Closer Look: Race Pumps Reinvents the Mechanical Fuel Pump

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Consider the mechanical fuel pump. It hangs off the side of your engine and does its thing: moving fuel from the tank up to your carburetor. The mechanical pump is simple, reliable—and thanks to Race Pumps, totally obsolete.

Race Pumps has engineered a better way to deliver fuel—a reciprocating-piston, variable displacement design that delivers the exact amount of fuel required without causing wild pressure fluctuations or fuel starvation at high rpms. The Race Pumps fuel pump has fewer moving parts, is rebuildable, and uses less engine power than traditional mechanical pumps and even electric fuel pumps.

Inside a Diaphragm Fuel Pump
The basic design of the conventional mechanical fuel pump hasn’t changed much since the ’40s. A flexible diaphragm acts on a chamber inside the pump; check valves at the chamber’s inlet and outlet ports force the fuel to flow in one direction only. A lever on the pump fits onto an eccentric lobe on the camshaft (some pumps have a pushrod between the lever and the cam eccentric). As the cam spins, it moves the lever and pulls the diaphragm down. This increases the size of the pump chamber and draws fuel into the pump. As the diaphragm pushes up to top dead center (aided by a diaphragm spring) the fuel is forced out of the chamber and into the feed line to the carburetor. Fuel pressure is regulated by the force applied by the diaphragm spring.

The diaphragm fuel pump’s design has several disadvantages. There are many moving parts that can wear out, mainly the diaphragm, diaphragm return spring, and the pump lever. These moving parts create heat, which can turn liquid fuel into a vapor. This in turn leads to the dreaded condition known as vapor lock, where fuel starvation literally shuts down the engine as it can’t burn vapor, only liquid fuel.

Diaphragm pumps are constant pressure pumps, which means they deliver the same amount of fuel regardless of how much the engine actually needs. That requires plumbing a bypass fuel regulator or a return line to send unused fuel back to the tank. Finally, the heavy diaphragm return spring can put as much as 125 psi of force on the pushrod. That accelerates wear on the pushrod and the cam’s eccentric lobe and takes a good chunk of engine horsepower to operate. And a few horsepower can make the difference between winning and losing.

Inside the Race Pump
As mentioned before, the Race Pump fuel pump is a variable displacement, piston-operated design. It has a “floating” O-ring valve that continually adjusts to the engine’s fuel demands, so the Race Pump delivers only as much fuel as the engine can actually use. You can see how the pump operates in this animation.

The Race Pump is far more efficient than an old-fashioned diaphragm fuel pump. Here are some of the pump's other big advantages:
• 450 gph free flow rating
• Can support from 200 to 2,500 horsepower
• High capacity eliminates high rpm fuel starvation
• Generates just 25 psi of pushrod pressure—uses less horsepower
• Does not add heat to the fuel—reduces chances of vapor lock
• Eliminates the need for a bypass regulator or return line
• Simple design means fewer parts to wear out
• Compact design allows more chassis clearance

One other important advantage of the Race Pumps' fuel pump is how it improves fuel flow quality. The pump’s piston design delivers fuel that is dead-nuts consistent in both volume and pressure at all rpms. That steady delivery means the fuel pressure regulator has an easier time maintaining the proper pressure level. The result is smooth, consistent fuel flow to the carburetors (or injectors on EFI engines), which allows the engine to operate more efficiently and predictably. If you’ve ever had an engine hiccup at high rpm because of a drop in fuel pressure or volume, you know how cool this is.

The Race Pumps' fuel pump is currently available in versions for small block Chevy, big block Chevy, and small block Ford. Versions for 429/460 Ford, small block Chrysler, and big block Chrysler should be available in early 2008. The pump’s stainless steel internal bits means it is compatible with gasoline, ethanol, E85, and methanol; the housing is durable hard-anodized billet aluminum. You can even refresh your Race Pump with an inexpensive rebuild kit, available directly from Race Pumps.

Race Pumps Fuel Pressure Regulators
The Race Pumps' fuel pumps put out some serious pressure in unregulated form; the pump for carburetors is rated at 50 psi, and the EFI pump is rated at a whopping 150 psi. Needless to say, they require a serious fuel pressure regulator to keep that output under control. Race Pump happens to have one. The aptly named Race Pumps fuel pressure regulator is the only one designed specifically for use with the company’s fuel pumps. It features a lightweight ceramic valve and a high-tension spring. The combination ensures smooth, rock-steady fuel pressure at all rpms—no more pressure fluctuation or “creep“ that can play havoc with fuel delivery, especially on a nitrous or supercharged engine. The Race Pumps regulator can also be vacuum-referenced at a 1:1 ratio with engine vacuum. That helps reduce surging at idle and sudden pressure drops when you get off the throttle at high rpm.

The Race Pumps regulator also features a big 1/2 inch NPT inlet and two 3/8 inch NPT outlets—no worries about fuel starvation due to pipes that are too small. The regulator is available in versions for carburetors (7-15 psi) and EFI (45-75 psi) running either gasoline or methanol. You can get the regulator with an idle bleed to drop fuel pressure at idle; Race Pumps even makes a boost-reference regulator for forced induction applications that increases fuel pressure at a 1:1 ratio with boost pressure.

Yes, a Race Pumps fuel pump and regulator combo is more expensive than a conventional mechanical setup. But consider that the about the only way to match the flow potential of a bolt-on Race Pumps setup is with a high-flow electric fuel pump and all of its attendant plumbing, wiring, and packaging problems. Factor in Race Pumps’ reliable fuel delivery, lower power consumption, and near-bulletproof construction, and it starts to look like almost like a bargain.