Dual 40K 40mm Dual Carb Kit, For Type 2 & Type 4

OVERVIEW

Unlock the true performance potential of your flat-four power plant with the EMPI Dual 40K 40mm Dual Carb Kit, specifically engineered for the heavy-duty demands of Type 2 Transporters and Type 4 engines. If you are tired of the sluggish throttle response and flat spots associated with aging stock single-throat carburetors, this kit is the definitive solution for achieving a smoother idle, increased horsepower, and superior reliability. These 40mm carburetors are designed to provide a significant volumetric efficiency boost, allowing your engine to breathe deeper and react faster to every input. Whether you are hauling a fully loaded Westfalia up a mountain grade or looking for more spirit in your Type 4-powered Porsche 914 or VW 411, the 40K series provides the perfect balance of streetable manners and high-end flow capacity that modern air-cooled enthusiasts demand.

What sets the EMPI 40K apart from generic alternatives is the attention to detail in the casting and internal engineering. We have extended the carburetor base to accommodate a wide variety of air cleaner options, including EMPI velocity stacks, giving you the flexibility to customize your engine bay''s aesthetics and performance profile. For those who take their rigs off-road or to the drag strip, a specialized brass vent tube has been integrated into the design to prevent fuel sloshing and flooding during high-incline maneuvers or rapid acceleration. Furthermore, the vacuum circuitry has been refined to allow for the seamless integration of a single vacuum advance distributor, ensuring that your timing curve remains optimal without sacrificing the rock-solid idle performance these dual carbs are known for. This is a comprehensive, bolt-on performance upgrade that transforms the driving dynamics of your vintage Volkswagen.

FITMENT

• VW Bus (Type 2): 1972-1979 models equipped with 1700cc, 1800cc, and 2000cc Type 4 engines.
• VW 411 / 412: All years equipped with the Type 4 engine platform.
• Porsche 914: 1.7L, 1.8L, and 2.0L four-cylinder engines (requires appropriate engine tin clearance).
• Custom Builds: Any upright or pancake-style engine utilizing Type 4 cylinder heads and intake configurations.

SPECS

• Carburetor Model: Dual EMPI 40K (40mm Dual Throat).
• Venturi Size: 28mm (Standard pre-installed).
• Main Jets: 115 (Pre-installed).
• Air Correction Jets: 200 (Pre-installed).
• Idle Jets: 52 (Pre-installed).
• Manifold Material: High-quality cast aluminum specifically ported for Type 4 heads.
• Linkage Type: Heavy-duty hex-bar linkage system for precise throttle synchronization.
• Fuel Requirement: Requires a regulated fuel pressure of 3.0 to 3.5 PSI.
• Vent Tube: Integrated brass anti-slosh vent tubes for off-road and racing stability.
• Vacuum Ports: Dedicated ports for vacuum advance distributor compatibility.
• Air Filters: High-flow chrome top assemblies with washable gauze elements included.
• Hardware: Includes all necessary gaskets, studs, and mounting hardware for a complete installation.

PRO TIPS

Tip 1: Precise Fuel Pressure is Mandatory. One of the most common mistakes when installing the EMPI 40K kit is relying on the stock mechanical fuel pump without a regulator. These carburetors are highly sensitive to fuel pressure; anything over 3.5 PSI can overcome the needle and seat, leading to flooding, poor idling, and potential engine damage. We strongly recommend installing a high-quality adjustable fuel pressure regulator and a gauge to lock in a steady 3.0 PSI. This ensures the float bowls stay at the correct level, providing consistent fueling across the entire RPM range.

Tip 2: Synchronize for Success. To get that "sewing machine" smooth idle, you must synchronize the airflow between the two carburetors using a high-quality snail-style Uni-Syn or electronic flow meter. Don''t rely on just the linkage adjustments. First, disconnect the linkage rods and adjust the idle bypass screws and idle speed screws until both carburetors pull the exact same volume of air at idle. Only once the carbs are balanced should you reconnect and adjust the linkage rods. This prevents "clashing" between the banks and ensures instantaneous throttle response without the engine stumbling.

Tip 3: Account for Heat Soak in Type 4 Engines. Type 4 engines, especially in the cramped engine bays of a Bus, generate significant heat. When installing your dual carb kit, ensure that your fuel lines are routed away from the cylinder heads and exhaust manifold. Use high-quality insulated fuel line or fire-sleeve protection. Additionally, ensure your engine tin is complete and sealed; any missing tinware will allow hot air from the cylinders to rise and heat the carburetor bodies, which can lead to vapor lock or "percolation" of the fuel in the bowls after the engine is shut off.