Knightshade

Seriously, what's your deal exactly? The folks who built the brake system on the IS-F say you're wrong. The folks who built the F-sport brakes say you're wrong. Me, all the tech guys at CL, Smooth1, Gaugster, and everyone else who has posted in this thread either way all say you're wrong. The guy who designs ABS systems for a living and has literally written books on braking systems says you're wrong. The guy who actually tested the two pads in question say you're wrong. And you just keep sticking your fingers in your ears and jumping up and down insisting it just isn't true while tossing out groundless accusations of dishonesty and misquoting. with absolutely zero to back any of it up except a glaring ignorance of what brake pads actually do.

No, you saw a link to the thread where it was described instead. You also saw half a dozen experts on braking systems (including two companies WHO DESIGN BRAKES FOR LEXUS) telling anyone who can read english that it's impossible for brake pads to reduce stopping distance. Most certainly not in the "one panic stop" situation you claimed it did. You're literally the ONLY person here who thinks otherwise at this point. Apparently only because you're incapable of admitting you're wrong.

There's a key point right there even if you don't realize you made it. Yup, all those things can change how hard you need to push the pedal to stop the car. None of them can change the distance in which the car is capable of stopping though. They're two entirely different things. Unless you have some kinda muscle problem where you can't push the pedal normally I guess... then it might matter.

Again, you keep trying to offer completely unrelated comparisons. A Lambo vs. a Truck? Huh? How about a lambo vs. a lambo. Or a truck vs. a truck? Now change the brake pads. Did stopping distance (as previously defined) decrease? Nope. It can't. Pedal effort required might change, but you won't be able to stop the car any shorter than you could with the other pads. From 15 mph or 60 mph, or 100 mph that will remain true.

Yes, as I posted like 4 pages ago. Someone testing with both sets of pads and found identical distances. Because physics requires that to be the case. Just like me, the ABS engineer, Brembo, Stoptech, and now even Smooth1 have told you. You're the only person involved who still doesn't understand how brakes work or why you were wrong in what you wrote in your "one panic stop" post.

No I'm not. It was barkat who wrote the "one panic stop" post. Brake pads don't reduce stopping distance under any braking scenario though, if you define braking distance honestly. (and don't bring in completely different braking systems having no relevance to the 2IS of course) Braking distance- the minimum distance in which a vehicle is capable of making a single stop at a given speed. This is generally tested/measured by car makers, car magazines, etc by slamming the brake pedal to achieve maximum force and most commonly tested from 60 or 100 mph. Change the pads all you want, the car will still be capable of stopping in the same distance. You can certainly use less pedal pressure and get -longer- distances, and those longer distances might see variance in pedal pressure required for a given distance depending on the pad. But you won't see any shorter ones. Likewise if you're making repeated high-speed stops in a short period of time (ie- racing for example) you could well see -longer- distances sooner than later depending on the pad you use as some will begin to fade before others. But no pad will make them -shorter- they will just keep them from getting longer for a few extra stops.

I'm not sure how it's a trick question. It's a simple question based on the actual situation that exists. And somewhere in there you actually admitted I was correct and Barkat was wrong... thank you. even if you had to add "If someone invented something totally different from what exists now, the answer would change!" one more time :P

No, the car didn't create a shorter stopping distance BTW... stopping distance isn't measure based on partial pressure braking. We went over that pages ago. The car with either pad can comfortably stop in 55 feet, just with differing pedal input. As PF explains changing your pad doesn't change braking distance, but it CAN change the feel of the system (ie amount of pedal input needed for a given force, but you'll still generate that force with either pad just with differing inputs)... It can even stop in less distance that that, an indentical distance with either pad, if you mash the brake pedal. You know, the panic stop. THE ACTUAL TOPIC OF THE THREAD.

Yes, I said the pads can change the distance under the ABS threshold for a given unchanging pedal pressure. I then added (and you failed to quote) that either set of pads can stop in the -same- distance, it would just require a different amount of pedal effort. So the pads aren't changing the distance the car is -capable- of stopping in, they're just changing the feel of the system (it requiring more or less pedal pressure for the same result). Which I mentioned from the very begining (feel) as one of the things pads CAN change. We aren't discussing top fuel racer acceleration though, nor wedge braking systems that don't exist on our current cars and use a completely different system (no brake fluid even). Likewise we're not discussing jet packs strapped to the cars and actuated with a pad/rotor combo in some way. Let me ask you a direct question, since you seem to want to dance around anything resembling a direct answer by throwing up crazy scenarios- Yes, or no- Can different pads (that can both engage the ABS system properly) on the -existing braking system on an IS350- change the stopping distance of a single panic stop on not-overheated brakes. Yes, or no? Barkat insists yes. I know it's no. Which is it? (and if yes, please explain how, without invoking any parts or technologies that aren't actually on the car)

Only 13 speakers if you don't have ML... and honestly they're just component separates (4 tweeters, 4 mids, 4 woofers, then one sub)... size and wattage are well known... the ML has a different setup (2 surround speakers in the back deck and a center speaker in the dash, plus swapping the 3-part sets in the rear door for a bigger mid and a tweet...and a digital amp). Personally, the ML sounds pretty close to much much more expensive systems so that was plenty enough for me, and way cheaper, than looking at the aftermarket. If you already have the car with the factory Non-ML system though it wouldn't be that tough to replace just the speakers... The woofer and tweeter sizes are pretty standard... you'd just have to find a 3-way component set that had a small enough mid... here's a set for example that'd work but for the 3" mid (instead of the 2.6")... it's possible a 3" would fit in the mounting location but I haven't taken the doors apart and measured how much space is back there- http://www.woofersetc.com/index.cfm?fuseac...product_id=4312 Those are a bit spendy, but nice... you can see why the ML system's a good deal though :P

Yes, the Mark Levinson option :P Other than that it'd be DIY.

Yes, that is a cop out. Since we weren't talking about what possible future systems might do. We were talking about what the CURRENT system on the 2IS can do. Will you please answer the actual question being asked? As to the wedge system, again, it's a -completely- different system. It uses a pad, but the system around the pad isn't anything like the kind used on virtually every vehicle in the world today. It'd be like asking why certain mods for a gasoline engine don't respond exactly the same way when done on a diesel engine...I mean both make a car go, so they MUST be the same, right? Not exactly. All the discussion that has occured thusfar is about modern hydraulic braking systems, where the pad doesn't matter for a panic stop so long as it can engage ABS. If my suggested reverse rocket system somehow incorporated a pad that changed thrust of the rockets that would impact braking distance too, but it'd still have nothing to do with what was actually being discussed. So again I ask, concerning the -actual topic- who was correct? If you're saying I am correct about what we're actually talking about, and Barkat might possibly be correct some day n the future when they completely change way brakes work then please say that. Right now it just sounds like you're trying not to hurt his feelings... which is commendable, but it'd be nice if people reading thie thread in the future had a clear enough picture of how things actually work on their actual cars, not some theoretical future having no current relevance to the 2IS. That's part of why I've tried to provide so many sources verifying my info, including the folks who designed both the IS-F and F-sport braking systems.

Because that isn't a hydraulic brake system like we've been discussing this entire time? Likewise, backward firing rocket motors in front of the braking car will stop it faster too, but that's not what we've been discussing all these pages either :) (EWB is a lot more practical for a car though, and is a very cool technology... it's just not on our cars (or virtually any yet)) I'd like to ask you a question though- For the case actually under discussion, in your opinion, who is correct, myself, or barkat?

That's generally where me, the ABS engineer, Stoptech, Brembo, and others are. I can't speak to where Barkat is as he appears to live in a universe with different physical laws :P

*rotfl* Uh...ok. If you refuse to discuss this with someone who knows what the word misquote actually means and has explained in great detail why you're wrong on almost everything you've posted in the thread, has provided source after source explaining why you are wrong, and whom you baselessly called dishonest, I guess I'll just have to struggle through and find some way to continue getting up in the morning. By the way, pads won't change braking distance in the morning either.

Yes, those were your exact words. Which I used in a post that had YOUR ENTIRE POST quoted at the top. Seriously dude. Exact words where? IN YOUR POST. "I'm talking one panic stop from road speed." You even quoted it back to me several times in your last few posts. Just... wow. Read again. Read it all. Quote it all. I did. Are you having problems with the display on your computer or something? I quoted your ENTIRE post at the top of mine. Then I pointed out one part from it, word for word. In what language is that "misquoting" you? Almost every sentence of your post is wrong in some way, here I'll break it down for you- "The pads do stop the car, as they stop the wheel/tire assembly." Wrong- The tires stop the car. The pads don't stop anything at all. The pads translate force from the calipers to the rotors. That's all they do. "The faster they are able to do that the shorter the stopping distance. It can vary 10 to 20%. " No, it can't. They do that instantly. They translate the clamping force to the rotors instantly. It's what they do. Any pads that can engage ABS will do this and provide the same stopping distance. "The effiency with which the pad is able to slow down the wheels and hence the car is not the same for different materials. The pads don't just grab the rotors and stop the wheels." The pads don't slow down the wheels, the rotors do. The efficiency of the pads DOES change with material, about the only thing in the entire post you are right about, but since both pads generate enough force to engage ABS they are both providing the maximum force that can be used. Pads that transmit a higher amount of force do NOT change stopping distance as that force can not be used by the car. "The coefficient of friction of the pads is a major factor in stopping distance. I'm talking one panic stop from road speed. " ABSOLUTELY FALSE. According to me, according to the ABS system designer. According the Brembo. According to Stoptech. Even according to the other folks in this thread. "There is still energy (heat) to be dissipated here as well as initial friction to slow the wheels way before the lockup occurs." Again, time does not appear anywhere in the brake force equation. Heat goes largely into the metal of the rotors, the pads aren't "dissipating" anything during the stop... both heated pads and rotors do transfer heat out of them into the air to cool in general though. I'm not even sure what you think you're trying to express there...but the heat has nothing at all to do with stopping distance for one panic stop, because any properly designed OEM system has enough heat capacity to handle it, regardless of pads used. "Read up." You're right on the suggestion, you just directed it at the wrong party.

Yes, those were your exact words. Which I used in a post that had YOUR ENTIRE POST quoted at the top. Seriously dude. Exact words where? IN YOUR POST. "I'm talking one panic stop from road speed." was the complete sentence. Which I used right below YOUR ENTIRE POST FOR CONTEXT. You even quoted it back to me several times in your last few posts. Just... wow.

Yes, those were your exact words. Which I used in a post that had YOUR ENTIRE POST quoted at the top. Seriously dude.

The pads do stop the car, as they stop the wheel/tire assembly. The faster they are able to do that the shorter the stopping distance. It can vary 10 to 20%. The effiency with which the pad is able to slow down the wheels and hence the car is not the same for different materials. The pads don't just grab the rotors and stop the wheels. The coefficient of friction of the pads is a major factor in stopping distance. I'm talking one panic stop from road speed. There is still energy (heat) to be dissipated here as well as initial friction to slow the wheels way before the lockup occurs. Read up. I brought this back BTW so folks can see how the debate began, and what it was about. Barkat insisted that for "one panic stop from road speed" pads would be a major factor in stopping distance. That's absolutely 100% false, as I've shown repeatedly since, and as agreed on by the half dozen or so sources I've provided (including the guy who actually tested it on a 2IS with both sets of pads). Bringing up a slew of other scenarios (including the couple related to repeated high speed braking I've already mentioned) isn't really relevant to the original question. I'm happy to talk about other situations, but there's a reason I was discussing one specific scenario (the typical panic stop that most folks use as their "stopping distance" test on cars.)...a situation where pads (if they can engage ABS) make no difference whatsoever. You need to stop the misquoting and stop the little flames. I'm sure they sound good to you but they are dishonest and some are very close to rule violations. There is no such thing as the brake pads instantly stopping the rotating wheel/tire/brake assembly. That short time it takes to stop the rotation adds to the braking distance because it takes place before the tires stop and reach their limit of adhesion. That time translates to distance. That's a fact and nothing you have said or cited disproves it. How did I misquote you when I quoted your entire post in full? You calling me dishonest when I've been nothing BUT honest sounds a lot more like a flame than anything I said. And everything I'd said disproved your claim. Even Smooth1 and Gaugster have agreed for the specific case you were discussing that you are wrong. Do you even know what a brake pad does? Because it really doesn't sound like it. "time" does not appear anywhere in the equation to compute braking force. The pads never "stop" anything at all. All the pad does is take the clamping force from the caliper and apply it to the rotor. To calculate the force acting on the rotor you need to know the clamp load from the caliper and the coefficient of friction of the pad. It's an instantaneous calculation. The pad is a pad, it doesn't need "time" to generate maximum force if the caliper is already providing it. Your continued insistence on this belies a gross lack of understanding of what the parts you're discussing are even doing.

Todays braking systems utilize every aspect of braking from the driver input to the road and the surface your driving on. The entire braking system is only as good as the weakest component. Sometimes that's not the tires. I don't drive from 0-60 and then just slam on the brakes and get out. I drive my car in the real world. And in the real world, pads matter, rotors matter, tires matter, everything matters. That's great. None of it was the actual topic though. We went through this the last time you tried to make a post that sounded informed and had nothing to do with the discussion. The discussion was stopping distance. Which is generally measure as a slam-the-brake-pedal stop. Most commonly from 60-0. By pretty much everybody who tests stopping distance. You keep wanting to bring in racing (last time) or "real world" (this time- which you don't actually define) and then insist it has bearing on what we're discussing. I've said since the begining I am NOT talking about racing or other abuse of brakes...but also mentioned repeatedly how pads -can- matter there, and in what ways. Are you just grasping for something even marginally related you can try to be right about now? Because it's a topic I already covered pages ago in the thread. And even then, better pads CAN NOT improve stopping distance. They CAN increase the number of stops you get before stopping distance gets _worse_ due to fade though.. which isn't at all the same thing. They still don't shorten the distance of an initial stop. They can't. Again, I suggest you read the conclusions of the PF article... it explains the 4 things that brake system modifications can accomplish, most of them having to do with changing the feel of the system or increasing its ability to handle thermal extremes you might encounter on a track. I went over them more simply earlier in the thread. none of the things that those mods changed was stopping distance though. Even the folks trying to -sell- you brake upgrades (the honest ones anyway, like stoptech and brembo) admit that. I don't know, I tend to think that when I apply the brakes from say 45 mph, and the car comes to a stop, that is a stopping distance. Just because I haven't engaged an ABS system, doesn't mean I have or haven't acheived a point at which the brakes are applied and the car comes to stop. If I apply more pressure on the rotors, the car will have a shorter stopping distance. If I apply less, then it will take longer to stop, coorect? So if I change the brake pad, and I find myself having to apply more lever force to achieve the same stopping distance from 45 mph, then the pad did make a difference in my stopping distance correct? Even though I have compensated for that by pressing harder on the brakes? Or no, it's all the same? In order to reliably test stopping distance when changing a part you have to repeat identical conditions. Now, if you get a robot to engage the pedal at the same pressure every time at the same speed, you'd have something. A human with his foot though? Not as much. Hence why stopping distance is generally the slam-the-brake test, usually done from 60. It's repeatable. (and was the exact type of stop the thread was about, hence why I requoted barkats original misinformed post about how pads matter in that type of stop when they do not) In the specific example you cite though, no, the pad didn't change your stopping distance, it changed the amount of force you had to apply to the pedal. The car was still capable of stopping in the same distance in both examples you gave. Now, here's the thing... if you had slammed on the brake at 45 you would have stopped in a shorter distance (regardless of pad) right? So changing the pad made no difference to the best potential stopping distance you could get at 45 mph. You now seem to be trying to bring up stopping when using less than the maximum input force. Which seems kinda weird when talking about stopping distance. You're essentially asking "How long does it take me to stop when I'm not trying my hardest to stop?" Which is pretty hard to quantify. But certainly if you're applying well UNDER the amount of pressure that would engage ABS then different pads (as well as other things) could change the distance it would take the car to stop given a fixed pedal input. I'm not sure how that's really relevant unless you have a very very weak leg or something, in which case you'd want a pad that required the minimum possible input force. For people with normal leg strength any decent pad will stop the car from 45 in whatever distance less than the "optimal slam the brakes" distance they want it to, but the amount of input force required might vary.

The pads do stop the car, as they stop the wheel/tire assembly. The faster they are able to do that the shorter the stopping distance. It can vary 10 to 20%. The effiency with which the pad is able to slow down the wheels and hence the car is not the same for different materials. The pads don't just grab the rotors and stop the wheels. The coefficient of friction of the pads is a major factor in stopping distance. I'm talking one panic stop from road speed. There is still energy (heat) to be dissipated here as well as initial friction to slow the wheels way before the lockup occurs. Read up. I brought this back BTW so folks can see how the debate began, and what it was about. Barkat insisted that for "one panic stop from road speed" pads would be a major factor in stopping distance. That's absolutely 100% false, as I've shown repeatedly since, and as agreed on by the half dozen or so sources I've provided (including the guy who actually tested it on a 2IS with both sets of pads). Bringing up a slew of other scenarios (including the couple related to repeated high speed braking I've already mentioned) isn't really relevant to the original question. I'm happy to talk about other situations, but there's a reason I was discussing one specific scenario (the typical panic stop that most folks use as their "stopping distance" test on cars.)...a situation where pads (if they can engage ABS) make no difference whatsoever.

Yeah, troll alert........ We're splitting hairs here and it seemed to have turned into a personal thing. It's all about static vs. dynamic friction IMO. Methods for applying the brakes are different from ABS vs. non-ABS vehicles. It is a matter of deciding which of the many factors (tires, road, brakes, brake lines, fluid, Pre-Collision System, vehicle weight etc...) has the most dominate affect on the stopping distance of the vehicle. In less then ideal conditions like rain and snow, it’s all about the tires 100% as locking up the wheels is easy. In very ideal condition, tires are still a very major factor but some of the other aspects can come into play IMO. Knightshade is considering a very special application of the brakes where only the ISx50 is considered and maximum force is applied and the wheels will lock up instantly. Others have declared this to be a falsehood and then went on to discuss the “other aspects” I mentioned above. I think Knightshade is correct given that his example is very specific and limited. The other comments are true for a host and “what if” scenarios – most of which can be relevant for daily drivers. Regards, Can you cite any specific conditions that occur in the real world, outside a racetrack or a chase scene from a Bond movie, where different brake pads (both in good condition and capable of engaging the ABS system) will improve stopping distance? The only one I can think of where pads would matter at all is driving down a steep mountain... which would be another case like I discussed where some pads might take longer to fade, this preserving the same stopping distance over a longer period of time, not actually improving it per se. But of course using lower gears would mitigate that significantly, and would be the proper way to drive in that situation.... the 2IS makes this fairly easy even with the auto.

Todays braking systems utilize every aspect of braking from the driver input to the road and the surface your driving on. The entire braking system is only as good as the weakest component. Sometimes that's not the tires. I don't drive from 0-60 and then just slam on the brakes and get out. I drive my car in the real world. And in the real world, pads matter, rotors matter, tires matter, everything matters. That's great. None of it was the actual topic though. We went through this the last time you tried to make a post that sounded informed and had nothing to do with the discussion. The discussion was stopping distance. Which is generally measure as a slam-the-brake-pedal stop. Most commonly from 60-0. By pretty much everybody who tests stopping distance. You keep wanting to bring in racing (last time) or "real world" (this time- which you don't actually define) and then insist it has bearing on what we're discussing. I've said since the begining I am NOT talking about racing or other abuse of brakes...but also mentioned repeatedly how pads -can- matter there, and in what ways. Are you just grasping for something even marginally related you can try to be right about now? Because it's a topic I already covered pages ago in the thread. And even then, better pads CAN NOT improve stopping distance. They CAN increase the number of stops you get before stopping distance gets _worse_ due to fade though.. which isn't at all the same thing. They still don't shorten the distance of an initial stop. They can't. Again, I suggest you read the conclusions of the PF article... it explains the 4 things that brake system modifications can accomplish, most of them having to do with changing the feel of the system or increasing its ability to handle thermal extremes you might encounter on a track. I went over them more simply earlier in the thread. none of the things that those mods changed was stopping distance though. Even the folks trying to -sell- you brake upgrades (the honest ones anyway, like stoptech and brembo) admit that.

Yes, but the pads -still- don't change stopping distance. I notice you go after the source written in 1991, but not the numerous others, like Brembo and Stoptech who say the same thing -today-.... that pads CAN NOT change stopping distance. and of course I know the formula for the force involved in braking... that lovely 1991 article explains it in great detail in fact. The only place in the equation that the pads enter at all is when you mutliply the force from the caliper by the pads coefficient of friction. As long as the pads can engage the ABS system you will come up with a number greater than the amount of force the vehicle can make use of due to the limitations of the tires. (that would in fact be WHY the ABS system ends up engaging). Thus a higher amount of force from a higher CoE would be completely wasted extra force. It certainly wouldn't make the car stop faster. It couldn't. As to my "ego"... hardly. I was very polite the first several times I explained Barkats error to him. It was only when he (and you) kept jumping up and down insisting you must be right despite all evidence to the contrary and that clearly I had no idea what I was talking about despite every expert on the topic agreeing with me that I began taking on a less polite tone. Even when Barkat devolved to "Nu uh!" replies I continued to provide reliable sources and articles all supporting the point I was making while he provided nothing but "Nopenopenope!" I don't think it's my ego that was having a problem here. And I'm not sure why you feel I'm "not tech" when I appear to be the only one in the debate who actually understood the articles that were being posted and had the correct answer from the beginning. If you or barkat were "tech" you would've admitted the point after the first source or two that explained the technical reasoning for pads not changing stopping distance.... or after the third or forth, or after.... well, you ge the point.

I admit your points would be compelling if we were arguing over you eating your broccoli or brushing your teeth before nap time. Here? Not so much.