36mm Venturi, for 45 Dcoe Weber Carburetors

Overview

When it comes to fine-tuning a high-performance air-cooled engine, the venturi is the absolute heart of your induction system. This EMPI 36mm Main Venturi for Weber 45 DCOE carburetors is designed for the serious enthusiast who understands that "off-the-shelf" is rarely "perfect." In the world of side-draft carburetors, the venturi (or choke) dictates the velocity of the air as it passes through the carburetor barrel. By selecting this 36mm size, you are optimizing your 45 DCOE for a specific power band, typically favoring a robust mid-range and top-end pull without sacrificing the signal strength required to pull fuel from the main circuit. Whether you are running a high-revving 1914cc or a torque-heavy 2276cc, swapping your venturis allows you to tailor the engine''s personality to your specific driving needs, ensuring that you don''t suffer from the "bogging" associated with oversized chokes or the "choking" associated with undersized ones.

Crafted with precision to meet the exacting standards of the EMPI performance line, this 36mm venturi is a direct replacement for original Weber components or EMPI HPMX/DCOE equivalents. The smooth internal taper is engineered to minimize turbulence, allowing for a laminar flow that maximizes CFM (Cubic Feet per Minute) while maintaining enough vacuum to keep the fuel atomized perfectly. This is particularly crucial for Volkswagen Beetle, Karmann Ghia, and Bus owners who utilize side-draft setups for low-profile engine bays or racing applications. Don''t let a mismatched intake setup hold back your dual-carbureted beast. Upgrading to the correct venturi size is often the "missing link" in achieving that elusive, perfect spark plug color and a throttle that snaps to attention the moment you bury your right foot. Sold individually, these are a must-have for any tuner''s jetting box.

Fitment

This 36mm Main Venturi is designed specifically for the following carburetor models and applications:

• Carburetor Models: Genuine Weber 45 DCOE, EMPI 45 DCOE, and other high-quality 45mm side-draft clones.
• VW Type 1: Beetle, Super Beetle, and Karmann Ghia equipped with side-draft manifolds.
• VW Type 2: Bus, Transporter, and Westfalia models (1950-1979) utilizing performance dual 45 DCOE setups.
• VW Type 3: Squareback, Fastback, and Notchback models where low-profile side-drafts are required.
• Custom Builds: Sand rails, buggies, and trikes running air-cooled Type 1 or Type 4 upright conversions with side-draft induction.
• Engine Displacements: Typically recommended for 1835cc, 1914cc, 2017cc, 2110cc, 2276cc, and 2332cc engines depending on cam profile and head flow.

Technical Specifications

• Internal Diameter: 36mm (The "Choke" size).
• External Diameter: Precision machined to fit 45mm DCOE carburetor bodies.
• Material: High-grade die-cast alloy for thermal stability and corrosion resistance.
• Component Type: Main Venturi (Removable).
• Part Number: 43-5615-0.
• Quantity: Sold Each (2 required per carburetor, 4 required for a dual-carb setup).
• Finish: Natural machined alloy for smooth airflow transition.

Pro Tips from the Appletree Garage

Tip 1: The 4mm Rule for Street Performance

When selecting a venturi for your Weber 45 DCOE, a general rule of thumb for a high-performance street engine is to choose a venturi size that is roughly 4mm to 6mm smaller than the throttle plate diameter. Since you are using a 45mm carburetor, this 36mm venturi sits right in the "sweet spot" for large-displacement street engines. It provides enough airflow to support high RPMs while maintaining a high enough air velocity at lower speeds to prevent the "lazy" throttle response often found when people jump straight to a 38mm or 40mm venturi on an engine that can''t breathe that much air.

Tip 2: Proper Seating and Alignment

During installation, it is absolutely vital that the venturi is seated completely flush against the internal shoulder of the carburetor barrel. We often see tuners struggle with erratic idling or "popping" through the carb because the venturi set screw was tightened before the venturi was fully home. Always ensure the locking screw and its associated nut are tightened securely, but don''t over-torque them, as you can distort the carb body. Use a small amount of light oil on the outer surface of the venturi to help it slide into position without galling the aluminum body of your Weber.

Tip 3: Synchronization is Key

Whenever you change the venturi size in your carburetors, you are fundamentally changing the air-to-fuel ratio and the vacuum signal seen by the jets. You MUST re-synchronize your carburetors using a high-quality snail-type flow meter after installation. Changing to a 36mm venturi will likely require a change in your Main Jet and Air Corrector Jet sizes to compensate for the increased airflow. If you are moving up from a 34mm venturi, expect to go up a few steps on your main jets to keep your air-fuel mixture from leaning out at wide-open throttle.