Air Jet, 165 for D-Series Carb, Sold Each

OVERVIEW

Precision tuning is the heartbeat of any high-performance air-cooled Volkswagen engine, and the EMPI 165 Air Jet for D-Series carburetors is a critical component in achieving that perfect stoichiometric balance. Designed specifically for the D-Series platformwhich includes the popular HPMX and DCOE style performance carburetorsthis air jet plays a vital role in controlling the fuel-to-air ratio as your engine climbs into the higher RPM range. When you are pushing your Beetle, Ghia, or Sand Rail to its limits, the air jet works in conjunction with the emulsion tube to "bleed" air into the main fuel circuit, preventing the mixture from becoming overly rich as air velocity increases. A size 165 jet provides a specific calibration point that allows for fine-tuning the high-speed circuit, ensuring that your flat-four stays responsive and powerful without the risk of stumbling or fouling plugs during spirited driving.

Crafted from high-quality, corrosion-resistant brass, these jets are machined to exacting tolerances to ensure consistent flow rates across every unit. At Appletree Automotive, we understand that "close enough" isn''t an option when it comes to carburetor calibration. Whether you are building a street-legal sleeper or a dedicated off-road dune buggy, having the right air jet size is the difference between an engine that gasps for breath and one that screams toward the redline. This 165 air jet is an essential tool for the serious tuner''s arsenal, allowing you to compensate for engine modifications, exhaust changes, or specific atmospheric conditions. Because these are sold individually, you have the flexibility to buy exactly what you need for your dual-carb setup, ensuring that both banks of your engine are perfectly synchronized for maximum efficiency and longevity.

FITMENT

This air jet is designed for D-Series performance carburetors, typically found on the following air-cooled Volkswagen models and custom applications:

• VW Beetle (Type 1): 1950 through 1979 (All models equipped with D-Series/HPMX/DCOE carburetors)
• VW Karmann Ghia: 1956 through 1974
• VW Bus / Transporter (Type 2): 1950 through 1971 (1200cc, 1500cc, and 1600cc upright engines)
• VW Type 3 (Squareback, Fastback, Notchback): 1961 through 1973
• VW Thing (Type 181): 1973 through 1974
• Custom Applications: Dune Buggies, Sand Rails, Manx-style bodies, and Trikes utilizing EMPI D-Series or Weber-style side-draft/down-draft carburetors.

SPECS

• Brand: EMPI
• Part Number: 44-1064-0
• Jet Size: 165
• Series Compatibility: D-Series (Fits HPMX, DCOE, and similar performance platforms)
• Material: Precision-machined Brass
• Sold As: Individually (Each)
• Function: High-speed air bleed calibration
• GTIN: 707924438215

PRO TIPS

1. Understanding the Inverse Relationship

When tuning your D-Series carburetor, it is vital to remember that air jets have an inverse effect on the mixture compared to main fuel jets. While a larger main jet makes the mixture richer, a larger air jet (like moving from a 160 to a 165) actually leans out the mixture at high RPMs. If your engine feels like it is "blubbering" or losing power at the top of the gear, you may need to increase your air jet size to lean out the top end. Conversely, if you experience a high-speed lean pop or surging, you might need to go to a smaller air jet to keep more fuel in the circuit. Always make incremental changes and read your spark plugs after a high-speed "plug chop" to verify your settings.

2. Altitude and Environmental Adjustments

Air density changes significantly with altitude and temperature, which directly impacts your carburetor''s jetting requirements. If you are taking your VW from sea level up into the mountains for an off-road event, the thinner air will naturally make your engine run richer. Increasing the size of your air jet to a 165 or higher can help compensate for this by introducing more air into the emulsion process, helping to maintain performance even when the oxygen levels drop. Keep a small selection of jets in your tool roll so you can adjust your D-Series carbs on the fly when traveling through different elevations or during extreme seasonal temperature shifts.

3. Maintenance and Cleaning Best Practices

Never use a steel wire, needle, or drill bit to clean a brass air jet. The orifices are machined to extremely precise dimensions, and even a microscopic scratch can alter the flow characteristics and ruin the jet''s calibration. If you suspect a clog or varnish buildup, always use a dedicated aerosol carburetor cleaner and high-pressure compressed air to clear the passage. When installing your new 165 air jets, ensure they are seated firmly but do not over-tighten them, as the brass threads can be damaged if excessive force is applied. A snug fit with a properly sized flat-head screwdriver is all that is required to keep them secure.