why have bigger brakes?
22 July 2013, 06:52 PM
#123
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What do bigger brakes do?
Eg-
My car is was 215bhp and I upgrade power to 350 and get told get bigger brakes to stop better. But have kept with std 4pot and change to grooved discs and better pads.
Or another car is 600bhp has bigger brakes cus I have big bhp.
Scenario...
Both the above cars are the same make and model.
And are travelling at the same 90mph and need to stop.
Why does bigger brakes make any difference when both cars are doing the same speed?
Eg-
My car is was 215bhp and I upgrade power to 350 and get told get bigger brakes to stop better. But have kept with std 4pot and change to grooved discs and better pads.
Or another car is 600bhp has bigger brakes cus I have big bhp.
Scenario...
Both the above cars are the same make and model.
And are travelling at the same 90mph and need to stop.
Why does bigger brakes make any difference when both cars are doing the same speed?
And do you feel endowed by fresh knowledge?
22 July 2013, 08:48 PM
#124
From "how stuff works"
http://auto.howstuffworks.com/auto-p...-calipers4.htm
All of these technologies can increase the braking power provided by a caliper. For smaller cars that typically aren't driven at high speeds, this extra braking power isn't really necessary. However, the faster and more powerful a vehicle is, the more it will benefit from high-performance calipers.
There are certain limitations to just how much the vehicle's brakes and its calipers can do to stop a vehicle; while they may be able to bring the wheels to a stop, it's up to the gripping power of the tires to do the rest, and improved brake parts can't help beyond a certain point. However, there are several ways in which brake calipers can be (and have been) improved. Some common features found in performance brake calipers include:
Bigger pistons -- The larger the pistons are, and the greater the area over which they come in contact with the brake pads, the more clamping force they have on the rotor.
More pistons -- Low-end floating brake calipers have a single piston, on the inboard side. Low-end fixed calipers have a single pair of pistons, flanking the rotor disc. High-performance calipers can have multiple pins or pairs of pins, mounted on opposing sides of the rotor. Six-piston models are increasingly common and even 12-piston models are not unheard of. Increasing the number of pistons also serves to increase the clamping force of the caliper.
Less heat retention -- In a sense, your brakes can be thought of as a device for converting movement into heat. As the vehicle slows down, all of that kinetic energy has to go somewhere and most of it ends up as heat. If you want to look at it another way, all that friction between the brake pads and the rotor generates heat in much the same way that striking a match generates heat. If too much heat builds up, the brakes begin to fade, or become less effective. So, the better ventilated the brake calipers are, the better they perform. Also, the larger the surface of the brake rotor, the more the heat is spread out.
Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back.
http://auto.howstuffworks.com/auto-p...-calipers4.htm
All of these technologies can increase the braking power provided by a caliper. For smaller cars that typically aren't driven at high speeds, this extra braking power isn't really necessary. However, the faster and more powerful a vehicle is, the more it will benefit from high-performance calipers.
There are certain limitations to just how much the vehicle's brakes and its calipers can do to stop a vehicle; while they may be able to bring the wheels to a stop, it's up to the gripping power of the tires to do the rest, and improved brake parts can't help beyond a certain point. However, there are several ways in which brake calipers can be (and have been) improved. Some common features found in performance brake calipers include:
Bigger pistons -- The larger the pistons are, and the greater the area over which they come in contact with the brake pads, the more clamping force they have on the rotor.
More pistons -- Low-end floating brake calipers have a single piston, on the inboard side. Low-end fixed calipers have a single pair of pistons, flanking the rotor disc. High-performance calipers can have multiple pins or pairs of pins, mounted on opposing sides of the rotor. Six-piston models are increasingly common and even 12-piston models are not unheard of. Increasing the number of pistons also serves to increase the clamping force of the caliper.
Less heat retention -- In a sense, your brakes can be thought of as a device for converting movement into heat. As the vehicle slows down, all of that kinetic energy has to go somewhere and most of it ends up as heat. If you want to look at it another way, all that friction between the brake pads and the rotor generates heat in much the same way that striking a match generates heat. If too much heat builds up, the brakes begin to fade, or become less effective. So, the better ventilated the brake calipers are, the better they perform. Also, the larger the surface of the brake rotor, the more the heat is spread out.
Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back.
22 July 2013, 09:56 PM
#125
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dunx
P.S. AP six pots (330) + std STI rear Brembos with decent pads.
22 July 2013, 10:32 PM
#126
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23 July 2013, 12:25 AM
#128
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I believe Stephen Hawking because he explains things I don't understand in a manner that I can, not because everyone else thinks he's a doyen of his particular field.
And Prof. Hawking doesn't get by simply by saying that some people's views are rubbish.
And brevity to some is suppression to others.
So, who, in your highly respected view, has been posting "rubbish" ?
23 July 2013, 12:29 AM
#129
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From "how stuff works"
http://auto.howstuffworks.com/auto-p...-calipers4.htm
All of these technologies can increase the braking power provided by a caliper. For smaller cars that typically aren't driven at high speeds, this extra braking power isn't really necessary. However, the faster and more powerful a vehicle is, the more it will benefit from high-performance calipers.
There are certain limitations to just how much the vehicle's brakes and its calipers can do to stop a vehicle; while they may be able to bring the wheels to a stop, it's up to the gripping power of the tires to do the rest, and improved brake parts can't help beyond a certain point. However, there are several ways in which brake calipers can be (and have been) improved. Some common features found in performance brake calipers include:
Bigger pistons -- The larger the pistons are, and the greater the area over which they come in contact with the brake pads, the more clamping force they have on the rotor.
More pistons -- Low-end floating brake calipers have a single piston, on the inboard side. Low-end fixed calipers have a single pair of pistons, flanking the rotor disc. High-performance calipers can have multiple pins or pairs of pins, mounted on opposing sides of the rotor. Six-piston models are increasingly common and even 12-piston models are not unheard of. Increasing the number of pistons also serves to increase the clamping force of the caliper.
Less heat retention -- In a sense, your brakes can be thought of as a device for converting movement into heat. As the vehicle slows down, all of that kinetic energy has to go somewhere and most of it ends up as heat. If you want to look at it another way, all that friction between the brake pads and the rotor generates heat in much the same way that striking a match generates heat. If too much heat builds up, the brakes begin to fade, or become less effective. So, the better ventilated the brake calipers are, the better they perform. Also, the larger the surface of the brake rotor, the more the heat is spread out.
Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back.
http://auto.howstuffworks.com/auto-p...-calipers4.htm
All of these technologies can increase the braking power provided by a caliper. For smaller cars that typically aren't driven at high speeds, this extra braking power isn't really necessary. However, the faster and more powerful a vehicle is, the more it will benefit from high-performance calipers.
There are certain limitations to just how much the vehicle's brakes and its calipers can do to stop a vehicle; while they may be able to bring the wheels to a stop, it's up to the gripping power of the tires to do the rest, and improved brake parts can't help beyond a certain point. However, there are several ways in which brake calipers can be (and have been) improved. Some common features found in performance brake calipers include:
Bigger pistons -- The larger the pistons are, and the greater the area over which they come in contact with the brake pads, the more clamping force they have on the rotor.
More pistons -- Low-end floating brake calipers have a single piston, on the inboard side. Low-end fixed calipers have a single pair of pistons, flanking the rotor disc. High-performance calipers can have multiple pins or pairs of pins, mounted on opposing sides of the rotor. Six-piston models are increasingly common and even 12-piston models are not unheard of. Increasing the number of pistons also serves to increase the clamping force of the caliper.
Less heat retention -- In a sense, your brakes can be thought of as a device for converting movement into heat. As the vehicle slows down, all of that kinetic energy has to go somewhere and most of it ends up as heat. If you want to look at it another way, all that friction between the brake pads and the rotor generates heat in much the same way that striking a match generates heat. If too much heat builds up, the brakes begin to fade, or become less effective. So, the better ventilated the brake calipers are, the better they perform. Also, the larger the surface of the brake rotor, the more the heat is spread out.
Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back.
) quite a few people on here have the right idea.Accordingly I hope most sleep (slept) well tonight.
( Just 3 lines - now that's brief. )
23 July 2013, 12:31 AM
#130
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23 July 2013, 12:38 AM
#132
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And how do we determine that?
I believe Stephen Hawking because he explains things I don't understand in a manner that I can, not because everyone else thinks he's a doyen of his particular field.
And Prof. Hawking doesn't get by simply by saying that some people's views are rubbish.
And brevity to some is suppression to others.
So, who, in your highly respected view, has been posting "rubbish" ?
I believe Stephen Hawking because he explains things I don't understand in a manner that I can, not because everyone else thinks he's a doyen of his particular field.
And Prof. Hawking doesn't get by simply by saying that some people's views are rubbish.
And brevity to some is suppression to others.
So, who, in your highly respected view, has been posting "rubbish" ?
23 July 2013, 12:48 AM
#133
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Well you did when you talked about the engine producing a positive torque output to the wheels during the braking phase when it is in fact being motored, which also made your comment about more powerful and less powerful engines rubbish (assuming all things equal in terms of compression and other losses, as explained in my post at the end of page 3).
I haven't seen any evidence to the contrary - apart from your 'expertise' of course.
Oh - and what I did was make a comment that would continue the discussion.
By the time this thread's finished we'll all know a lot more about how brakes work, and the theory behind them.
It's called 'teasing out maximum information', because only when all possibilities and probabilities have been commented upon will some of us be far better enlightened.
23 July 2013, 01:02 AM
#134
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So - you prove I'm incorrect.
I haven't seen any evidence to the contrary - apart from your 'expertise' of course.
Oh - and what I did was make a comment that would continue the discussion.
By the time this thread's finished we'll all know a lot more about how brakes work, and the theory behind them.
It's called 'teasing out maximum information', because only when all possibilities and probabilities have been commented upon will some of us be far better enlightened.
I haven't seen any evidence to the contrary - apart from your 'expertise' of course.
Oh - and what I did was make a comment that would continue the discussion.
By the time this thread's finished we'll all know a lot more about how brakes work, and the theory behind them.
It's called 'teasing out maximum information', because only when all possibilities and probabilities have been commented upon will some of us be far better enlightened.
Go and read any decent books about engines in general and you might learn a bit about how they work. Or just go out and drive your car, change down gears and feel engine braking at work lol
23 July 2013, 01:19 AM
#135
ok so in simple terms, 2 identical cars both the same weight,
1 with 450bhp
2 with 300bhp
from a to b using the power properly you are going to arrive at b going a damm sight faster in the 450bhp car, assuming the driver has no track training and only guesses braking distances i would take the 450bhp car with larger brakes all day long. as proven by mr clarkson in the slk 120mph and stopped in the distance allowed for 60mph.
1 with 450bhp
2 with 300bhp
from a to b using the power properly you are going to arrive at b going a damm sight faster in the 450bhp car, assuming the driver has no track training and only guesses braking distances i would take the 450bhp car with larger brakes all day long. as proven by mr clarkson in the slk 120mph and stopped in the distance allowed for 60mph.
23 July 2013, 01:21 AM
#136
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Ask any mechanical engineer worth his salt and he will explain it to you. I spent my last 2 years at uni testing engines on an engine dynamometer which provides torque values, as you would expect and guess what there are negative torque values there. Alongside this there was a course in advanced IC engines taught by one of the world most respected lecturers in this field.
Go and read any decent books about engines in general and you might learn a bit about how they work. Or just go out and drive your car, change down gears and feel engine braking at work lol
Go and read any decent books about engines in general and you might learn a bit about how they work. Or just go out and drive your car, change down gears and feel engine braking at work lol
Do you think I don't know "a bit about how they (engines) work"?
That's what I've been doing for 35 years, and that's why my pads need changing at longer intervals than most.
Oh - and partly why I seem to get the upper range of mpg on all the cars I've owned.
As DM said earlier, "no appols necessary, I knew where you were coming from".
You clearly don't.
LOL.
But we won't fall out.
We're Scooby fanatics after all.
23 July 2013, 09:31 AM
#137
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But does this apply to Subarus and/or A/4WD cars?
I know white Ford Transit drivers (the colour refers to the vehicle, before anyone says anything) often think they're behind the wheel of an awesome machine but................
Anyway, as your dad is so kind, my daughter's fezza has packed up.
I wonder if.............
(All done in the best possible taste
)
I know white Ford Transit drivers (the colour refers to the vehicle, before anyone says anything) often think they're behind the wheel of an awesome machine but................
Anyway, as your dad is so kind, my daughter's fezza has packed up.
I wonder if.............
(All done in the best possible taste
)No fezza help, he hates working on cars
Last edited by trails; 23 July 2013 at 09:33 AM. Reason: makes sense now!
23 July 2013, 01:25 PM
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23 July 2013, 02:29 PM
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23 July 2013, 02:35 PM
#142
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23 July 2013, 02:52 PM
#143
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What about it? If you are engine braking the ECU is in overun mode and injects no fuel. If you just use the brakes and dip the clutch then the engine goes into idle and uses fuel to keep ticking over. If you use the brakes and engine brake then you are wasting fuel indirectly by heating up the brakes.
23 July 2013, 05:07 PM
#144
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trackday brakes????
does anyone have experience of massive caliper and disc conversions for track day use on imprezas? something about 332mm+ brembo/tarox/ap racing? i'm running 18x8. i spent £700 on an ebc disc/pad combo and it simply wasn't up to trackday use in the slightest. orange stuff pads basically destroyed after one day (i wasn't even on track that much and the disc warped!) i dont mind spending 2 grand as long as the brakes dont die on their **** after 1 session. any suggestions people???
23 July 2013, 05:15 PM
#145
does anyone have experience of massive caliper and disc conversions for track day use on imprezas? something about 332mm+ brembo/tarox/ap racing? i'm running 18x8. i spent £700 on an ebc disc/pad combo and it simply wasn't up to trackday use in the slightest. orange stuff pads basically destroyed after one day (i wasn't even on track that much and the disc warped!) i dont mind spending 2 grand as long as the brakes dont die on their **** after 1 session. any suggestions people???
23 July 2013, 09:05 PM
#150
does anyone have experience of massive caliper and disc conversions for track day use on imprezas? something about 332mm+ brembo/tarox/ap racing? i'm running 18x8. i spent £700 on an ebc disc/pad combo and it simply wasn't up to trackday use in the slightest. orange stuff pads basically destroyed after one day (i wasn't even on track that much and the disc warped!) i dont mind spending 2 grand as long as the brakes dont die on their **** after 1 session. any suggestions people???