If you drive a late-model Challenger, Charger, or 300, the fuel system in your car is a little different from the fuel systems we're used to in our older Mopars. Controlled by the car's onboard computer, the fuel system is likely the last part of the car you're concerned about, as modern fuel injection systems are a reliable and accurate way to deliver and meter fuel. Of course, fuel injection requires higher fuel pressure than a carburetor, so the fuel delivery system in a late-model Mopar is designed with an electric fuel pump located in the tank. While this factory pump provides an adequate supply of fuel for a stock or mildly modified Hemi, in a supercharged car like our '09 Challenger R/T, we're pushing the limits of what a stock pump can handle.
If our engine were pushing 700 or more horsepower, we'd be required to change the pump to keep it from running lean, but at the 500 horsepower range like our supercharged 5.7 Hemi, there's another option that doesn't require removing the pump and sending unit or replacing the fuel pump. Easy Performance Products offers a product called the Flow Charger, that simply wires into the electrical system, boosting the voltage to your fuel pump. Better yet, the Flow Charger module can be triggered to boost the voltage when needed, and supply the factory voltage to the pump during normal driving.
The premise of the Flow Charger is simple. Since the fuel pump is driven by an electrical motor, supplying higher voltage than the normal 12 to 14 volts supplied by the car's battery will turn the motor, and fuel pump, faster to deliver more fuel. Of course, the increase in fuel flow depends on the voltage supplied to the pump, and the Flow Charger can either supply a steady 16.5 volts like the one we're installing in our Challenger, or with separate voltage control connectors can supply a variety of voltages up to 20 volts maximum. Because the electric motor of the factory fuel pump is designed to withstand a range of voltage, no damage is done to the pump.
A great feature of this product is that it can be triggered to boost voltage to the fuel pump by any contact closure switch placed between the module's green and blue wires. Since our engine is supercharged, we'll be using a boost pressure switch to trigger our Flow Charger. You could also use a throttle position sensor (TPS) switch, manifold air pressure (MAP) switch, or mass air flow (MAF) switch for this function, and each is easy to wire up.
With a boost switch like we're using, the Flow Charger will only supply additional voltage to the fuel pump while boost is being developed, meaning that during normal driving and cruising the fuel pump operates at normal voltage and capacity. Once the boost switch sees positive pressure and closes the contact, the Flow Charger increases voltage to the fuel pump for higher pump output. With aftermarket fuel pumps, this unit can increase fuel flow by up to 60 percent at the highest 20 volt setting. With our factory fuel pump and the unit's standard 16.5 volt setting, we'll likely see an additional 20 percent fuel flow.
For users who want the maximum voltage, a potentiometer can be installed between the black and brown wire if desired, or an Easy Performance dealer can provide voltage control connectors of different resistances to install between the two wires. Wiring the Flow Charger is easy, and the unit has a built-in power fuse. The Flow Charger also has high power conversion efficiency (96 percent), so it causes a minimum draw on the car's electrical system to do its work. The unit also contains a hermetically sealed circuit board, and operates silently thanks to something Easy Performance calls high frequency switch mode control.
1 The fuel tank in modern LX Mopars is what’s called a saddle tank, and it is located in
2 The Flow Charger increases voltage to the factory fuel pump for additional fuel flow. S
3 We decided to locate our Flow Charger in the Challenger's trunk, where it is easy to wi
4 To activate our Flow Charger, we're using a boost pressure switch wired between the mod
5 We actually used a T-fitting and plumbed our switch along with the fitting for the boos
6 Located under the luggage compartment in the trunk of our Challenger, the Flow Charger
Installing the Flow Charger is straight forward, and the unit can be mounted anywhere, since it is simply wired in place and not an actual part of the fuel system. We installed ours in the trunk compartment of our Challenger, in the lower area near the battery, which made much of the wiring easy. If you can perform simple wiring and mechanical tasks, installing the Flow Charger is easy to do yourself, and much less involved than removing and replacing the factory fuel pump. Other than wiring the unit into the electrical system, the only additional modification is to replace the 20-amp fuel pump fuse (number six fuse in the rear power distribution center) with the supplied 30-amp fuse.
After installation, we didn't really notice any difference in fuel pressure, but did notice that fuel pressure seemed to remain more constant at full throttle. Testing voltage at the unit with a volt meter, we saw the voltage increase when the boost pressure switch was activated. Without a fuel flow meter, it's hard to tell exactly how much more fuel the pump is providing, but we did improvise a test of our own using a stop watch and gas can.
Tapping into the fuel line and with the engine not running, we turned the ignition on and used a stopwatch to measure how long it took to fill a one gallon gas can both with and without the Flow Charger engaged. Granted this was not an entirely scientific test, but we did see that with the voltage boosted to 16.5 volts by the Flow Charger, it took approximately 30 percent less time to fill the one gallon gas can, equating to a 30 percent increase in fuel flow. So if you want more fuel to your late-model Hemi without dousing yourself in gas, the Flow Charger from Easy Performance is a great option.
7 The positive and negative wires from the Flow Charger simply go to the positive side of
8 The fuel pump access panel is located under the rear seat on the driver side of the car
9 The Flow Charger is very efficient, but Easy Performance still recommends replacing the