Text by Jim Mozart
Photos by Moore Good Ink
First, unlike any other, this fuel pump has a variable-speed motor. Hence it can deliver prodigious amounts of fuel at fully open throttle and minimal amounts at idle. Its variable-speed ability overcomes the chief trouble with big, powerful, high-flow single-speed fuel pumps—heat. Because high flow pumps work just as hard at idle as at fully open throttle they become hot at slow engine speeds and consequently overheat the fuel. Often they eventually self-destruct as a result.
|Second, unlike any other, this fuel pump is of DC (direct current) brushless design. Therefore current draw is significantly reduced and brush wear and brush drag are eradicated. For the uninitiated, an electric motor spins by way of a set of brushes that ride against a commutator on an armature. As voltage is applied to the brushes, it causes the armature to spin. Sound simple? It really is. However there are some problems with that design. In a brush-type motor, the brushes are constantly in contact with the spinning armature. As such, there is a small amount of drag on the armature at all times. In addition, the friction created by the contact also creates heat. Heat is not a desirable attribute in an electric fuel pump motor. In addition to this, a DC brush motor is only capable of operating at one speed. In the case of an electric fuel pump, this means the motor will continue to spin at the same speed and provide the same amount of fuel flow at all times—whether the engine is operating at fully open throttle or at idle. Thus the use of a fuel regulator is necessary to stop the flow of fuel at times when fuel is not required. One of two things happens at this point. Either the pump becomes “dead-headed” or if a bypass-return type fuel regulator is used, the surplus fuel will be returned to the tank by way of a bypass line. In a “dead-head” condition, the electric pump will actually be held in an almost “stalled” condition. Although the motor will still be spinning, fuel pressure builds, placing a severe load on the electric motor. In a bypass condition, the pump will continue to spin at its normal rpm; however, there still remains the concern of friction and heat. Enter brushless motors. Brushless motors have a fixed armature inside. As voltage is fed to the armature it creates a magnetic field, which causes a set of magnets and rotor to spin. Brushless motors offer several advantages. Because there are no windings on the rotor, and with no friction involved such as with a brush-type motor, heat is held to a minimum. With little or no heat generated none of it can be transferred to the fuel. All of this means the motor housing can be fully enclosed to protect it from dirt or other undesirable matter. Unlike a conventional electric motor which operates with a commutator and brushes, a brushless fuel pump eliminates brush drag and substantially diminishes amperage draw. Most importantly, however, it pioneers the variable-speed electric fuel pump.With over five years in its development, Fuelab has taken its patented, brushless, digital fuel delivery technology to a whole new level with the introduction of their Prodigy line of fuel pumps. When combined with the company’s new electronic fuel regulator, suddenly the variable-speed Prodigy becomes the first high-flow pump to supply the exact amount of fuel when necessary and in the amount necessary.However, this is a fuel pump which can be used just like any other, operating with any conventional dead-head or bypass-return style regulator. In fact, while operating with conventional regulators it can function at two speeds: high and low. Connect two 12-volt wires, a power and a ground, to the unit, while a third wire can be connected to a simple on-off switch. When the third wire is grounded, the fuel pump will adopt low-speed mode. Low-speed mode, in fact, can be induced automatically by using a throttle switch or a Hobbs switch.
Fuelab’s senior engineer Rob Scharfenberg says, “But the pump’s full capability cannot be fully appreciated until its united with either our electronic fuel regulator or an aftermarket ECU programmed to provide a signal to the pump’s third wire. When connected to either of these units only then can it demonstrate its technical virtuosity—its endless speed control.”
In instances where great amounts of fuel flow are needed, such as at fully open throttle, Fuelab’s Prodigy pump can do more than keep up with those demands. Designed for street-strip and drag race applications of up to 1,800 horsepower, the Prodigy pump can flow more than enough fuel to satisfy any engine’s appetite.
Fuelab’s award-winning electronic regulator is designed primarily for high boost fuel injected engines. Outwardly it resembles many other regulators on the market. But inside it reveals a unique and singular purpose. In the outlet port in the lower chamber resides a pressure transducer, which has the ability to monitor fuel pressure. At times when the fuel pressure remains constant, such as during idle or at low rpm, the transducer’s signal allows the fuel pump to operate at low-speed. This permits the pump to operate with low-current draw similar to that of a low output OEM fuel pump.
When the throttle is opened rapidly, fuel pressure has a tendency to drop, which provokes a signal to the pump, increasing its speed instantly. Scharfenberg says, “At fully open throttle, the regulator continually adjusts to find the minimum amount of flow needed. The pressure transducer senses the pressure on the restriction side of the regulator where the outlet port exits. If it senses the pressure is falling, it instructs the pump to increase flow. Conversely, if the pressure is too high, the transducer will direct the pump to slow down to decrease flow rate.
“Importantly, this reduces both heat build-up and current draw. The OEMs don’t worry too much about heat build-up,” Scharfenberg added, “because their flow rates are relatively low as is their current draw.”
But those who are well acquainted with high-flow electric fuel pumps will attest that current draw can be extreme and is usually predicated by the use of a relay to minimize high current draw through the attendant wires. Whether naturally aspirated with a carburetor, supercharged with a pressurized or unpressurized carburetor, or EFI with forced or unforced induction, Fuelab’s systems produce impressive flow rates and capacity with stable fuel pressure numbers. During testing, the company generated 75 psi with the Prodigy pump and electronic regulator with an amazing amount of stability both in flow and in pressure.