Brake disk/pad cooling
08-05-2013, 09:41 PM
#81
Advanced PassionFord User
Fluid dynamics is a very complex subject and I did generalise for simplicity. The basics are that to achieve a flow between one point and another e.g. one end of a duct to the other, you must have a pressure differential. The static pressure at the front of the brake duct at car driving speeds will only be very slightly higher than at the brake end of the duct, hence the flow would only be small. My "arbritary" figure of 150 mph is taken as the speed below which the "ram effect" of a forward facing duct opening is considered negligible. This figure is accepted in aircraft aerodynamics so will be equally relevant in motorsport for ducted cooling air flow and for "ram air" induction. If you want to see a can of worms, just Google about ram air induction and look at the opposing views as to whether this even exists at car speeds.
In addition to the static pressure differential causing flow, it must also be considered that the air at the front of the car is effectively moving towards the car at the speed of the car. The air will therefore have kinetic energy which will cause it to move along the duct. In opposition to this, the airflow down the duct will be turbulent so there will be frictional losses and heating.
This is why I considered trying fans to assist this flow. I haven't pursued it further as I don't have the technical ability to run the maths needed to get the theoretical answers. I don't run my car on the track and don't suffer from brake fade on the road so I can't justify spending the money to physically try it and see the empirical evidence. It may be that bigger fans would be needed to see a marked effect, I just don't know. The relatively small cost of trying it compared to other expensive brake upgrades may make it worth pursuing to someone who is experiencing brake heat issues.
In addition to the static pressure differential causing flow, it must also be considered that the air at the front of the car is effectively moving towards the car at the speed of the car. The air will therefore have kinetic energy which will cause it to move along the duct. In opposition to this, the airflow down the duct will be turbulent so there will be frictional losses and heating.
This is why I considered trying fans to assist this flow. I haven't pursued it further as I don't have the technical ability to run the maths needed to get the theoretical answers. I don't run my car on the track and don't suffer from brake fade on the road so I can't justify spending the money to physically try it and see the empirical evidence. It may be that bigger fans would be needed to see a marked effect, I just don't know. The relatively small cost of trying it compared to other expensive brake upgrades may make it worth pursuing to someone who is experiencing brake heat issues.
Cooling relies only on a mass flow of air across the brakes to maintain a temperature differential, the pressure only needs to be large enough to allow that flow to occur.
Ram air induction is a whole different situation
It's not moving at all, the car is, so no, the air wont possess kinetic energy.
When you consider the size of a radiator fan in a car and the airflow and heat energy is is able to dissipate, and then consider what you're suggesting, you'll see why its unlikely to work.
08-05-2013, 09:47 PM
#83
you havnt really made any point there as I said yes weight plus transfer is part of it but my point theres more to it than just weight
balance
weight of car
suspension settings ! hard/soft /over sprung /under spring dictates weight transfer or inertia
tyres ie grip levels to how this will effect the way the brakes are used faster cornering speed means less time on the brakes so less heat !
Chips point that his car is faster than a cup car so its more of a arse to slow down for the corners is not 100% correct its the fact the cup car is ideally built to carry speed better ! its not the fact the car is under powered it the fact the chassis and brakes are set to get the best from the car and chips Ł500 coilovers and Ł100 brakes wont even match the gear on the cup car so if the chips car was at the same chassis/tyre standard for his horse power for track use he wouldn't be on the brakes so much
Now we come to the organic item where normally most of the issues on a track or road start
As above they want aldi motorsport to do the job of harrods and think So my point is change the pads and maybe look at driving style to suite the car . I never mentioned towing with a cossie this is thread about how chip can kick more teeth out of his clio for not to much money and not crashing not proving how a cossie is at towing 
Well they might be fine in a full fat road car being used at 70% but we used all sorts of pads in race / track use yellows /reds/blues along with mintex pads ferrodo pads and cl's in fwd race cars weight 1040kg with driver 350 bhp is on slicks , old e30 pbmw 1280kg with driver 120 bhp , me csl 46 1270 with driver and my old skybus 1380kg without driver 480 bhp and we used brands and Silverstone to test all bakes suspension and geometry and found the yellows way to soft reds useless and the blues to hard and brital .The ds3000s over cooked very easily the mintex 55's and 66's great al through but high dust and pad wear and cl's x10's brilliant but by far not the cheapest
But I think this is one of those things where itll be hard to agree on im just stating fact we have found from a good range of cars put under massive strain like how chip wants to drive the clio
And the pad temps are very important yes they need to work on a road car cold and hot but again that can be helped by running the pads in right ! ok a 1166 or cl 10's wont wont be a oem pull up when cold but they can be better treated correctly !
balance
weight of car
suspension settings ! hard/soft /over sprung /under spring dictates weight transfer or inertia
tyres ie grip levels to how this will effect the way the brakes are used faster cornering speed means less time on the brakes so less heat !
Chips point that his car is faster than a cup car so its more of a arse to slow down for the corners is not 100% correct its the fact the cup car is ideally built to carry speed better ! its not the fact the car is under powered it the fact the chassis and brakes are set to get the best from the car and chips Ł500 coilovers and Ł100 brakes wont even match the gear on the cup car so if the chips car was at the same chassis/tyre standard for his horse power for track use he wouldn't be on the brakes so much
Now we come to the organic item where normally most of the issues on a track or road start
As above they want aldi motorsport to do the job of harrods and think So my point is change the pads and maybe look at driving style to suite the car . I never mentioned towing with a cossie this is thread about how chip can kick more teeth out of his clio for not to much money and not crashing not proving how a cossie is at towing Well they might be fine in a full fat road car being used at 70% but we used all sorts of pads in race / track use yellows /reds/blues along with mintex pads ferrodo pads and cl's in fwd race cars weight 1040kg with driver 350 bhp is on slicks , old e30 pbmw 1280kg with driver 120 bhp , me csl 46 1270 with driver and my old skybus 1380kg without driver
480 bhp and we used brands and Silverstone to test all bakes suspension and geometry and found the yellows way to soft reds useless and the blues to hard and brital .The ds3000s over cooked very easily the mintex 55's and 66's great al through but high dust and pad wear and cl's x10's brilliant but by far not the cheapest But I think this is one of those things where itll be hard to agree on im just stating fact we have found from a good range of cars put under massive strain like how chip wants to drive the clio
And the pad temps are very important yes they need to work on a road car cold and hot but again that can be helped by running the pads in right ! ok a 1166 or cl 10's wont wont be a oem pull up when cold but they can be better treated correctly !
Even doing it on the cheap its cost me many times that.
And if you can get me kw variant 2s for 500 quid a set I think me and you are going to be VERY rich as the queue for Clio owners at that price would be huge! Its no match for the cup racers but its a great road setup on these cars.
Last edited by Chip; 08-05-2013 at 10:31 PM.
08-05-2013, 10:00 PM
#84
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09-05-2013, 05:34 AM
#86
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don't know for certain mate but in one of the photo's it looked like he'd put an enclosed end onto the ducting to force over the disc. Not saying it was perect, just a potential solution that sprang to mind.
09-05-2013, 06:44 AM
#87
I wasn't being nasty chip just playing about about the current setup ! But it is just run of mill stuff . have you tried adapting spring rates .can you get a wider disc try ducting and a harder compound
Also have you looked at a bigger caliper for better coverage area
Also have you looked at a bigger caliper for better coverage area
Last edited by Jay,; 09-05-2013 at 07:19 AM.
09-05-2013, 08:59 AM
#88
If this car was in a race series I would worry about the things you are saying, but it isnt its on the driveway and gets used to go shopping or pop down the pub for something to eat and to fill in as a trackday hack till my other cars are finished.
Ive been playing around with these clios for a while now, and have a lot of friends who trackday and race them, so I dont need to try different spring rates etc to get in the right ballpark well enough for a trackday as I went straight in with something that I knew worked well anyway, like I said I think if you drove it you would be surprised how well it already works, so I cant understand why you are suggesting I waste a load of time to alter it around when Im already happy with how it corners etc anyway.
Its NOT a racecar, and it wont ever be one, so stop trying to think of it as one, its a fun road car and trackday hack that works really well other than I would like to cool the brakes a little more.
Last edited by Chip; 09-05-2013 at 09:02 AM.
09-05-2013, 09:04 AM
#89
PS
Its no wonder you never keep a car, Ive got one here that Im perfectly happy with in all but one minor detail, its completely fit for purpose, and you are suggesting that instead of just using it on trackdays and really enjoying it like I have been doing, instead I should pull it apart for no good reason and try and put it back together capable of being held up slightly more in corners by other trackday users than it already is? No wonder you never enjoy your own cars with that mentality, it works and I already REALLY enjoy doing trackdays in it so why start making a load of changes it doesnt need?
I know we all like to play about with modifying cars but I think you need to learn to go "oh cool, that works really well, im happy with that, I think I will just use it a lot now"
Its no wonder you never keep a car, Ive got one here that Im perfectly happy with in all but one minor detail, its completely fit for purpose, and you are suggesting that instead of just using it on trackdays and really enjoying it like I have been doing, instead I should pull it apart for no good reason and try and put it back together capable of being held up slightly more in corners by other trackday users than it already is? No wonder you never enjoy your own cars with that mentality, it works and I already REALLY enjoy doing trackdays in it so why start making a load of changes it doesnt need?
I know we all like to play about with modifying cars but I think you need to learn to go "oh cool, that works really well, im happy with that, I think I will just use it a lot now"
09-05-2013, 09:40 AM
#91
It seems to be a common problem with clios tbh, last time i was out at oulton park with my brothers 172 it was horrendous for brake fade. His is only a standard car running mintex 1144s at the time i think. (i know m1144s aren't really a track pad)
When we pulled back into the pits after the first session the brakes were smoking, and they never really recovered all day.
When we pulled back into the pits after the first session the brakes were smoking, and they never really recovered all day.
09-05-2013, 09:48 AM
#92
PS
Its no wonder you never keep a car, Ive got one here that Im perfectly happy with in all but one minor detail, its completely fit for purpose, and you are suggesting that instead of just using it on trackdays and really enjoying it like I have been doing, instead I should pull it apart for no good reason and try and put it back together capable of being held up slightly more in corners by other trackday users than it already is? No wonder you never enjoy your own cars with that mentality, it works and I already REALLY enjoy doing trackdays in it so why start making a load of changes it doesnt need?
I know we all like to play about with modifying cars but I think you need to learn to go "oh cool, that works really well, im happy with that, I think I will just use it a lot now"
Its no wonder you never keep a car, Ive got one here that Im perfectly happy with in all but one minor detail, its completely fit for purpose, and you are suggesting that instead of just using it on trackdays and really enjoying it like I have been doing, instead I should pull it apart for no good reason and try and put it back together capable of being held up slightly more in corners by other trackday users than it already is? No wonder you never enjoy your own cars with that mentality, it works and I already REALLY enjoy doing trackdays in it so why start making a load of changes it doesnt need?
I know we all like to play about with modifying cars but I think you need to learn to go "oh cool, that works really well, im happy with that, I think I will just use it a lot now"
I dont keep cars because i get bored easily plus if i could afford a better car range for the budget i have then i would probably keep one a tad longer but my car choice and how to finaince a car isnt the topic on this thread is it ?and really never would use a road car as a track toy and expect to be really good track car to so i dont follow the point to what this thread is about
You are over powering the brakes chip so i have given valid reasons to fix the problem from simple fix to the topend way i cant help you cant see that ! you are forgetting that using the car as a road car and track car the compromise gets bigger so you are very limited to what you can do on those size wheels ! i know its not a race car imo you asking a little to much from what you have
Last edited by Jay,; 09-05-2013 at 09:58 AM.
09-05-2013, 10:13 AM
#93
I dont keep cars because i get bored easily plus if i could afford a better car range for the budget i have then i would probably keep one a tad longer but my car choice and how to finaince a car isnt the topic on this thread is it ?and really never would use a road car as a track toy and expect to be really good track car to so i dont follow the point to what this thread is about
Summary:
I have a "fastroad" spec clio
It works (in my opinion, which for my car is all that matters) brilliantly on the road, and on the track, and I really enjoy using it for both
Ive noticed the brakes can fade if it gets really hammered on the braking
I'd like to add some cooling ducts to see if this can reduce the fade
If it cant then I will upgrade the brakes if I can do so fairly cheaply
If I cant get the brakes working fairly cheaply then I will lower the power till they do work, as I dont want to spend lots of time and money on it
You are over powering the brakes chip so i have given valid reasons to fix the problem from simple fix to the topend way i cant help you cant see that ! you are forgetting that using the car as a road car and track car the compromise gets bigger so you are very limited to what you can do on those size wheels ! i know its not a race car imo you asking a little to much from what you have
You seem to be trying to turn this into "lets build the ultimate clio" where as all I want is my own car as it is now, but with the brakes cooling down a little quicker.
09-05-2013, 10:16 AM
#94
It seems to be a common problem with clios tbh, last time i was out at oulton park with my brothers 172 it was horrendous for brake fade. His is only a standard car running mintex 1144s at the time i think. (i know m1144s aren't really a track pad)
When we pulled back into the pits after the first session the brakes were smoking, and they never really recovered all day.
When we pulled back into the pits after the first session the brakes were smoking, and they never really recovered all day.
Was your fade pad fade (hard pedal) or fluid fade (soft pedal) ?
09-05-2013, 11:08 AM
#95
The thread couldnt be simpler mate, what bit are you struggling with?
Summary:
I have a "fastroad" spec clio
It works (in my opinion, which for my car is all that matters) brilliantly on the road, and on the track, and I really enjoy using it for both
Ive noticed the brakes can fade if it gets really hammered on the braking
I'd like to add some cooling ducts to see if this can reduce the fade
If it cant then I will upgrade the brakes if I can do so fairly cheaply
If I cant get the brakes working fairly cheaply then I will lower the power till they do work, as I dont want to spend lots of time and money on it
I dont mind it being a compromise, I just want to make it a better compromise by adding some brake coolin to make the existing brakes as good as possible, and if they still arent good enough I can just lower the boost slightly or know I have to brake earlier on circuits that really hammer the brakes.
You seem to be trying to turn this into "lets build the ultimate clio" where as all I want is my own car as it is now, but with the brakes cooling down a little quicker.
Summary:
I have a "fastroad" spec clio
It works (in my opinion, which for my car is all that matters) brilliantly on the road, and on the track, and I really enjoy using it for both
Ive noticed the brakes can fade if it gets really hammered on the braking
I'd like to add some cooling ducts to see if this can reduce the fade
If it cant then I will upgrade the brakes if I can do so fairly cheaply
If I cant get the brakes working fairly cheaply then I will lower the power till they do work, as I dont want to spend lots of time and money on it
I dont mind it being a compromise, I just want to make it a better compromise by adding some brake coolin to make the existing brakes as good as possible, and if they still arent good enough I can just lower the boost slightly or know I have to brake earlier on circuits that really hammer the brakes.
You seem to be trying to turn this into "lets build the ultimate clio" where as all I want is my own car as it is now, but with the brakes cooling down a little quicker.
you coiuldnt be more wrong chip like i said earlier when YOU started on my car keeping skills and ill say it again i have given advice from cheap fixes to proper top end fix i couldnt care less wether you take it or not
i think duct air and use the 2500's then change the pads for one that will cope better and also change your driving style to go with the car which i mentioned a life time ago
09-05-2013, 11:31 AM
#96
About what? Was giving a summary of what I want from the car and where its at now, which bit was wrong?
Not sure its "skills" as such, more just a case of you being too focussed on the modifying them and not enough on using them IMHO, I see quite a lot of people like that, they build something good enough to use, but then instead of getting out and enjoying it, start ripping it apart and starting again.
Been guilty of it myself in the past too but these days im much more of the "cool, its good enough to use now, lets have some fun in it" mentality.
Only thing im after really at this stage is advice on ducting (as per my original post and every post since), if you have any of that it would be appreciated although people like Ali seem to have covered it really well now so I just need to get some time free to implement some of the suggestions.
Yes thats exactly what ive planned to do since before starting the thread, hence starting the thread to ask specifically about advice on the brake ducts.
Hopefully wont come to that as even on the yellowstuff it wasnt actually terrible and the DS2500 should be a reasonable upgrade from those, but I think I will try some RC8 after if not, then if that doesnt work, its probably just a case of notching the power back a touch, or simply choosing to throttle off a bit sooner on the straights and coast for a bit rather than accelerate up till its time to brake.
TBH mate I dont really see how my driving style could change much more in terms of to suit this car anyway, I already am fairly cautious on the brakes and pretty smooth etc anyway.
What changes do you think my driving style needs then? Other than backing off the throttle a touch sooner I cant really think of much so would certainly welcome some input.
like i said earlier when YOU started on my car keeping skills
Been guilty of it myself in the past too but these days im much more of the "cool, its good enough to use now, lets have some fun in it" mentality.
and ill say it again i have given advice from cheap fixes to proper top end fix i couldnt care less wether you take it or not
i think duct air and use the 2500's
then change the pads for one that will cope better
also change your driving style to go with the car which i mentioned a life time ago
What changes do you think my driving style needs then? Other than backing off the throttle a touch sooner I cant really think of much so would certainly welcome some input.
09-05-2013, 11:36 AM
#97
Its not something ive had a problem with on the mrs car, must have done 400 track sessions in it now and never had brake fade, but thats only 200bhp, and runs ds2500 pads, for that application they seem absolutely fine even on the standard brakes, although 1144 I think arent as good as the ds2500 IME.
Was your fade pad fade (hard pedal) or fluid fade (soft pedal) ?
Was your fade pad fade (hard pedal) or fluid fade (soft pedal) ?
09-05-2013, 11:38 AM
#98
It was pad fade, There could have been another issue though, he had only rebuilt the brakes the day before and said he had put a dab of copper slip on the backs of the pads. I did wonder whether with the heat from track use or him just being a clumsy sod it had managed to get onto the braking surface.
09-05-2013, 11:50 AM
#99
About what? Was giving a summary of what I want from the car and where its at now, which bit was wrong?
Not sure its "skills" as such, more just a case of you being too focussed on the modifying them and not enough on using them IMHO, I see quite a lot of people like that, they build something good enough to use, but then instead of getting out and enjoying it, start ripping it apart and starting again.
Been guilty of it myself in the past too but these days im much more of the "cool, its good enough to use now, lets have some fun in it"
Not sure its "skills" as such, more just a case of you being too focussed on the modifying them and not enough on using them IMHO, I see quite a lot of people like that, they build something good enough to use, but then instead of getting out and enjoying it, start ripping it apart and starting again.
Been guilty of it myself in the past too but these days im much more of the "cool, its good enough to use now, lets have some fun in it"
i have enjoyed all of them and done many miles in them Duct the average brakes you have it will make difference but not a top fix
09-05-2013, 12:19 PM
#100
Well largely based on I think the most trackdays you've ever done in any of your cars is probably not even a dozen?
Im not saying there is anything wrong with continually buying modifying and getting rid of cars if that is what you enjoy doing, im just saying its not my intention with this car, I have it working really well other than a very minor issue with the brakes getting hot, so I dont want to redo the suspension etc as Im happy with that.
You seem to be getting really offended that I just want to leave my own suspension etc alone as im happy with it?
To me that sounds like hardly using them and then selling them on. we're all different but personally if I have spent ages building a car I dont want to get rid of it after only half a dozen trackdays.
Thats what I have been planning to do since before starting the thread so seems a weird thing to think its useful to tell me to do now, but if you have any advice not yet given in the thread about the details of how best to do the ducting that would be useful input 
Not sure why you keep going on about my brakes being "100 quid brakes" or "average" etc though TBH, in the world of clios a set of Tarox 6 pots and 300mm disks is actually a way above average setup, even a basic 4 pot upgrade on the standard size disks is relatively unusual, as so few trackday goers in clios have 300bhp in the first place so the need for such brakes is pretty rare for this application.
Im not saying there is anything wrong with continually buying modifying and getting rid of cars if that is what you enjoy doing, im just saying its not my intention with this car, I have it working really well other than a very minor issue with the brakes getting hot, so I dont want to redo the suspension etc as Im happy with that.
You seem to be getting really offended that I just want to leave my own suspension etc alone as im happy with it?
ive used the skyline every day of ownership never really modified that to heavily did about 9 track days in it ! used the evo every day of ownership never really modified that either to much did 5 track days in it the type r i finished of the project sold it backto the guy for a stupid profit after 5 track days ! the st225 was mostly already modded by the last owner used every day of ownership and 6 track day s the final car is the cossie repaired all usual bodges renewed old dying parts stayed at stage 3 from last owners and is staying that way thats my last 7 years of motoring history seeing as your so interested i have enjoyed all of them and done many miles in them
i have enjoyed all of them and done many miles in them
Duct the average brakes you have it will make difference but not a top fix
Not sure why you keep going on about my brakes being "100 quid brakes" or "average" etc though TBH, in the world of clios a set of Tarox 6 pots and 300mm disks is actually a way above average setup, even a basic 4 pot upgrade on the standard size disks is relatively unusual, as so few trackday goers in clios have 300bhp in the first place so the need for such brakes is pretty rare for this application.
09-05-2013, 12:54 PM
#105
and as many trackdays i could fit in 
if you build a cover for the center vanes then make sure there is adaquate flow from the rear of it as it could end up holding the heat in the center of the rotor , If it was me i would lead a 75mm flexi tube from the hole in the bumper to the brakes like in the under car shot in the first post and use better pads !
The reason why your brakes are average is there are to small for the job in hand.So i agree there a good setup on as 180 bhp clio but not a 300 ish car but you already know this as you already said you wont change wheel size to accomadate brakes for the job
09-05-2013, 01:48 PM
#106
If I had a lot more money though, I would probably do that, they are epic cars.
09-05-2013, 01:51 PM
#107
if you build a cover for the center vanes then make sure there is adaquate flow from the rear of it as it could end up holding the heat in the center of the rotor , If it was me i would lead a 75mm flexi tube from the hole in the bumper to the brakes like in the under car shot in the first post and use better pads !
To me it seems like a plan with no downsides, so worth trying first, where as encasing them could give me issues if I have to stop suddenly where there is a lot of heat in the disks (red flag etc)
The reason why your brakes are average is there are to small for the job in hand.So i agree there a good setup on as 180 bhp clio but not a 300 ish car but you already know this as you already said you wont change wheel size to accomadate brakes for the job
09-05-2013, 02:17 PM
#108
So like this exampel from Ali basically:
Which should be relatively easy to incorporate into the mounting brackets weve made.
Should be quite easy to make a slot in that and push through a squashed end of a bit of ally tube to make a nozzle. And what I will probably do is cut it to a U shape so that it sort of implicitly directs towards the vanes, if that makes sense?
Which should be relatively easy to incorporate into the mounting brackets weve made.
Should be quite easy to make a slot in that and push through a squashed end of a bit of ally tube to make a nozzle. And what I will probably do is cut it to a U shape so that it sort of implicitly directs towards the vanes, if that makes sense?
Last edited by Chip; 09-05-2013 at 02:19 PM.
10-05-2013, 08:24 AM
#115
PassionFord Post Troll
This is a pic of our set up,
300mm by 24mm disc on a 4pot calliper
Wat we were suffering from on a long session is wobble down to thermal shock,
That's because we do no road miles to get a few heat cycles in to the disc.
So we used to take a spare pair of discs,
Now we are trying a new pad cl rc6 and a better quality disc, I will update our findings,
P.s. we have air ducting to brakes.
300mm by 24mm disc on a 4pot calliper
Wat we were suffering from on a long session is wobble down to thermal shock,
That's because we do no road miles to get a few heat cycles in to the disc.
So we used to take a spare pair of discs,
Now we are trying a new pad cl rc6 and a better quality disc, I will update our findings,
P.s. we have air ducting to brakes.
Last edited by nevsrevs; 10-05-2013 at 08:26 AM.
10-05-2013, 06:58 PM
#119
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10-05-2013, 07:52 PM
#120
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Chip, with regards to the 4 or 6 pot...is the pad coverage from the 6 pot not overly much on a 300mm disc?
I can remember the hassle 'back in the day' when people tried running twin caliper(increasing pad coverage) and ended up just overheating the discs.
Would running the same setup with a different compound pad end up putting so much heat into the disc that they could potential fail?
I can remember the hassle 'back in the day' when people tried running twin caliper(increasing pad coverage) and ended up just overheating the discs.
Would running the same setup with a different compound pad end up putting so much heat into the disc that they could potential fail?