Carbon Fiber Carburettor Velocity Stack Kit (50mm Tall) by Rennline. Porsche 911 / 912 / 356  ❭  M91KIT

Rennline Carbon Fiber Velocity Stacks (50mm Tall) | Precision Airflow & Top-End Power for cars with Carburettors
Set of 6 
The Rennline Carbon Fiber Velocity Stacks (50mm tall) are designed to optimise intake airflow and engine performance in high-revving applications. Constructed from ultra-lightweight carbon fibre, these 2" (50mm) stacks enhance air velocity and resonance, allowing for improved pressure pulse frequencies and more efficient airflow through the intake system.

Fits:

• Porsche 911 1965-1968 2.0L / 912 SWB (F)
• Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 356 1950-55
• Porsche 356A 1955-59
• Porsche 356B 1959-63
• Porsche 356C 1963-65

Compared to a 2.25" trumpet, these velocity stacks deliver superior high-RPM torque and throttle response, making them ideal for motorsport and performance-focused Porsche builds. With a standard 65mm mounting hole pattern, they’re designed for easy installation on a wide range of custom and carburettor-based setups.

Each velocity stack is sold individually and built to withstand the heat, vibration, and stress of competitive driving — offering both technical performance and sleek carbon aesthetics.

What Do Velocity Stacks Do?
Velocity stacks (also known as intake trumpets) are engineered to improve the airflow into the engine’s intake system, smoothing the transition of air and increasing volumetric efficiency.

Core Functions:

• Increase air velocity into the throttle body or carburettor.
• Improve top-end horsepower and torque output.
• Optimise pressure waves for enhanced combustion efficiency.
• Smooth airflow and reduce turbulence at the intake mouth.
• Deliver sharper throttle response at high RPM.

In short, they allow your engine to breathe more efficiently, resulting in better performance, faster throttle response, and improved sound.

Why Do Velocity Stacks Fail or Need Replacement?

Over time, velocity stacks — particularly older aluminium or plastic types — can degrade due to heat cycling, vibration, and exposure to contaminants.

Common Causes of Failure Include:

• Cracking or delamination from extreme heat and vibration.
• Corrosion or fatigue in metal-based versions.
• Airflow restriction caused by dirt or damage.
• Poor fitment leading to air leaks or misalignment.
• Material fatigue from repeated stress during performance driving.

When velocity stacks weaken or distort, airflow becomes uneven — reducing efficiency and potentially causing imbalanced fuel-air ratios or power loss.

Why Upgrade to Rennline Carbon Fiber Velocity Stacks?

Upgrading to Rennline’s carbon fibre design provides enhanced durability, lower weight, and optimal airflow characteristics — ideal for performance-focused engines and track cars.

Key Benefits:

• Increases torque and top-end power at high RPMs.
• Lightweight carbon construction for reduced mass and improved airflow.
• Precision 50mm height ideal for performance tuning.
• Improved pressure pulse frequency for enhanced throttle response.
• Direct-fit design with 65mm mounting holes.
• Sleek carbon fibre finish adds a professional motorsport aesthetic.

Rennline’s carbon fibre stacks combine engineering precision with performance-driven design — perfect for those seeking peak airflow efficiency and style.