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Decibel

Abbreviated dB. A unit of sound pressure. It can be used to measure the loudness of a vehicle's exhaust system, for example.

Decibel (dB)

A standard of measure for the relative loudness of a sound.

Deck

1. The flat, mating surfaces of an engine block and head. 2. The trunk of a passenger car. 3. To machine an engine block deck flat. 4. To dechrome the deck lid.

Deck Lid

The trunk door, or cover.

Deck Lid

See trunklid.

Deck Plate

A heavy metal plate that is bolted to an engine block during cylinder-honing operations.

Declutching Fan

An engine-cooling fan system, mounted on the water pump, having a temperature-sensitive device that governs or limits terminal speed.

Decoke

A British term for decarbonize.

Deep Cycling

A condition where a battery is completely discharged before it is recharged.

Deep Discharge

When a battery is run down so low that it cannot start a vehicle. One deep discharge can reduce a battery's lifespan by as much as 33 percent.

Deep Staging

A drag-racing technique where the driver uses minimum roll out to avoid breakout.

Deep Sump

An oil pan, used on some drag-race cars, that is deep enough to keep the oil away from the crankshaft at high RPM to slightly increase horsepower.

Deep-dish Wheel

A wheel with an extremely positive offset.

Deep-rolled Fillets

The transition radius between a journal and the cheeks of a crankshaft.

Default

A value or setting that a device or program automatically selects if you do not specify a subroutine.

Default Setup

The setup that exists as long as there are no changes made to the settings.

DEFI

Digital electronic fuel injection.

Deflection

1.An axial or radial movement away from the normal or standard axis of a part. 2. A bending or distorting motion; usually applied to a brake drum when it is forced out-of-round during brake application.

Deflection Angle

The angle at which oil is deflected inside a torque converter during operation; the greater the angle, the greater the torque applied to the output shaft.

Deflection Rate

The number of pounds required to compress a spring one inch (25.4 mm).