Brakes Front
OK so you’ve tuned the engine and suspension and your car is a real stormer. You come flying around a bend in your pefect motor pulling 5 g’s, your seatbelt is the only thing stopping you from being sucked out of the window and there’s grandad doing 20mph, traffic coming the other way……what now?
There are a few ways to help your car stop quicker, a number of factors influence the ability of the car to stop, these are the weight of the car, the grip with the road (influenced by tyres, conditions and weight distribution), the effectiveness of the front and rear brakes, the reactions of the driver and more. Probably the most effective way of improving braking is to upgrade your front brakes. There are many options available for almost any car as this article explains.
How it works
The principle of braking on a car is simple. Metal discs mounted to each hub are pinched by a set of pads which cause friction (and heat) causing the car to slow down. The pinching is achieved by hydraulic pressure created by the master cylinder pumping fluid into pistons in each brake caliper pushing them onto the pads and consequently the discs. Boring lecture part over.
Discs and Pads
One option is to fit uprated discs and pads. Most performance discs are vented, this means that the discs actually consists of 2 discs sandwhiched together, a gap in the middle allows air in between and veins formed into the metal in the gap help draw air in like an impeller. This air flowing into the gap helps cool the disc and increase efficiency. In order to help cooling further some discs are cross drilled, holes drilled through the discs allow further air movement and a slightly increased surface area allowing more cooling. Grooved discs work by giving some of the above benefits of cross drilled discs as well as a de-glazing action on the pads, constantly grinding a fresh layer off the surface of the pad creating a clean surface for more efficient braking. Combinations of grooved and cross drilled designs are available as well. There are many different brands of uprated discs available and are a simply swap for the standard plain factory fit items. Always change pads for new ones when changing discs because part worn pads can wear new discs unevenly and use only gentle braking for at least 200 miles of so to allow good bedding in of new discs and/or pads.
Biggers Discs
Another option is to fit bigger discs and/or calipers. In the case of bigger discs there is quite simply more friction creating more braking. Some kits are available that allow larger discs to be fitted while retaining the standard calipers, the calipers are mounted further away from the centre of the hub using special brackets supplied with the kit. Even with stanard calipers this will give an improvement.
Calipers
Bigger calipers such as 4-pot (4 pistons in each caliper) create more pressure and importantly a more uniform distribution of force onto the back of the pads and therefore more braking power. There are kits available consisting of new bigger 4-pot, 6-pot or even 10-pot calipers and bigger discs and can be bolted straight onto your car. Upgraded calipers of this kind vary tremedously in price, a favourite mod for some time was to fit 4-pot calipers from older cars like the Austin Princess which could be found at scrap yards for just a few quid. Full race setups are available for more cash, expect to pay around £1000 for a pair of front billet 4-pot calipers with alloy bells and discs. These will require large wheels to accomodate them, generally you will need 17 inch wheels to accomodate discs bigger than 320mm with bigger calipers.
Master Cylinder
The master cylinder is often overlooked but it's the device that delivers the pressure to the calipers, upgrading this can be quite cheap by swapping it for a larger bore master cylinder perhaps from a car higher up the range or a performance item. In some cases larger calipers will require a larger master cylinder to operate.
Lines and Fluid
The flexible pipe connecting the caliper to the solid brake fluid lines can be changed for braided hosing. This seems like a cosmetic gimmick but braided hoses won’t expand to the same extent as standard rubber ones when under pressure and therefore create a more solid brake pedal feel and improved braking effort. Always use good quality brake fluid, for performance DOT 5.1 rated fluid is best and will work better at higher temperatures associated with performance brake set-ups.
Remember whatever method you choose, you WILL see an improvement and you only have to call on those brakes just once in an emergency to realise it was money well spent. It could be the difference between safely pulling up and saving the your seat fabric from stains, or joining Grandad as a passenger and ruining amongst other things your perfect motor!
Pictures