34 ICT, EPC 34 & 38E Idle Jet

OVERVIEW

Precision tuning is the difference between a Volkswagen that merely runs and one that truly performs. This EMPI 34 ICT, EPC 34, and 38E Idle Jet in size .70 is a critical component for any enthusiast looking to dial in their fuel-air mixture for maximum responsiveness. Often overlooked, the idle jet is responsible for much more than just the engine''s behavior at a standstill; it governs the entire transition circuit up to approximately 2,500 to 3,000 RPM. When you are cruising through town or maintaining a steady speed in lower gears, your engine is relying heavily on the fuel metered through this tiny, precision-machined brass orifice. By upgrading or replacing your existing jets with the .70 size, you are providing a richer fuel delivery that is often necessary for larger displacement engines, performance camshafts, or cold-start environments where a leaner factory jet might cause hesitation.

At Appletree Automotive, we know that "flat spots" during acceleration are the bane of the air-cooled VW world. These hesitations often occur when the carburetor transitions from the idle circuit to the main circuit. Utilizing a .70 idle jet in your EMPI or Weber-style 34 ICT or 38E progressive carburetor can effectively bridge that gap, ensuring a smooth, linear power delivery that makes your Bug, Bus, or Ghia a joy to drive. This jet is manufactured to exacting tolerances, ensuring that the fuel flow is consistent across all cylinders when used in dual-carburetor setups. Whether you are building a rugged off-road rail or a concours-quality street cruiser, having the correct jetting is the final step in achieving the reliability and power your air-cooled engine is capable of delivering.

FITMENT

This idle jet is designed for use with a variety of popular aftermarket carburetor kits found on air-cooled Volkswagens and other specialty vehicles. It is compatible with the following models when equipped with EMPI 34 ICT, EPC 34, Weber 32/36 DGV, EPC 38E, or Weber 38 DGS carburetors:

• Volkswagen Type 1: Beetle and Bug (1950-1979)
• Volkswagen Type 1: Karmann Ghia (1956-1974)
• Volkswagen Type 2: Bus, Transporter, and Kombi (1950-1979)
• Volkswagen Type 3: Squareback, Fastback, and Notchback (1961-1973)
• Volkswagen Type 181: The Thing (1973-1974)
• Custom Applications: Dune Buggies, Sand Rails, Baja Bugs, and Trikes

SPECS

Technical specifications for the 74409.70 Idle Jet include:

• Jet Size: .70mm (0.70)
• Material: High-grade, precision-machined brass for corrosion resistance
• Carburetor Compatibility: EMPI 34 ICT, EPC 34, Weber 32/36 DGV, EPC 38E, Weber 38 DGS
• Application: Idle and Transition Fuel Circuit
• Quantity: Sold Individually
• Part Number: 74409.70 (Cross-reference: 43-5547-0)
• Thread Type: Standard Weber/EMPI metric idle jet threading

PRO TIPS

1. Curing the Mid-Range Stumble

If your engine experiences a "stumble" or "pop" when you lightly step on the gas from a stop, it is often a sign that your idle jet is too small. The .70 size is a popular choice for 1776cc to 1914cc engines that need a bit more fuel to smooth out that transition. Before swapping the jet, always ensure your timing is set correctly and your valves are adjusted, as mechanical issues can often mimic lean jetting symptoms. Once the mechanics are verified, installing the .70 jet can provide the extra fuel volume needed to eliminate lean-burn hesitations.

2. Cleanliness is Crucial

The orifice in a .70 idle jet is incredibly smallhardly larger than a human hair. Even the smallest speck of dust or fuel varnish can partially clog the jet, leading to a rough idle or a cylinder that "drops out" at low speeds. When installing these jets, never use a wire or a drill bit to clean them, as this will gouge the brass and change the flow characteristics. Always use compressed air or a specialized carburetor cleaning solvent. It is also highly recommended to run a high-quality fuel filter between the pump and the carburetors to prevent debris from reaching these sensitive components.

3. Synchronizing Dual Carburetor Setups

When running dual EMPI 34 ICTs, it is imperative that both carburetors utilize the exact same size idle jet. If you are stepping up to a .70 on the left side, you must do the same for the right. After installation, use a Uni-Syn or similar airflow meter to ensure both carburetors are pulling the same amount of air at idle. Because the idle jet affects the mixture up to 3000 RPM, mismatched jets will cause one bank of cylinders to run hotter or richer than the other, leading to uneven engine wear and a loss of overall fuel economy. Always re-adjust your idle mixture screws after changing jet sizes to find the new "sweet spot" for your engine''s vacuum signal.