Glossary of Terms

Glossary of Terms

This page, like the modifications page, is under constant construction. If you would like to add terms to this page or would like to correct or augment some of the descriptions, please e-mail me.

boost Referred to the amount of extra air (compressed air) pumped into the intake manifold by a supercharger or turbocharger. Usually measured in psi (pounds per square inch), inches of mercury, or bar.

cam gear / adjustable cam gear The cam gear is connected to the end of the camshaft. The timing belt connects the cam gear to the crank. An adjustable cam gear allows you to adjust the cam without removing the timing belt.

cam profile The shape of each lobe on a camshaft.

camber The angle along the vertical axis of the tire/wheel when looking at the car directly from the front or the rear. Camber is affected when cars are raised or lowered from stock. Negative camber is when the top of the tire is tilted closer to the car and the bottom of the tire is tilted outward (when looking from the front or the rear). Up to a certain degree (no pun intended) negative camber is ok and may even be desirable.

camshaft The part of the engine that controls the lifting of the intake and/or exhaust valves.

catalytic converter Found in the exhaust system after the headers and before the muffler. It takes hot exhaust and eliminates or reduces the harmful gases by means of chemical reaction.

connecting rod (conrod) Metal rod that connects the piston to the crankshaft.

CV joint Constant Velocity joint -- a type of universal joint used in the transaxle. They ensure that the input and output shafts are rotating at the same rate.

cylinder head The part of an engine that houses the valve train, exhaust and intake ports, combustion chamber, distributor, spark plugs, etc. It sits on top of the engine block.

detonation Occurs when hot spots (caused by engine deposits) in the combustion chamber ignites the air and fuel mixture prematurely. Also occurs after combustion if any unburned fuel is left in the combustion chamber. Also known as engine knock. Places great stress on the engine and leads to the destruction of the engine if ignored.

differential A gearbox that allows the transfer of power from the engine to be split into two outputs (axles) that can spin at different rates. During turns, the outer wheel needs to spin more than the other. Without a differential, turning would not be a pleasant experience.

DOHC Double Overhead Cam -- engine designed to use two camshafts; one for intake and one for exhaust.

drivetrain All the car's parts that make it move including the engine, transmission, differential, hub, shafts, etc.

ECU Electronic Control Unit

EFI Electronic Fuel Injection

Electronic Control Unit The computer that receives signals from various sensors and determines how much fuel to inject into the engine under various conditions.

flywheel A large, heavy disc that is attached to the end of the crankshaft. It adds inertia to the engine which results in smoother power flow.

forced induction Any method used to force more air into the combustion chamber. Nitrous, turbo, supercharger, and everything in between.

heel and toe A technique used by racing drivers that involves the use of all three pedals in a manual transmission equipped automobile. During shifting, the toe of the right foot controls the brake, while the heel of the same foot depresses the gas pedal. The left foot, of course, depresses the clutch. When executed properly, the effect is a smooth and efficient transfer of power between shifts.

horsepower A unit of measure used in representing the amount of energy or power produced by a device -- one horsepower is equal to the energy required (work) to move a 550 pound object one foot in one second. Also equivalent to 746 watts.

intake charge The mixture of air and fuel that flows into the intake manifold.

lean condition Refers to an air/fuel mixture that has more air than fuel -- may lead to detonation.

limited-slip differential A specially designed differential that not only allow the left and right axles to spin independently, but also has the ability to distribute the power to each axle even if one is slipping due to the loss of traction.

lockup differential A differential that locks the two outputs (axles) together , so there is no differential action giving you maximum traction.

main bearings The bearings in the engine block that supports the crankshaft.

MAP sensor Manifold Absolute Pressure sensor

naturally aspirated Refers to an engine that does not use any form of forced induction to achieve more performance.

neutral steering A condition in which the slip angle of the front and rear wheels are the same.

Nitrous Oxide (NO2) Nitrous oxide is a compound that is made up of two parts oxygen to one part nitrogen. A gas at room temperature and a liquid under pressure. When heated, it breaks down into its two elements.

NOS Brand name/logo for Nitrous Oxide Systems

overdrive A gear set in which the output shaft rotates faster than the input shaft.

oversteer Where the slip angle of the rear wheels are greater than that of the front wheels. The rear tires lose grip before front tires do. Happens more often in rear wheel drive cars.

parasitic drag Anything that robs power from the engine via pulleys (air conditioners, alternators, power steering, water pump, etc.) and direct connection.

polishing -- to polish (polished) Smoothing an engine's interior surfaces, usually the cylinder heads, to improve flow characteristics and/or to prevent hot spots.

porting -- to port (ported) Resizing an opening so it is matched with a mating surface.

pound/foot A unit of measure that is equivalent to a twisting force of one pound placed on a one foot long lever. Used to measure torque.

power Usually measured in horsepower, power is proportional to torque and rpm.

power band An rpm range where the majority of the engine's peak power is achieved. Usually starts at engine's peak torque and ends near the engine's peak power.

power shift or power shifting Refers to shifting gears without lifting the foot off the gas pedal. Shifting must be done quickly or the engine will rev too high. Don't let the engine rev more than 500 rpm between shifts. Not for the uncoordinated!

powertrain Includes the engine and the transmission.

progressive-rate springs A spring that is designed to be stronger as it is compressed. If it takes 50 pounds of force to compress the spring one inch, it would take more than 100 pounds of force to compress it an additional inch and so on.

PSI (psi) Pounds per square inch -- used to measure pressure. Normal atmospheric pressure at sea level is 14.7 psi.

redline The maximum recommended rpms for an engine. Refers to the upper limits of the rpm scale where engine damage will most certainly occur -- indicated on the tachometer by a red sector.

rich condition Refers to an air/fuel mixture that has more fuel than air -- may cause loss of power.

RPM (rpm) Revolutions Per Minute -- how many full turns the crankshaft makes in a minute.

SAE Abbreviation for Society of Automotive Engineers.

Si Honda abbreviation for Sport Induction. Si models are (with the exception of the R-Type) the top of the line cars.

SiR Honda abbreviation for Sport Induction Racing. SiR models are the top of line in Japan. Once in awhile, a select number of SiR's make it to N. America.

slip angle The difference in angles between the plane of the wheel and the rolling direction of the tire.

SOHC Single Overhead Cam -- engine designed to have one camshaft control both intake and exhaust valves.

stoichiometric condition A condition in which you have an ideal mixture of fuel and air -- between lean and rich. Correct stoichiometry is reached when you have 14.7 parts of air to 1 part fuel (gasoline). Perfect combustion.

supercharger, supercharged A method of forced induction in which air is forced into the intake manifold via a turbine attached to the crank pulley. Although the term supercharger describes the above, it can also be used to describe any method of compressing air into the engine, including turbochargers!

TDC Top Dead Center -- when a piston is at the top most position during the compression stroke. TDC can also refer to the top most position of the piston in the exhaust stoke, but "true" TDC is on the compression stroke.

torque steer A tendency for a car to steer to one side when power is applied. A condition that is particular to front wheel drive vehicles.

TPS Throttle Position Sensor. Measures the angle of the throttle plate and sends the information to the ECU.

transaxle A unit that houses both transmission and differential.

turbo lag The time it takes for the turbocharger to start taking effect.

turbocharger, turbocharged A method of forced induction in which air is forced into the intake manifold via a turbine that is powered by the exhaust from the engine.

Type-R (see) SiR.

understeer Where the slip angle of the front wheels are greater than that of the rear wheels. The front tires lose grip before rear tires do. The angle of the steering wheel is greater than normal -- requires more steering by driver. Happens more often in cars equipped with front wheel drive. Slight understeer is actually a desired condition.

valve float When the valves in your engine are no longer controlled by the valve springs -- your engine is more or less toast if this occurs.

valvetrain Refers to all the components that operate the valves (including the valves) in the engine's cylinder head.

VTEC
Variable Valve Timing and Lift Electronic Control

A Honda proprietary system in which cam timing, valve duration and lift is varied according to the needs of the driver -- fuel economy (normal driving) and power (pedal to the metal). Each cam has two profiles and rpm determines the shifting from one profile to the other.

waste gate A device that limits the boost in a turbocharger via a valve. The waste gate bypasses the exhaust under certain conditions. Without a waste gate, a turbocharger will destroy an engine by over boosting the intake charge.

WOT Wide Open Throttle - throttle is open all the way as in pedal to the metal, let as much air into the intake manifold as possible.

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Updated April 23, 2000.

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boost	Referred to the amount of extra air (compressed air) pumped into the intake manifold by a supercharger or turbocharger. Usually measured in psi (pounds per square inch), inches of mercury, or bar.
cam gear / adjustable cam gear	The cam gear is connected to the end of the camshaft. The timing belt connects the cam gear to the crank. An adjustable cam gear allows you to adjust the cam without removing the timing belt.
cam profile	The shape of each lobe on a camshaft.
camber	The angle along the vertical axis of the tire/wheel when looking at the car directly from the front or the rear. Camber is affected when cars are raised or lowered from stock. Negative camber is when the top of the tire is tilted closer to the car and the bottom of the tire is tilted outward (when looking from the front or the rear). Up to a certain degree (no pun intended) negative camber is ok and may even be desirable.
camshaft	The part of the engine that controls the lifting of the intake and/or exhaust valves.
catalytic converter	Found in the exhaust system after the headers and before the muffler. It takes hot exhaust and eliminates or reduces the harmful gases by means of chemical reaction.
connecting rod (conrod)	Metal rod that connects the piston to the crankshaft.
CV joint	Constant Velocity joint -- a type of universal joint used in the transaxle. They ensure that the input and output shafts are rotating at the same rate.
cylinder head	The part of an engine that houses the valve train, exhaust and intake ports, combustion chamber, distributor, spark plugs, etc. It sits on top of the engine block.
detonation	Occurs when hot spots (caused by engine deposits) in the combustion chamber ignites the air and fuel mixture prematurely. Also occurs after combustion if any unburned fuel is left in the combustion chamber. Also known as engine knock. Places great stress on the engine and leads to the destruction of the engine if ignored.
differential	A gearbox that allows the transfer of power from the engine to be split into two outputs (axles) that can spin at different rates. During turns, the outer wheel needs to spin more than the other. Without a differential, turning would not be a pleasant experience.
DOHC	Double Overhead Cam -- engine designed to use two camshafts; one for intake and one for exhaust.
drivetrain	All the car's parts that make it move including the engine, transmission, differential, hub, shafts, etc.
ECU	Electronic Control Unit
EFI	Electronic Fuel Injection
Electronic Control Unit	The computer that receives signals from various sensors and determines how much fuel to inject into the engine under various conditions.
flywheel	A large, heavy disc that is attached to the end of the crankshaft. It adds inertia to the engine which results in smoother power flow.
forced induction	Any method used to force more air into the combustion chamber. Nitrous, turbo, supercharger, and everything in between.
heel and toe	A technique used by racing drivers that involves the use of all three pedals in a manual transmission equipped automobile. During shifting, the toe of the right foot controls the brake, while the heel of the same foot depresses the gas pedal. The left foot, of course, depresses the clutch. When executed properly, the effect is a smooth and efficient transfer of power between shifts.
horsepower	A unit of measure used in representing the amount of energy or power produced by a device -- one horsepower is equal to the energy required (work) to move a 550 pound object one foot in one second. Also equivalent to 746 watts.
intake charge	The mixture of air and fuel that flows into the intake manifold.
lean condition	Refers to an air/fuel mixture that has more air than fuel -- may lead to detonation.
limited-slip differential	A specially designed differential that not only allow the left and right axles to spin independently, but also has the ability to distribute the power to each axle even if one is slipping due to the loss of traction.
lockup differential	A differential that locks the two outputs (axles) together , so there is no differential action giving you maximum traction.
main bearings	The bearings in the engine block that supports the crankshaft.
MAP sensor	Manifold Absolute Pressure sensor
naturally aspirated	Refers to an engine that does not use any form of forced induction to achieve more performance.
neutral steering	A condition in which the slip angle of the front and rear wheels are the same.
Nitrous Oxide (NO2)	Nitrous oxide is a compound that is made up of two parts oxygen to one part nitrogen. A gas at room temperature and a liquid under pressure. When heated, it breaks down into its two elements.
NOS	Brand name/logo for Nitrous Oxide Systems
overdrive	A gear set in which the output shaft rotates faster than the input shaft.
oversteer	Where the slip angle of the rear wheels are greater than that of the front wheels. The rear tires lose grip before front tires do. Happens more often in rear wheel drive cars.
parasitic drag	Anything that robs power from the engine via pulleys (air conditioners, alternators, power steering, water pump, etc.) and direct connection.
polishing -- to polish (polished)	Smoothing an engine's interior surfaces, usually the cylinder heads, to improve flow characteristics and/or to prevent hot spots.
porting -- to port (ported)	Resizing an opening so it is matched with a mating surface.
pound/foot	A unit of measure that is equivalent to a twisting force of one pound placed on a one foot long lever. Used to measure torque.
power	Usually measured in horsepower, power is proportional to torque and rpm.
power band	An rpm range where the majority of the engine's peak power is achieved. Usually starts at engine's peak torque and ends near the engine's peak power.
power shift or power shifting	Refers to shifting gears without lifting the foot off the gas pedal. Shifting must be done quickly or the engine will rev too high. Don't let the engine rev more than 500 rpm between shifts. Not for the uncoordinated!
powertrain	Includes the engine and the transmission.
progressive-rate springs	A spring that is designed to be stronger as it is compressed. If it takes 50 pounds of force to compress the spring one inch, it would take more than 100 pounds of force to compress it an additional inch and so on.
PSI (psi)	Pounds per square inch -- used to measure pressure. Normal atmospheric pressure at sea level is 14.7 psi.
redline	The maximum recommended rpms for an engine. Refers to the upper limits of the rpm scale where engine damage will most certainly occur -- indicated on the tachometer by a red sector.
rich condition	Refers to an air/fuel mixture that has more fuel than air -- may cause loss of power.
RPM (rpm)	Revolutions Per Minute -- how many full turns the crankshaft makes in a minute.
SAE	Abbreviation for Society of Automotive Engineers.
Si	Honda abbreviation for Sport Induction. Si models are (with the exception of the R-Type) the top of the line cars.
SiR	Honda abbreviation for Sport Induction Racing. SiR models are the top of line in Japan. Once in awhile, a select number of SiR's make it to N. America.
slip angle	The difference in angles between the plane of the wheel and the rolling direction of the tire.
SOHC	Single Overhead Cam -- engine designed to have one camshaft control both intake and exhaust valves.
stoichiometric condition	A condition in which you have an ideal mixture of fuel and air -- between lean and rich. Correct stoichiometry is reached when you have 14.7 parts of air to 1 part fuel (gasoline). Perfect combustion.
supercharger, supercharged	A method of forced induction in which air is forced into the intake manifold via a turbine attached to the crank pulley. Although the term supercharger describes the above, it can also be used to describe any method of compressing air into the engine, including turbochargers!
TDC	Top Dead Center -- when a piston is at the top most position during the compression stroke. TDC can also refer to the top most position of the piston in the exhaust stoke, but "true" TDC is on the compression stroke.
torque steer	A tendency for a car to steer to one side when power is applied. A condition that is particular to front wheel drive vehicles.
TPS	Throttle Position Sensor. Measures the angle of the throttle plate and sends the information to the ECU.
transaxle	A unit that houses both transmission and differential.
turbo lag	The time it takes for the turbocharger to start taking effect.
turbocharger, turbocharged	A method of forced induction in which air is forced into the intake manifold via a turbine that is powered by the exhaust from the engine.
Type-R	(see) SiR.
understeer	Where the slip angle of the front wheels are greater than that of the rear wheels. The front tires lose grip before rear tires do. The angle of the steering wheel is greater than normal -- requires more steering by driver. Happens more often in cars equipped with front wheel drive. Slight understeer is actually a desired condition.
valve float	When the valves in your engine are no longer controlled by the valve springs -- your engine is more or less toast if this occurs.
valvetrain	Refers to all the components that operate the valves (including the valves) in the engine's cylinder head.
VTEC	Variable Valve Timing and Lift Electronic Control A Honda proprietary system in which cam timing, valve duration and lift is varied according to the needs of the driver -- fuel economy (normal driving) and power (pedal to the metal). Each cam has two profiles and rpm determines the shifting from one profile to the other.
waste gate	A device that limits the boost in a turbocharger via a valve. The waste gate bypasses the exhaust under certain conditions. Without a waste gate, a turbocharger will destroy an engine by over boosting the intake charge.
WOT	Wide Open Throttle - throttle is open all the way as in pedal to the metal, let as much air into the intake manifold as possible.