Performance Brakes
Whether a car is used on the road or track an efficient braking system is probably the most important asset of your car. For good handling brakes should perform consistently with moderate pedal force and be free from fade with even the hardest use. Improving braking efficiency is a much easier way to go faster than increasing power!
This is one of the few areas of modification where road and track plans vary little. It really is best to get the highest performance braking system you can afford or modify your existing set-up to get the best from it. Of course this depends on your budget and the regulations you may need to adhere to.
It is worth remembering that a lot of braking efficiency can be lost through unevenly worn or “warped” (usually this is caused by pad deposits building up on the disc) discs. We are not talking large distances either - anything more than 0.10mm at the edge will reduce efficiency and cause judder. So remember that even if you do have uprated discs already, if they have seen hard use it will be worth checking the run-out. Our range of grooved and dimple drilled discs will deglaze the pad better ensuring consistent braking and reducing stopping distances.
Braided brake hoses can improve pedal feel and braking power as well as ensuring greater longevity.
Fluid is so often overlooked on road and even track cars. Ensure it is changed annually and make sure you opt for a high boiling point product. Remember not to mix silicon fluid (DOT 5.0) with DOT 3,4 or 5.1. Silicon fluid can offer very good performance but there are some problems with it in that rather than absorbing water the water is dispersed and then hides away in the system. You will hope it is not hiding in a calliper as it will boil very quickly and cause possible brake failure. This will not be a problem if you regularly change the fluid. Also though you need to flush the system before using silicone. Essentially the best method is to keep using the same base as you are using now (either Glycol or Silicone).
With brakes if your regulations or car permits it then try and add cooling vents or pipes to the front brakes. The front brakes will do most of the work so by aiding cooling you can prevent fade.
Technical Corner
With regard to braking it’s always helpful to refresh the basic rules of brake systems. If you fit larger discs you will increase the braking mechanical advantage. This will reduce pedal effort. If you find this results in brakes that are too sensitive for track use you can increase pedal effort by changing the master cylinder or removing the brake servo. A larger master cylinder bore size will increase pedal effort but reduce pedal travel. Master cylinders are usually available in inch sizes, pedal effort in lbs per sq inch and piston sizes in mm (great!).
Some formulas will demonstrate what you might end up with:
If you increase disc size from 284mm to 300mm you would end up with a 5% decrease in the pedal force required to get the same braking force. Therefore a 100lb force required before would become 95lb
New pedal force = Pedal force x (Old brake disc radius/New brake disc radius)
The rolling radius of the tyre has the opposite effect - increase the diameter of the tyre/wheel combination and you increase the pedal force required.
New pedal force = Pedal force x (Old tyre radius/New tyre radius)
In this case if you went from a 14” Wheel with 195/60 up to a 16” wheel with 205/55 you would increase the pedal effort required by 10%.
When looking at master cylinders the formula is as follows:
New pedal force = Pedal force x (new master cylinder bore diameter²/ old master cylinder bore diameter)²
Because of the square in the above formula the effect of a change is more pronounced. E.g a move from a 1” master cylinder to a 1.25” master cylinder will change the pedal force required from 100lbs to 156lbs.
Next thing to remember is bigger pistons in the calipers mean more force and, therefore, less pedal effort. Bigger pistons in the calipers mean more pedal movement. For comparing one brake to another on the same car, you can simply multiply the total caliper piston area times the effective radius. If you have a sliding calliper although it has piston(s) on one side the area should be doubled. A single piston sliding calliper with the same piston size as a twin fixed calliper will have the same clamping force.
When planning your braking modifications it is a good idea to consider these factors. Naturally bigger brakes often require bigger wheels so the two cancel each other out to a degree.
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Big Brake Kits from AP Racing, Compbrake and Stoptech
High Performance brake pads for Trackday and circuit use which work from cold
Extremely high performance, high friction pads for competition use only
EBC grooved and dimple drilled brake discs
Fast Road Pads
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VertPower Ltd T/as Balance Motorsport are based in Henfield, West Sussex. We are close to Brighton and Worthing
