Fuel Pressure Optimization For Porsche's Pmo Carb

Porsche enthusiasts have been opting for PMO Carburetors since 1997, when they were first introduced. PMO is the original manufacturer of 911 carburetor conversions and is the only company in the world dedicated solely to providing such conversions. The PMO triple-throat carburetor is a significant improvement over the original Weber carb and manifold design. Complete upgrade kits, including manifolds, linkage, K&N® air cleaners, fuel lines, and hardware, are available for purchase. The fuel pressure for a PMO carb Porsche is not specified, however, it is important to note that each carburetor style has an optimal fuel pressure range. While the owner's manual will provide specific instructions, a Fuel Pressure Regulator can be used to adjust and maintain consistent fuel pressure.

PMO carburetor features and benefits

The PMO carburetor was designed to be a state-of-the-art carburetor. It offers a range of features and benefits, including:

• An enlarged throttle body size that improves airflow capacity compared to the original, which only offered an enlarged 46mm throttle plate. The PMO carburetor is available in three different sizes: 40mm, 46mm, and 50mm.
• A re-designed fuel inlet system that allows for a higher and more balanced flow rate with leak-free delivery compared to the OE banjo bolt set-up.
• The use of aerospace-quality materials and casting technology throughout, with precision-machined components for maximum flow and more exact tuning.
• One-piece stainless steel throttle shafts that are machined and micro-polished to a tolerance of .002” for a lifetime of smooth throttle action. The EDM cut slots deliver precise butterfly fitment and alignment for improved throttle response. Oversized ball bearings support the throttle shafts to eliminate binding and air leaks, improving performance over the OE carburetors.
• Compatibility with commercially available IDF floats and jets for maximum tunability and performance.
• Gaskets, diaphragms, and seals that are E85 compatible.
• An integrated fuel sight glass for safer and more efficient level setting, with no disassembly or special tools required for fine-tuning.
• An improved transition port design for superior off-idle performance.
• CNC-machined intake manifold runner dimensions offer improved flow characteristics and tunability compared to OE castings.

In comparison to Weber carburetors, the PMO induction carburetors offer several advantages. The PMO carburetors have an entirely enlarged throttle body, whereas the Weber carburetors only have an enlarged throttle plate. This means that the PMO carburetors have significantly improved airflow capabilities. Additionally, Weber never made a 50mm carburetor for large displacement or racing applications, while PMO offers this size.

The PMO induction carburetors also address several known issues with the Weber carburetors. The Weber carburetors suffer from throttle shaft wear, air leaks, and binding, leading to degrading throttle plate action and performance. The PMO carburetors utilize a one-piece, machined stainless steel throttle shaft supported by large ball bearings, ensuring a lifetime of smooth throttle action. The PMO carburetors also feature a sight glass float bowl, allowing for accurate fuel level setting without the need for partial carb disassembly, as is required with the Weber IDA method.

PMO vs Weber carburetors

PMO and Weber carburetors are both used in Porsche vehicles, but there are some key differences between the two. PMO carburetors are known for their improved drivability and performance compared to the original Weber carburetors. They offer a more enlarged throttle body size, which results in significantly improved airflow capacity. Additionally, PMO carburetors feature a redesigned fuel inlet system that allows for a higher and more balanced flow rate, as well as the use of aerospace-quality materials and casting technology.

On the other hand, Weber carburetors, such as the 46mm version, have a simpler design where only the throttle plate is enlarged. Weber also suffers from issues like throttle shaft wear, air leaks, and binding, which can degrade performance over time.

PMO carburetors address the issues found in Weber carburetors and offer several advantages. Firstly, they utilize a one-piece machined stainless steel throttle shaft supported by large ball bearings, ensuring smooth throttle action and reducing performance degradation. Secondly, PMO carburetors have a sight glass float bowl that allows for accurate fuel level settings without the need for partial carb disassembly, as seen in Weber IDA carburetors. Thirdly, PMO carburetors have an improved fuel inlet system that provides a higher flow capacity and reduces leakage issues commonly found in Weber carburetors. Lastly, PMO carburetors have internal components manufactured to tight tolerances, ensuring improved performance and even fuel and air metering, making tuning easier.

In summary, PMO carburetors build upon the architecture of Weber carburetors while simplifying and enhancing performance. They offer improved airflow capacity, better fuel flow rate and balance, smoother throttle action, and easier tuning. These advantages make PMO carburetors a popular choice for Porsche enthusiasts seeking enhanced performance and reliability.

PMO intake manifolds

To select the correct PMO intake manifold, you must first determine the base engine's year and displacement. The original fuel system on the engine type will dictate the manifold port shape, and then it is a matter of matching the port size and carb size desired. The PMO intake manifold sets include intake manifolds, gaskets, and hardware.

The PMO intake manifolds offer improved performance and tuning benefits over cast manifold runners. They are CNC-machined for highly accurate and consistent dimensions, resulting in improved flow characteristics. This precision also ensures even fuel and air metering between each stack, making tuning easier.

PMO carburetor packages

The PMO carburetor packages come in 40mm, 46mm, and 50mm sizes, catering to different engine displacements ranging from 2.0L to 3.8L. Each package includes an installation kit with components such as an insulator flange set, crossbar linkage set, power brake check valve, and a fuel pressure control unit.

The 40mm PMO carburetor package is offered for 2.0L to 2.8L engines, with options for both street and performance setups. The 46mm package is suitable for 2.8L to 3.4L engines, and the 50mm package caters to the largest engine displacements, from 3.5L to 4.0L.

In addition to the standard components, PMO offers a range of optional extras for custom tuning, including main and idle jets, emulsion tubes, and air correctors. PMO carburetor packages also feature enlarged throttle body sizes, re-designed fuel inlet systems, and precision-machined components made from aerospace-quality materials.

PMO's carburetor packages offer improved airflow capacity, balanced flow rates, and leak-free fuel delivery compared to original equipment. The one-piece stainless steel throttle shafts are designed for a lifetime of smooth throttle action and are supported by oversized ball bearings to eliminate binding and air leaks.

Recommended fuel pressure

Fuel pressure is a critical aspect of engine performance, and it's important to ensure that it is set correctly for your Porsche's PMO carburetor. While the specific fuel pressure recommendation for PMO carburetors in Porsches may not be publicly available, here is some general information about fuel pressure and recommendations for carbureted engines.

Each carburetor style performs best within a specific fuel pressure range, and you can refer to the owner's manual for your carburetor for specific set-up and tuning instructions. As a basic guideline, the fuel pressure for street engines and performance engines can vary. For example, Quadrajet street engines and Quadrajet performance engines will have different optimal fuel pressure settings.

Maintaining consistent fuel pressure is crucial, and this can be achieved using a Fuel Pressure Regulator. If the fuel pressure is too low, it can cause the fuel bowls to run dry. On the other hand, if the pressure is too high, it can force an excessive amount of fuel into the engine, leading to issues such as fouled spark plugs.

When it comes to PMO carburetors for Porsches, it's important to note that they are designed to meet the needs of both street and performance engines. PMO offers a range of carburetor sizes, from 40mm to 50mm, catering to engines from 2.0 to 3.6 litres. The PMO carburetor was designed with a larger throttle body, improved fuel inlet system, and precision-machined components, all of which contribute to enhanced airflow capacity and fuel delivery.

Complete PMO carburetor kits typically include pre-jetted and sized carburetors, manifolds, linkage, air cleaners, pressure control units, and other necessary components. It is important to have mechanical experience or expertise when ordering and installing these kits to ensure the correct specifications for your specific Porsche model and engine configuration.

In summary, the recommended fuel pressure for any carbureted engine, including those with PMO carburetors, will depend on the specific style and requirements of the carburetor. Referring to the owner's manual and seeking guidance from experienced mechanics are essential steps to ensure optimal engine performance and avoid potential issues related to incorrect fuel pressure settings.

Frequently asked questions