In preparation for the 1.5 and 2.0, it's time to start collecting some common acronyms associated with forced induction and tuning. The idea is to edit this list as we become more educated on the new platforms. But for now we can use this as a starting point.
If you'd like to suggest edits or additions, feel free to post in the comments and I'll add accordingly.
Credit where credit is due; the initial list was taken from member "Abilor" and other very knowledgeable guys on Mazdaspeedforums.org.
AFR – Air Fuel Ratio. The mixture of fuel and air entering the engine cylinders and being combusted. Calculated by a sensor which examines exhaust gas for oxygen content, AFR is measured in lambda, which is the same for all fuels. 1 Lambda = 14.7:1 AFR with petrol/gasoline. 1 Lambda represents different air to fuel ratios with different fuels, and is more consistent regardless of your gasoline/ethanol mixture.
ALT - Absolute Load Targets. Many ECUs use load based targeting to calculate other variables such as boost PSI. Whether or not this applies to Honda remains to be seen.
APP – Absolute Pedal Position for Drive by Wire.
BAT - Boost Air Temperature. The temperature of the air entering the engine at the intake manifold; an upgraded intercooler can bring these temperatures down, which is a VERY good thing.
BCS - Boost Control Solenoid. In addition to EBCS aka boost control solenoid (see WGDC)
BOV – Blow Off Valve. Vents excess boost pressure to the atmosphere (VTA).
BPV – Bypass Valve. Recirculates excess boost pressure through the system.
BT – Boost Targets. Your map’s boost targets across the RPM range. Also can mean Big Turbo, and upgraded turbo.
BTDC - Before Top Dead Center. A relative position of an engine's crankshaft used for calibrations.
CAI - Cold Air Intake. In naturally aspirated motors, CAIs can reduce intake temps for better performance. In forced induction motors, they do little to improve intake temps except at idle, due to the heat created by the passage of air through the turbo.
CAN - Controller Area Network. Communication protocol used by automotive manufacturers to communicate data between computer modules within a vehicle. Includes ABS computer, ECU/PCM, radio/climate controls, instrument cluster, etc.
CAT – Catalytic Converter. Transforms hydrocarbons into more inert states that are better for the environment. Typically referenced using lowercase letters, ex. "I deleted my cat."
CBE – Cat-Back Exhaust. An exhaust that reduces pressure by placing CAT’s or other restrictive elements further away from the engine, reducing pressure.
CC - Combustion Chamber. This is where the magic happens: fuel and air are compressed by the piston in the cylinder, ignited by the spark plug, and combustion pushes the piston back down the cylinder imparting force to the crankshaft.
CEL - Check Engine Light. The yellow light on the instrument cluster that alerts you to an ECU self-diagnosis of an issue; the "code" for the issue can be pulled by a OBD2 reader, and researched on the forums for resolution.
DBW - Drive By Wire. Substitution of traditional human interface elements with electromechanical actuators; in our case, usually refers to the electronic manipulation of the throttle plate given the input of the accelerator pedal.
DISI – Direct Injection Spark Ignition. It injects fuel directly into the cylinders, which has a cooling effect, aiding combustion. More here:
http://auto.howstuffworks.com/direct-injection-engine.htm
DP – Downpipe. The pipe coming straight off the exhaust manifold and leading to the CBE. Upgraded DP’s are generally less restrictive due to placing a high flowing CAT in the exhaust stream (if one is present), reducing back pressure and allowing the turbo to spool faster. They are less restrictive because they use one which allows exhaust gases to pass through it with less resistance. Resistance causes back pressure and slows the spool of the turbo, which increases low end torque but ultimately decreases peak output. Many factory turbos are engineered to spool quickly to maximize low end torque and throttle response, hence the restriction.
EBCS - Electronic Boost Control Solenoid. The device which, when subjected to the WGDC, physically closes the wastegate to build boost.
ECU – Engine Control Unit. The computer that makes realtime adjustments to your engine’s performance as dictated by the turning parameters you are running (factory or otherwise).
EGR - Exhaust Gas Recirculation. Mainly there for emission control at the expense of buildup of unwanted contaminants.
EGT - Exhaust Gas Temp.
EWG - External Waste Gate. A wastegate that is located independent of the turbo.
FMIC – Front Mount Intercooler. A radiator type unit, but in reverse, that cools air driven by exhaust pressure from the turbo, which heats the air up; cooler air combusts better, so it’s necessary to cool it before entering the turbo intake. FMIC’s are usually located in front of the car’s radiator, or adjacent to it, and significantly reduce “heat soak” under all conditions except at idle. An FMIC bleeds off some of the heat caused by pressurization of air by the turbo (the air entering the cylinders), not exhaust pressure (the air exiting the cylinders). "Heat Soak" refers to the tendency of the Intercooler to become hot itself, and therefore loose effectiveness as a heat dissipation device. This effect is exacerbated slightly by engine bay temperature where air induction occurs.
g/s - Grams per Second. see MAF
HPFP – High Pressure Fuel Pump in direct injection motors.
IAT - Intake Air Temperature. The temperature of the air passing through the MAF; not nearly as critical as BAT. Comparing Intake Air Temperature to Boosted Air Temperature can be used to determine the cooling efficiency of the Intercooler. Also, a lower IAT will result in lower BATs under normal operation, but variances in IAT seem to have less of an effect than similar variances in BAT.
IM - Intake Manifold. The network of piping that allows air from a single intake to enter four separate cylinders. The smoother the airflow, the better.
IWG - Internal Wastegate. A wastegate physically located within the turbo.
KR – Knock Retard. The degree to which the ECU is reducing engine timing to prevent detonation. It is important to know the causes of Knock (detonation), which you can discern via KR in an engine that is mechanically sound. Lean AFRs, hot BATs, advanced timing, all cause KR. Ideally, at WOT (wide open throttle), there will be little to no KR.
LTFT - Long Term Fuel Trim. The average value the ECU is using to adjust fuel injection to reach target AFR's. Will fluctuate while ECU is being "trained" after first 50 - 100 miles of being reset.
MAF – Mass Air Flow sensor. The reader that senses the air flowing into the engine; the ECU uses it’s realtime values to make critical calculations regarding how much fuel to inject into the engine. The ECU's calculations change depending on learned long term fuel trims (LTFT) in closed loop operation. These fuel trims are expressed as a percentage error between requested AFR/Lambda and observed AFR/Lamba. +2% means 2% more air is coming in than expected (and requires 2% more fuel to achieve requested AFR/Lambda), and -2% is just the opposite.
MAP - Manifold Absolute Pressure. Measured at the intake manifold post intercooler (same sensor as BAT).
MBC - Manual Boost Controller. A device which the driver can operate to control boost levels from inside the cockpit.
MBT - Minimum Timing for Best Torque.
NVH - Noise, Vibration, and Harshness.
OBD-II - On-Board Diagnostics protocol II. Definied by the Society of Automotive Engineers (SAE) document J1979. The required standard PID protocol for all cars sold in the US after 1996.
OCC - Oil Catch Can. An additional reservoir in the oil circulation of the engine (PCV) that prevents crankcase contaminants from entering the IM.
OEM – Original Equipment Manufacturer. An OEM part is a stock part.
OTS - Off The Shelf. After used when referring to standard tuning maps vs. custom maps.
PCV - Positive crankcase ventilation.
http://www.aa1car.com/library/pcv.htm
PID - Parameter Identification. Term used for a signal input to the PCM/ECU, a value calculated by the PCM/ECU, or a system staus flag. Many are defined by the OBD-II protocol, and some are manufacturer-specific.
PNP - Plug and Play. A device that can be used immediately and easily after installation.
PSI – Pounds per Square Inch. A pressure measurement when calculating boost.
RP - Race Pipe. A portion of an exhaust with the cat deleted.
RPM – Revolutions Per Minute. The rotating speed of the engine crankshaft.
SRI - Short Ram Intake. Often used with turbo inducted motors to improve throttle response with minimal negative impacts to intake temps (post-IC).
STFT - Short Term Fuel Trim. The real-time value of adjustments made by ECU to reach targeted AFR.
TB - Throttle Body. The part of the air intake system that controls the amount of air flowing into the engine.
TDC - Top Dead Center. A position of the engine's crankshaft used to calibrate timing.
TIH/TIP - Turbo Inlet Hose or Turbo Inlet Pipe. This pipe is the second half of an intake that leads directly to the turbo turbine. On cars which use a larger than stock turbo (BT or Big Turbo), the intake and the TIP are one piece.
TMIC – Top Mount Intercooler. A radiator type unit, but in reverse, that cools air driven by exhaust pressure from the turbo, which heats the air up; cooler air combusts better, so it’s necessary to cool it before entering the turbo intake. TMIC’s are located on top of the engine and are generally accompanied by a ram style induction system to channel airflow. Larger TMIC’s are more efficient and can be used to help optimize boost, but are still prone to “heat soak”. See FMIC.
TP – Throttle Position. The position of the throttle on the engine applied by the ECU through Drive by Wire system. The ECU controls TP based on fueling, boost, load, or other parameters identified by the manufacturer.
TP - Test Pipe. A portion of the exhaust with a cat deleted.
VE - Volumetric Efficiency. For turbo cars, this metric is usually between 60-85%.
VTA – Vents to Atmosphere.
VVT - Variable Valve Timing
WGA - Waste Gate Actuator. Deploys the Wastegate.
WGDC – Waste Gate Duty Cycle. The values that operate the wastegate’s closing percentage; the higher the percentage, the more the wastegate is closed, and the more boost is built and crammed into the intake manifold for more power.
WMI - Water Meth Injection. A method of spraying a coolant into the engine cylinders to improve compression and reduce KR.
WOT – Wide Open Throttle. Otherwise known as “Lead Foot”
If you'd like to suggest edits or additions, feel free to post in the comments and I'll add accordingly.
Credit where credit is due; the initial list was taken from member "Abilor" and other very knowledgeable guys on Mazdaspeedforums.org.
AFR – Air Fuel Ratio. The mixture of fuel and air entering the engine cylinders and being combusted. Calculated by a sensor which examines exhaust gas for oxygen content, AFR is measured in lambda, which is the same for all fuels. 1 Lambda = 14.7:1 AFR with petrol/gasoline. 1 Lambda represents different air to fuel ratios with different fuels, and is more consistent regardless of your gasoline/ethanol mixture.
ALT - Absolute Load Targets. Many ECUs use load based targeting to calculate other variables such as boost PSI. Whether or not this applies to Honda remains to be seen.
APP – Absolute Pedal Position for Drive by Wire.
BAT - Boost Air Temperature. The temperature of the air entering the engine at the intake manifold; an upgraded intercooler can bring these temperatures down, which is a VERY good thing.
BCS - Boost Control Solenoid. In addition to EBCS aka boost control solenoid (see WGDC)
BOV – Blow Off Valve. Vents excess boost pressure to the atmosphere (VTA).
BPV – Bypass Valve. Recirculates excess boost pressure through the system.
BT – Boost Targets. Your map’s boost targets across the RPM range. Also can mean Big Turbo, and upgraded turbo.
BTDC - Before Top Dead Center. A relative position of an engine's crankshaft used for calibrations.
CAI - Cold Air Intake. In naturally aspirated motors, CAIs can reduce intake temps for better performance. In forced induction motors, they do little to improve intake temps except at idle, due to the heat created by the passage of air through the turbo.
CAN - Controller Area Network. Communication protocol used by automotive manufacturers to communicate data between computer modules within a vehicle. Includes ABS computer, ECU/PCM, radio/climate controls, instrument cluster, etc.
CAT – Catalytic Converter. Transforms hydrocarbons into more inert states that are better for the environment. Typically referenced using lowercase letters, ex. "I deleted my cat."
CBE – Cat-Back Exhaust. An exhaust that reduces pressure by placing CAT’s or other restrictive elements further away from the engine, reducing pressure.
CC - Combustion Chamber. This is where the magic happens: fuel and air are compressed by the piston in the cylinder, ignited by the spark plug, and combustion pushes the piston back down the cylinder imparting force to the crankshaft.
CEL - Check Engine Light. The yellow light on the instrument cluster that alerts you to an ECU self-diagnosis of an issue; the "code" for the issue can be pulled by a OBD2 reader, and researched on the forums for resolution.
DBW - Drive By Wire. Substitution of traditional human interface elements with electromechanical actuators; in our case, usually refers to the electronic manipulation of the throttle plate given the input of the accelerator pedal.
DISI – Direct Injection Spark Ignition. It injects fuel directly into the cylinders, which has a cooling effect, aiding combustion. More here:
http://auto.howstuffworks.com/direct-injection-engine.htm
DP – Downpipe. The pipe coming straight off the exhaust manifold and leading to the CBE. Upgraded DP’s are generally less restrictive due to placing a high flowing CAT in the exhaust stream (if one is present), reducing back pressure and allowing the turbo to spool faster. They are less restrictive because they use one which allows exhaust gases to pass through it with less resistance. Resistance causes back pressure and slows the spool of the turbo, which increases low end torque but ultimately decreases peak output. Many factory turbos are engineered to spool quickly to maximize low end torque and throttle response, hence the restriction.
EBCS - Electronic Boost Control Solenoid. The device which, when subjected to the WGDC, physically closes the wastegate to build boost.
ECU – Engine Control Unit. The computer that makes realtime adjustments to your engine’s performance as dictated by the turning parameters you are running (factory or otherwise).
EGR - Exhaust Gas Recirculation. Mainly there for emission control at the expense of buildup of unwanted contaminants.
EGT - Exhaust Gas Temp.
EWG - External Waste Gate. A wastegate that is located independent of the turbo.
FMIC – Front Mount Intercooler. A radiator type unit, but in reverse, that cools air driven by exhaust pressure from the turbo, which heats the air up; cooler air combusts better, so it’s necessary to cool it before entering the turbo intake. FMIC’s are usually located in front of the car’s radiator, or adjacent to it, and significantly reduce “heat soak” under all conditions except at idle. An FMIC bleeds off some of the heat caused by pressurization of air by the turbo (the air entering the cylinders), not exhaust pressure (the air exiting the cylinders). "Heat Soak" refers to the tendency of the Intercooler to become hot itself, and therefore loose effectiveness as a heat dissipation device. This effect is exacerbated slightly by engine bay temperature where air induction occurs.
g/s - Grams per Second. see MAF
HPFP – High Pressure Fuel Pump in direct injection motors.
IAT - Intake Air Temperature. The temperature of the air passing through the MAF; not nearly as critical as BAT. Comparing Intake Air Temperature to Boosted Air Temperature can be used to determine the cooling efficiency of the Intercooler. Also, a lower IAT will result in lower BATs under normal operation, but variances in IAT seem to have less of an effect than similar variances in BAT.
IM - Intake Manifold. The network of piping that allows air from a single intake to enter four separate cylinders. The smoother the airflow, the better.
IWG - Internal Wastegate. A wastegate physically located within the turbo.
KR – Knock Retard. The degree to which the ECU is reducing engine timing to prevent detonation. It is important to know the causes of Knock (detonation), which you can discern via KR in an engine that is mechanically sound. Lean AFRs, hot BATs, advanced timing, all cause KR. Ideally, at WOT (wide open throttle), there will be little to no KR.
LTFT - Long Term Fuel Trim. The average value the ECU is using to adjust fuel injection to reach target AFR's. Will fluctuate while ECU is being "trained" after first 50 - 100 miles of being reset.
MAF – Mass Air Flow sensor. The reader that senses the air flowing into the engine; the ECU uses it’s realtime values to make critical calculations regarding how much fuel to inject into the engine. The ECU's calculations change depending on learned long term fuel trims (LTFT) in closed loop operation. These fuel trims are expressed as a percentage error between requested AFR/Lambda and observed AFR/Lamba. +2% means 2% more air is coming in than expected (and requires 2% more fuel to achieve requested AFR/Lambda), and -2% is just the opposite.
MAP - Manifold Absolute Pressure. Measured at the intake manifold post intercooler (same sensor as BAT).
MBC - Manual Boost Controller. A device which the driver can operate to control boost levels from inside the cockpit.
MBT - Minimum Timing for Best Torque.
NVH - Noise, Vibration, and Harshness.
OBD-II - On-Board Diagnostics protocol II. Definied by the Society of Automotive Engineers (SAE) document J1979. The required standard PID protocol for all cars sold in the US after 1996.
OCC - Oil Catch Can. An additional reservoir in the oil circulation of the engine (PCV) that prevents crankcase contaminants from entering the IM.
OEM – Original Equipment Manufacturer. An OEM part is a stock part.
OTS - Off The Shelf. After used when referring to standard tuning maps vs. custom maps.
PCV - Positive crankcase ventilation.
http://www.aa1car.com/library/pcv.htm
PID - Parameter Identification. Term used for a signal input to the PCM/ECU, a value calculated by the PCM/ECU, or a system staus flag. Many are defined by the OBD-II protocol, and some are manufacturer-specific.
PNP - Plug and Play. A device that can be used immediately and easily after installation.
PSI – Pounds per Square Inch. A pressure measurement when calculating boost.
RP - Race Pipe. A portion of an exhaust with the cat deleted.
RPM – Revolutions Per Minute. The rotating speed of the engine crankshaft.
SRI - Short Ram Intake. Often used with turbo inducted motors to improve throttle response with minimal negative impacts to intake temps (post-IC).
STFT - Short Term Fuel Trim. The real-time value of adjustments made by ECU to reach targeted AFR.
TB - Throttle Body. The part of the air intake system that controls the amount of air flowing into the engine.
TDC - Top Dead Center. A position of the engine's crankshaft used to calibrate timing.
TIH/TIP - Turbo Inlet Hose or Turbo Inlet Pipe. This pipe is the second half of an intake that leads directly to the turbo turbine. On cars which use a larger than stock turbo (BT or Big Turbo), the intake and the TIP are one piece.
TMIC – Top Mount Intercooler. A radiator type unit, but in reverse, that cools air driven by exhaust pressure from the turbo, which heats the air up; cooler air combusts better, so it’s necessary to cool it before entering the turbo intake. TMIC’s are located on top of the engine and are generally accompanied by a ram style induction system to channel airflow. Larger TMIC’s are more efficient and can be used to help optimize boost, but are still prone to “heat soak”. See FMIC.
TP – Throttle Position. The position of the throttle on the engine applied by the ECU through Drive by Wire system. The ECU controls TP based on fueling, boost, load, or other parameters identified by the manufacturer.
TP - Test Pipe. A portion of the exhaust with a cat deleted.
VE - Volumetric Efficiency. For turbo cars, this metric is usually between 60-85%.
VTA – Vents to Atmosphere.
VVT - Variable Valve Timing
WGA - Waste Gate Actuator. Deploys the Wastegate.
WGDC – Waste Gate Duty Cycle. The values that operate the wastegate’s closing percentage; the higher the percentage, the more the wastegate is closed, and the more boost is built and crammed into the intake manifold for more power.
WMI - Water Meth Injection. A method of spraying a coolant into the engine cylinders to improve compression and reduce KR.
WOT – Wide Open Throttle. Otherwise known as “Lead Foot”
Ford might get pissed that your honda is using Eco Boost
