[southpaw]

Can someone explain if and why fitting grooved or drilled brake discs improves the braking performance of the car over fitting standard stuff?

I'm thinking of improving the brakes on my car, as to be honest they're awful - there isn't a solid bite on the brakes and I just don't have any confidance in them. The first time I drove a reasonably new Civic I stopped about 8m short of the first junction I got to the brakes were so much more effective. I'm thinking EBC Greenstuff pads to start with but I may as well look into putting new discs on, but will grooved discs be any better than flat standard ones?

Thanks

[Turby]

You might be confusing braking performance with servo assistance. The puma probably has less servo assistance than the CTR does. Just press harder

FWIW a large majority of competition cars don't have servos at all - the driver has to press the pedal hard if they want to stop. Benefits include much better feel for what the brakes / tyres are doing under braking. Downside you have to press harder.

[glover]

i dont agree with all this the brakes are really hard and un responsive but its better cus you get more feel, at the end of the day there still servod anyway. Just that ford did a poor job of it, and i have the larger 260mm brakes. Give me a better servo anyday, its one of the weak points of the car. Id hate to time the 60-0 time for the puma and compare it to other cars cus unles your arnold schwartneger your gna struggle to press the pedal to stop as well as other cars (with better servos).
my 1.3 encore fiestas brakes felt better than the 1.7 pumas...

[big g]

im running ebc grooved and dotted disks and green stuff pads on my fiesta zs. there is an improvement in brakeing as there is less brake fade than std disks and pads

[littledragon]

i have heard the groved and dimpled discs crack easily. but not 100% sure if its true.

i have to agree the standard puma brakes are rubbish. i didnt understand why it got 5/5 stars on evo and there were no bad points to mention of. the brakes are clearly the worse performance of the puma.

[southpaw]

You might be confusing braking performance with servo assistance. The puma probably has less servo assistance than the CTR does. Just press harder

Sorry, I didn't quite make myself clear. One of the things I love about my Puma is that I get way way more feel of what the car is doing than any other car I've driven. It makes me feel so much more connected with the car and its easier to understand what its doing. For example, I hated the Lexus RX300 I drove as the steering felt totally unconnected, and I didn't like the BMW 6 series as the throttle response was awful and the car felt too big to control easily.

I just want more stopping power as I don't have confidance in my brakes that they will stop me in enough time should I ever need to brake hard, for example if a child ran out in front of me. I haven't got a clue when the brake discs or pads were last replaced on my car but I thought if I upgraded to better quality stuff then it might give me that tiny bit more braking force I just want to know what the grooves actually do and how they help... Does that all make sense now? I don't have ABS by the way, so just pressing harder locks up the wheels (as I've already found out!)

[Clawz]

Pads and disks heat up during braking. After a while when they get hot, gasses start to form, and they are floating between the pad and the disk. See it as aquaplaning, but now with hot gasses instead of water, and brake components instead of tyres and the road.
The grooves or holes allow the gasses to escape from the disk, and the pad can continue to bite the disk.
However, drilled disks are prone to cracking due to the constant heat cycling, so go for grooved ones.


I was one of the people that posted a couple of topics and posts on the 'bad' brakes of the Puma on here. I wished they were better. I found i had to push (too) hard on the pedal, and indeed, they didn't fill me with confidence when braking hard and then making small adjustments in braking power. Also, the small disks made them heat up rather quick, thus fade quick.

Now, after nearly 9 months of Puma driving, i'm starting to like the lack of servo-assistance. Much and much better feel than the over-servoed Volkswagen brakes! (and just about everything is over-servoed on VW's! You can steer with your nose!)
The standard pre-2000 (238mm) Puma brakes are still too small though. They have enough initial bite for my bog-standard tyres (i can get the ABS to cut in on a dry road = max stopping power from the tyes reached); but they are too small heat-capacity-wise, and after a couple times braking from 60-20 it's over. Certainly nothing for trackwork.

I don't know what size of disks you have on your Puma, but according to a Dutch pumadriver (pumamartin), replacing your brake hoses with braided ones will almost completely remove that lack of confidence. It will stiffen up the pedal a bit, and rid you of that 'oh no i'm never going to stop in time!' feeling when storming down the motorway.


Turby, what did you put on your super-high-speed-good-looking sprintPuma? I need new disks soon, and i'm pondering about the 260 or the 280mm upgrade from Pumaspeed, on standard prop alloys. The car is mostly used as a normal road car though (only hoping it will see some track action in it's lifetime), so i'm thinking 280 is a bit over the top.
Do you have any advice/tips/guidelines/anything?

This post has been edited by Clawz: 01 March 2007 - 07:22 PM

[southpaw]

The standard pre-2000 (238mm) Puma brakes are still too small though. They have enough initial bite for my bog-standard tyres (i can get the ABS to cut in on a dry road = max stopping power from the tyes reached); but they are too small heat-capacity-wise, and after a couple times braking from 60-20 it's over. Certainly nothing for trackwork.

I've got a '98 Puma with the small brakes. I've managed to get brake fade from them, and that wasn't on a motorway with lots of braking from high speeds, it was just me having fun on country roads Thanks for the explanation Clawz, its helped me understand whats going on

[scumski]

I find them fine on a 2001 1.7.
You may be interested to know the AA did a comparison and they outperformed an Audi A3,MazdaMX5 ,Alfa 145,and the ewww nasty car.stopping in 24.5 metres from 50 mph on a dry road.

[Clawz]

Exactly my point: the brake power is fine/good. However, when the disks are warmed up after a couple of stops ...

And you probably have the later brake setup (255 instead of 238 mm), don't know when the switch was made exactly...

[glover]

I find them fine on a 2001 1.7.
You may be interested to know the AA did a comparison and they outperformed an Audi A3,MazdaMX5 ,Alfa 145,and the ewww nasty car.stopping in 24.5 metres from 50 mph on a dry road.

they obviously didnt use my car then lol

[JopieBK]

...I thought if I upgraded to better quality stuff then it might give me that tiny bit more braking force ...I don't have ABS by the way, so just pressing harder locks up the wheels (as I've already found out!)

If you're can lock the wheels, then the brakes already provide more than enough braking force. Better quality stuff will just make it easier to lock the wheels, it won't stop you any sooner.

No-one's asked you about your tyres or tyre pressures. Sticky tyres will make much more difference to stopping distances than brake upgrades.

[Turby]

I run Mondeo V6 callipers, 280mm vented discs (not drilled / grooved), with AP600 race fluid and Mintex 1155 pads and braided brake lines - fine for a double driven sprint car, which is used *really* hard for about 3-4 minutes. Fitting larger brakes will add extra unsprung weight for extra heat capacity which will never be used.

As said by someone here previously, by far the biggest factor in braking performance is tyres. I run very soft Yokohama A048R tyres, and still have the ability to lock the brakes (ABS cuts in) when brakes / tyres are up fully up to working temperatures. Max braking G is around 1.1 before ABS cuts in - though when I have to brake this hard it meant I messed up! IMHO the corner exit speed is critical and its much to judge with slightly softer / longer period of braking.

I could save a bit more weight by running 4 pot ally callipers - but I don't know how much this will save.

BTW the rear brakes are totally standard i.e. drums.

For extended hard driving sessions eg track days I would probably upgrade to Mintex 1166 or F4R pads and 295mm discs with ally bells.

[southpaw]

If you're can lock the wheels, then the brakes already provide more than enough braking force. Better quality stuff will just make it easier to lock the wheels, it won't stop you any sooner.

No-one's asked you about your tyres or tyre pressures. Sticky tyres will make much more difference to stopping distances than brake upgrades.

I've locked the wheels up once, which was me braking very hard to stop for some traffic lights, on a wet road, so not ideal braking conditions. Upgrading the pads may be enough, I'm not sure. By the way, does the DOT rating of the brake fluid make much difference? I know 5.1 DOT won't boil as easily, but does this help braking performance?

And I'm running P6000's at the moment, which have about 3k of use on them so plenty of tread left. I'm putting F1's or T1-R's on next time

[steve18n]

5.1 DOT is completely unnecessary on a road car, especially a Puma. I have gone from 239mm solids to 258mm vented and they will only really fade from illegal speeds... I think some grooved discs and higher temperature pads like Mintex Extreme would do wonders for the high speed fade. As said there is still enough power from them.

I have had T1-R's & F1's, and the F1's are a much better tyre, especially in the wet when the Toyos really do suck. I'm just about to put 4 new GSD3 F1's on, can't wait!

I would also say that drum brakes are absolutely useless. I know that most of the braking is done up front, but I have recently done a rear disc converison using 2.0 Focus hubs, callipers etc... The improvement is very good, much more braking power and stability. The discs are still only warm after a drive which shows how easily they are coping. The car used to squirm up front, but now it's solid as a rock and stops very well. I also have braided hoses on the rear and some waiting to go on the front, which have helped pedal feel.

[Hezz]

I have recently done a rear disc converison using 2.0 Focus hubs, callipers etc... The improvement is very good, much more braking power and stability. The discs are still only warm after a drive which shows how easily they are coping. The car used to squirm up front, but now it's solid as a rock and stops very well. I also have braided hoses on the rear and some waiting to go on the front, which have helped pedal feel.

Fancy doing a "how to" matey

[southpaw]

Anyone got a rough price for having braided brake hoses supplied and fitted?

[steve18n]

For a how to take a look at this technical article on UKFN (UK Fiesta Network), my regular forum. You may need to sign up to see it.

>>'How to'<<

A full set of braided hoses front and rear can be had for ~£65 from Pumaspeed. Fitting prices will vary a lot depending on where you go but shouldn't be too much.



Check out how much clearance there is, even with a 3mm spacer! I can get my fingernail in there, but that's it! I have some 15"s I'm refurbing at the moment with rather more clearance.

This post has been edited by steve18n: 04 March 2007 - 04:28 AM

[m_kitty]

brakes are so subjective that you can only really get something you like by being very lucky or doing a lot of testing.

braided hoses: there were a lot of horror stories a while ago about sudden failures, they do take a lot of slop out of the system though in my experiance.

grooves were developed to remove gasses generated by pads, that was back in the 80's i think, these days pads are degassed during manufacture, nowadays they look good and give a bit more bite when the pads are near to cooking and make a strange noise when braking hard.

drilled: as i recall these are to disperse water but do suffer from cracking

dimpled: i guess they collect dust quite well?

i've done back to back tests on grooved disks verses regular, same pads, car and driver - absolutely no differance

pads make a huge differance to feel, our puma runs omp road pads and they bite well from cold and work to a reasonable temperature, they have made the post 2000 setup on our car ok, after driving the puma for a couple of days, the focus brakes felt a bit soggy.

the only differance fluid makes to the braking performance is if you use silicon fluid it does soften the pedal a bit. no reason not to use 5.1 no reason to use it either.

turby, have you tried running solid disks rather than vented, you can save a fair bit of weight that way, i wonder if a rear disk setup would be lighter as well?

[e3silversurfer]

i read that drilled are not good as they are consider "damaged" in a way cuz the molecular structure of the metal has been destroyed when drilled. If you really want good "drilled" holes in the pads, they should be casted into and not drilled. Something I think is right scientifically. correct me if i am wrong. grooved ones are casted therefore they do not crack.

silver surfer

PS: although I am a expert in computer, science and electronics, I am an idiot in car mechanics