When large injectors are fitted to high output engines, low impedance injectors will often give a better idle quality because of this fact.

So, 322cc divided by 5 64hp maximum fuel flow with this injector.

If you want to be pedantic, its the mass of the fuel (not the volume) which is the critical factor.

Assuming a normal fuel density, the mass of the fuel in pounds per hour can be worked out by Dividing the cc per minute figure by 10.5.

For this injector, that gives a mass flow of 30.6 poundshour.

So 30.6 poundshour multiplied by 2.04 gives a horsepower capability of 62.4hp - the same as we got from the ccminute figure.

This means that you need to multiply this rating by the number of injectors that are to be used.

So, if you were using the Impulse RS 322cc injectors in a 4 cylinder engine (with one injector per cylinder) the max power that the injectors could deliver fuel for would be about 249.6hp.

All of these figures are assuming that you are running an average fuel pressure of 43psi and at 90 duty cycle.

They are more expensive and complex than saturated circuit drivers, and are not generally used with domestic production ECUs.

They are primarily used in aftermarket high performance systems.

Most high flow injectors are low resistance (2-5 ohms) and use a peak and hold driver to activate them.

The Peak current is the amount required to quickly jolt the injector open, and then the lower Hold current rating is used to keep it open for as long as the ECU commands.

These require the extra kick from the higher current to keep the opening and closing time of the injector stable at the higher fuel flow rate.

With this type of driver, 12 volts is still delivered to the injector, but due to the its low resistance, the current in the driver circuit is high.

How high Using Ohmss Law we can calculate the current rating (12v2 ohms 6 amps).

This is substantial current flow and a Saturated Injector cannot handle it.

Even though 6 amps may be available to operate the injector, the maximum it is allowed to reach is 2 or 4 amps, depending on the drivers current limit.

This type of driver works by supplying 12 volts to the injectors and the ECU turns it on and off to establish a fuel injector pulse.

In general, if an injector has a high resistance specification (12-16 ohms) the ECU uses a 12 volt saturated circuit driver to control it.

This means that the current flow in the driver and injector circuit stays low keeping the components nice and cool for long life.

Conversely, a downfall of a Saturated Circuit driver is that it has a slower response time (and closing time) than a peak and hold type.

This slower time can somewhat decrease the usable operating range of the injector energized by this driver.

An injector operating on a saturated circuit driver typically has a reaction time of 2 milliseconds while a peak and hold driver typically responds in 1.5 ms.

The trend lately is to use high impedance types in most production cars.

The best way to determine impedance is to put a digital ohmmeter across the two electrical connections and see what it reads.

The primary advantage of low impedance injectors is a shorter triggering time.

25317628 Fuel Injector Data Sheet