Hey, does anyone have anything good, bad or indifferent to say about Ferodo DS2500 pads???
I made a general enquiry about up-speccing the brake system and received this novel (edited) of a response...
"Most standard brake systems, once equipped to handle the heat generated under racing conditions, are more than adequate for events like the Targa and other club racing duties.
If we think of the brake system as a chain that is only as strong as its weakest link, and heat as its enemy, we find that the weakest link in a road brake system is the friction materials. A good quality standard road compound will have a maximum c.w.t (continuous working temperature) of around 300 degrees C. An Aussie V8 Supercar generates around 650 degrees C at the end of Conrod. What we need to do is put proper race compounds into our road calipers, as the smaller road brake system is not as good at dissipating heat as the larger brake systems and can generate temperatures equivalent to larger race cars.
The problem you may come across when looking for proper race compounds for your road calipers is that the manufacturers of the race compounds will generally only manufacture pads for recognized race calipers such as Brembo, AP, Alcon etc or homologated road calipers such as the early EVO and WRX calipers. They are just not interested in tooling up to produce a run of ’73 Mercedes 280E pads on the off chance that someone wants to take one racing.
RACEBRAKES 0800BRAKES are able to supply or manufacture race pads for any type of caliper with race compounds that will handle temperatures of at least 700 degrees C. Some compounds will handle much more. These compounds perform from dead cold and make a blindingly good street pad regardless of their racing abilities.
The next weakest link in the chain is the Brake Fluid. There is no point having materials sitting in the wheels able to handle 700+ degrees C if your brake fluid is going to boil as soon as you put them to the test. First let us dispel a few common misconceptions. You do NOT want to use a DOT 5 brake fluid. DOT 5 is the rating given to silicone brake fluid (more correctly called Silicone Basal Brake Fluids or SBBF’s) We must also not confuse “silicone” fluids with “synthetic” fluids. Silicone fluids are not miscible (mixable) with conventional fluids however synthetic race fluids can be mixed with conventional road fluids. Very handy if you have rolled the car in the back of beyond, tipped all your race fluid out of the reservoir, but the car will still be driveable if only you can top up your master cylinder. Remember, mixing standard brake fluid with your race fluid will proportionally dilute the properties of your race fluid.
Now back to the DOT rating. All brake fluid, apart from silicone fluids, are hydroscopic which means that they will absorb moisture. The higher the DOT rating, the less hydroscopic they are. In other words, the less moisture they will absorb over a given period. Over time this will contribute to a brake fluids “wet boiling point”. Using a high DOT rating in a road car theoretically means that you will not have to change your fluid as often as you would if you were using a lower DOT rated fluid. This however does not apply to a race car as a race cars brake system produces so much moisture and debris that the laws of longevity are not really relevant.
Silicone fluids are NOT hydroscopic, meaning that they will not absorb moisture. This however is their downfall. All brake systems produce moisture. Particularly race brake systems as it is the extreme temperature changes that cause excessive moisture build up. As the brake system produces moisture, a conventional brake fluid will absorb it but a silicone fluid won’t. The moisture is still in the system but instead of absorbing into the brake fluid (admittedly reducing its boiling point), it just sits there in little water pockets waiting for the brake system to get hot so that it can vaporise. Even a well soaked brake fluid will have a higher boiling point than water.
RACEBRAKES 0800BRAKES handy hint: Avoid the risk of vaporizing your brake fluid at all costs. The results of a brake pedal going to the floor can be extremely hazardous to your health. Replace your silicone fluid with a proper race fluid. We have found ELF’s XT3167 to be very good value for money. We know that silicone fluid is kind to your paintwork if you spill it, but what are your priorities?
Keeping in mind that a DOT 5 is a silicone fluid, the highest DOT rating available for a conventional or synthetic fluid is a DOT 5.1 (notice the point one). So while a DOT rating has its place, what we are really looking for in a race fluid is a high dry boiling point. Interestingly, two of the best race fluids on the planet today, Brembo’s LCF600 Plus (this is the stuff that they tip into the Ferrari F1 cars) and Castrol’s SRF are both rated as DOT4+.
Incidentally, the minimum dry boiling point requirements of a DOT 4 fluid is 230 degrees C, DOT 5 (silicone) is 250 degrees C and DOT 5.1 has a minimum dry boiling point requirement of 260 degrees C. Admittedly, most off the shelf DOT4 road fluids will exceed the minimum requirements. In comparison, Brembo’s LCF600 Plus has a dry boiling point of 316 degrees C and Castrol’s SRF has a dry boiling point of 310 degrees C.
The other (and some would argue most important) advantage of a proper race fluid is that it is a lot less compressible than standard road fluids. In other words, they are less squashy. The less compressible race fluids help eliminate a lot of your spongy pedal and long pedal travel problems. It really is a shame when people spend hundreds of dollars outfitting their vehicles with braided hoses to firm up the pedal, then go and put a road fluid (or even worse, a silicone fluid which is highly compressible) into their car to save themselves a few dollars??
Now that we have our fluids sussed, the third weak link in the chain now becomes the rotors.
RACEBRAKES 0800BRAKES can of course supply 2 piece race rotors. However, once the price of manufacturing hats to make them fit your vehicle is taken into account, it seems almost churlish to wrap your standard road calipers back around them so we go shopping for a pretty set of four pots and there goes the budget.
As this discussion is centered around a “bang fer yer buck” makeover of a standard road brake system, we will be concentrating on what to do with your standard road rotors.
Firstly, RACEBRAKES 0800BRAKES and the manufacturers of road rotors do NOT officially recommend the use of non race rotors for motorsport use. However, RACEBRAKES 0800BRAKES are more than happy to supply quality road rotors for these purposes if it suits the clients budget or is mandatory because of control class rulings. The reality is that a lot of people go racing very successfully on road rotors.
The minimum requirement for racing on road rotors is… Make sure they are above the minimum thickness as specified by the rotor or vehicle manufacturer. The thinner a rotor gets, the less its ability to dissipate heat, which will increase the risk of it warping or cracking.
RACEBRAKES 0800BRAKES handy hint: Proper race pads are of course designed to dissipate heat efficiently. If we had a dollar for every client that suffered continual warping problems while racing on road oriented “performance pads” who then found that their warping problems were eliminated by using a proper racing friction material…..
Cross drilled and Slotted Rotors.
As a general rule of thumb, we at RACEBRAKES 0800BRAKES will try to steer you away from cross drilled rotors. The main advantage of cross drilled rotors is unsprung weight which is of course extremely critical on very light weight cars. However, having all those holes drilled through them makes them a bit of a “grenade” rotor, prone to warping and cracking when used on heavier vehicles that generate a lot of heat under braking. A very light weight car will, of course, not generate as much heat under braking therefore cross drilled rotors may not be such an issue.
The other advantage of cross drilled rotors is their ability to de-gas and continually de-glaze the disc pads.
These processes, without the disadvantages of cross drilling, are to be found in “slotted only” disc rotors.
No point in having the flash, powerful race pads in the car if they glaze up and lose their efficiency.
However, slotted rotor upgrades are NOT an absolute necessity if you are running modern, high coefficient race materials that perform from dead cold in your road calipers.
At the end of the day, we must remember that a brake system is only as good as the vehicles tyres and that a properly set up big race brake system will always beat a properly set up smaller road brake system. But that is a different story for different budgets.
Braided hose upgrades can be added on top of these packages at an average cost of NZ$80 - NZ$100 per hose.
You will need a really good reason not to do the fluid upgrade, and if that is your choice we recommend at least putting fresh road fluid in. Caliper upgrades are not usually necessary (or allowed in a lot of race classes) but if you are after the look of a big red Brembo you will need to budget around NZ$1000 per caliper."
Ends (thank god).