: Poop different"
Last edited by Sun Ra; 03-29-2013 at 12:13 AM.
01-22-2004, 11:25 AM
#110
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I read a few books on the Icrap. It is the way to go. I've never used it, but I'm an expert on it. Many plumbers with 30 years of experience say it is no better than a regualr toliet, but they are all wrong. The Icrap is the way to go and you all are all stupid!
01-22-2004, 03:08 PM
#111
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Watt and Forklift. NOW THAT's FUNNY.
01-22-2004, 06:09 PM
#112
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Guys, Thanks for making my life better. I did a search on the ICRAP and came across and even more *upstanding* product called the IPEED. Apple is disputing the name.
01-22-2004, 07:30 PM
#113
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View on the subject from another engineer (mechanical) /driver...
As far as what Color is referring to I would have to say that I strongly agree. Simply put, the fastest way around a corner is to stay on the edges of the friction circle (all directions) for a given car and setup. These components of the friction circle are accelerations and the largest accelerations lead to the highest speeds and lowest time spent during a lap.
One major error in the refutations of Color's argument are the inclusions of suggested driving techniques by drivers and instructors. While it may be extremely difficult for amateur and even most professional drivers to always follow the pattern that Color is describing, the laws of physics are not up to question. The "smooth, slow-braking" (wtf is this?) and "rocker" techniques of driving to name a few are simply that - techniques. They may represent a method which makes a particular setup simpler to drive near the limit, but in that sense your driver is the limiting factor - NOT the physics behind the situation. Look at Mark Donohue 30 years ago - he realized the benefits of trail braking when he raced against Formula One drivers in his (I believe) Formula A car. He was faster than most of the european drivers simply because they did braking, turning and accelerating all separately. Mark reiterated his trail braking, "American" style of driving as one of his largest consistent Unfair Advantages.
Another major error is the inclusion of a particular car in this argument. Reguardless of the performance and dynamics of a vehicle - the same principles apply. The stastics of the car may affect ultimate capability and ease of operation no doubt - but they will NOT affect physical principles.
Conclusion:
In terms of the laws of physics there is no way to refute what Color is saying. While it may take one hell of a driver to accomplish this near 100% of the time (in a 911 it may be quite difficult, I simply don't know) - the rule still applies. Maximization of acceleration components will guarantee the lowest laptimes if the proper lines are taken.
If there is something mathematically or physically inconsistent with this line of thinking I would like to be corrected.
As far as what Color is referring to I would have to say that I strongly agree. Simply put, the fastest way around a corner is to stay on the edges of the friction circle (all directions) for a given car and setup. These components of the friction circle are accelerations and the largest accelerations lead to the highest speeds and lowest time spent during a lap.
One major error in the refutations of Color's argument are the inclusions of suggested driving techniques by drivers and instructors. While it may be extremely difficult for amateur and even most professional drivers to always follow the pattern that Color is describing, the laws of physics are not up to question. The "smooth, slow-braking" (wtf is this?) and "rocker" techniques of driving to name a few are simply that - techniques. They may represent a method which makes a particular setup simpler to drive near the limit, but in that sense your driver is the limiting factor - NOT the physics behind the situation. Look at Mark Donohue 30 years ago - he realized the benefits of trail braking when he raced against Formula One drivers in his (I believe) Formula A car. He was faster than most of the european drivers simply because they did braking, turning and accelerating all separately. Mark reiterated his trail braking, "American" style of driving as one of his largest consistent Unfair Advantages.
Another major error is the inclusion of a particular car in this argument. Reguardless of the performance and dynamics of a vehicle - the same principles apply. The stastics of the car may affect ultimate capability and ease of operation no doubt - but they will NOT affect physical principles.
Conclusion:
In terms of the laws of physics there is no way to refute what Color is saying. While it may take one hell of a driver to accomplish this near 100% of the time (in a 911 it may be quite difficult, I simply don't know) - the rule still applies. Maximization of acceleration components will guarantee the lowest laptimes if the proper lines are taken.
If there is something mathematically or physically inconsistent with this line of thinking I would like to be corrected.
01-22-2004, 08:03 PM
#114
Burning Brakes
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Originally posted by Steve in FL
This thread is getting real old real fast and the entertainment value is going downhill.
ColorChange: Do you agree that your theory about ABS all the way to the apex is not the classic definition of trail braking? If not, quoting your opentrackracing link says it isn't: "Once you are done with your braking, which should be before the apex, now is the time to start feeding in the gas". I'm in the camp with Bob that trail braking is not always the fast way thru a corner. Maybe in the theoretical world of the smooth 90 degree turn it'd always work but as has been mentioned race track designers and most drivers find those really boring. Your atomicwidget link regarding the Skip Barber course supports that as well: "Trail braking is the technique they teach for taking turns 2, 8 and 11 at Laguna." Note they don't say it works on all corners.
Hopefully now we have established your theory you can brake all the way to the apex at the ABS threshold is not trail braking. This removes a large part of the support for your theory. Once you get your car on track and record some data on the application of your theory (can I call it "ABSolute Apexing"?
) you can come back and tell us the results. You want us to have an open mind that your theory is plausible, we want you to have an open mind that theory doesn't always apply in the real world.
This thread is getting real old real fast and the entertainment value is going downhill.
ColorChange: Do you agree that your theory about ABS all the way to the apex is not the classic definition of trail braking? If not, quoting your opentrackracing link says it isn't: "Once you are done with your braking, which should be before the apex, now is the time to start feeding in the gas". I'm in the camp with Bob that trail braking is not always the fast way thru a corner. Maybe in the theoretical world of the smooth 90 degree turn it'd always work but as has been mentioned race track designers and most drivers find those really boring. Your atomicwidget link regarding the Skip Barber course supports that as well: "Trail braking is the technique they teach for taking turns 2, 8 and 11 at Laguna." Note they don't say it works on all corners.
Hopefully now we have established your theory you can brake all the way to the apex at the ABS threshold is not trail braking. This removes a large part of the support for your theory. Once you get your car on track and record some data on the application of your theory (can I call it "ABSolute Apexing"?
) you can come back and tell us the results. You want us to have an open mind that your theory is plausible, we want you to have an open mind that theory doesn't always apply in the real world.
Not to be "putting words into his ( CC's) mouth"... but, wasn't the orginial premise...." USING ABS for maxinium Braking FULLY INTO THE TURN RIGHT UP TO THE APEX is the fastest way !
When people started questioning the wisdom of that premise... THEN... we got CC'... using the "Trail Braking" arguement!
I don't see anyone saying that... "Trail Braking" is not a valid method that can be used in some corners! On the other hand... using Full on Maxinium Braking ie. locking up the ABS until reaching corner apex on all corners... is questionable at best and PROBABLY down-right DANGEROUS in some corners!!!
A simple example would be any OVAL such as INDY or Daytona! They certainly have corners... BUT I'm not suggesting anyone attempt to go around those tracks using CC's method!
01-22-2004, 09:55 PM
#115
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Usually you don't brake for the corners for at Daytona and only sometimes at Indy...
Again I think the point Color is making is that you should be completely on the egde of your car's friction circle at all times. What may be more consise is to say there are certain times where you may slightly vary this technique. For example, the Carousel at Elkhart Lake is not something you really apex (I guess you can say you do but that is splitting hairs). I believe that Color was referring to turns that require full braking, turning and acceleration out.
Only driver error would create a dangerous situation. ABS will simply put you car at a degree of slip (generally 15-20%) that is optimal for steering. If you look at a lateral frictional coefficient (u) vs. slip graph you will see a sharp rise in u with a maximum around 15-20%. Then it slowly drops off till it hits zero at full lockup. The ABS system modulates the brakes at a very high frequency to keep within this slip range...this is reguardless of what the rest of the car is doing. You may be giving up tire grip by turning, but you can still maintain rotational slip on the tires thus trading off traction in near perfect harmony. The frequency is so fast that it maintains almost all the balance of the car.
Can you see how ABS eliminates variability in driver brake modulation? 99.9% of the time if you don't blow your entry speed or line by a huge margin, you will make it through the turn. Furthermore, a driver that is hitting his entry speed and line at the proper limits with ABS will never be beat by a conventional system unless it is Schumacher behind the wheel.
ABS automatically trades off traction for you - braking is now a binary control. That is the power of the concept that COLOR is explaining.
Again I think the point Color is making is that you should be completely on the egde of your car's friction circle at all times. What may be more consise is to say there are certain times where you may slightly vary this technique. For example, the Carousel at Elkhart Lake is not something you really apex (I guess you can say you do but that is splitting hairs). I believe that Color was referring to turns that require full braking, turning and acceleration out.
On the other hand... using Full on Maxinium Braking ie. locking up the ABS until reaching corner apex on all corners... is questionable at best and PROBABLY down-right DANGEROUS in some corners!!!
Can you see how ABS eliminates variability in driver brake modulation? 99.9% of the time if you don't blow your entry speed or line by a huge margin, you will make it through the turn. Furthermore, a driver that is hitting his entry speed and line at the proper limits with ABS will never be beat by a conventional system unless it is Schumacher behind the wheel.
ABS automatically trades off traction for you - braking is now a binary control. That is the power of the concept that COLOR is explaining.
01-22-2004, 10:43 PM
#116
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God Thank You FormulaOne10!
It took courage to jump in on this discussion, especially to support the truth and you did that, thank you. And no, it isn't me under a new name!
I agree with everything you said.
TrumperZ06: Please do not put words in my mouth, especially wrong words. I never said that! As I started vehemently in my 1/9 post, and restated in my 1/21 post. My guess is is that you are not serious and are trying to rile me and it did not work. Please disregard the post.
It took courage to jump in on this discussion, especially to support the truth and you did that, thank you. And no, it isn't me under a new name!
I agree with everything you said.TrumperZ06: Please do not put words in my mouth, especially wrong words. I never said that! As I started vehemently in my 1/9 post, and restated in my 1/21 post. My guess is is that you are not serious and are trying to rile me and it did not work. Please disregard the post.
01-23-2004, 03:40 AM
#117
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: Here's your 1st post!!!
Originally posted by ColorChange
Gentlemen, I haven't tested it myself in that I haven't had my car out on the track but driving into the corner and jamming (all possible force) on the brakes should be faster.
That’s right. Here is how you drive with ABS. Hit your brake point and JAM, STAND, PUSH YOUR FOOT THROUGH THE FLOOR. Stay there, when you hit your corner entry velocity on the right line, turn in, WHILE STILL STANDING ON THE BRAKES! The ABS system should brake far better than you ever can and you will drive faster, brake deeper than ever before. You corner entry velocity with abs should be faster than your non abs velocity because the ABS/PSM system will automatically reduce the braking force to the front wheels as you order them to turn, all while still keeping the rears in ABS mode. Can’t do that with any normal brakes unless you are going to left foot brake ala Schumi.
Now, if you don’t think I’m a wacko from that statement you might say “what if I need to bleed off some speed”. Same thing, go full throttle, jam the brakes for a sort time (however long as needed to reach your desired speed, and move on. With ABS (a good 4-wheel ABS), it will do everything better than you ever could on your own. If it is a very short braking zone and/or you have a poorly set-up car you may have some suspension upset to deal with and you may want to back off in that scenario, but as a general rule, with 4-wheel abs there is no brake modulation!!!
Gentlemen, I haven't tested it myself in that I haven't had my car out on the track but driving into the corner and jamming (all possible force) on the brakes should be faster.
That’s right. Here is how you drive with ABS. Hit your brake point and JAM, STAND, PUSH YOUR FOOT THROUGH THE FLOOR. Stay there, when you hit your corner entry velocity on the right line, turn in, WHILE STILL STANDING ON THE BRAKES! The ABS system should brake far better than you ever can and you will drive faster, brake deeper than ever before. You corner entry velocity with abs should be faster than your non abs velocity because the ABS/PSM system will automatically reduce the braking force to the front wheels as you order them to turn, all while still keeping the rears in ABS mode. Can’t do that with any normal brakes unless you are going to left foot brake ala Schumi.
Now, if you don’t think I’m a wacko from that statement you might say “what if I need to bleed off some speed”. Same thing, go full throttle, jam the brakes for a sort time (however long as needed to reach your desired speed, and move on. With ABS (a good 4-wheel ABS), it will do everything better than you ever could on your own. If it is a very short braking zone and/or you have a poorly set-up car you may have some suspension upset to deal with and you may want to back off in that scenario, but as a general rule, with 4-wheel abs there is no brake modulation!!!
01-23-2004, 03:44 AM
#118
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: And here's your second post..... NOW talking about "trail Braking"....
Originally posted by ColorChange
Sorry Bob: While I agree with a soft release of the brake pedal (of course), trail braking is by definition faster in most circumstance! The ABS system will control the amount of slip in the tires, normally <20%. So, when you are in 4 wheel abs braking, hit your corner entry velocity and turn the damn car in, the abs will have no choice but to give up on the braking force to the front wheels while still applying as much braking force as the rears can handle. Therefore, all four wheels are on the friction circle for a greater amount of time. QED faster!
Fixed wing, while I agree with a lot of trail braking being good (normally), the ABS DOES give absolute priority to steering as I described above. The only thing it controls is braking force so if your slippage is too high, less braking allowed, not less steering.
Sorry Bob: While I agree with a soft release of the brake pedal (of course), trail braking is by definition faster in most circumstance! The ABS system will control the amount of slip in the tires, normally <20%. So, when you are in 4 wheel abs braking, hit your corner entry velocity and turn the damn car in, the abs will have no choice but to give up on the braking force to the front wheels while still applying as much braking force as the rears can handle. Therefore, all four wheels are on the friction circle for a greater amount of time. QED faster!
Fixed wing, while I agree with a lot of trail braking being good (normally), the ABS DOES give absolute priority to steering as I described above. The only thing it controls is braking force so if your slippage is too high, less braking allowed, not less steering.
01-23-2004, 05:00 PM
#120
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Formulaone10
Below is the statement from Color which began the "discussion". Note it is a cut and paste from the post - unexpurgated and unedited. It is precisely this statement which shall we say accelerated matters. Since then CC has turned it into a discussion of trail braking. I respect the fact that you support the theory of trail braking being viable for every car and every corner. Depending on how one defines trail braking, this can be nearly true - enough to allow it as a generalization in fact. I'm not really sure what definition of trail braking is operative. For example, I said trail braking is a usefulk technique with cars that tedn to understeer. I think everyone agrees. If that is true, then it would be in appropriate in an oversteering car and perhaps even in an understeering car. Then again it depends on how far into the corner you stay on the brakes.
Look at the quote below and you'll understand why a bunch of us do not agree. When I trail brake, I am on the brakes but generally lifting off to gradually shift weight back to the rear contact patches as I approach the apex. That's far from full ABS in my book.
-------------------------
"With ABS (theoretical,)
Hit your braking point and JAM (hard enough to guarantee abs on all 4 tires, don’t stop when you feel pulsation, only 1 tire may be in abs) on the brakes. Hit your turn in speed at the right point and turn in … still standing on the brakes. Continue through the turn with the brakes jammed."
__________________
If you support the above theory, that's ok with me. We don't have to agree but I do appreciate a calm exchange of views and perhaps diverging opinion without the "colorful" statements "You are Stupid" etc. which have polluted the discussion.
Best,
Below is the statement from Color which began the "discussion". Note it is a cut and paste from the post - unexpurgated and unedited. It is precisely this statement which shall we say accelerated matters. Since then CC has turned it into a discussion of trail braking. I respect the fact that you support the theory of trail braking being viable for every car and every corner. Depending on how one defines trail braking, this can be nearly true - enough to allow it as a generalization in fact. I'm not really sure what definition of trail braking is operative. For example, I said trail braking is a usefulk technique with cars that tedn to understeer. I think everyone agrees. If that is true, then it would be in appropriate in an oversteering car and perhaps even in an understeering car. Then again it depends on how far into the corner you stay on the brakes.
Look at the quote below and you'll understand why a bunch of us do not agree. When I trail brake, I am on the brakes but generally lifting off to gradually shift weight back to the rear contact patches as I approach the apex. That's far from full ABS in my book.
-------------------------
"With ABS (theoretical,)
Hit your braking point and JAM (hard enough to guarantee abs on all 4 tires, don’t stop when you feel pulsation, only 1 tire may be in abs) on the brakes. Hit your turn in speed at the right point and turn in … still standing on the brakes. Continue through the turn with the brakes jammed."
__________________
If you support the above theory, that's ok with me. We don't have to agree but I do appreciate a calm exchange of views and perhaps diverging opinion without the "colorful" statements "You are Stupid" etc. which have polluted the discussion.
Best,