Kline Innovation Valvetronic Exhaust System for 991.1 Porsche 911 Carrera

Kline Innovation Valvetronic Exhaust System for 991.1 Porsche 911 Carrera

The seventh generation of the 911, known as the 991 turbo, has undergone remarkable evolutionary advancements. The introduction of an expanded wheelbase and improved axle-to-engine geometry has significantly enhanced weight distribution and stability during cornering. Additional weight reductions have been achieved through the use of composites and aluminum, including improvements made to the exhaust system when compared to its predecessor, the 997. One may wonder how much further the factory exhaust can be enhanced. The answer is simply astonishing.

The Sound

• Building upon the design successes of the 996 and 997 ranges, Kline has set a high benchmark in creating the 991 Carrera exhaust. Incorporating their iconic ideal x-pipe geometry, meticulously tuned silencer configuration, Inconel 625 material, and exclusive acoustic silencer packing materials, they have crafted a system that is renowned for its perfect sound. The result is an exhaust system with zero drone and a higher-pitched, fiery roar during high revs and full throttle.
• The x-pipe geometry, recognized for its distinct sound characteristics, is a recurring feature in all Kline systems. This x-pipe structure, a product of extensive research and development focused on exhaust note tonality, may appear simple, but slight variations in its geometry profoundly impact gas resonance at different rev ranges and gas throughput, thereby significantly influencing the sound produced.
• When the valve is open, the system becomes fully free-flowing, with the exhaust discharge flowing exclusively through the x-pipe and a short resonator section of the silencer. This setup softens the harsh edges of the exhaust note, resulting in an aggressive yet smooth sound that is attention-grabbing and fills the cabin with a satisfying audio experience.
• During valve closure, gases pass through four chambers, four resonated sections, and the x-pipe, producing a slightly louder and smoother sound compared to stock, while maintaining near silence during cruising.
• Inconel’s resonant qualities contribute to an exhaust note richness that is unparalleled by any other material, delivering an immersive and captivating in-person experience.

The Performance

• While final data on exact power figures is still being reviewed, preliminary tests indicate that the racing variant in the range can achieve a maximum power gain of approximately 21-25whp and 28-34nm of torque. Options are available with various HJS catalysts, including 100 cell or 200 cell.

Stainless Steel

• In the exhaust manufacturing industry, the common choice is 304-grade stainless steel. This grade offers a good balance of strength, thermochemical stability, cost-effectiveness, and ease of production, making it suitable for constructing durable exhaust systems. However, stainless steel is relatively heavy compared to other materials. While it shares a similar density to regular steel, it lacks in tensile strength, limiting its potential for high-performance exhaust components. Additionally, the thicker walls required by stainless steel may result in a more muted and less vibrant exhaust sound.

Inconel

• In aerospace applications, durability and heat resistance are of utmost importance, making Inconel 625 the material of choice. Widely used in the production of critical parts, particularly exhaust turbine blades for high-performance jet engines, Inconel is highly regarded in Formula One exhaust systems and has been favored by manufacturers for elite hypercar projects such as the McLaren P1 and Aston Martin 177. With the ability to withstand temperatures exceeding 1000°C, Inconel prioritizes lightweight design.
• Inconel exhibits extraordinary properties, including exceptionally high tensile strength and remarkable thermochemical stability. However, working with Inconel presents challenges due to its difficult machinability and specific welding requirements, requiring specialized skills and time-consuming techniques. Furthermore, the unique properties and specialized manufacturing processes associated with Inconel.

Carbon Fiber

• Carbon fiber reinforced polymer, boasting a tensile strength-to-weight ratio that surpasses all metals, exhibits remarkable properties. Known for its lightweight and high-strength characteristics, carbon fiber is a favored material in various industries, including automotive and aerospace. Its exceptional strength and rigidity make it an ideal choice for applications that require both performance and durability. Carbon fiber components not only contribute to weight reduction but also offer improved stiffness, enhancing overall vehicle dynamics and handling. While carbon fiber is renowned for its technical and aesthetic appeal, its production and manufacturing processes are complex and require specialized expertise. Additionally, the utilization of carbon fiber often results in higher costs compared to other materials.

Specifications

• Cross Sections:
  • Center Silencer Section: 60mm
  • Wing Silencers: 60-57mm
  • Catalysts: 118mm OD
• Materials:
  • Standard 304 Grade Stainless Steel Weight:
    • Wing Silencers: 6.5kg each
    • Center Silencer: 11.9kg
  • Inconel 625 Formula One Grade Material Weight:
    • Wing Silencers: 3.8kg each
    • Center Silencer: 7.2kg
  • Tails:
    • Made from aerospace grade carbon fiber, and a choice of inconel or stainless steel inserts

Applications

• Porsche 911 Carrera: 991.1 (2011-2015) – 3.4L / 3.8L Flat-6

Notes

• It is worth noting the presence of manifolds and carbon fiber tips depicted in the images; however, it should be emphasized that they are not included as part of the standard package

About Kline Innovation

At Kline, exhaust design is approached with utmost seriousness. The company adopts a no-compromise stance when it comes to delivering a product that meets the highest standards and satisfies customers’ expectations. Kline offers a comprehensive original equipment design and manufacturing service. Starting from provided drawings or design briefs, the team utilizes advanced 3D modeling techniques to create final designs. They also provide valuable consultation during the process and are capable of manufacturing tooling and fixtures for production, as well as handling final production runs, particularly catering to low to medium volume needs. Kline’s commitment to excellence ensures that customers receive a top-quality product without any compromises.

Development

• All projects at Kline are executed entirely in-house, utilizing a diverse range of processes. These internal capabilities include laser scanning, CNC laser cutting, CNC mandrel bending, tubing and silencer manufacturing, CNC welding, pressings, CNC milling, mould manufacturing, and autoclave carbon fiber production. Notable automotive clients, such as W Motors with their Fenyr Supersport, Corbellati Missile, and RUF Automobil, have recently collaborated with Kline.
• Kline has expanded its design and manufacturing process by incorporating laser scanning capabilities. This valuable addition enables the team to achieve enhanced precision in both design and quality control, resulting in an exceptional end product for customers. The adoption of laser scanning technology at Kline showcases the company’s unwavering dedication to delivering superior outcomes.