Tech Articles

1. After installing a larger (or secondary) fuel pump for my EFI engine, the fuel rail pressure went up and my regulator won't adjust it back down, what's wrong?

1. I'm looking at an Aeromotive EFI fuel pump for my new engine but I need 60 PSI and your website says it only puts out 43 PSI. Do you have one with more pressure?

1. I want to convert my EFI engine to a carburetor, how can I "knock the pressure down" coming out of my EFI pump? What Aeromotive regulator should I use for this?

1. I'm looking at an Aeromotive EFI fuel pump for my new carbureted engine, but I need 7 PSI and your catalog (or your website) says it puts out 43 PSI. Won't this flood the engine?

A crucial part of owning a performance engine is knowing the requirement for proper fuel flow and pressure, then researching to find a fuel system able to meet those requirements. Engine performance and reliability depend on this. After having invested in and installed a quality fuel system, to then find that the gauge is making fuel pressure appear out of control, unstable and unpredictable, is surprisingly common, not to mention alarming and frustrating.

Changing the fuel pressure on an EFI System is an effective method of affecting engine performance and making more power. However, there are many do's and don'ts, and rules of thumb that can be frustrating to learn the hard way. Below are many small but key points, tips and insights all "tuners" should know and understand before cranking on that Adjustable Regulator.

Today, the combination of EFI and modern engine technology have allowed us the freedom to create the ultimate street driven race car. Ordinary combinations produce 300-500 HP and the stock EFI fuel system has proven flexible enough to cover that, but hardcore engine combinations now exceed this easily, with 600-800 FWHP possible with bolt on parts and serious combinations between 800-1,400 FWHP. Go above 500-600 FWHP and we exceed the limits of a modified stock fuel system, requiring a complete fuel system makeover. The biggest obstacle to major upgrades is often the fuel tank itself. In the past, the debate often centered around whether to modify the stock tank or install a racing fuel cell. Today, many more options exist, thanks to a series of extraordinary product developments from Aeromotive.

CARBURETORS STILL RULE in many forms of racing and on many street machines and watercraft. Converting to EFI has obvious benefits but brings high cost, complexity and in many forms of racing isn't legal. Those who choose or are forced to run a carburetor are turning to expensive, custom-built models for better performance. Often the custom shop will advise a fuel pump upgrade, suggesting a fuel pump rated to support as much as 4-6 times engine horsepower. The reason given is the effect acceleration has on filling the float bowl, driving the standing fuel back against the pump, raising head pressure, killing volume and preventing flow. Seldom questioned is the static, stop-and-go nature of the system itself.

The first step in choosing the correct fuel pump for any engine is to establish how much horsepower will be made and the amount of fuel required to support it. To be safe, start by estimating HP on the high side and efficiency or BSFC for the fuel of choice on the low side. A typical gasoline engine will use less than 1lb of fuel to make 1 HP for 1 hour, so expect the BSFC number to be less than 1. Different engine combinations, power adders, opting for ethanol or methanol fuel, even fuel octane ratings and different tuning approaches, will have a profound impact on BSFC. Consider these factors carefully.

The Aeromotive Fuel Pump Speed Controller (FPSC) has built-in safeguards to protect itself and the engine. The integrated processor on the circuit board is programmed to continuously monitor certain operating conditions including current draw, operating voltage and RPM input. If key operating conditions should fall outside of expected parameters, the FPSC may default into self protect mode, shutting itself and the fuel pump off. When this occurs, all LED indicator lights on the FPSC will flash in unison.

The Aeromotive Fuel Pump Speed Controller (FPSC) uses a progressive speed control strategy, meaning as the engine RPM increases the fuel pump speeds up with it. Each new FPSC is fully tested from the factory and preset for full pump speed at 2,500 engine RPM. It's important to calibrate the high RPM set point for your unique engine combination. Since pump speed increases with the engine RPM, raising the RPM point for full speed still feeds the engine properly in the mid-range while vastly reducing the fuel recycle rate at idle and cruise to keep fuel cool during long drives.

All Aeromotive EFI Bypass Regulators allow intake manifold pressure, vacuum and boost, to affect the regulated fuel pressure. When a fuel pressure regulator is referenced to manifold pressure, it acts to mirror manifold pressure changes with equal changes in fuel rail pressure resulting in lower fuel rail pressure with manifold vacuum and higher fuel rail pressure with boost. The effect occurs on a 1:1 ratio, where the regulator raises and lowers fuel pressure in sync with the change in manifold pressure.

All Aeromotive Carburetor Bypass Regulators are designed to allow the regulated fuel pressure to be vacuum or boost referenced on a 1:1 ratio with PSI. The purpose of the boost reference feature is to ensure fuel pressure at the inlet of the needle-and-seat rises with boost, offsetting any air pressure opposing fuel flow at the outlet of the needle and seat, in the float bowl itself.

Guidelines for selecting the correct size Fuel Filter for the outlet side of your Aeromotive Fuel Pumps.

Guidelines for selecting the correct size Fuel Filter for the inlet side of your Aeromotive Fuel Pumps.

Selecting the correct fuel line hose is dependent on the type of application. Once selected, the right fuel line hose can help prevent premature failure and damage to other components.