Emulsion Tube, F2, for IDF, HPMX, DCOE DCO, EPC Carbs

OVERVIEW

Precision tuning is the heartbeat of any high-performance air-cooled engine, and the EMPI F2 Emulsion Tube is a critical component for those seeking to master the air-fuel delivery of their Weber or EMPI carburetors. The emulsion tube acts as the mechanical "brain" of the main circuit, responsible for mixing air from the air corrector jet with fuel from the main jet before it enters the venturi. In the world of performance VWs, choosing the right emulsion tube series is the difference between a crisp, responsive throttle and a sluggish engine plagued by flat spots. The F2 profile is specifically engineered for high-demand scenarios, often favored in large displacement engines or racing applications where a richer mixture is required during the transition into high-RPM operation. By optimizing the atomization process, this tube ensures that your fuel charge is finely misted, leading to more efficient combustion and a noticeable increase in power delivery across the power band.

Crafted with the exacting standards that Appletree Auto customers expect, these EMPI emulsion tubes are manufactured from high-quality brass to ensure long-term durability and resistance to modern fuel additives. Whether you are running a set of dual 44 HPMXs on a 2276cc stroker or dual 48 IDFs on a dedicated drag car, the F2 tube provides the specific aeration characteristics needed to maintain the correct mixture when the engine is under heavy load. Many tuners find that the F2 series is the "secret sauce" for engines that struggle with leaning out at the top end or those utilizing exceptionally large venturis. Don''t settle for "close enough" when it comes to your jetting; upgrading to the correct emulsion tube series is a fundamental step in achieving a professional-grade tune that protects your engine and maximizes your investment in performance hardware.

FITMENT

This F2 Emulsion Tube is designed for use in the following carburetor models and air-cooled Volkswagen applications:

• Carburetor Compatibility: Weber IDF (36, 40, 44, & 48mm), EMPI HPMX (40 & 44mm), Weber DCOE & DCO (40, 42, 45, & 48mm), EMPI EPC (48 & 51mm), and Weber IDA (2-Barrel models).
• Volkswagen Type 1: Beetle, Super Beetle, and Karmann Ghia (typically 1600cc to 2332cc+ performance builds).
• Volkswagen Type 2: Bus, Transporter, and Westfalia (Type 1 and Type 4 engine configurations).
• Volkswagen Type 3: Squareback, Fastback, and Notchback (Dual carb conversions).
• Volkswagen Type 181: The Thing.
• Off-Road: Dune Buggies, Sand Rails, Manx-style bodies, and Baja Bugs.
• Custom Engines: Any air-cooled or water-cooled engine utilizing genuine Weber or EMPI performance carburetors.

SPECS

Technical specifications for the EMPI 43-5670-0 Emulsion Tube:

• Part Number: 43-5670-0.
• Tube Series: F2 (Specific hole pattern for performance enrichment).
• Material: Heavy-duty machined brass for corrosion resistance.
• Application: Main circuit fuel atomization.
• Compatibility: Interchangeable with original Weber components.
• Quantity: Sold individually (Order 2 for dual 1-barrel setups, 4 for dual 2-barrel setups).
• Precision: High-tolerance drilling for consistent flow rates across multiple cylinders.

PRO TIPS

1. Understanding the F2 Richer Bias

The F2 emulsion tube is generally considered a "richer" tube compared to the standard F11 typically found in many out-of-the-box carburetors. Because the F2 has fewer holes or holes positioned differently in the tube wall, it allows less air to mix with the fuel at certain vacuum levels, resulting in a denser, richer fuel mixture. This is incredibly beneficial for engines that experience a "lean pop" or hesitation when the main circuit kicks in, especially if you are running large venturis that reduce signal strength at lower RPMs. If you have tried increasing your main jet size but the engine still feels "thin" at high speeds, the F2 might be exactly what you need to stabilize the mixture.

2. Cleanliness and Seating are Paramount

When installing new emulsion tubes, cleanliness cannot be overstated. Even a tiny microscopic fragment of brass or a piece of lint can clog the precise air-bleed holes on the F2 tube, causing an entire cylinder to run lean or misfire. Before installation, blast the jet stacks with high-quality carburetor cleaner and compressed air. Furthermore, ensure the emulsion tube is seated fully within the jet block. If it is not seated properly, fuel can bypass the metering circuit entirely, leading to an uncontrollably rich condition and poor idle-to-main transition. Always double-check that your air corrector jet is tightened firmly on top of the emulsion tube to lock it in place.

3. The Synergy of the Jetting Stack

Remember that the emulsion tube does not work in a vacuum; it is part of a "stack" consisting of the Main Jet, the Emulsion Tube, and the Air Corrector Jet. When moving to an F2 tube, you may need to re-evaluate your Air Corrector size. Since the F2 provides a richer profile, you might find that you can run a slightly larger Air Corrector to "lean out" the very top of the RPM range while still enjoying the mid-range punch the F2 provides. Tuning is an iterative processkeep a log of your changes and always read your spark plugs after a high-speed "plug chop" to ensure your F2 tubes are providing the stoichiometric balance your air-cooled VW demands for longevity and power.