ABOUT US

Forty years ago Pierce Manifolds Inc. built its first manifold for installing a Weber DGV carburetor the MGB... Fast forward Pierce Manifolds Inc today has the largest Weber carburetor/ parts in the world. Pierce Manifolds Inc is also the world's largest manufacturer of intake manifolds for

Weber carburetors. PMI also offers restoration on vintage carburetors. We have restored over 7000 Webers to date.   

Edoardo Weber began his automotive career working for Fiat, first at their Turin plant (in 1914) and later at a dealership in Bologna. After the war, with gasoline prices high, he reached a certain success in selling conversion kits for running trucks on kerosene instead.[1] The company was established as Fabbrica Italiana Carburatori Weber in 1923 when Weber produced carburetors as part of a conversion kit for Fiats. Weber pioneered the use of two-stage twin barrel carburetors, with two venturis of different sizes, the smaller one for low speed running and the larger one optimised for high speed use. In the 1930s Weber began producing twin-barrel carburetors for motor racing where two barrels of the same size were used. These were arranged so that each cylinder of the engine has its own carburetor barrel. These carburetors found use in Maserati and Alfa Romeo racing cars. Twin updraught Webers fed superchargers on the 1938 Alfa Romeo 8C competition vehicles.[2] After Weber's death in 1945, Fiat finally assumed control of the company in 1952. In time, they were fitted to standard production cars and factory racing applications on automotive marques such as Abarth, Alfa Romeo, Aston Martin, BMW, Chrysler, Ferrari, Fiat, Ford, Lamborghini, Lancia, Lotus, Maserati, Morgan, Porsche, Renault, Triumph and Volkswagen. In 1986, Fiat also took control of Weber's competitor Solex, and merged the two into a single company (Raggruppamento Controllo Motore, or the "Engine Management Group"). This was then reorganized as Magneti Marelli Powertrain S.p.A. in 2001.[1] Genuine they were produced in Bologna, Italy up until 1992, when production was transferred to Madrid, Spain, where they continue to be produced today. They are sold for both street and off-road use, with the twin choke sidedraught DCOE being the most common one. They are sold in what is referred to as a Weber Conversion kit. A Weber conversion kit is a complete package of them, intake manifold or manifold adapter, throttle linkage, air filter and all of the necessary hardware needed to install the Weber on a vehicle. In modern times, fuel injection has replaced carburetors in both production cars and most modern motor racing, although they are still used extensively in classic and historic racing. They are also supplied as high quality replacements for problematic OEM carburetors. Weber fuel system components are distributed by Magneti Marelli, Webcon UK Ltd., and, in North America, by several organizations, including Worldpac, marketing under the Redline name. Other suppliers include Overseas Distributing and Pierce Manifolds are marked with a model code on the mounting flange, the body, or on the cover of the float-chamber.[3] This begins with a number which originally indicated the diameter (in millimetres) of the throttle bore, but later lost this significance. If this number has a single pair of digits, both chokes are of the same diameter and operate together; if it has two pairs of digits separated by a stroke (e.g. 28/36), there are primary and secondary chokes that are opened one after the other, usually of differing diameter.[4] These numbers are followed by a group of letters, which indicates various features: the DCOE is a sidedraught unit, all others being downdraught; the DCD has a piston-type starter valve as opposed to a strangler choke; and so on.[5] After the letters there will be a further number, which may be followed by a letter, e.g. 4B, 13A; these indicate the series.[6] The full designation might be 40 DCOE 29, 45 DCOE 9, etc The invention of mechanical injection for gasoline-fueled aviation engines was by the French inventor of the V8 engine configuration, Leon Levavasseur in 1902.[2] Levavasseur designed the original Antoinette firm's series of V-form aircraft engines, starting with the Antoinette 8V to be used by the aircraft the Antoinette firm built that Levavasseur also designed, flown from 1906 to the firm's demise in 1910, with the world's first V16 engine, using Levavasseur's direct injection and producing around 100 hp (75 kW; 101 PS) flying an Antoinette VII monoplane in 1907. The first post-World War I example of direct gasoline injection was on the Hesselman engine invented by Swedish engineer Jonas Hesselman in 1925.[7][8] Hesselman engines used the ultra-lean-burn principle and injected the fuel in the end of the compression stroke and then ignited it with a spark plug, it was often started on gasoline and then switched over to run on diesel or kerosene. The Hesselman engine was a low compression design constructed to run on heavy fuel oils. Direct gasoline injection was applied during the Second World War to almost all higher-output production aircraft powerplants made in Germany (the widely used BMW 801 radial, and the popular inverted inline V12 Daimler-Benz DB 601, DB 603, and DB 605, along with the similar Junkers Jumo 210G, Jumo 211, and Jumo 213, starting as early as 1937 for both the Jumo 210G and DB 601), the Soviet Union (Shvetsov ASh-82FN radial, 1943, Chemical Automatics Design Bureau - KB Khimavtomatika) and the USA (Wright R-3350 Duplex Cyclone radial, 1944). Immediately following the war, hot rodder Stuart Hilborn started to offer mechanical injection for race cars, salt cars, and midget racers,[9] well-known and easily distinguishable because of their prominent velocity stacks projecting upwards from the engines on which they were used. The first automotive direct injection system used to run on gasoline was developed by Bosch, and was introduced by Goliath for their Goliath GP700 automobile, and Gutbrod in 1952. This was basically a high-pressure diesel direct-injection pump with an intake throttle valve. (Diesels only change the amount of fuel injected to vary output; there is no throttle.) This system used a normal gasoline fuel pump, to provide fuel to a mechanically driven injection pump, which had separate plungers per injector to deliver a very high injection pressure directly into the combustion chamber. The 1954 Mercedes-Benz W196 Formula 1 racing car engine used Bosch direct injection derived from wartime aircraft engines. Following this racetrack success, the 1955 Mercedes-Benz 300SL, the first production sports car to use fuel injection, used direct injection. The 1955 Mercedes-Benz 300SLR, in which Stirling Moss drove to victory in the 1955 Mille Miglia and Pierre Levegh crashed and died in the 1955 Le Mans disaster, had an engine developed from the W196 engine. The Bosch fuel injectors were placed into the bores on the cylinder wall used by the spark plugs in other Mercedes-Benz six-cylinder engines (the spark plugs were relocated to the cylinder head). Later, more mainstream applications of fuel injection favored the less-expensive indirect injection methods. Chevrolet introduced a mechanical fuel injection option, made by General Motors' Rochester Products Division, for its 283 V8 engine in 1956 (1957 U.S. model year). This system directed the inducted engine air across a "spoon shaped" plunger that moved in proportion to the air volume. The plunger connected to the fuel metering system that mechanically dispensed fuel to the cylinders via distribution tubes. This system was not a "pulse" or intermittent injection, but rather a constant flow system, metering fuel to all cylinders simultaneously from a central "spider" of injection lines. The fuel meter adjusted the amount of flow according to engine speed and load, and included a fuel reservoir, which was similar to a carburetor's float chamber. With its own high-pressure fuel pump driven by a cable from the distributor to the fuel meter, the system supplied the necessary pressure for injection. This was a "port" injection where the injectors are located in the intake manifold, very near the intake valve. In 1956, Lucas developed its injection system, which was first used for Jaguar racing cars at Le Mans. The system was subsequently adopted very successfully in Formula One racing, securing championships by Cooper, BRM, Lotus, Brabham, Matra, and Tyrrell in the years 1959 through 1973.[10] While the racing systems used a simple fuel cam for metering, a more sophisticated Mk 2 vacuum based shuttle metering was developed for production cars. This mechanical system was used by some Maserati, Aston Martin, and Triumph models between 1963 and 1975.[11] During the 1960s, other mechanical injection systems such as Hilborn were occasionally used on modified American V8 engines in various racing applications such as drag racing, oval racing, and road racing.[12] These racing-derived systems were not suitable for everyday street use, having no provisions for low speed metering, or often none even for starting (starting required that fuel be squirted into the injector tubes while cranking the engine). However, they were a favorite in the aforementioned competition trials in which essentially wide-open throttle operation was prevalent. Constant-flow injection systems continue to be used at the highest levels of drag racing, where full-throttle, high-RPM performance is key.[13] In 1967, one of the first Japanese designed cars to use mechanical fuel injection was the Daihatsu Compagno. Another mechanical system, made by Bosch called Jetronic, but injecting the fuel into the port above the intake valve, was used by several European car makers, particularly Porsche from 1969 until 1973 in the 911 production range and until 1975 on the Carrera 3.0 in Europe. Porsche continued using this system on its racing cars into the late seventies and early eighties. Porsche racing variants such as the 911 RSR 2.7 & 3.0, 904/6, 906, 907, 908, 910, 917 (in its regular normally aspirated or 5.5 Liter/1500 HP turbocharged form), and 935 all used Bosch or Kugelfischer built variants of injection. The early Bosch Jetronic systems were also used by Audi, Volvo, BMW, Volkswagen, and many others. The Kugelfischer system was also used by the BMW 2000/2002 Tii and some versions of the Peugeot 404/504 and Lancia Flavia. A system similar to the Bosch inline mechanical pump was built by SPICA for Alfa Romeo, used on the Alfa Romeo Montreal and on U.S. market 1750 and 2000 models from 1969 to 1981. This was designed to meet the U.S. emission requirements with no loss in performance and it also reduced fuel consumption. Electronic injection Because mechanical injection systems have limited adjustments to develop the optimal amount of fuel into an engine that needs to operate under a variety of different conditions (such as when starting, the engine’s speed and load, atmospheric and engine temperatures, altitude, ignition timing, etc.) electronic fuel injection (EFI) systems were developed that relied on numerous sensors and controls. When working together, these electronic components can sense variations and the main system computes the appropriate amount of fuel needed to achieve better engine performance based on a stored "map" of optimal settings for given requirements.[14] The first commercial EFI system was the Electrojector, developed by the Bendix Corporation and was offered by American Motors Corporation (AMC) in 1957.[15][16] The Rambler Rebel, showcased AMC's new 327 cu in (5.4 L) engine. The Electrojector was an option and rated at 288 bhp (214.8 kW).[17] The EFI produced peak torque 500 rpm lower than the equivalent carburetored engine[12] The Rebel Owners Manual described the design and operation of the new system.[18] (due to cooler, therefore denser, intake air[citation needed]). The cost of the EFI option was US$395 and it was available on 15 June 1957.[19] Electrojector's teething problems meant only pre-production cars were so equipped: thus, very few cars so equipped were ever sold[20] and none were made available to the public.[21] The EFI system in the Rambler ran fine in warm weather, but suffered hard starting in cooler temperatures.[19] Chrysler offered Electrojector on the 1958 Chrysler 300D, DeSoto Adventurer, Dodge D-500, and Plymouth Fury, arguably the first series-production cars equipped with an EFI system. It was jointly engineered by Chrysler and Bendix. The early electronic components were not equal to the rigors of underhood service, however, and were too slow to keep up with the demands of "on the fly" engine control. Most of the 35 vehicles originally so equipped were field-retrofitted with 4-barrel carburetors. The Electrojector patents were subsequently sold to Bosch. Bosch developed an electronic fuel injection system, called D-Jetronic (D for Druck, German for "pressure"), which was first used on the VW 1600TL/E in 1967. This was a speed/density system, using engine speed and intake manifold air density to calculate "air mass" flow rate and thus fuel requirements. This system was adopted by VW, Mercedes-Benz, Porsche, Citroën, Saab, and Volvo. Lucas licensed the system for production in Jaguar cars, initially in D-Jetronic form before switching to L-Jetronic in 1978 on the XK6 engine. Bosch superseded the D-Jetronic system with the K-Jetronic and L-Jetronic systems for 1974, though some cars (such as the Volvo 164) continued using D-Jetronic for the following several years. In 1970, the Isuzu 117 Coupé was introduced with a Bosch-supplied D-Jetronic fuel injected engine sold only in Japan. In 1984 Rover fitted Lucas electronic fuel injection, which was based on some L-Jetronic patents, to the S-Series engine as used in the 200 model. In Japan, the Toyota Celica used electronic, multi-port fuel injection in the optional 18R-E engine in January 1974.[22] Nissan offered electronic, multi-port fuel injection in 1975 with the Bosch L-Jetronic system used in the Nissan L28E engine and installed in the Nissan Fairlady Z, Nissan Cedric, and the Nissan Gloria. Nissan also installed multi-point fuel injection in the Nissan Y44 V8 engine in the Nissan President. Toyota soon followed with the same technology in 1978 on the 4M-E engine installed in the Toyota Crown, the Toyota Supra, and the Toyota Mark II. In the 1980s, the Isuzu Piazza and the Mitsubishi Starion added fuel injection as standard equipment, developed separately with both companies history of diesel powered engines. 1981 saw Mazda offer fuel injection in the Mazda Luce with the Mazda FE engine and, in 1983, Subaru offered fuel injection in the Subaru EA81 engine installed in the Subaru Leone. Honda followed in 1984 with their own system, called PGM-FI in the Honda Accord, and the Honda Vigor using the Honda ES3 engine. The limited production Chevrolet Cosworth Vega was introduced in March 1975 using a Bendix EFI system with pulse-time manifold injection, four injector valves, an electronic control unit (ECU), five independent sensors, and two fuel pumps. The EFI system was developed to satisfy stringent emission control requirements and market demands for a technologically advanced responsive vehicle. 5000 hand-built Cosworth Vega engines were produced but only 3,508 cars were sold through 1976.[23] The Cadillac Seville was introduced in 1975 with an EFI system made by Bendix and modelled very closely on Bosch's D-Jetronic. L-Jetronic first appeared on the 1974 Porsche 914, and uses a mechanical airflow meter (L for Luft, German for "air") that produces a signal that is proportional to "air volume". This approach required additional sensors to measure the atmospheric pressure and temperature, to ultimately calculate "air mass". L-Jetronic was widely adopted on European cars of that period, and a few Japanese models a short time later. In 1980, Motorola (now NXP Semiconductors) introduced the first electronic engine control unit, the EEC-III.[24] Its integrated control of engine functions (such as fuel injection and spark timing) is now the standard approach for fuel injection systems. The Motorola technology was installed in Ford North American products. In the 1970s and 1980s in the U.S. and Japan, the respective federal governments imposed increasingly strict exhaust emission regulations. During that time period, the vast majority of gasoline-fueled automobile and light truck engines did not use fuel injection. To comply with the new regulations, automobile manufacturers often made extensive and complex modifications to the engine carburetor(s). While a simple carburetor system is cheaper to manufacture than a fuel injection system, the more complex carburetor systems installed on many engines in the 1970s were much more costly than the earlier simple carburetors. To more easily comply with emissions regulations, automobile manufacturers began installing fuel injection systems in more gasoline engines during the late 1970s. Open-loop fuel injection systems had already improved cylinder-to-cylinder fuel distribution and engine operation over a wide temperature range, but did not offer further scope to sufficient control fuel/air mixtures, in order to further reduce exhaust emissions. Later closed-loop fuel injection systems improved the air–fuel mixture control with an exhaust gas oxygen sensor. Although not part of the injection control, a catalytic converter further reduces exhaust emissions. Fuel injection was phased in through the latter 1970s and 80s at an accelerating rate, with the German, French, and U.S. markets leading and the UK and Commonwealth markets lagging somewhat. Since the early 1990s, almost all gasoline passenger cars sold in first world markets are equipped with electronic fuel injection (EFI). The carburetor remains in use in developing countries where vehicle emissions are unregulated and diagnostic and repair infrastructure is sparse. Fuel injection is gradually replacing carburetors in these nations too as they adopt emission regulations conceptually similar to those in force in Europe, Japan, Australia, and North America. Many motorcycles still utilize carburetored engines, though all current high-performance designs have switched to EFI. NASCAR finally replaced carburetors with fuel-injection, starting at the beginning of the 2012 NASCAR Sprint Cup Series season. In the 1970s and 1980s in the U.S. and Japan, the respective federal governments imposed increasingly strict exhaust emission regulations. During that time period, the vast majority of gasoline-fueled automobile and light truck engines did not use fuel injection. To comply with the new regulations, automobile manufacturers often made extensive and complex modifications to the engine carburetor(s). While a simple carburetor system is cheaper to manufacture than a fuel injection system, the more complex carburetor systems installed on many engines in the 1970s were much more costly than the earlier simple carburetors. To more easily comply with emissions regulations, automobile manufacturers began installing fuel injection systems in more gasoline engines during the late 1970s. Open-loop fuel injection systems had already improved cylinder-to-cylinder fuel distribution and engine operation over a wide temperature range, but did not offer further scope to sufficient control fuel/air mixtures, in order to further reduce exhaust emissions. Later closed-loop fuel injection systems improved the air–fuel mixture control with an exhaust gas oxygen sensor. Although not part of the injection control, a catalytic converter further reduces exhaust emissions. Fuel injection was phased in through the latter 1970s and 80s at an accelerating rate, with the German, French, and U.S. markets leading and the UK and Commonwealth markets lagging somewhat. Since the early 1990s, almost all gasoline passenger cars sold in first world markets are equipped with electronic fuel injection (EFI). The carburetor remains in use in developing countries where vehicle emissions are unregulated and diagnostic and repair infrastructure is sparse. Fuel injection is gradually replacing carburetors in these nations too as they adopt emission regulations conceptually similar to those in force in Europe, Japan, Australia, and North America. Many motorcycles still utilize carburetored engines, though all current high-performance designs have switched to EFI. NASCAR finally replaced carburetors with fuel-injection, starting at the beginning of the 2012 NASCAR Sprint Cup Series season. System overview The process of determining the necessary amount of fuel, and its delivery into the engine, are known as fuel metering. Early injection systems used mechanical methods to meter fuel, while nearly all modern systems use electronic metering. Determining how much fuel to supply The primary factor used in determining the amount of fuel required by the engine is the amount (by weight) of air that is being taken in by the engine for use in combustion. Modern systems use a mass airflow sensor to send this information to the engine control unit. Data representing the amount of power output desired by the driver (sometimes known as "engine load") is also used by the engine control unit in calculating the amount of fuel required. A throttle position sensor (TPS) provides this information. Other engine sensors used in EFI systems include a coolant temperature sensor, a camshaft or crankshaft position sensor (some systems get the position information from the distributor), and an oxygen sensor which is installed in the exhaust system so that it can be used to determine how well the fuel has been combusted, therefore allowing closed loop operation. Supplying the fuel to the engine Fuel is transported from the fuel tank (via fuel lines) and pressurised using fuel pump(s). Maintaining the correct fuel pressure is done by a fuel pressure regulator. Often a fuel rail is used to divide the fuel supply into the required number of cylinders. The fuel injector injects liquid fuel into the intake air (the location of the fuel injector varies between systems). Unlike carburetor-based systems, where the float chamber provides a reservoir, fuel injected systems depend on an uninterrupted flow of fuel. To avoid fuel starvation when subject to lateral G-forces, vehicles are often provided with an anti-surge vessel, usually integrated in the fuel tank, but sometimes as a separate, small anti-surge tank. EFI gasoline engine components Single-point injection Single-point injection (SPI) uses a single injector at the throttle body (the same location as was used by carburetors). It was introduced in the 1940s in large aircraft engines (then called the pressure carburetor) and in the 1980s in the automotive world (called Throttle-body Injection by General Motors, Central Fuel Injection by Ford, PGM-CARB by Honda, and EGI by Mazda). Since the fuel passes through the intake runners (like a carburetor system), it is called a "wet manifold system". The justification for single-point injection was low cost. Many of the carburetor's supporting components - such as the air cleaner, intake manifold, and fuel line routing - could be reused. This postponed the redesign and tooling costs of these components. Single-point injection was used extensively on American-made passenger cars and light trucks during 1980-1995, and in some European cars in the early and mid-1990s. Continuous injection In a continuous injection system, fuel flows at all times from the fuel injectors, but at a variable flow rate. This is in contrast to most fuel injection systems, which provide fuel during short pulses of varying duration, with a constant rate of flow during each pulse. Continuous injection systems can be multi-point or single-point, but not direct. The most common automotive continuous injection system is Bosch's K-Jetronic, introduced in 1974. K-Jetronic was used for many years between 1974 and the mid-1990s by BMW, Lamborghini, Ferrari, Mercedes-Benz, Volkswagen, Ford, Porsche, Audi, Saab, DeLorean, and Volvo. Chrysler used a continuous fuel injection system on the 1981-1983 Imperial. In piston aircraft engines, continuous-flow fuel injection is the most common type. In contrast to automotive fuel injection systems, aircraft continuous flow fuel injection is all mechanical, requiring no electricity to operate. Two common types exist: the Bendix RSA system, and the TCM system. The Bendix system is a direct descendant of the pressure carburetor. However, instead of having a discharge valve in the barrel, it uses a flow divider mounted on top of the engine, which controls the discharge rate and evenly distributes the fuel to stainless steel injection lines to the intake ports of each cylinder. The TCM system is even more simple. It has no venturi, no pressure chambers, no diaphragms, and no discharge valve. The control unit is fed by a constant-pressure fuel pump. The control unit simply uses a butterfly valve for the air, which is linked by a mechanical linkage to a rotary valve for the fuel. Inside the control unit is another restriction, which controls the fuel mixture. The pressure drop across the restrictions in the control unit controls the amount of fuel flow, so that fuel flow is directly proportional to the pressure at the flow divider. In fact, most aircraft that use the TCM fuel injection system feature a fuel flow gauge that is actually a pressure gauge calibrated in gallons per hour or pounds per hour of fuel. .