Kurtz

iTrader: (1)

But all your beliefs are wrong.

And the people who design and sell the BBKs even say you're wrong.

I directly quoted both Brembo and Stoptech, who both state you are wrong.

I directly quoted a brake engineer who designs brake systems for Ford and others who says you're wrong.

I directly quoted a national police equipment testing center that publishes reports on police brake testing that says you're wrong.


The only person who thinks you're right here...is you. (and apparently some guys on youtube who wouldn't know proper testing if it bit them on the brake pad)


Nobody has said BBKs do "nothing" at all.

We've tried, many times, in vain apparently, to explain that they do nothing to shorten braking distance

They do quite a bit for thermal control on cars used on the track though. Which is where they're geuinely useful. Rather than on street cars, where they are nothing but marketing hype. That you apparently have totally bought into.

Kurtz

iTrader: (1)

So they teach you how to fix brakes. And you didn't say if they addressed stopping distance specifically.

But everyone who disagrees with is the people who design and engineer brakes. They tend to know a bit more about the science behind what's going on.



But to reach the best stopping distance you are applying the maximum force available. And beyond the point of wheel lock/ABS additional force is useless... which is why a BBK is useless for stopping shorter.

ABS was created so you could continue to steer the car, since presumably you're hitting the brakes that hard in effort to avoid hitting something.

Because they don't. Even the people who design and sell them say that.

That's why you have ABS. But if threshold braking (what you are describing) your deceleration is still limited by your tires because they are not capable of using as much force as even the OEM brakes can produce... if they WERE then you couldn't lock the wheels.

Since you can it's direct evidence that the tires, not the brakes, are your limitation in stopping distance.

This is the basic point that keeps going entirely over your head.

They don't do anything before then either except let you use slightly less pedal pressure for the same result in stopping distance.

If your leg is really weak I guess that might be important, but it still won't stop your car any shorter.

You keep saying it but it keeps being wrong.

Because the tire always skids/locks/or engages ABS. Even with the OEM brakes.

Hence the "extra" force of the BBK is 100% useless because the tire is already beyond it's ability to use it before it does anything for you.

Except that again, 100% of the "extra" force is useless because the tire can't do anything with it.

The tire is the only thing that matters

Once it reaches its limit, which the stock brakes can do, MORE force doesn't help it.


Yes, and since the tires are kept right -at- their limit, "more force" would be useless. Which is why a bigger brake won't help. At all.



Again you quote a bunch of math without understanding any of it, nor how it does anything to help you stop shorter.

Read Pulp Friction, it gives every single step of the math in figuring brake forces, and explains, specifically, why any force greater than the tires ability is wasted force.



Let me try and explain this even MORE simply since you continue to fail to get it-



At a basic level the brakes apply force to the tire.

The more force they apply, the closer the tire gets to the limit of the road/tire interface.

Stock brakes can supply 100% of the force that will cause the tire to exceed that limit. Anything LESS than that limit, obviously, the stock brakes can ALSO provide.

Now please explain why in the world you think even MORE force that the tire can't use would help. At all.

kene

iTrader: (2)

lol x 3..
sigh .. all I can say to you is I agree to disagree.

God Bless..

ALLCHILL

No, actually the function of the free fall equation was an analogy. It was one of the first examples taught in my high school physics class for good reason. You see, there can be multiple facts based on the scenario. Key word here is scenario, remember this. In the real world, there can be many scenarios and still be correct as long as you define them. To simplify, in a vacuum (scenario 1), the sum of the forces is massxacceleration. Scenario 2, outside a vacuum and considering drag and you will need to apply the drag equation. Notice, in both cases, they are correct given the defined facts. In other words, the scenarios are defined. This is an essential concept that you eventually realized. Don’t worry, I’ll point out when you do. Perhaps my example between a body that is tucked in and sprawled was a little unclear. The only thing I misunderstood, or in this case over-estimated, was your ability to connect the dots. You really couldn’t figure out the key difference between the two scenarios? You’ve drawn a vector before right?
That said, let's run it back for you:

Originally Posted by ALLCHILL
your brakes matter and can reduce braking distance in many scenarios.

So i gave a scenario:

Quote:
Originally Posted by ALLCHILL View Post
So upgrading from drum brakes to disk brakes with abs can not make your stopping distance shorter?

OH defined scenario! Is this not a scenario when the brakes matter? Simply arguing against my scenario with your scenario is still a scenario. This already goes against your initial argument with what I said.

Heres another one i mentioned:
...isn't it possible an unskilled driver with abs be able to stop shorter than one without?"

Zing! You again, replied with the scenario on top of my scenario. Only now you account for ABS and what era the car was made (now all of a sudden matters to you -read brake system of the day).



So ABS matters now? brake systems from cars of a specific timeframe matter now? Disregard the many formulas/materials per brake component that account for locking the wheels? These are all real world scenarios that should be defined. This reminds me of a vacuum situation… only we’re ignoring a lot more than just drag.

I hope you realize your scenarios to counter mine are supporting what I said from jump.

Originally Posted by ALLCHILL
your brakes matter and can reduce braking distance in many scenarios.

You asked if some of the things you quoted (your good at that I noticed) sounded familiar. Well yea, you copied and pasted exactly what Brembo said (so you swapped two words around to sound original –good for you). But note that even Brembo is careful to define the speed (read scenario) and conclude with "at these speeds". Did you also catch the word “primarily”?

"At the speeds that stopping distance is generally measured from (60 to 70mph), the test is primarily testing the tire's grip on the pavement. As delivered from the manufacturer, nearly all vehicles are able to engage the ABS or lock the wheels at these speeds. Therefore, an increase in braking power will do nothing to stop the vehicle in a shorter distance."

By the way, Nearly all vehicles does not mean all. So again, is it possible some vehicles would benefit from a brake upgrade? Yes, in this particular scenario from 60 to 70 mph.

So through all the tech sheets, formula sheets per brake component you managed to find another quote you liked/ripped off. To answer your question, yes it sounds familiar; its your end all argument again.

Stoptech's quote - "The brakes don't stop the vehicle - the tires do."

But even then you are missing the main theme I stress. There are many scenarios that can be applied and still be a true statement. You just have to define them. Notice Stoptech states, "This means that braking distance measured on a single stop from a highway legal speed or higher is almost totally dependent upon the stopping ability of the tires in use"

Wait, Almost.... why almost? Quick, find a quote from Tire Rack!


Unlike you, I will not search, cut and paste random quotes that I come across. This is a forum and your posts should reflect some real life experience. So rather than search around or in your case reference no-name people (pulp friction?) for help to prove a point I never fully disagreed to begin with is making yourself look truly like a clown. I will not further perpetuate (notice how I used the text that you cut and pasted) that garbage and speak from actual experience. Which brings me to the issue that i’m sensing here. You completely lack track experience. I recommend really driving hard with different cars instead of referencing random narrative that you do not fully understand (and worse, recommend others to read). Drive with a car with and without abs. Drive alone, with an instructor, and 3 buddies. Notice the change in weight and how it affects the ability of the brakes to lock the wheels. Note the speed. Drive on different tracks to sense the difference of a downhill slope can make while approaching a corner. The possibilities of the real world are endless. Here’s another analogy and try not to think too hard this time: You are basically reading a golf book thinking you will fully understand the game. Based on how narrow minded your logic is, you aren’t even going to the range. Get out and drive hard (pun intended). OR continue to play it safe and reference the scenario of the magic brakes that are able to lock up the wheels given every scenario and or engage abs? Is that what Brembo I mean you said? Kidding aside, stop cutting up text and leaving out critical information to create the illusion that you know anything.

Kurtz, you post almost 4 times a day. No wonder you have no track experience and have no idea what youre talking about. You’re in front of the computer all day long. And really for what? To argue against statements like this?

I’m sick of using the word “scenario” but it’s a proven teaching method. So wth, one more time.

Originally Posted by ALLCHILL
your brakes matter and can reduce braking distance in many scenarios.


Don't laugh this guy needs help.

Kurtz

iTrader: (1)

No, you won't.

I think you weren't paying much attention in class.

In both cases force= mass times acceleration.

That's a fundamental law of motion.

In the second case the value of acceleration is impacted by air resistance however. But the equation for force is always mass times acceleration and doesn't care a bit about the atmosphere.

Only in ones nobody was talking about (when the brakes are so undersized they can't lock the wheels... which hasn't been true of production cars in decades and was rarely ever true of production cars).

That's not really "many" scenarios unless you drive a lot of antique cars with modern tires... but nobody has this issue with the car that's actually on topic here (the 2IS).


And you're even wrong in your own scenario.

If the drum brakes can engage ABS then no, switching to discs will not change your stopping distance.

But again, when was the last time anybody actually produced a car with drums in the front? Hell, can you even name a production car with drum front brakes and ABS or are you once again making up things that never existed?




Nope...not if they can engage ABS.


What?

I'm pretty sure it always matted since nobody else was trying to discuss the braking performance of their Studebaker.

Are you confused and think you're on an antique car forum or something?

Because any car from this century stops exactly as short with factory brakes as it will with the biggest BBK they made for the car.


No, they really aren't, unless you own a time machine.

Do you own one? That'd be the first genuinely interesting addition you've offered the thread, so please tell us about it!


No, they can't, so long as the original ones can engage ABS.

Which virtually ALL of them ever made can.


Right. An increase in braking power will do nothing to stop the vehicle in a shorter distance.

Brembo doesn't provide braking distance tests from 80 mph either. Or 90. Or 100. Or any speed. Because they know that your brakes don't change your stopping distance.

But 60-70 is the maximum legal speed almost everywhere in the US, so it was a relevant number to include.

Yes, suitable disclaimer in case some crazy guy with a 1930s braking system and 2010 tires crashes his time machine car and decides to sue them if they'd said all car.

Indeed... your DeLorean is all set for an upgrade!

Over here in the real world, not so much though.

In fact, if any such car existed, wouldn't the people who make their living selling BBKs be shouting up and down about how their BBK actually does reduce stopping distance on the brand new 2011 Kia Time Machine? yet they aren't. Instead they went out of their way to include an item in their FAQ telling you their BBKs will not reduce stopping distance. Wonder why. It's almost like they actually understand brakes like you do not.

Because the weather and road surface also matters. It's the tires that stop the car, and more specifically, the friction coeffcient between those tires and the road. The things that can change that are:

The tires.
and
The road
(which can change based on the road itself, or the weather).

That second part is what the almost is for.

Again I can provide the very simple mathemetically formula for braking distance if you like. It doesn't ask about your rotors or pads though, because they're not relevant. It DOES ask about the tire/road CoF though.


Do you have a BBK that can control the weather? That'd be almost as cool as your time machine!



yes, I know, because you'd utterly fail to find any reliable science or engineering based sources that agree with you.


Great... let us know when you get some and realize a BBK won't shorten your stopping distance like all the people who actually engineer, design, and race for a living already know!


They are.. all of which I've done... likely in many more, and faster, cars than you have (supras, porsches, GTOs, impalas, boosted aristos, f-bodies, vettes, maseratis, etc)... and none of which have anything to do with braking distance as it relates to bigger brakes... because bigger brakes won't change your braking distance.


Not really... but it's somewhat better than your case where you're reading a golf book then telling us how much you know about football.


Magic?

That's the real world friend.

Of the dozens of cars I've owned and driven I've never seen one that couldn't lock the wheels or engage ABS on the OEM brake system.

The only time a BBK was at all useful was on a track where thermal control mattered, and here's a hint: it didn't matter for reducing braking distance.

Again... what?

My posts have repeatedly provided specific, sourced, facts, engineering, and mathematics.

Yours have contained basic errors in 8th grade physics and a lot of "I bet I can think of some situation you're wrong, though I can't actually provide any real example of one"... oh, and unfounded personal attacks on my experience while providing absolutely no evidence of your own.

Statements where people are posting misinformation about something as important as stopping their car?

Yeah, actually, that is sort of important.

(But mainly I'm in front of a computer a lot so I can earn a lot of $ and afford to own and drive nice cars both on the street and track, and learn important things like upgrading to a BBK won't help your stopping distance.




Except you can't actually provide any.

But again, your brakes can not reduce your stopping distance in any scenario where the stock ones can lock the wheels or engage ABS.

Which is most cars ever made, virtually all cars from the last nearly half-century, and certainly is every Lexus ever made (this is a lexus forum, right?)


No name people?

The author of that article has done brake system and electronics engineering for Delphi, Bosch, Ford, and others as well as engineering racing brake systems.

He's also a brake control system consultant for Stoptech.

At the direct request of the SAE he developed 5 Professional Development seminars focusing on brake control systems, vehicle dynamics, and brake system design.

He has, literally, written several books on brake engineering.

That's the guy who outright states you have no idea what you are talking about.

What were your qualifications again?

lobuxracer

iTrader: (2)

kene and allchill - bring something other than innuendo to this discussion. Pulp Friction was written by James Walker, a brake system engineer and resource to SAE, Stoptech, Ford, and a number of other organizations as well as an SCCA racer for many years. He is also a published author on braking systems.

SAE trainer for braking and stability systems.



If you can't cite a reference with better or even equal credentials (Wikipedia and YouTube are useless here), then you really need to go back to school, study basic physics, and learn why you are wrong.

Long posts with useless misinformation as above will only result in more people recognizing your failure to understand basic physics.

kene

iTrader: (2)

WOW you're Nuts!


Originally posted by KURTZ:
"Quote:
Originally Posted by ALLCHILL View Post
So upgrading from drum brakes to disk brakes with abs can not make your stopping distance shorter?
And you're even wrong in your own scenario.

If the drum brakes can engage ABS then no, switching to discs will not change your stopping distance.

But again, when was the last time anybody actually produced a car with drums in the front? Hell, can you even name a production car with drum front brakes and ABS or are you once again making up things that never existed?"





If the ABS can engage drums then switching to discs will not make a difference?!

You're Mad!

discs surpass drums in damn near every scenario in consumer level cars. With abs or without abs. period.



I'm so riled up with this statement I haven't even finished reading the rest of the post.



EDIT Added:




Originally posted by KURTZ:

"Originally Posted by ALLCHILL View Post
Heres another one i mentioned:
...isn't it possible an unskilled driver with abs be able to stop shorter than one without?"

Zing! You again, replied with the scenario on top of my scenario. Only now you account for ABS and what era the car was made (now all of a sudden matters to you -read brake system of the day).
What?

I'm pretty sure it always matted since nobody else was trying to discuss the braking performance of their Studebaker.

Are you confused and think you're on an antique car forum or something?

Because any car from this century stops exactly as short with factory brakes as it will with the biggest BBK they made for the car."





-What about the you tube videos I posted.... the results were seen there.

Kurtz

iTrader: (1)

You're so riled up because you saw something you don't understand and are sure it's wrong for reasons you're incapable of explaining despite it actually being correct?

I suppose that's good reason to be riled up at least...


disc vs. drum has no relevance at all to stopping distance if both can lock the wheels or engage ABS (though again I'd ask you to provide an example of any car ever made with front drums and ABS)

discs are an improvement over drums for many reasons, but you don't seem to understand what they are (fewer parts, easier to service, better cooling between multiple hard stops, better water shedding, etc) or why they're not relevant to the discussion we're having of stopping distance.

Just like BBKs provide certain specific advantages in certain specific situations, you just don't understand that "better stopping distance" isn't one of those advantages because a BBK won't stop the car any shorter than the OEM brakes will as long as both can lock the wheels or engage ABS.

kene

iTrader: (2)

Ok its the braking power that acts upon the wheel assembly as an opposing torque to the inertia that is already imposed on the vehicle in motion. the bigger rotor equates to more opposing torque on the wheel assembly. This allows for a more precise and quicker braking effect on the wheel assembly.

I will try to put this in as "Layman's Terms" as possible.

This is at the Brake pedal level(from my so little experience)

ok lets say with a small rotor you have this many "degrees of preciseness" (best possible choice of words I could think)
At the start of the red zone is when the wheels lock up.




====================


and with a BBK rotor you would have this many "degrees of preciseness"

=====================


Everything below is the possible ergonomics benefit of a BBK.


What I am trying to show is that with a BBK you do not need to smash on the brake to cause them to lock up. Instead(If you really want to lock up your wheels... why I dunno) you are supposed to be able to accomplish the same task with far less pedal travel. The same task can be done in an area far from the pedals "end of travel limit".

What this translates to(I will say for me at the least) is I can control my braking much better with the "up and down" pivot of my foot versus doing the same and also having to using my leg(thigh, calf, knee, etc[choose your pick]..which is not as easy, or as precise to control the brake pedal).

The thing(I speak for myself here) using your whole leg is great for is locking up the brakes. Which I try to avoid.


The Example listed above is VERY Rudimentary.

Kurtz

iTrader: (1)

There's youtube videos of bigfoot and UFOs too... do you believe those as well?


Now go look for some actual scientific testing with real results... you won't find any that support your position.

When folks test the identical car, with identical tires, in identical conditions, changing ONLY the brake kit (rotors/pads/etc) they will find no significant difference in stopping distance. Because the laws of physics require that result.


A good example is when folks tested the same Porsche using factory brakes or the $10,000 PCCB upgrade brakes, but with the same tires.

Results were consistently within 1 foot of each other.

Because the brakes don't stop the car, the tires do.


Now, if they'd tested say 100 stops back to back to back from 100 mph, they'd EVENTUALLY see longer stopping distance from the stock brakes when they finally overheated. But they'd never see shorter ones with either set, and both would continue to provide identical stopping distance under any normal street driving conditions (where you never stop from 100 mph 100 times in a row without cooling down).

(and Porsche has really good brakes even stock so you'd probably be better off using a different car if you want to test fade resistance of OEM vs. aftermarket brakes).


http://www.caranddriver.com/features...ce_cars_page_4

At the beginning of that same article they make the same point I've been making over and over too-

They go on to explain that it's only in fade resistance you'll see a difference in braking systems... and to test that they had to subject the cars to conditions they'd never see in normal driving (ie repeated 100 mph stops right after each other)

Kurtz

iTrader: (1)

It's so rudimentary it has nothing whatsoever to do with the topic we're actually discussing.


I agree that big huge brakes will require a lighter touch on the brake pedal to get maximum braking.

But you'll still stop in exactly the same distance as the OEM brakes.

You'll just have pushed the pedal slightly less hard to do it.

(So would a larger brake pedal assembly by the way, more leverage you know... But that also wouldn't stop you any shorter... in fact page 1 of the Pulp Friction article discusses exactly that)

If you have a really weak leg I suppose that's important, but if you're looking to stop the car in a shorter distance and have normal adult strength it's pretty irrelevant to the discussion.

kene

iTrader: (2)

YES KURTZ...IF YOU ARE IN A LOSS OF CONTROL OF YOUR VEHICLE(i.e. SKIDDING) DRUMS OR DISC BRAKES. WILL NOT MAKE A DIFFERENCE.

Now if you are not in a loss of "controlled braking"(I.E. SKIDDING) Discs with ABS will work far better than Drums with ABS.


There are you happy now. If not Please disprove my statement. Cause I am willing to 100%, Bonafide, Guarantee, that half the members on this site do not plan to SKID from the second the brake pedal is touched to the point of contact or the car comes to a complete stop.

Hence,(with all the math and even taking tech data and equations from Stoptech's site[Reff = rotor radius...posted in bold in my previous posts]) why Increasing the rotor Radius/diameter does have a positive effect on braking(Up to a point, that realistically we don't see these sized rotors sold on the market).

kene

iTrader: (2)

PLEASE is there anyone out there who has a stock setup on their vehicle at the moment, and maybe a BBK laying around in the garage they have not installed yet? Cause If you do please have a friend video tape your braking from a given point before and after. Please list the speed at which you begin to brake to as well. And also chalk marks for measuring every couple of feet would be great. So we could put this to an end. Oh and before you go BBK remember to use the same big rims and tires on the stock setup as well.

I'm trying to piece together my BBK at the moment, and its not going as fast as I would like.

Kurtz

iTrader: (1)

Apparently you don't even know what ABS does, or why, if you think that engaging it causes the car to suffer a loss of control and be "skidding"

Again, I'd encourage you to stop posting until you have even a basic understanding of the words you are using or the topic we're discussing.

You have no idea, whatsoever, how any part of the braking system works, or what it does, yet continue to insist that every expert on the topic can't possibly be correct about it.

Plus, again, if you can show me any car ever put into production with both front drum brakes AND ABS, please do so... otherwise see again the whole "stop talking" advice.

I would expect that, except for you, none of them expect to skid, since they probably understand the point of ABS.

Apparently you don't even know what ABS does, or why, if you think that engaging it causes the car to suffer a loss of control and be "skidding"

Again, I'd encourage you to stop posting until you have even a basic understanding of the words you are using or the topic we're discussing.

You have no idea, whatsoever, how any part of the braking system works, or what it does, yet continue to insist that every expert on the topic can't possibly be correct about it.

Plus, again, if you can show me any car ever put into production with both front drum brakes AND ABS, please do so... otherwise see again the whole "stop talking" advice.

Increasing rotor diameter can have many positive effects.

It's just that shorter braking distance isn't one of them.

So says stoptech themselves (and Brembo, and Car and Driver, and the NLETC, and guys who design and engineer brakes for a living... and pretty much everyone else on earth who understand physics or brakes)




Can you explain why those results would convince you when actual precision testing using professional equipment, from Car and Driver and others, that all say EXACTLY WHAT I HAVE BEEN TELLING YOU IS TRUE, did not convince you?

Do you only believe things when they're poorly tested and not when properly done? That'd certainly clarify the source of many of your opinions...

If you don't like Car and Driver how about these guys who found YET AGAIN A BBK DOESN'T STOP THE CAR SHORTER-

http://www.europeancarweb.com/tech/0...kes/index.html


Look... someone tested stock versus a BBK (a $17,000 BBK by the way).

And amazingly both cars stopped in the same distance

Just like physics requires.

Just like everyone except you and ALLCHILL understand they must.

06isDriver

Goodness gracious....Point, set, match to Kurtz for pete's sake!