SU HS4 HIF38 HIF4 H4 1.5" Vortex Ram Pipe Velocity Stack

Vortex 1.5" Velocity Stack for SU Carburettors – 35mm Intake

One 3D-printed 1.5" tall “Vortex” velocity stack for SU carburettors with a 35mm intake.

This SU carburettor intake trumpet is also commonly described as a ram pipe, velocity stack or air horn; check the 35 mm intake and listed carburettor fitment before ordering.

Designed to improve intake flow, this Vortex velocity stack has been developed with the A-Series engine tuning principles discussed in the highly regarded works of David Vizard in mind.

Development testing indicated an approximately 5.2% improvement in intake flow over the standard A-Series setup.

The Vortex design provides a smooth, controlled transition into the carburettor, helping optimise airflow into the engine.

The IPNG Vortex Design: Spiral Airflow Vanes & A-Series Research

IPNG Automotive developed the Vortex range with reference to established carburettor induction principles explained by David Vizard in Tuning the A-Series Engine, including the importance of inlet shape, smooth air entry and the wider intake system. This is IPNG's own product design, not a collaboration with or endorsement by the author.

The 1.5" HS4/HIF38-family Vortex stack uses a short radiused entry and IPNG’s internal spiral guide vanes, intended to influence the direction of the incoming air near the carburettor mouth. The internal spiral, or helical flow-guiding, feature is intended to introduce a controlled rotational component (swirl) to the incoming airflow. It is a design objective, not a guarantee of greater power or efficiency on every engine.

Development testing: IPNG has reported an approximately 5.2% airflow improvement for this specific Vortex design when compared with a standard A-Series intake setup. This is an airflow comparison, not a measured 5.2% engine power increase; results depend on the complete intake and engine installation.

Fitment

Designed to fit:

• SU HS4
• SU HIF 38
• SU H4
• SU HIF4

These carburettors are commonly found across a wide range of classic British vehicles, including Minis, Jaguars, Triumphs, MGs and other compatible applications.

Key Features

• 1.5" tall Vortex velocity stack
• 35mm intake size
• Designed for compatible SU carburettors
• Vortex internal design developed to optimise intake airflow
• Approximately 5.2% increased intake flow over the standard A-Series setup during development testing
• Developed with reference to David Vizard's A-Series engine tuning principles
• Smooth bellmouth-style intake entry
• Manufactured from high-temperature-resistant plastic
• Other sizes and lengths available

Installation

Difficulty: ★☆☆☆☆
Estimated Time: Approximately 10–20 minutes, depending on carburettor setup

The velocity stack is designed to fit directly to the compatible SU carburettor using the existing mounting arrangement.

Before use, ensure the stack is securely fitted and that there is sufficient clearance within the engine bay.

What's Included

• 1 × 1.5" Vortex velocity stack – 35mm intake

Carburettor NOT included.

Material & Finish

3D printed using high-temperature-resistant plastic, making it suitable for use within demanding automotive environments.

Custom Options

Other intake sizes and velocity stack lengths are available.

Please get in touch if you require a different size or configuration.

For the same 35mm SU fitment, compare the 2" Vortex stack (IP-0044) or longer 2.5" Vortex stack (IP-0046). If your carburettor is an SU HIF44, use the dedicated HIF44 2" Vortex stack (IP-0010) instead.

Important Information

This is an aftermarket IPNG performance component and is not manufactured by or affiliated with SU, Mini, Jaguar, Triumph or MG.

The stated airflow improvement is based on development testing and may vary depending on the specific carburettor, engine and intake configuration.

IPNG Part Number

IPNG SKU: IP-0045

Vortex Fitment & Selection Guide

Not sure which Vortex stack is right for your carburettor? Use our Vortex velocity stack fitment & selection guide to compare carburettor fitment, intake or bore size, stack height and IPNG part number.