DCOE Carburettor Velocity Stack set - ram pipe design

DCOE Carburetor Velocity Stacks – Technical Performance Set (4 pcs, PA-CF)

These velocity stacks are engineered for DCOE-type carburetors and designed using the airflow and intake-tuning principles described in Performance Tuning in Theory & Practice — Four-Strokes by A. Graham Bell.

They provide optimized inlet geometry, improved flow efficiency, and allow you to tune the intake system to your engine’s torque and power needs.

Key Technical Features

Precision Bellmouth Geometry

Each stack uses a smooth, high-radius bellmouth to minimise entry turbulence, reduce boundary-layer separation, and improve volumetric efficiency—especially at high airflow demand.

Functional Length Options

Available in multiple diameter–length configurations so you can match the intake tract to your engine’s cam profile and target RPM range:

• Longer stacks (e.g., 76 mm) → stronger mid-range torque
• Medium stacks (50 mm) → balanced power delivery
• Shorter stacks (38 mm) → improved high-RPM response

This follows Bell’s tuning principle: total intake length directly influences the timing of pressure-wave harmonics that assist cylinder filling.

Available Variants

(D = Carburetor throat diameter, L = Stack length)

• 40-38L
• 40-50L
• 40-76L
• 45-38L
• 45-50L
• 45-76L
• 48-38L
• 48-50L
• 48-76L
• 50-38L
• 50-50L
• 50-76L

Material: PA-CF (Carbon-Fiber Nylon)

Each set is printed in PA-CF, offering:

• High stiffness
• Heat resistance
• Dimensional stability
• Excellent surface finish

Ideal for high-vibration and under-bonnet environments

This makes the stacks suitable for both functional automotive use and performance prototyping.

Why These Stacks Work

Based on Bell’s four-stroke theory:

• A properly shaped bellmouth can reduce inlet losses by up to 20% compared to sharp-edge entries.
• Intake length tuning allows you to shift torque characteristics without modifying the carburetor or manifold.
• Clean airflow into the carburetor improves throttle response and cylinder filling across the rev range.

What You Receive

• 1 full set of 4 velocity stacks
• Printed in PA-CF carbon-fiber reinforced nylon - dark grey color