Big brakes...yes or no?

[GordonD]

What is your obsession with putting bigger discs on it? The Westy probably has 4-pots as it's got 15" wheels and fairly little disks (and also goes a hell of a lot quicker)

You're driving a moderately quick Clio at rediculous speeds and then tanking the brakes on. Drive properly and you won't have a problem.

Pads and braided lines definately, and a set of high carbon discs will be good on top of that but not essential. AND NO THEY DON'T NEED TO BE BIGGER!!!

I've said this before.

On the road the size of the brakes is determined by the weight of the vehicle. At every corner you're coming down from the speed limit to the speed you can negotiate the corner. Down a steep grade its a matter of gravity and mass. Power doesn't come into it. You'd increase the size of the brakes on a road car if you were towing a trailer, for example.

On the track there is no speed limit so the size of the brakes is determined by the power of the vehicle because the amount of the energy the brakes have to dissipate is only limited by the amount the engine was able to add to the car since the last corner. Weight doesn't come into it.

So a trackday type vehicle like the Westfield that has an absurdly powerful engine for the size of the car also needs to have absurdly large brakes. It needs the brakes out of a vehicle of its power not its weight. And if its got to fit good brakes inside wheels that a relatively small because the vehicle is scaled down in weight and size its not surprising they use every trick they can, like using 4-pot calipers. On the other hand a Clio Trophy car doesn't need much extra in the way of brakes, just better pads, because it has very little more power than a standard car.

If you are using a Clio on the track its not its weight that's important, its its power. If you have substantially increased the engine's power you may need to substantially increase the brakes' power to because you've substantially increased the the amount of kinetic energy that has to be taken out at the end of each straight.

Its just basic physics.

 

[Diesel_Power]

What is your obsession with putting bigger discs on it? The Westy probably has 4-pots as it's got 15" wheels and fairly little disks (and also goes a hell of a lot quicker)

You're driving a moderately quick Clio at rediculous speeds and then tanking the brakes on. Drive properly and you won't have a problem.

Pads and braided lines definately, and a set of high carbon discs will be good on top of that but not essential. AND NO THEY DON'T NEED TO BE BIGGER!!!

I've said this before.

On the road the size of the brakes is determined by the weight of the vehicle. At every corner you're coming down from the speed limit to the speed you can negotiate the corner. Down a steep grade its a matter of gravity and mass. Power doesn't come into it. You'd increase the size of the brakes on a road car if you were towing a trailer, for example.

On the track there is no speed limit so the size of the brakes is determined by the power of the vehicle because the amount of the energy the brakes have to dissipate is only limited by the amount the engine was able to add to the car since the last corner. Weight doesn't come into it.

So a trackday type vehicle like the Westfield that has an absurdly powerful engine for the size of the car also needs to have absurdly large brakes. It needs the brakes out of a vehicle of its power not its weight. And if its got to fit good brakes inside wheels that a relatively small because the vehicle is scaled down in weight and size its not surprising they use every trick they can, like using 4-pot calipers. On the other hand a Clio Trophy car doesn't need much extra in the way of brakes, just better pads, because it has very little more power than a standard car.

If you are using a Clio on the track its not its weight that's important, its its power. If you have substantially increased the engine's power you may need to substantially increase the brakes' power to because you've substantially increased the the amount of kinetic energy that has to be taken out at the end of each straight.

Its just basic physics.

So cars with what, an extra 5-10bhp warrants biggers discs, calipers and more pistons that you can shake a stick at, because most clios here only have light tuning.

If were talking physics then surely the way to go is by uprating the properties of your existing pads and discs and brake lines? Improving the quality of these results in less unsprung weight which would help grip levels, ride quality etc. If the setup does start to fade (which is highly unlikely unless you cant drive properly or your doing a non stop tour of the nurburgring) then simply let the brakes cool and head back out? I can see the point your trying to make, i just dont subscribe to it, i think the disadvantages outweigh the advantages.

 

[graham_172]

shed motorsport do a big brake kit that fits under 15" wheels. yes 15" wheels. http://www.shedmotorsport.com/brakes.htm

 

[fmp_]

What is your obsession with putting bigger discs on it? The Westy probably has 4-pots as it's got 15" wheels and fairly little disks (and also goes a hell of a lot quicker)

You're driving a moderately quick Clio at rediculous speeds and then tanking the brakes on. Drive properly and you won't have a problem.

Pads and braided lines definately, and a set of high carbon discs will be good on top of that but not essential. AND NO THEY DON'T NEED TO BE BIGGER!!!

I've said this before.

On the road the size of the brakes is determined by the weight of the vehicle. At every corner you're coming down from the speed limit to the speed you can negotiate the corner. Down a steep grade its a matter of gravity and mass. Power doesn't come into it. You'd increase the size of the brakes on a road car if you were towing a trailer, for example.

On the track there is no speed limit so the size of the brakes is determined by the power of the vehicle because the amount of the energy the brakes have to dissipate is only limited by the amount the engine was able to add to the car since the last corner. Weight doesn't come into it.

So a trackday type vehicle like the Westfield that has an absurdly powerful engine for the size of the car also needs to have absurdly large brakes. It needs the brakes out of a vehicle of its power not its weight. And if its got to fit good brakes inside wheels that a relatively small because the vehicle is scaled down in weight and size its not surprising they use every trick they can, like using 4-pot calipers. On the other hand a Clio Trophy car doesn't need much extra in the way of brakes, just better pads, because it has very little more power than a standard car.

If you are using a Clio on the track its not its weight that's important, its its power. If you have substantially increased the engine's power you may need to substantially increase the brakes' power to because you've substantially increased the the amount of kinetic energy that has to be taken out at the end of each straight.

Its just basic physics.

whilst what some of what you have said makes sense, i disagree.

Weight will always play a part when braking.

For example scooby STI brakes are fine for the road, but track day nuts change to 6 pots front, 4 pots rear. The car has no extra power, but it is to over come fade, give better stopping force at higher speeds etc.

Going back to the clio, i garuntee that a clio with sorted brakes, will be quicker than a standard clio on standard brakes around a track. No extra power involved or weight involved.

A 4 pot setup will scrub off speed faster than a normal setup at high speeds, will negate brake fade, and will perform better.

 

[fmp_]

shed motorsport do a big brake kit that fits under 15" wheels. yes 15" wheels. http://www.shedmotorsport.com/brakes.htm

yup, as seen here....

http://www.cliosport.net/forum/showthread.php?t=282598

 

[foxon]

i`ve got 300mm 4 pots behind my 16" turinis - just, defo DON`T fit 17" rims imo

 

[Peperami]

shed motorsport do a big brake kit that fits under 15" wheels. yes 15" wheels. http://www.shedmotorsport.com/brakes.htm

yup, as seen here....

http://www.cliosport.net/forum/showthread.php?t=282598

Its not a 'big brake kit' though is it? Discs same size as standard?

 

[clio_luke]

i used to get fade on my standard 182 setup. easy solution tho, my front pads and discs needed replacing anyway so i got some brembo max discs, foredo pads, braided hoses and some dot5.1 fluid.
no complaints at all since i had that setup

 

[fmp_]

yup, as seen here....

http://www.cliosport.net/forum/showthread.php?t=282598

Its not a 'big brake kit' though is it? Discs same size as standard?

well its bigger than standard, using 295mm disc.

But it was designed to fit under 15's.

as we all know clio's handle best on 15's. Hence the criteria of the design.

 

[edde]

I'm suprised. That's one of the first decent comments about EBC I've heard.

Had a bad experience myself with Green Stuff and their Combi discs on my Integra. Heard from others their products aint too hot.

There new compund green stuff is better than there old stuff.

i have had ds2500 pads on my car before and i warped the disks at Donny since i have been running the performance friction 97 pads i can brake later and harder and i have not warped any of the three sets of disks that have been on the car with the one set of pf97 pads

You cannot warp disks harder pads at the end of the day would warp the disk if they could more.

i used to get fade on my standard 182 setup.

The real issue on the 182 is the brakes cannot cool down due to the desing of the alloys.

 

[GordonD]

I've said this before.

On the road the size of the brakes is determined by the weight of the vehicle. At every corner you're coming down from the speed limit to the speed you can negotiate the corner. Down a steep grade its a matter of gravity and mass. Power doesn't come into it. You'd increase the size of the brakes on a road car if you were towing a trailer, for example.

On the track there is no speed limit so the size of the brakes is determined by the power of the vehicle because the amount of the energy the brakes have to dissipate is only limited by the amount the engine was able to add to the car since the last corner. Weight doesn't come into it.

So a trackday type vehicle like the Westfield that has an absurdly powerful engine for the size of the car also needs to have absurdly large brakes. It needs the brakes out of a vehicle of its power not its weight. And if its got to fit good brakes inside wheels that a relatively small because the vehicle is scaled down in weight and size its not surprising they use every trick they can, like using 4-pot calipers. On the other hand a Clio Trophy car doesn't need much extra in the way of brakes, just better pads, because it has very little more power than a standard car.

If you are using a Clio on the track its not its weight that's important, its its power. If you have substantially increased the engine's power you may need to substantially increase the brakes' power to because you've substantially increased the the amount of kinetic energy that has to be taken out at the end of each straight.

Its just basic physics.

whilst what some of what you have said makes sense, i disagree.

Weight will always play a part when braking.

For example scooby STI brakes are fine for the road, but track day nuts change to 6 pots front, 4 pots rear. The car has no extra power, but it is to over come fade, give better stopping force at higher speeds etc.

Going back to the clio, i garuntee that a clio with sorted brakes, will be quicker than a standard clio on standard brakes around a track. No extra power involved or weight involved.

A 4 pot setup will scrub off speed faster than a normal setup at high speeds, will negate brake fade, and will perform better.

A scooby STI needs better brakes for ANY track use because it has only has a good a brakes as it needs for the amount of power you can actually use on the road without killing yourself or someone else or losing you licence.

A Clio Sport isn't a scooby STI. Its only a sporty car, not a looney car.

And will a Clio Sport with better brakes lap faster? There's a thousand different things you do the car to make it lap faster. Some will cost more and achieve less benefit, others will cost less and achieve more benefit. I don't doubt better brakes will have some benefit. But are they needed? The improvement in brakes you NEED depends on how much you've increased the power.

 

[fmp_]

my point about the STI was just in return of your theory of only needed bigger brakes if you have extra power.

And as you rightly said, there are all sorts of factors that will make a clio lap faster. But were talking about brake size here.

What i am disagreeing with is your statement that you ONLY need better brakes if you have increased power. Which although is a very good idea, i still say you can reap the benefits of a more power brake setup on a standard powered car.

But i guess we will have to agree to disagree!

All i know if i am very happy with my 4 pot setup on my standard powered 172 (for the mo ). and they give me far more confidence etc.

 

[GordonD]

The question of whether an essentially standard-horsepower Clio Sport NEEDS any more than upgraded pads for track use is answered by the Clio Trophy rules. The people with expertise who wrote those made a decision. There's no evidence they got it wrong. The cars weren't running off the track and crashing all the time because of brake fade or whatever else. There would have been an outcry demanding the rules be changed pretty quickly if that was the case.

I was just trying to make the point that someone who has upgraded the power of their Clio Sport may well find that they do need to do more than that.

 

[fmp_]

let us not forget that they are running full slicks, and therefore can carry far more speed into a corner. Therefore not needing to use the brakes as much. Plus with the short cut gearbox's werent they topping out at only 120mph? (i may be wrong on that).

But anywho, we all have different idea's and opinions, its nice to air them without it becoming a slagging match which is often the case!

 

[Andy GDI]

let us not forget that they are running full slicks, and therefore can carry far more speed into a corner. Therefore not needing to use the brakes as much. Plus with the short cut gearbox's werent they topping out at only 120mph? (i may be wrong on that).

But anywho, we all have different idea's and opinions, its nice to air them without it becoming a slagging match which is often the case!

agreed... carrying speed into the corners = less braking..

 

[homer simpson]

edde vbmenu_register("postmenu_3477914", true);
Quote:
Originally Posted by homer simpson
i have had ds2500 pads on my car before and i warped the disks at Donny since i have been running the performance friction 97 pads i can brake later and harder and i have not warped any of the three sets of disks that have been on the car with the one set of pf97 pads

You cannot warp disks harder pads at the end of the day would warp the disk if they could more .
Quote:

well that's not quite trew as the better the pad the less time you spend on the middle pedal and the less heat you build up threw the disk

 

[MarkCup]

Interesting stuff!

What I can say is that I'm running an almost standard engine - and money spent on brakes has so far yielded the biggest lap-time improvement over and above anything else.

 

[clio_luke]

i used to get fade on my standard 182 setup.

The real issue on the 182 is the brakes cannot cool down due to the desing of the alloys.[/quote]

i changed my standard 182 wheels for oz ultralegs too, made a big difference

 

[edde]

well that's not quite trew as the better the pad the less time you spend on the middle pedal and the less heat you build up threw the disk

The amount of energy you want the brakes to absorb is directly linked to heat.

 

[Birdthom]

Necessary braking capacity isn't just dictated by power or weight on track, but a combo of the two. More power carrying standard weight in to braking zone = more speed to scrub off. Standard power with unreduced weight = lots of mass to slow down.
Lightweight cars (eg caterfields) usually don't need big brakes on track unless they are enormously powerful. Even quick caterfields have deliberately small discs (usually not even drilled or grooved either) to minimise wheel size and unsprung weight. But heavy cars almost always need enormous brakes to cope on track. If heavy cars are powerful too then the brakes need to be monstrous.

Unless a clio has well over 200bhp or has a bootful of cement the standard disc size is fine.

HTH

 

[The Seer]

Necessary braking capacity isn't just dictated by power or weight on track, but a combo of the two. More power carrying standard weight in to braking zone = more speed to scrub off. Standard power with unreduced weight = lots of mass to slow down.
Lightweight cars (eg caterfields) usually don't need big brakes on track unless they are enormously powerful. Even quick caterfields have deliberately small discs (usually not even drilled or grooved either) to minimise wheel size and unsprung weight. But heavy cars almost always need enormous brakes to cope on track. If heavy cars are powerful too then the brakes need to be monstrous.

Unless a clio has well over 200bhp or has a bootful of cement the standard disc size is fine.

HTH

You'll find that most Caterham's that are lighter than the usual models, i.e. Superlight variants do have big brakes and 4 pots. Why? because big brakes and more pistons = better braking it's simple sceince and nearly all of motorsport subscribes to this.

 

[banx22]

This seem like a good discussion;

As far as i'm aware 4 pots are better than standard 2 pot because it means that more pressure can be applied to the discs over a larger area of the pad. It also means that the disc is being used more effectively as the pressure is more even across the whole disc because 4 pistons are pushing on the pad instead of 2 larger ones.

Bigger discs means that bigger pads can be used which means more friction can be applied which means more stopping power.

The bigger the brakes the more they can slow down before they begin to experience brake fade due to heat build up, which is a consequence of how much work they are doing which is related to how much mass they have to slow down, and how fast that mass is travelling (momentum is also important).

A fast car that is light will mean the brakes will do less work which means they can be used later on corner approach and entry and won't fade away. Less time on the brakes means faster lap times.

A fast but heavy car will need to apply the same brakes much earlier because they have more to slow down and will lose some braking ability as the brakes heat up quicker due to them working harder to slow down the heavier mass. To over come this they would need to use larger brakes.

Standard discs and pads are adequate but on track they will heat up quicker and braking ability will fade. this is what race teams are trying to reduce by using larger brakes but there is a limit. if the brakes are to large for the car they will never get hot enough to work correctly without the driver using them more often (to build the heat up) but this is counter productive to having them in the first place.

The only Reason i would upgrade the brakes to 4 pots would be because they look very cool !! (Red brembo calipers)

 

[homer simpson]

well that's not quite trew as the better the pad the less time you spend on the middle pedal and the less heat you build up threw the disk

The amount of energy you want the brakes to absorb is directly linked to heat.

yes but the beter the pads the less time you spend on them and the later you can brake

 

[MarkCup]

The amount of energy you want the brakes to absorb is directly linked to heat.

yes but the beter the pads the less time you spend on them and the later you can brake

That's right, you can brake later because the brakes are working harder in a shorter period of time slowing the car down by turning all that kinetic energy into heat.

You might be on the pedal less, but the pads will get hotter and do more work - venting and/or cooling aside, how much speed you need to lose, and how often you do it determines how hot your discs/pads get...nothing else.

 

[Birdthom]

Slight tangent from disc size, but I can see the logic in going to 4 pots if you're really serious about track work, but not increasing the disc size. Bigger discs means more unsprung/rotating weight due to discs themselves and increase in wheel size so would probably cause more problems than it solves in terms of performance. Anyway, it's only a clio at the end of the day!

 

[The Seer]

Slight tangent from disc size, but I can see the logic in going to 4 pots if you're really serious about track work, but not increasing the disc size. Bigger discs means more unsprung/rotating weight due to discs themselves and increase in wheel size so would probably cause more problems than it solves in terms of performance. Anyway, it's only a clio at the end of the day!

I doubt the rotating weight weight would be that much of a disadvantage since it'd would hardly be noticed. 284mm up to 300 mm isn't really that much of an increase.

As for 4 piston calipers in general, the outcome I'm sure is better all round regardless of track usage. The urgency and braking distance due to increased force by the uprated caliper must be better.

Why not increase the disc size as an option if it's available. Ok, not a great deal of increased mm but every little helps.