CPR Racing – Fuel Injector Terminology Glossary
At CPR Racing, we believe that knowledge is horsepower. Below is a helpful glossary of key terms to help you better understand how fuel injectors work and how they’re measured, tested, and maintained.
Fuel Injector Terminology Glossary
At CPR Racing,Total Fuel Systems, we believe that knowledge is horsepower. Below is a glossary of key terms every enthusiast and professional should know about fuel injectors and fuel systems.
Base Fuel Pressure:
The regulated pressure during start-up and idle. With a 1:1 rising rate regulator, this is the constant pressure the injector operates under, regardless of boost.
CC/Min (Cubic Centimeters per Minute):
Metric unit for injector flow rate. Depends on test fluid and pressure. (See Bernoulli’s Principle)
Diffuser Plate:
Located at the bottom of many injectors, these plates shape spray patterns and can restrict flow. Often welded on.
Duty Cycle:
Percentage of time an injector stays open per cycle. Dependent on RPM.
Ferrous (Metals):
Metals containing iron. Required for injector magnetic actuation, but susceptible to corrosion.
Hygroscopic:
Ability of a substance to absorb and hold water. Common with ethanol-based fuels.
Impedance:
Coil resistance measured in ohms. High-Z = high impedance; Low-Z = low impedance.
Injector Length:
Measured from center of upper o-ring to lower o-ring. Common lengths: 64mm, 53mm, 38mm.
Lb/hr (Pounds per Hour):
Imperial unit for injector flow rate. Also dependent on fluid and test pressure.
Multi-Port Injection (MPI):
One injector per cylinder. Fuel is delivered near intake valves. Can be sequential, batch, or simultaneous.
Peak and Hold:
Used with low-Z injectors. Initial “peak” current opens injector; reduced “hold” current maintains flow and improves closing speed.
Pickling:
Preserving your fuel system by flushing with regular fuel to displace corrosive alcohol-based fuels.
Pulse:
One fueling event for an injector, usually during intake stroke in MPI systems.
Pulse Width:
Duration in milliseconds that an injector stays open per fueling event. Used to calculate duty cycle.
Saturated:
Signal used for high-Z injectors. Constant current is applied to keep injector open throughout the pulse.
Fuel Injector Terminology Glossary
At CPR Racing,Total Fuel Systems, we believe that knowledge is horsepower. Below is a glossary of key terms every enthusiast and professional should know about fuel injectors and fuel systems.
Base Fuel Pressure:
The regulated pressure during start-up and idle. With a 1:1 rising rate regulator, this is the constant pressure the injector operates under, regardless of boost.
CC/Min (Cubic Centimeters per Minute):
Metric unit for injector flow rate. Depends on test fluid and pressure. (See Bernoulli’s Principle)
Diffuser Plate:
Located at the bottom of many injectors, these plates shape spray patterns and can restrict flow. Often welded on.
Duty Cycle:
Percentage of time an injector stays open per cycle. Dependent on RPM.
Ferrous (Metals):
Metals containing iron. Required for injector magnetic actuation, but susceptible to corrosion.
Hygroscopic:
Ability of a substance to absorb and hold water. Common with ethanol-based fuels.
Impedance:
Coil resistance measured in ohms. High-Z = high impedance; Low-Z = low impedance.
Injector Length:
Measured from center of upper o-ring to lower o-ring. Common lengths: 64mm, 53mm, 38mm.
Lb/hr (Pounds per Hour):
Imperial unit for injector flow rate. Also dependent on fluid and test pressure.
Multi-Port Injection (MPI):
One injector per cylinder. Fuel is delivered near intake valves. Can be sequential, batch, or simultaneous.
Peak and Hold:
Used with low-Z injectors. Initial “peak” current opens injector; reduced “hold” current maintains flow and improves closing speed.
Pickling:
Preserving your fuel system by flushing with regular fuel to displace corrosive alcohol-based fuels.
Pulse:
One fueling event for an injector, usually during intake stroke in MPI systems.
Pulse Width:
Duration in milliseconds that an injector stays open per fueling event. Used to calculate duty cycle.
Saturated:
Signal used for high-Z injectors. Constant current is applied to keep injector open throughout the pulse.