Air Dam:
A skirt that replaces the front stone-shield of a car. The air dam helps to redirect the flow of air around the car at high speeds which in turn helps to create a type of suction to the road.

Back Pressure:
The amount of pressure that builds up in an exhaust system due to a restrictive muffler.

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.

Bore & Stroke: (B&S)
Refers to the size of your piston (or bore) as compared to the length the piston travels (stroke).

Bushings:
Typically rubber or polyurethane pieces that fit between two metal parts. Bushings are used to absorb friction and noise as well as provide a cushion between metal parts to prevent wear or breakage.

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. Measured in Degrees.

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.

Cam Shafts or cams:
A long thick bar in your motor (for OHC's it is located in the head of the motor) with lobes that control the opening and closing of your 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.

Cat Back Exhaust:
The part of the exhaust system that comes after the catalytic converter.

C/R: Compression Ratio:
C/R is the difference in the volume between the combustion chamber (area at the top of the piston when it is at TDC) and the displacement of the piston. The higher the ratio, the more power the combusted gases produce.

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.

DIY:
Do it yourself

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.

Foot/Pound;
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.

Forced Induction:
The process of forcing more air into your intake which is return provides more power. Forced Induction refers to such engine add on's as Turbo Chargers, Super Chargers, or Nitrous Oxide.

Fuel Pressure Regulator or FPR:
An FPR is a devise that maintains a steady flow of fuel to your engine. With out the FPR, your car may suffer leaning (not enough fuel) upon hard acceleration which requires larger amounts of fuel than a regular steady pace would.

Headers:
Pipes that direct the flow of your exhaust ports to the exhaust system.

Head work:
Work such as PnP (pot and polish - not plug and play!)and 3 angle valve jobs being done to your engine head.

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.

Hybrid (in automotive terms):
A word usually used to describe a car that has undergone an engine swap, from a lower model to a higher model. However, a hybrid turbo can describe a T03/04 turbo is which the T04 housing is used with the T03 turbo internals or vise versa. Any part can be a hybrid once it has been modified by interchanging parts to achieve a desired result.

Intake Charge:
The mixture of air and fuel that flows into the intake manifold.

Intercooler:
A device that helps to cool a forced induction intake charge. In example, the turbo sends the charged air to the intercooler where it cools off then flows to the intake manifold. The purpose for cooling the intake charge is that cool air compresses better and helps to prevent detonation.

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 allows the left and right axles to spin independently, but also has the ability to distribute the power to each axle evenly, 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.

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. The measurement process of forced intake on forced induction cars. The higher the PSI, the more air being forced into your intake, the faster your car will go. Also known as boost. 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.

Spoiler:
A wing placed on the rear hatch or trunk of a car that helps to hold down the rear end of a car during high speed drive by creating down-force, thus preventing the rear wheels from losing contact with the road (most effective on cars where the rear wheels are the drive wheels).

Straight Pipe: an exhaust system that flows from the exhaust ports to the muffler without any interference in between such as a catalytic converter.

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.

Strut bars:
These are bars or braces that extend from one strut/shock tower to the other above the car. The purpose is to prevent body flex during cornering.

Sway bars:
These are bars mounted beneath the car from left wheel to right wheel, both in the front and most cars the back. The purpose is to prevent body roll on hard cornering which may cause you to lose control of the car. All cars come stock with swaybars, however, upgrading to swaybars of a thicker diameter helps to improve performance.

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.

Traction:
traction is process of your tires gripping the road. Also referred to as "hooking up." When people say "I have no traction" it means that when they take off from a dead start that their tires spin instead of catching the ground and putting the car into motion

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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