Can in question is a standard 1.7 Puma which I've stripped out to do a few track days. The inner doors skins are gone, seats replaced, together with a few other things I estimate to have lost around 80kg so down to just under a ton hopefully. It's on standard wheels but with R888 tyres.

It was MOT failure, one of the reasons being that one of the front calipers is seized. The calipers, discs and pads are knackered. They are OE 1998 spec, ie 238mm vented with a single pot caliper.

My first thoughts were to bin all that and go bigger but I have a friend who says that 238mm is actually the optimal size for a car of that power and weight because they need to get hot in order for race pads to work properly. The car will do minimal mileage, trailered about and only driven in anger. So I've no requirement for longevity in the pad choice.

We debated for long enough that I actually think he thinks 280mm from a Fiesta ST which was my decision based on cost/my perceived performance gain are actually going to be worse due to them cooling down too quickly.

Please help me settle this. Small and hot or large and potentially less hot but with more mechanical advantage.

Thanks.

 

why not use cossie brakes

 

I'm open to suggestions but this debate is more theoretical 'what size/pad combo is best' rather than how I'm going to execute whatever changes I decide upon.

I've actually bought the Fiesta calipers but they're missing the carriers so I'm not quite there yet in terms of a solution!

 

I'm more shocked ford used 238mm brakes on a puma and not the 260mm brakes as found on mk5 zetec S. Sure i can see the point of pads needing heat for grip but over long periods of time you get heat glaze. Just put the st brakes on and make sure you get good pads.

 

The later cars have 260mm but mine is a 1998.

 

His theory has a little merit, I have been in some little cars(Pug 106 etc) that had 280mm Wilwoods and they worked so much better when hot on track than on road(but that's not to say they lacked on the road if that makes sense).

However one decent lap to get some heat in and they were amazing so it's not like a session wouldn't be enough time to heat them up.

Go bigger.

 

the brakes are piddly, get some bigger ones on and be done with it

you don't need to worry about pads etc if you are going to go big but if you want to stick to standard wheels then a 280 is about the biggest you are going to get

2wd cossie discs, 4wd calipers
bit of spacing
job done

the added mechanical advantage of the bigger stoppers will far outweigh the hot/cold arguement even if you use really shitty motor factor pads as you've got twice the surface area to paly with effectivly

 

I use 285mm discs with single pot callipers on my 205 (Gti-6 brakes). and i'd hazard a guess that it weighs the same or less than your puma..

with track day pads in, they might take a few corners or a lap to heat up.. but when they are, they are VERY good.. the advantage of bigger brakes is the resistance to fade..

TBH mate, i'd look MORE closely at your choice of calliper from the point of view of
the PAD CONTACT AREA.. thats why i see results with mine IMHO, because the discs aint that big really, but the pad contact area is HUGE.

 

Larger and less hot,

You can tailor the pad range to suit the weight and driving conditions of the vehicle.

Its unusual for a light fwd car on a track day to get an uprated system out of its operating temperature range, but it is very easy to do it on standard.

The idea is to get rid of the heat not keep it !!

 

bottom line is that he's got a puma with xr2 brakes on it, they might have been fine for an xr2 way back in 1982, but they aren't going to be any good really today, especially on a track regardless of what type of disc or pad he uses as a 238mm disc

if there is a bolt on upgrade that is readily available, as said, you can then find out what sort of pads ill suit your particular application the best

 

The Fiesta ST stuff is apparently bolt-on but it's still only a single pot caliper.

 

I use yellowstuff track pads on the road, and they work 99% from cold, so I'd give them a try.
On the gf's astra I fade the brakes all the time, they are 236mm vented, with greenstuff pads, other astra owners rave about these on astras, but I've now got 288mm with redstuff to go on, which again work perfectly from cold.
tabetha

 

lots of factors to decide here...cost,wheels etc...... as a cheap option st170 set up(300mm) with braided hoses,castrol srf and yellow stuff would be good on the track... then you can add 4 pots later on when cash allows.if its smaller wheels 280mm would do and also duct the brakes.

 

What about the Ford Racing Puma Alcon set-up?

 

I'm keeping the 15s, already bough the tyres.

Alcons are a little over budget and quite rare used.

 

alot of money, and have issues with getting wheel offsets to clear calipers

 

I ran a Fiesta ST brake conversion on my old FRST nd that stopped very well indeed. Should be more than up to taming your Puma.

 

i fitted a set of 4wd cossie discs and callipers to my old puma. had to cutr off the abs rings tho, but if its not a road car anymore that wont matter. just take the bulb out the dash lol.

with the std wheels tho, i had to use a spacer for the wheel to clear the calliiper. only had eibach hub centric ones in 20mm thus increasing the front track by 40mm.

they were awesome. never once had any fade and if you wanted to, you could lock them up at 90.

 

280 Fiesta ST calipers still go for quite a bit.

But cheap as chips 280mm MK3 mondeo 280mm calipers & pads, drill hub out to 12mm. Use ST170 discs.

 

mk3 mondeo's all use 300mm discs mate

 

Grr - s'what I meant - bloody brain not communicating with fingers.. ST170 discs are 300 after all.

Been a group buy on my forum and I knew I'd get something wrong..lol

 

Not sure if the 300s will go under the wheels.

So just so I'm clear - you would recommend going larger?

 

agreed 100%. With the bigger setup, u can run less aggressive pads, get a more consistent feel/bite and better all round as long as u are not carrying to much extra weight due to them

The lads with the wilwoods, need to take their pads down a step so that the brakes are more consistent.

Cheers
RW

 

the bigger the brakes the more stopping power you have
then you find out what sort of pads will be best for your application
you only start to over brake a car when you start putting 58 pot 700mm discs on a mini