I

IC

Intercooler

IC

Intake closing

IDC

Injector duty cycle

IMEP

Indicated mean effective pressure

Indicated Horsepower

Indicated Horsepower The maximum power a given engine can theoretically produce.

Indicated Mean Effective Pressure

Indicated Mean Effective Pressure The force generated against the piston top by the combustion process. It is directly measured by a pressure transducer in the chamber.

Inducer

Inducer on the compressor is intake of airflow to the compressor and are always smaller than the exducer (on the compressor side). On the Turbine side of a turbo the Inducer is where the exhaust from the engine comes in to the turbine. However on the turbine side the inducer is larger than the exducer.

Inj#

inj#= number of injectors

Injector Pulse

The time in milliseconds that a fuel injector is held open to flow a given amount of fuel.

Injector Size

An electronic fuel injector’s flow rating in lbs/ hr at 85-percent duty cycle. Also noted in cc/ sec for most import applications.

injF

injF= calculated injector flow (cc) @ IDC

InjS

injS= injector flowin cc @ 100% IDC (static flow)

Installed Height

The installed valve spring height when the valve is closed.

Intake Temp @ Valve

APS DR525 can cool a 300d charge temp to 95d under the correct conditions.

Intake Valve Opening Point (IO)

Normally measured in degrees before top dead center (BTDC).

IO

Intake opening

J

Journal Bearings

Fits inside the bore of the bearing housing and prevents radial movement of the shaft & wheel.

K

L

Liter

L/D

Lift-to-diameter ratio

Lambda - λ

λ - lambda

lbs/hr

Pounds per hour

lbs/min

Pounds per minute

lbsF

lbsF= calculated lbs of fuel used per hour

Lobe Displacement Angle (LDA)

The number of camshaft degrees separating the centerlines of the intake and exhaust lobes. Also referred to as Lobe Separation Angle (LSA) or simply “Lobe Center.”

Lobe Separation Angle (LSA)

Same as Lobe Displacement Angle. Most commonly used reference.

LSA

Lobe separation angle