At Powerbrake, we believe strongly in the beneﬁts of machining our multi-piston calipers from solid billet. All of our championship winning X-Line and R-Line race calipers are machined from high-grade aerospace aluminum billets. Machining from billet is admittedly an expensive way to manufacture calipers but it results in a ﬁnished product that exhibits exceptional levels of strength and rigidity.
How do we bring our billet X-Line calipers to the market at such competitive prices? Through signiﬁcant investment in state-of-the-art 5-axis CNC production equipment that allows us to machine the calipers with maximum eﬃciency. The fact that we machine all of our calipers from billet, matched to the FEA enhanced caliper designs themselves, results in calipers with an impressive rigidity to overall size ratio. The slim proﬁle of the calipers reduces un-sprung weight and aids with wheel clearance.
All Powerbrake X-Line race calipers feature a Mil-Spec Type-3 hard anodize ﬁnish for maximum wear resistance and durability. Our particular anodizing process results in a unique dark grey color that gives and attractive but purposeful look. Our X-Line race calipers are not available in other colors.
Caliper - Logos:
Our logos are applied to our calipers using advanced laser technology. This creates visually appealing contrast between the logo and the dark grey caliper color and the logos on our X-Line calipers will not be damaged by heat, brake ﬂuid or solvents, as is the case with paint in-lay logos used by many big brake kit manufacturers. The Powerbrake logo anagram is also neatly CNC machined into each X-Line caliper near the caliper bridge. Brake calipers operate in a very challenging environment. They are exposed to debris, carbonized brake pad material, constantly ﬂuctuating temperatures and environmental conditions.
Powerbrake has focused on ensuring that our X-Line brake calipers will remain looking good under the widest possible range of operating conditions.
The high-tensile caliper cross-bolts used in the assembly of our X-Line calipers are manufactured for us in Europe and coated with a proprietary high-tech black coating. This coating oﬀers exceptional corrosion resistance, while not negatively aﬀecting bolt strength at all. The bolt positions across our entire X-Line caliper range are the result of extensive FEA analysis and deliver optimum caliper rigidity. The cross-bolts
are inserted into the caliper from the inboard side resulting in maximum wheel clearance.
Powerbrake X-Line race calipers all feature castellated stainless-steel pistons. Stainless steel is signiﬁcantly more expensive to manufacture caliper pistons from than the aluminum pistons used by many of our competitors but the beneﬁts are well worth the investment. Stainless steel transfers heat far slower than aluminum. The result is that stainless steel pistons slow the transfer of heat from the brake pads to the calipers seals and brake ﬂuid, hereby reducing the chances of boiling brake ﬂuid and also extending seal life. The castellated scallops machined into our X-Line pistons allow the super-heated air in the piston cavity to escape, which further helps with temperature management.
Caliper Fluid Crossover Tubes:
The seamless ﬂuid crossover tubes ﬁtted to our X-Line calipers are manufactured from a CuNi alloy. Like it or not, the friction involved in braking results in high-frequency vibrations within the brake calipers. Our seamless CuNi ﬂuid crossovers handle vibration far better than the coated steel or stainless steel ﬂuid crossovers commonly used in the industry.
Many other caliper manufacturers use seamed crossover tubes that can split along the seams with long- term exposure to vibration. Our CuNi alloy also oﬀers excellent corrosion resistance. Finally, our ﬂuid crossovers are all ﬁtted with high temperature silicone sheaths that pull against the caliper bridge section and further dampen vibration and protect the tubes.
Caliper Maximum-Temperature-Recording (MTR) System
All Powerbrake X-Line calipers feature our MTR system. The system provides a permanent record of the maximum operating temperature reached by the caliper. This is far more valuable information than you get from reading caliper surface temperatures with a heat gun once the car arrives back in the pits (which we so often see people doing).
Feedback from our X-Line race customers has been extremely positive with regards to the MTR system over the years. Conscientious race and track day customers will really appreciate this feature as it provides valuable data in the support of brake ﬂuid choice etc. The inclusion of a max temp recording system on big brake kit range at no extra charge is unique to Powerbrake on the world market.
All other caliper hardware components (including: Pad retaining pins, Bleed screws, Tube nuts and Pad abutment plates) are manufactured from stainless steel to ensure highest levels of corrosion resistance.
The disc friction rings used in our X-Line disc assemblies are cast from a proprietary high-carbon cast iron alloy that provides excellent durability and stability under the high thermal loads experienced under fast road or track day driving. The discs feature our curved, directional, staggered cooling vane design that increases cooling vane surface area for optimal cooling.
The standard-production slot pattern chosen for our X-Line discs is our well-proven “RS” pattern that provides a good balance between functional aspects such as eﬃcient removal of friction gasses, carbonized pad material and water (when driving in the rain) and practical aspects such as low levels of noise, vibration and harshness (NVH) braking. The slot pattern also provides good bite and release characteristics.
Every single Powerbrake disc is measured for run-out and disc thickness variation (DTV) using Swiss measuring equipment. When it comes to QC, there is no batch or statistical quality checking of Powerbrake discs. Every single disc is measured. Our machining tolerances are up to three times tighter than the industry norm.
All our X-Line disc rings are coated with a proprietary black surface coating. The discs are chemically de-greased before the application of this coating to ensure that no machining ﬂuids or other contaminants that can be absorbed the brake pads and negatively aﬀect brake performance are present on our discs at all. The coating is able to withstand extremely high temperatures and is ﬂexible enough to expand and contract without ﬂaking or peeling oﬀ of the disc surface during the constant thermal expansion and contraction cycles experience by the brake disc.
Our X-Line discs require no cleaning or preparation using solvents at all. Simply ensure that the car's hub is clean and ﬁt the disc assemblies as they come out of the box. The black coating will be removed by the brake pads in the pad track areas within the ﬁrst 4-5 brake applications. The un-swept areas of the disc will remain coated. While our disc coating was primarily designed to ensure that there was zero presence of oils and contaminants on our disc surfaces at the time of ﬁtting (and was not in fact designed to provide corrosion protection), practical experience has shown that the non-swept areas of our coated X-Line discs will in fact resist the common formation of unsightly surface rust on the non-swept areas of the discs quite well (depending on environmental conditions in your area). This results in a far more visually appealing assembly visible through the car's wheels.
Disc Maximum Temperature Recording (MTR) System
Unique to Powerbrake, all X-Line disc friction rings feature our MTR system that provide a permanent record of the peak operating temperature reached by the discs. This information is extremely valuable when selecting correct pad compounds for your application. The thermal-paint tabs are applied to the outside diameter of all X-Line disc rings (on both the inboard and outboard disc plates).
Each single-change paint color (4-levels: Blue, Green, Orange and Pink) changes to white when a speciﬁc temperature is reached, hereby providing a record of the peak operating temperature of the disc. We also add a multi-change paint that can be used with a provided colour gradient chart to further reﬁne the results to a more speciﬁc temperature. The simple information required to interpret the results recorded by the MTR system on our X-Line discs is provided in the instruction manual that accompanies every X-line big brake kit.
The light-weight disc hats used in our X-Line disc assemblies are machined from a solid billet of high grade aluminum alloy. Again, machining brake components from solid billet is expensive but it results in an extremely strong ﬁnished part. All hat designs undergo FEA strength and thermal analysis to conﬁrm strength and rigidity under load. The hats are then ﬁnished with a Type-3 Mil-Spec hard anodise for maximum durability and service life. Logos and other information are then laser etched on the outboard face of the hats.
At Powerbrake we have many years of R&D invested in disc ﬂoat systems. We have developed advanced ﬂoat systems for our full race brake systems for applications ranging from circuit racing to FIA oﬀ-road and Dakar Rally applications. For our X-Line big brake kits, we decided to go with our most advanced ﬂoat system designated: X-Float.
Our X-Float system allows the disc friction ring to expand and contract radially without any restriction as it heat and cools. This signiﬁcantly reduces stresses within both the disc friction ring and the disc hat and reduces the chance of disc distortion and cracking, while ensuring a very consistent brake pedal feel.
The system also allows full axial ﬂoat once approximately 5% brake pedal pressure is applied. As soon as the driver comes oﬀ the brake pedal, the system stops the axial ﬂoat in the oﬀ-brake condition. In other words, our X-Float system provides all of the positives of full-ﬂoating race disc assemblies but without the negatives often associated with full-ﬂoating discs, such as piston knock-back when jumping curbs on track or after S-bends. The X-Float system also runs very quiet, with none of the rattling and noise normally associated with full-ﬂoating race disc assemblies.
Caliper Mounting Brackets
X-Line caliper mounting brackets are machined from billet aircraft grade aluminum alloy, FEA enhanced for strength and rigidity and Type-3 Mil-Spec hard anodised. One detail to note is that we use a patented thread type for the radial mount bolts that secure our X-Line calipers to the caliper mounting brackets.
Since our X-Line calipers feature a solid caliper re-enforcement bridge, you need to remove the two caliper radial mount bolts in order to change pads. For this reason we use a patented self-locking thread in our mounting brackets.
This patented thread style is extensively used in the aerospace industry due to its increased strength over conventional threads as well as its self-locking properties. This means that no thread lockers / Loctite are required on our radial mount bolts at all. Combine this with a proprietary coating on the radial mount bolts themselves that has excellent lubricity properties and you have a system that provides excellent torque accuracy, requires no thread locking ﬂuids, is very easy to assemble and disassemble quickly and is stronger than conventional threads.
The brake lines included with our X-Line big brake kits feature an extruded Teﬂon inner lining that is highly resistant to the aggressive chemical properties of modern brake ﬂuids, as well as being able to handle far higher temperatures than rubber. The Teﬂon lining is covered by 32 strands of tightly woven stainless-steel braid that acts as the muscle of the hose, providing incredible resistance to expansion under pressure. Our stainless braid is covered with a “carbon-look” polymeric outer layer that prevents dirt from getting between the stainless braid and the Teﬂon inner lining. The end ﬁttings on our hoses are all machined from Grade-304 stainless steel as opposed to the plated, mild steel ﬁttings used by many of our competitors. The resulting hose assemblies oﬀer the best possible pedal feel, matched to excellent durability and corrosion resistance.
As with all Powerbrake big brake kits, each X-Line kit is tailored to the speciﬁc vehicle. This involves careful software modelling of correct brake balance, brake torque outputs and pedal feel using our proprietary brake simulation software (developed in-house) which is a key element in the success of our entire range of big brake kits. The software allows us to enter all aspects of the factory brake system on the car as well as all key data aﬀecting chassis dynamics under braking. Our engineers can then simulate braking events at various negative G's and analyse dynamic weight transfer for the chassis in question.
They are then able to perfectly optimise brake the torque outputs delivered by our big brake kit by changing disc diameters, caliper piston ratios and brake pad friction co-eﬃcient. The result is that the caliper piston diameters / ratios, disc sizes and pad compounds in each kit are tailored to the vehicle platform in question. Our X-Line big brake kits will perfectly integrate with the ABS, EBD and other stability control systems on the vehicle. When driving a car ﬁtted with a Powerbrake X-Line big brake kit, you will feel this attention to detail coming through by the way that the vehicle chassis reacts under braking.