Dual 44 HPMX Carburetor Kit, By EMPI

OVERVIEW

When you are ready to wake up your air-cooled engine and experience true performance, the EMPI Dual 44 HPMX Carburetor Kit is the definitive upgrade. Engineered to provide a massive boost in horsepower and torque, this kit replaces your restrictive single carb setup with a high-flow dual-throat system that allows your engine to breathe exactly the way it was meant to. Whether you are building a spirited daily driver or a weekend track machine, the HPMX series delivers crisp throttle response and a roar that only a dual-carbureted VW can produce. Every component in this kit has been curated to ensure a seamless transition to high-performance induction, giving you the reliability you need for the long haul and the power you crave for every green light. At Appletree Auto, we know that performance is nothing without precision, and this kit delivers both in a package that looks as good as it performs.

This comprehensive kit is built around the 44 HPMX carburetors, which are world-renowned for their versatility and ease of tuning. EMPI has paired these carburetors with high-quality offset aluminum intake manifolds and a heavy-duty aircraft-style hex bar linkage to ensure that your throttle synchronization remains precise and consistent even under high-heat conditions. One of the greatest advantages of the HPMX platform is its compatibility with industry-standard IDF jets, allowing you to fine-tune your fuel-to-air ratio for any altitude or engine displacement configuration. From the chrome-topped air cleaners to the included hardware and gaskets, this kit provides a professional-grade solution that transforms your engine bay into a powerhouse of efficiency. Please note that while this kit is designed for a bolt-on experience, some modification to the factory fan shroud may be necessary to ensure perfect clearance for the linkage and carburetor bodies.

FITMENT

• Volkswagen Beetle: 1966-1977 (Dual Port Engines)
• Volkswagen Karmann Ghia: 1966-1974 (Dual Port Engines)
• Volkswagen Thing (Type 181): 1973-1974
• Custom Applications: Sand Rails, Dune Buggies, and Trikes utilizing Type 1 VW Dual Port Engines
• Engine Compatibility: Optimized for 1776cc to 2110cc displacement builds

SPECS

• Carburetor Model: Dual 44 HPMX (IDF Style Configuration)
• Main Jets: 135
• Idle Jets: 55
• Air Correction Jets: 200
• Venturis: 36mm
• Exhaust Pump Jet: .550
• Accelerator Pump Jet: .50
• Intake Manifolds: Polished Offset Cast Aluminum
• Linkage: Hex Bar Style with Aircraft-Quality Heim Joints
• Air Cleaners: High-Flow Gauze Elements with Chrome Top and Base Plates
• Fuel Type: Gasoline (Requires 2.5 to 3.0 PSI Fuel Pressure)
• Hardware: Includes all necessary gaskets, studs, and mounting hardware

PRO TIPS

1. Prioritize Fuel Pressure Regulation

One of the most common mistakes when installing HPMX or IDF-style carburetors is running too much fuel pressure. Most stock VW mechanical pumps, and certainly many aftermarket electric pumps, output well over 4 PSI. These carburetors are designed to operate optimally at 2.5 to 3.0 PSI. If the pressure is too high, it will overcome the needle and seat, leading to flooding, inconsistent idling, and potential engine fires. We strongly recommend installing a high-quality fuel pressure regulator and a gauge between the pump and the carburetors to ensure your fuel delivery is stable and safe.

2. Manifold Alignment and Shroud Clearance

During the installation of the offset aluminum manifolds, always "dry fit" the components before final torquing. Because air-cooled VW engines can have slight variations in width depending on the stroke and shim stacks used, the manifolds may sit closer to the fan shroud than expected. If you find the linkage or carb body is touching the shroud, don''t force it. Use a mallet or a specialized tool to slightly "dimple" the shroud or trim the sheet metal as needed. A clear path for the hex bar linkage is vital to prevent the throttle from sticking, which is a significant safety concern.

3. Mastering the Synchronization

To get that smooth, sewing-machine idle that dual carbs are famous for, you must use a "snail-style" airflow meter (synchronizer). Do not attempt to tune these by ear or by counting turns on the screws. First, ensure your linkage is disconnected so each carb is resting on its idle stop. Balance the airflow between the left and right carburetors