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Clivew
Member
This is an excerpt from the Bosch manual for their ABS system. Bosch is a huge company with massive experience in all aspects of automotive.
Flexible rubber brake hose expansion causes the same thing, volume increase on the pressure side, which reduces ABS effectiveness and increases stopping distances.
Knightshade
Well-Known Member
I have- it's just factually wrong and contradicted by the half a dozen expert sources I've provided.
Again- I cited half a dozen sources.
none of which you appear to have read.
Because I specifically caught you claiming one of them didn't address brake lines when it spends several paragraphs on them.
What it shows is when you claimed my first source didn't address brake hose, compliance, or its impact on performance, you were not factually correct.
It addresses those exact things, over several paragraphs, and explicitly rejects your claim about them.
<citation needed>
Meanwhile back in the essay you didn't read we find this conclusion:
James Walker Jr said:
Not sure how much clearer a rejection of your claim from an industry expert you can expect.
Then surely you can provide multiple sources that support your own claims that are more complex, right?
I've given you half a dozen now- including technical whitepapers from brake manufacturers all supoporting my argument and debunking yours.
Where's your sources? Where's your evidence?
No, it's not impossible at all.
The simplistic view here is yours.
There's lots of ways to make braking distance worse
Many aftermarket BBKs do exactly that in fact because they don't do anything about the factory proportioning that is assuming OEM brake parts.
So braking distance gets worse
But the biggest BBK in the world can't make stopping distance better than a properly working OEM system- because the tires, not the brakes, are what stop the car.
The goal of the ABS system is to maximize the friction between tire and road while still letting you steer the car.
So yes if you have an inferior ABS map applied, braking gets worse
This actually happened on the model 3 at launch
There was a software bug that caused issues with the ABS mapping.
It make stopping distances after the first stop much longer in some cases.
Tesla fixed it with an OTA update- such that it was back to stopping as short as possible given the tires.
(and guess what happens when people with the non-P brakes swap on the same PS4s tires the P comes with? their stopping distance drops down to P numbers... without doing anything to the braking system.
Because again the tires stop the car
Sweet, FINALLY a source.
Of course... it says "performance" not "stopping distance.
Those aren't the same thing.
It's weird how you keep failing to find any sources to actually support your claims.
<citation needed>
This is factually false. OEMs do not put the perfect setup on their cars, they consider many factors such as manufacturing expenses as well as compatibility with other components. Why do you think that OEMs develop different braking systems as the same car model evolves? If any existing OEM brake system was already the best, they would never revise them.
I can also prove it with data from dragy showing that changing absolutely nothing on my car except using aftermarket rotors (the same diameter, 1mm thicker) with different pads, reduced my 60-0 stops by almost 10 feet, with no other changes done to the car, on the same street, with the same conditions, on the same day.
You seem to be contradicting yourself. So now "performance" isn't stopping distance? You said it was earlier.
Ravire
Member
Upgraded brakes will produce the same amount of stopping force as the stock brakes but will get to that maximum stopping force slightly faster than the stock brakes. That’s what he’s saying. What you’re saying about tires is true and I agree with that statement but it’s like you purposefully let everything fly over your head. Instead of always being ready to argue maybe you should be ready to comprehend since it’s not a trait you exercise very often.
The way he is aiming his debate would be similar to someone saying an engine doesn't make the car accelerate, it's the tires. And no matter what you do to the engine, it will not accelerate any faster.
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Uncle Paul
Well-Known Member
Biggest track benefits to performance brakes is consistant braking, better brake feel, allowing you to precisely modulate your brakes slowing your car, better heat dissapation for multiple braking applications.
For the street they provide little single use emergency stopping improvement, but better feel is important to some.
For the street they provide little single use emergency stopping improvement, but better feel is important to some.
eladts
Member
It is true when you go to the extreme. That's why to get better acceleration in the Roadster 2 you will need the SpaceX package.
Clivew
Member
Knightshade - you are confusing a theoretical shortest stopping distance if every tyre on the car were decelerated at exactly the correct rate to obtain the perfect slip of each tyre to create maximum grip, from braking point to stopping the car. In reality this stopping distance is not achievable because of too many variables in the tyre, road surface etc, and tolerances in the braking system. Incremental improvements in the braking system can however shorten the stopping distance closer to this theoretical minimum.
Compare it to a theoretical fastest lap time of a car around a circuit, where the speed of the car and steering angle are exactly right all of the time to create the perfect slip angle of tyre against tarmac, which produces maximum grip and the fastest cornering speed. In reality, it's a lap time you aim to achieve, but is impossible to attain. BUT, improvements in driver skill, experience, and in the chassis of the car like better suspension, stiffer suspension bushes, etc, etc, will help you get closer to this theoretical lap time.
Let me ask you a final question. If you drove a car with an ABS system you could turn off, would you be able to brake the car to a stop in exactly the same distance with the ABS turned off and with it turned on?
Compare it to a theoretical fastest lap time of a car around a circuit, where the speed of the car and steering angle are exactly right all of the time to create the perfect slip angle of tyre against tarmac, which produces maximum grip and the fastest cornering speed. In reality, it's a lap time you aim to achieve, but is impossible to attain. BUT, improvements in driver skill, experience, and in the chassis of the car like better suspension, stiffer suspension bushes, etc, etc, will help you get closer to this theoretical lap time.
Let me ask you a final question. If you drove a car with an ABS system you could turn off, would you be able to brake the car to a stop in exactly the same distance with the ABS turned off and with it turned on?
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eladts
Member
The SpaceX 'package' doesn't have anything to do with tire upgrades
When you start with the stickiest road tires available, there is nothing to upgrade. You have to bypass the tires altogether. Drag racers use parachutes for breaking for the same reason.
Clivew
Member
When Bosch write 'performance' they are assuming the reader isn't an idiot.
When we talk about reducing the acceleration perfomance of a car, it means it accelerates slower, yeah?
When a manufacturer writes in their ABS manual that a flexing caliper reduces performance, they are obviously talking about braking performance and that means the car will decelerate slower.
It also means that if you fit a caliper that flexes less, or brake lines that expand less, you will improve braking performance, and thus decelerate faster.
They also write 'performance' and not braking performance because their system also improves cornering performance (trail braking phase) as well as braking performance.
Unless of course you think Bosch and all the hundreds of race teams that fit their ABS system to improve braking perfomance, don't know what they are doing because they haven't read your linked idiots guide to braking.
When we talk about reducing the acceleration perfomance of a car, it means it accelerates slower, yeah?
When a manufacturer writes in their ABS manual that a flexing caliper reduces performance, they are obviously talking about braking performance and that means the car will decelerate slower.
It also means that if you fit a caliper that flexes less, or brake lines that expand less, you will improve braking performance, and thus decelerate faster.
They also write 'performance' and not braking performance because their system also improves cornering performance (trail braking phase) as well as braking performance.
Unless of course you think Bosch and all the hundreds of race teams that fit their ABS system to improve braking perfomance, don't know what they are doing because they haven't read your linked idiots guide to braking.
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Clivew
Member
You've contradicted yourself with these statements. Is it the same or worse?
And nothing can improve on the standard OEM ABS system, even a high end, high fidelity and extremely expensive system made by Bosch?
Your logic and argument here is that nothing can improve on the standard OEM braking system. Non OEM high perfomance brake components can only make it worse, but can't improve braking performance?
You obviously have no understanding of the financial constraints and compromises made when designing an OEM brake system for a car like the Model 3. Highest possible braking performance is not the ultimate goal, and can always be improved upon with high quality and more optimised components.
Actually the majority of drag cars use parachutes as a secondary braking system in the event that the brakes fail. It's required by racing organizations and the insurance companies that insure the tracks.
Not to argue that point, but this is the actual reason.
Clivew
Member
You do know what a white paper is right?
It’s basically a marketing document which has limited basic technical info, aimed at the layman like yourself who has a limited technical understanding. It’s not going into anywhere near the depth that I am discussing on here, for good reason. People like you just would not understand it.
White papers are great, they enable a large percentage of potential buyers of their products to understand the basics.
Well, I whole heartedly agree with everything written in the white paper, especially the graph that shows that fitting an optimised aftermarket Stoptech brake kit, reduces the braking distance, compared to the OEM set-up.
So, the ‘white paper’ you are quoting, agrees exactly with what I have been saying all along.
Replacing components of a braking system with higher quality optimised parts can reduce the stopping distance compared to OEM.
I’ve read the white paper properly, thanks, but I’m not sure you have.
I think Knightshade has sloped off to think about things. I guess we won't be getting any sort of apology any time soon.
Knightshade
Well-Known Member
ALMOST but not quite.
It would be like saying once you've exceeded the traction of the tires then no matter what you do to the engine it won't accelerate faster.
Which is correct.
A 600 hp car sitting there just spinning the tires won't go any quicker with 800 hp.
Likewise a car that can already engage ABS with X amount of braking force won't stop any shorter if it can generate 2X braking force.
Once you are at the limit of the tire either way, MOAR force does not help (and can sometimes hurt)
Weird you quote my post then miss what it actually said.
I specifically said brake parts and tires impact performance on a track
In fact I even made the point they do so in DIFFERENT ways
Me said:
So track performance is more than only the minimum stopping distance being discussed (and the one that's relevant in street use, since unlike a track you're not stopping repeatedly from 120 mph over and over without cooling things down)
So no, I didn't contradict anything.
That would depend on the skill of the driver.
There are a (very very small number, though many think they're a member) of people who can threshold brake as well or better than a good ABS computer.
And there are a (very very large number) of people who can't.
No, I haven't.
Maybe I was writing too much for the "layman" for you though?
The point was (again re-read the original post I made) that the P and non-P stop in the same distance with the same tires.
In general upgrading the brakes can't stop you shorter than the OEM pads/rotors/etc on a modern vehicle
(ie anything made in the last couple decades that can already engage ABS with the stock brakes).
Because once you've done that, as pointed out via basic physics, the only variable impacting stopping distance is the friction between tire and road
Which is limited (as far as parts of the car)- every single time- by the tire.
It's why folks swapping P tires onto a non-P Tesla, even though it means they're going from P brakes to "regular" brakes, get P stopping distance once they swap.
Because the tire- not the brakes- stop the car.
I'm not aware of an aftermarket replacement ABS system for a Tesla- are you?
And adding a customized 3rd party ABS computer is pretty far afield from swapping rotors/pads/calipers which are the differences in all available brake upgrade kits I'm aware of for the car... (and the difference from P to non P as well).
it's not an issue of finance here, but one of safety.
As the stoptech whitepaper points out- OEM ABS computers generally are a few percent biased toward safe operation.
Which is what you'd want on a street car.
If you have a way to dial that safety back out for track use- knock yourself out- there's lots of personal tuning to your specific driving style you might find of value there.
But it's not really applicable to a street driven car.
Indeed- let's revisit my first post on this topic
Me said:
You've now apparently tried to drag the discussion of comparing the P and non-P in street use here over to "Well what if we had a custom-designed-just-for-this-car super expensive aftermarket ABS computer optimized for the shortest possible stop, stability be damned??"
Weird.
When it's a technical paper that tells you you're wrong, it's "written for the layman" and has "dumbed down" info.
When you think it supports your point, it's assuming the reader is smart and is gosphel fact presented.
This is complete nonsense.
For example bigger rotors can offer enhanced THERMAL performance to your braking system in track situations without reducing stopping distance at all
It would just mean you can make more repeated stops without them getting longer
Not that they ever get shorter than before the swap.
So when you said only an idiot would think they meant something other than braking performance....and then admitted they might mean something other than that...um... yeah....
I think you have this backward.
You saw the chart, then didn't read what it said below it.
Lemme help.
The entire point of the article was about the fact many aftermarket brake kits ignore the factory bias, and do nothing to work with it.... so they can often make stopping distances worse
The marketing aspect there is Stoptech designs their kits with the OEM bias in mind- hence why other brands kits make it worse and theirs doesn't.
Such kits can overly front bias, making braking worse- or overly rear bias making not just braking distance worse, but making stability worse as well.
In all cases what you're playing around with is maximizing the ability of the system to get the most out of the tires
Because- again, the thing that actually stops the car is the tire/road interface.
In fact, in the paragraph right under your chart they tell you that yet again.
Stoptech white paper said:
I think Knightshade has sloped off to think about things. I guess we won't be getting any sort of apology any time soon.
Not sure what you think I have to apologize for.... citing half a dozen sources when I make a point?
Wish more folks would.
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Needsdecaf
Active Member
This argument is highly amusing.
Knightshade, your point regarding tires being the ULTIMATE determiner of braking force (i.e. the maximum braking force that can be applied) is correct. You reach a point where a tire's contact patch is maxmimzed, and then physics cannot be ignored. There is only so much grip you can possibly have, and therefore only so much ultimate maximum deceleration. You are correct, the road / tire interface is the only thing that actually stops the car.
I also agree with you when you say that many BBK's do not help a vehicle to stop in a shorter distance. This is for various reasons. They're not properly sized for the car, or the car's stock braking system is already capable of producing maximum braking force in a reasonable time. And so on and so forth. However....
You're ignoring the dynamics of the situation. A vehicle's contact patch is not static. A vehicle does not go to maximum braking force every single time the brakes are applied. It can't. Weight transfer will change the size of the contact patch, dramatically increasing the potential for the front brakes to work as the car undergoes braking. So how fast you reach the state of maximum contact patch is important. Maintaining that maximum braking force is important. Is the gas from the braking buffering back against the pad (this is what slotted and / or drilled rotors are for, not for cooling)? Is the pad overheating and no longer able to maintain maximum grip against the rotor? How fast you can get to that maximum braking force which maximizes the traction area of the tire is important. And if you can maintain that maximum force. There are a lot of factors that go into engineering a braking system, and a tire's contact patch is only one variable in the equation.
You're focused on one thing only. What you're focused on isn't incorrect, it's just not the whole picture.
Knightshade, your point regarding tires being the ULTIMATE determiner of braking force (i.e. the maximum braking force that can be applied) is correct. You reach a point where a tire's contact patch is maxmimzed, and then physics cannot be ignored. There is only so much grip you can possibly have, and therefore only so much ultimate maximum deceleration. You are correct, the road / tire interface is the only thing that actually stops the car.
I also agree with you when you say that many BBK's do not help a vehicle to stop in a shorter distance. This is for various reasons. They're not properly sized for the car, or the car's stock braking system is already capable of producing maximum braking force in a reasonable time. And so on and so forth. However....
You're ignoring the dynamics of the situation. A vehicle's contact patch is not static. A vehicle does not go to maximum braking force every single time the brakes are applied. It can't. Weight transfer will change the size of the contact patch, dramatically increasing the potential for the front brakes to work as the car undergoes braking. So how fast you reach the state of maximum contact patch is important. Maintaining that maximum braking force is important. Is the gas from the braking buffering back against the pad (this is what slotted and / or drilled rotors are for, not for cooling)? Is the pad overheating and no longer able to maintain maximum grip against the rotor? How fast you can get to that maximum braking force which maximizes the traction area of the tire is important. And if you can maintain that maximum force. There are a lot of factors that go into engineering a braking system, and a tire's contact patch is only one variable in the equation.
You're focused on one thing only. What you're focused on isn't incorrect, it's just not the whole picture.
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