Anti-lag (ALS anti-lag system)
An engine management feature in which fuel is burnt half in exhaust manifold instead of cylinder. This keeps the turbo-charger spinning during non-acceleration (like gear-shifts or braking). It virtually eliminates turbo-lag. When you hear a rally car pop and bang, this is the ALS working.

Co-driver
Also referred to as “navigator,” the co-driver sits beside the driver in the rally car. Depending on the type of rally, the co-driver is responsible for reading either stage notes or course notes to the driver. The co-driver does not take turns driving.

Cutting
Sometimes rally drivers clip the inside of turns in the road to reduce total distance traveled and maintain higher speed through corners. At times, it can be unsafe to cut corners - hidden rocks, stumps, ditches - so it is not uncommon to hear a co-driver read “Don’t cut!” as part of the stage notes.

Diffs (Differentials)
All four-wheel drive rally cars have three separate differentials or “diffs.” The purpose of a diff is to distribute engine power to the wheels. The center diff distributes power between the front and rear axles. The front and rear diffs distribute power between the left and right wheels. Diffs can be active, passive, mechanical or electrical.

Hairpin
A hairpin is a slow, 180 degree turn. On tight hairpins, you might see a rally driver utilize the handbrake to help rotate the car around the tight turn.

Leg
A leg refers to each part of the rally, separated by a fixed minimum stopping time. Typically each day of a rally is a different leg.

Notes
Notes are descriptions of the roads used in the rally. The co-driver calls the notes to the driver so the driver knows what to expect. In the Rally-America championship, the organizer provides each team with notes. However, in many rallies across the world, the driver and co-driver get to pre-run the rally roads at slow speeds in a street car in order to create their own notes. The notes are essentially detailed code, and normally consist of some way of measuring distance (usually numbers like "5" for 50 meters), and another way to measure severity of the corner ("5" for fast and "2" for slow). Notes also contain various words to caution, remind or control the driver (like "Keep line," or "Stone in,” or “Don’t cut.”)

Oversteer
Oversteering occurs when the car turns more than the driver expects.

Parc Expose
An area where all competing cars are parked together and put on display for fans to enjoy up close.

Parc Ferme
An area where all competing rally cars must be parked and left alone. Typically used overnight or upon completion of the rally.

Puncture
A flat tire.

Regrouping
Regrouping refers to a scheduled stop, during which time cars remaining in the rally are regrouped. No service is allowed during a regroup.

Recce (short for Reconnaissance)
When a driver and co-driver pre-run the competitive route at legal public speeds in a non-competition car, the term "recce" is used. The driver and co-driver use the recce to create their stage notes. Rally America does not currently conduct recce at events, due to time and budget constraints on teams.

Road Section
A section of public road where rally cars must travel at legal speeds and obey all traffic laws. Road sections typically link the timed competitive sections and are also links to and from service areas. They are also known as "transits."

Service
When a rally team’s technicians (service crew) work on the car, this is deemed service. There are usually several designated times for service that take place in a controlled service area. No one except the driver and co-driver may work on the car outside of service. A service could last from 10 to 60 minutes. Teams receive penalties for exceeding this allowed time.

Service Area
The area in which team technicians service the rally cars. Here you will find all the teams and their trucks, tents and equipment. Unlike a pit area in circuit racing, a rally’s service area can be a field, the side of a road or a parking lot.

Special Stage
A timed competitive section of road. A Special Stage is always closed to public traffic. Most rallies have between 10 and 20 Special Stages. Each stage can range from a few miles to over 20 miles in length.

Super Special Stage
A stage that is run in a specially built arena or on a specially constructed course. Usually, more than one car can run the stage simultaneously, or even head to head on split tracks. A Super Special Stage provides a way for casual rally fans to see some action without needing to head deep into the forests.

Tarmac
This term is used in rallying to refer to paved roads in asphalt. Tarmac derives from its commercial name, Tarmacadam, which is used in a type of asphalt.

Turbo Lag
A small delay in power delivery caused by the time it takes the turbo to spool up the turbine blades, thus creating boost. When the gas pedal is pressed, the engine revs up faster than the turbine blades. Hence, normal cars experience a small delay before extra power from turbo kicks in. The turbo is powered by the exhaust gases exiting the engine.

Understeer
This is a condition exhibited when a car's front wheels have little or no grip and are unable to steer the vehicle. A car that understeers will not turn in as well or at all. On gravel roads understeer may be more pronounced due to the lack of grip available.