The braking demands for any performance or race vehicle are one of the most important considerations to accommodate when conducting a full build. Every application should be carefully reviewed before hastily slapping on an off-the-shelf big brake kit in the hopes that everything will jive. Many misconceptions exist around braking system design and technology, so it is important to educate yourself before blindly groping for the largest rotor diameter and piston count your wallet will allow.
Brakes are application specific
The braking needs of a street car differ dramatically from those of a high performance race car, as do those of a 4×4 where the brakes are subjected to even more abuse. Better understanding the differences between a circuit race car braking system and a rally braking system is no easy task. But demands on brake manufacturers are such that it could be the difference between winning and losing.
In the last 10 years and more, Pretoria based Powerbrake has grown into filling the niche market of rally and off-road brake systems. Priding themselves in personal customer relationships they have developed an individually-tailored, brake package manufacturing business for customers worldwide with some notable achievements in the world famous Dakar Rally.
“Everything from the seal polymers to the internal wiper seals, which are not common in circuit racing, all has to be taken into account when you are designing for rally and off-road. It’s a slightly different recipe. Dust, mud, water, ice and vibration are all far more severe under rally conditions than any track car will experience. To ensure continuing longevity, brakes must be engineered to withstand these conditions,” explained Clive Murphy, Managing Director of Powerbrake.
“Powerbrake was formed to develop a range of high-performance and race brake products that would offer local race teams and enthusiasts a range of extremely tough, durable race components that would offer exceptional brake performance at a competitive price.”
“Many brake manufacturers world-wide start off supplying their brake components to the high-performance street market and then eventually move into the track and race markets. At Powerbrake the primary focus from the outset was on racing. We later added high performance street, track day and 4×4 products that incorporate direct technology transfer from our championship winning race products.”
“Powerbrake’s very first brake system design, that included an X-Line PB44L caliper (featuring separate pad-per-piston design) and heavy-duty two-piece floating rotor assemblies (featuring staggered cooling vane design) were supplied to the factory-backed BMW Super Production Car team competing in the premier A-Class of the Bridgestone Production Car National Championship race series. At the time the team moved from a well-known European brand to Powerbrake.”
Clive Murphy, Managing Director of Powerbrake, in front of the company’s Haas UMC-750 arrived at virtually the same time. It is a 5-axis vertical machining center with XYZs of 762mm x 508mm x 508mm, has a 630mm x 500mm integrated 2-axis trunnion rotary table, a 40 taper, a Renishaw probe, a 22.4 kW vector drive, 12 000 rpm, inline direct-drive, 40+1 side mount tool changer and 30.5 m/min rapids. The Haas UMC-750 machines all of Powerbrake’s aluminium components, including the calipers, from their own proprietary aluminium blocks
Powerbrake first purchased a Haas TM 2P toolroom mill that has XYZ travels of 1 016mm x 406mm x 406mm, 40 taper, 5.6 kW vector drive, 6000rpm and a 10-station automatic tool changer. The machine takes care of the company’s cast iron alloy machining
“After fitting the Powerbrake system to the first factory car, the team reported significant gains in brake performance and durability. They soon ordered the same Powerbrake system for the second car in the team. The BMW Super Production Car team remained Powerbrake customers for six years after this, until withdrawing from the race series. During this time they achieved countless race wins and won the National Championship in 2014 while running Powerbrake.”
“In 2008 a number of Ferrari F430 Challenge race cars were imported into South Africa by the Forza Racing team. These were destined to race in the competitive GT Challenge race series. The cars were factory fitted with carbon ceramic (CCM) rotors and it soon became apparent that the carbon ceramic rotors would not hold up well to sustained race use on South African tracks. In addition to this, the replacement cost for the CCM rotors was prohibitive.”
“Forza Racing approached Powerbrake to develop a complete front and rear replacement brake system that would do away with the factory fitted CCM rotors (and OEM calipers) and employ cast-iron rotors and billet 6-piston race calipers instead for increased durability and reduced running costs. Powerbrake developed their X-Line PB62E 6-piston race caliper and a new 356mm x35mm two-piece rotor design for the F430C GT Challenge cars. Not only did the new brake system offer improved brake performance, improved durability and significantly reduced running costs but the Powerbrake system also weighed no more than the CCM factory system.”
“The Powerbrake F430C system was very successful and Powerbrake ended up exporting a number of these systems to F430C owners world-wide. Many of these cars are still racing on these Powerbrake systems today, competing in both sprint and endurance events of up to 9-hours in duration. Based on the performance of the brake systems supplied to the Forza Racing Ferrari’s, other teams racing in the GT Challenge Series soon started approaching Powerbrake and brake systems were developed and supplied for Porsche’s, Noble’s and Turbo-charged Lotus Exige’s also competing in the series.”
Powerbrake have set up their own fixtures on the table of the Haas TM 2P toolroom mill and the toolroom mill will machine two discs in a cycle, for example
Powerbrake’s range of high-performance and race brake products
“Jumping forward Nissan Motorsport used Powerbrake for their entry in the 2009 Dakar Rally and subsequently we have been supplying the factory Toyota Motorsport team, now known as Toyota Gazoo Racing SA, for their Dakar Rally entries. They have had great success in the grueling event and have had four podium finishes since 2012 while we have been associated with them. 19% of all cars competing in the 2016 Dakar Rally were running Powerbrake race calipers and/or discs, with leading teams running our PB62IW water-cooled caliper.”
Although now a fully fledged manufacturer of their own product this has not always been the case. Clive Murphy worked for a company that imported high performance and race brake components from Europe before the company decided to focus on other core product lines when the South African rand took a tumble in the early 2000s. Murphy was involved in the development phase of a range of locally developed brake discs before the he was working for decided to concentrate on its other core products.
“That was in 2004, and rather than just drop the development work I decided to purchase the rights and go on my own. It takes between 1 000 and 1 500 hours to develop a new race caliper. This includes design, FEA, CAM, prototype machining and on-car testing.”
“At the time, we were a bunch of design engineers with a dream and no machining experience. We had the know-how on all the other elements and to get our product to market we relied on outsourcing the machining of the products. This comes with its problems but it also allowed us to get on our feet, break into the world market and start developing more systems for different applications. In addition to our head office in Pretoria, we opened two international sales offices, one in Switzerland to cater for our customers in Europe, Middle East, Asia and the other in the USA, which is run by my brother.”
Association with Haas
“Eventually in 2015 we decided it was time to start moving manufacturing in-house. Most general engineering machine shops in South Africa have a mindset of 3-axis machining and we knew this was not our style. It was 5-axis or nothing. We wanted the flexibility of 5-axis and the other benefits that come with 5-axis machining such as reduced setup times and increased accuracy on each part, while still saving time in the cycle times.”
“This is when we contacted Haas Factory Outlet South Africa. From the outset they have been knowledgeable and service orientated, using their international experience to guide us. A CNC machine’s performance is all about what you hang on to it, that makes the difference. This includes the tooling, CAM software and workholding or fixtures. The Haas machines that we have purchased have certainly come up to expectation and we machine them hard.”
“The first machine to arrive in August last year was a Haas TM 2P toolroom mill that has XYZ travels of 1 016mm x 406mm x 406mm, 40 taper, 5.6 kW vector drive, 6000rpm and a 10-station automatic tool changer.”
“This machine takes care of all our cast iron alloy machining. We have set up our own fixtures on the table and the toolroom mill will machine two discs in a cycle, for example. All our other cast iron components are also machined on the Haas TM 2P.”
“Our discs are supplied in kits, both for off-road and high performance, and are cast from a proprietary high-carbon cast iron alloy that offers unmatched wear life and durability. The discs are machined to tolerances up to 3x tighter than the industry norm. Finished discs are coated in our proprietary “dry” silver or black coating, which results in the disc never having been exposed to lubricants or cutting fluids at any time during the manufacturing process.”
Haas UMC-750 5-axis vertical machining center
“The Haas UMC-750 arrived at virtually the same time. It is a 5-axis vertical machining center with XYZs of 762mm x 508mm x 508mm, has a 630mm x 500mm integrated 2-axis trunnion rotary table, a 40 taper, a Renishaw probe, a 22.4 kW vector drive, 12 000 rpm, inline direct-drive, 40+1 side mount tool changer and 30.5 m/min rapids.”
“On the Haas UMC-750 we machine all our aluminium components, including the calipers, from our own proprietary aluminium blocks. Individual features on the various components change considerably, with a wide variety of lengths, diameters and bore sizes. There are also various milled slots, under-cuts, holes and chamfers to be considered.”
“Our two tooling suppliers – Sandvik Coromant and TaeguTec – have been very helpful in setting us up with the correct tooling and holders. But it was the workholding that we struggled with. Because we don’t mess around when machining we needed solid fixturing.”
“We came across the grip-fix stamping technology from Lang Technik Germany. The stamping technology, also called pre-stamping, is a patented technology where the workpiece is stamped outside of the machine tool with up to 20 tons of hydraulic pressure, before being clamped in the Makro-Grip 5-Axis Vise with a form-closure effect. Clamping scenarios that require high holding power, but where the danger of workpiece deformation exists, can be mastered with the stamping process. For 5-sided machining, where optimal accessibility has to be achieved, stamping technology in connection with the Makro-Grip 5-Axis Vise is almost predestined. The unit is supplied as either a fixed or a mobile one.”
Discs ready for packaging
Calipers made by Powerbrake
“For our complete design-to-manufacturing solution with professional-grade CAD, CAM and FEA we have settled on Autodesk Inventor HSM Pro and Autodesk Fusion 360 CAD/CAM, a cloud-based software tool for 2.5D, 3D and 5-axis, with advanced CNC milling and turning CAM solutions that can be fully integrated with most of the main line software.”
“Currently under consideration is further investment in CNC machines that may include a further Haas 5-axis mill as well as a Haas lathe. We are also in the process of finishing off seven new products that will be launched at the Performance Racing Industry Trade Show in the US in December 2016.”
“Today Powerbrake has grown to offer a full range of big brake kits, high-carbon direct replacement rotors and bespoke race brake systems for hundreds of street, track day and full race applications.”
“At Powerbrake we have one clear objective. To design, manufacture and deliver high-performance and race brake components that offer exceptional performance and durability at a fair price. There are certainly cheaper products out there as well as many far more expensive ones. At Powerbrake you will find championship winning products that are extremely well engineered, manufactured to the highest standards, that have been proven in the toughest motor sport events on the planet, all at surprisingly competitive prices.”
“This is made possible through significant investment in state of the art CAD, CAM and FEA software as well as cutting edge Haas 5-axis CNC production equipment that results in design and production efficiency that gets passed on to our customers.”