AP Racing Catalogue Issue 4

35 visit www.apracing.com for installation drawings & up to date product range details INTRODUCTION The AP Racing range of ventilated and solid brake discs have been developed with the benefit of unparalleled experience in brake technology, to meet the severe demands encountered under Race, Rally and Road conditions. RACE: Our extensive range includes discs to suit all of the most demanding series in the world. Teams competing in F3, WRC, GT and Endurance, Nascar and many global Touring car championships use AP Racing discs. ROAD: As well as our successes on the circuits and stages of the world, AP Racing has developed disc braking systems for many leading volume and specialist High Performance vehicle manufacturers including Aston Martin, Bugatti, Caterham, Ford, HSV, Koenigsegg, Morgan, Lotus, Seat and TVR, to name a few. DYNAMOMETER TESTING Not everything can be modelled yet, so validation testing is essential. Our proven dynamometers, have been supplemented by a third, more powerful NVH machine equipped with state of the art features. Three fully operational machines give us even more significant testing capabilities and help us demonstrate why AP Racing brake discs are the best. AP Racing dynamometer plots provide data examples such as temperature and Friction Co-efficient comparison. NUMERICAL SIMULATION AP Racing has continued to develop a unique thermal simulation software, in order to predict overall brake system temperatures on a real life cycle. This simulation is particu- larly useful for selection of brake specifications, and wear predictions for endurance races. It is able to calculate bulk temperatures and compare different brake system solutions for various vehicles and race tracks. RESEARCH AND DEVELOPMENT Over the last nine years AP Racing has placed increased emphasis on advanced research and simulation to complement the existing technol- ogy, test and manufacturing processes of our competition and road discs. Product improvement is continuous, using feedback from our state of the art dynamometer and track testing, AP Racing are able to offer brake discs with optimum performance and cooling characteristics for any application. DEVELOPMENT TOOLS AP Racing are equipped with state of the art design tools which have enabled us to study disc performance to a level not hitherto possible. FEA: CFD AND THERMAL STRESS ANALYSIS Thermal simulation enables assessment of brake disc cooling without having to build costly prototypes. AP Racing has reached a high degree of confidence using these methods and has adopted FEA as the base of our design process. This enables AP Racing to tailor disc design to a given application. R&D EXAMPLES The latest example of howour disc development department have benefited the AP Racing disc range. - Alternative Drive Systems ‘I’ Drive discs mounting system has been developed to offer an update/alterntive drive solution from the existing race bobbin design. The new system increas- es the drive lug strength capability that’s required for higher weight and braking performance race cars. Major Advantages are: - Design Analysis has shown a 31% reduction in stress compared to the conventional race brake bobbin drive system. - ‘I’ Drive design has been proven/approved on vehicles up to a mass of 2000kg. BRAKE DISCS - General Information DESIGN AP Racing share innovations in the R&D processes between Race and Road projects, the basic function is the same for both although each has different service requirements. ◘ Race Discs are submitted to high braking and thermal loads. These loads are repeated frequently over many laps or stages. The service life is short and noise and comfort are not really an issue. Race discs normally employ a separate disc and bell assembly which are generally available in two types: - Light Duty - 2 piece bolted assemblies. - Heavy Duty - 2 piece floating assemblies. A given disc has to fit many different customer cars, so they require custom mounting bells. ◘ Road Discs, however have relatively low and infrequent loads, although vehicle mass increases compared to race cars which generates high brak- ing torques. Road Discs have comfort and long service life requirements. Costs of each item also have to remain low for the OEM and the end user when replacement time arrives. For road cars, many applications use 1 piece disc and bell assemblies, due to high volume production require- ments. High performance vehicles and Big Brake Kits usually use 2 piece bolted assemblies, enabling a heavy disc fitment similar to a race set-up. - Light Duty - 1 piece disc and bell assembly. - Heavy Duty - 2 piece bolted assemblies. DISC CHOICE The choice of a particular size and type of disc will depend on the characteristics of the vehicle. Experience with the type of installation or racing format is very important. AP Racing has a wealth of experience of all types of racing and our Technical Section will be pleased to advise on disc choice. Some of the main considerations in this choice are: HOMOLOGATION AND REGULATION In Group A and certain other classes of racing, brake equipment is restricted to that Homologated by the manufacturer with the FIA. Where applicable, you must therefore choose a disc size / type which has been Homologated. E.g. only 4 grooves are allowed in Formula 3. DISC DIAMETER AND THICKNESS Disc diameter and thickness are major factors in basic stopping power. Usually the largest diameter disc that can be installed in a particular wheel profile is chosen to maximise braking power unless low weight, poor tyre adhesion or required brake balance dictate otherwise. Disc thicknesses normally increase with disc diameter and in proportion to vehicle weight, and hence work done and cooling required. Standard disc sizes should be used wherever possible, as this improves availability. DISC HANDING RIGHT / LEFT HAND IDENTIFICATION Most AP Racing brake discs feature curved vanes and are handed. They should be installed with the cooling vanes running back from the inside to outside diameters, in the direction of rotation as indicated in the sketch. DISC RUBBING DEPTHS (SWEPT DEPTH) It is important to match the swept area of the disc to the Pad / Caliper combination that is intended to be used, to avoid any large cold areas which could lead to disc distortion. To make this easier, the radial depth of all AP Racing brake pads is incorporated into the part number (the “D” Number e.g. D46, D50 & D54). Normally the Pad / Caliper is positioned so that the top edge of the pad is level with the nominal disc outside diameter. However it is normal to make the eye diameter on the inboard face (Non mounting side) slightly smaller in diameter than the mounting side to match the thermal char- acteristics of the two disc faces and avoid distortion in use. The amount of this under-hang will vary according to the installation and is part of the disc designers art, but analysis carried out by AP Racing shows that 2mm on radius (4mm on diameter) is sufficient in most cases. N.B. THE PAD SHOULD NEVER OVERHANG THE DISC, AS THIS WILL LEAD TOA NUMBER OF BRAKING DIFFICULTIES. DISC ROTATION DISC ROTATION VEHICLE DIRECTION LEFT HAND DISC RIGHT HAND DISC