The air valve opens progressively in response to engine speed and throttle opening, gradually allowing more air to flow through the secondary side of the carburetor.

The carburetted versions feature an unusual Weber 28 / 30 carb ( replacing the unreliable Ford VV unit ) with a manifold vacuum-actuated secondary choke ( power valve ), instead of the more usual sequential linkage which opens the secondary butterfly at 3 / 4 to full throttle.

Manifold vacuum may also be " ported " where the opening is placed so it is normally above the throttle plate at idle, but as the butterfly valve opens, the opening is effectively below it, and the opening sees nearly the full manifold vacuum.

The first method is to use a throttle air bypass ; this may be an external bypass valve or a solenoid valve which opens the throttle 12-20 degrees.

Full throttle is achieved when the gas pedal is depressed, sending an electronic signal to the ECU, which in turn regulates the lift of each valve event, and opens it all the way up.

Greg had the stick forward and the throttle up before he heard the two `` Rogers ''.

Greg slammed his throttle to the fire wall and rammed up the RPM, and the engine responded as if it had been waiting.

As the throttle is opened up slightly from the fully closed position, the throttle plate uncovers additional fuel delivery holes behind the throttle plate where there is a low pressure area created by the throttle plate blocking air flow ; these allow more fuel to flow as well as compensating for the reduced vacuum that occurs when the throttle is opened, thus smoothing the transition to metering fuel flow through the regular open throttle circuit.

The radio is wired up to either electronic speed controls or servomechanisms ( shortened to " servo " in common usage ) which perform actions such as throttle control, braking, steering, and on some cars, engaging either forward or reverse gears.

This arrangement provides a set of discrete ratios that, combined with the varying of the throttle, allow final-drive speeds from less than one up to about 25 miles per hour ( 40 km / h ), with the lower speeds used for working the land and the highest speed used on the road.

When much more power output is required, the engine speed and throttle opening are increased until the exhaust gases are sufficient to ' spin up ' the turbocharger's turbine to start compressing much more air than normal into the intake manifold.

At T + 68 into the mission, the CAPCOM Richard Covey informed the crew that they were " go at throttle up ", and Commander Scobee confirmed the call-his last recorded words were his response, " Roger, go at throttle up.

Since BitTorrent makes up a large proportion of total traffic, some ISPs have chosen to throttle ( slow down ) BitTorrent transfers to ensure network capacity remains available for other uses.

* The clutch pedal is then released, the driver matches the engine RPM to the gear RPM either using the throttle ( accelerator ) ( when changing down ) or waiting for RPM to decrease ( when changing up ) until they are at a level suitable for shifting into the next gear.

This requires the driver to shift into neutral, apply throttle to bring the RPM up to a suitable speed, and finally shift into gear.

Driving over " rolling " terrain, with gentle up and down portions, can usually be done more economically ( using less fuel ) by a skilled driver viewing the approaching terrain, by maintaining a relatively constant throttle position and allowing the vehicle to accelerate on the downgrades and decelerate on upgrades, while reducing power when cresting a rise and adding a bit before an upgrade is reached.

Covey was the CAPCOM operator during the STS-51-L launch who uttered the infamous words, " Challenger, go at throttle up.

Covey also served as Mission Control spacecraft communicator ( CAPCOM ) for Shuttle Missions STS-5, 6, 61-B, 61-C, and 51-L ( it was his voice that said the now infamous words, " Challenger, go at throttle up .").

Next up were two V8s with 10. 75: 1 compression ratios: a four barrel making and the Trophy 421 HO ( High Output ) with triple Rochester two-barrel carburetors operated by a progressive throttle linkage, rated at.

The first automotive application of the lock-up principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking when the throttle was floored for quick acceleration or as the vehicle slowed down.

Throttle response from the digital throttle was ratcheted up and feedback through the steering wheel was enhanced.

In petrol engines, instead, vacuum is obtained as a side-effect of the operation of the engine and the flow restriction created by the throttle plate.

As the throttle is progressively opened, the manifold vacuum is lessened since there is less restriction on the airflow, reducing the flow through the idle and off-idle circuits.

The tops of the rods are connected to a vacuum piston and / or a mechanical linkage which lifts the rods out of the main jets when the throttle is opened ( mechanical linkage ) and / or when manifold vacuum drops ( vacuum piston ).

This additional force is supplied by the manifold vacuum generated by air flow being obstructed by the throttle on a running engine.

This force is greatly reduced when the engine is running at fully open throttle, as the difference between ambient air pressure and manifold ( absolute ) air pressure is reduced, and therefore available vacuum is diminished.

Because of low vacuum at high RPM, reports of unintended acceleration are often accompanied by complaints of failed or weakened brakes, as the high-revving engine, having an open throttle, is unable to provide enough vacuum to power the brake booster.

This had the drawback that manifold vacuum varies depending on throttle position, and is almost non-existent under wide-open throttle, when the wipers would slow down or even stop.

A blowoff valve is connected by a vacuum hose to the intake manifold after the throttle plate.

As they do not maintain a throttle vacuum, they are not subjected to the same engine braking effects.

Due to the downward movement of the pistons and the restriction caused by the throttle valve, in a reciprocating spark ignition piston engine, a partial vacuum ( lower than atmospheric pressure ) exists in the intake manifold.

The computer adjusted spark timing based on manifold vacuum, engine speed, engine temperature, throttle position over time, and incoming air temperature.

Manifold vacuum is an effect of a piston's movement on the induction stroke and the choked flow through a throttle in the intake manifold of an engine.

Manifold vacuum is present in all naturally aspirated engines that use throttles ( including carbureted and fuel injected gasoline engines using the otto cycle or the two-stroke cycle ; diesel engines do not have throttle plates ).

When the throttle is opened ( in a car, the accelerator pedal is depressed ), ambient air is free to fill the intake manifold, increasing the pressure ( filling the vacuum ).

Between points 4 and 5, the liquid refrigerant goes through the expansion valve ( also called a throttle valve ) where its pressure abruptly decreases, causing flash evaporation and auto-refrigeration of, typically, less than half of the liquid.

A spring pulls the throttle open and as the engine gains speed, increased air flow from the blower forces the vane back against the spring, partially closing the throttle.

* Centrifugal: a flyweight mechanism driven by the engine is linked to the throttle and works against a spring in a fashion similar to that of the pneumatic governor, resulting in essentially identical operation.

Some include spring loading to provide some small torque so that with little or no input torque ( trailing throttle / gearbox in neutral / main clutch depressed ) the drive wheels are minimally coupled.

The top three then began to battle for the lead but none was able to close in on the other while Mansell continued to drop back, fighting a faulty throttle return spring.

Failures in the control system could theoretically cause a runaway vehicle, although this is no different from the throttle return spring snapping on a traditional mechanical throttle vehicle.