Heel-and-toe shifting [1] is an advanced driving technique used mostly in performance driving with a manual gearbox, [2] although some drivers use it on the road in everyday conditions in the interest of effectiveness. It involves operating the throttle and brake pedals simultaneously with the right foot, while facilitating normal activation of the clutch with the left foot. It is used when braking and downshifting simultaneously (prior to entering a turn), and allows the driver to "blip" the throttle to raise the engine speed and smoothly engage the lower gear.
Heel-and-toe shifting is used before entry into a turn while a vehicle is under braking, preparing the transmission to be in the optimal range of rpm to accelerate out of the turn. One benefit of downshifting before entering a turn is to eliminate the jolt to the drivetrain, or any other unwanted dynamics. The jolt will not upset the vehicle as badly when going in a straight line, but the same jolt while turning may upset the vehicle enough to cause loss of traction if it occurs after the turn has begun. Sporting vehicles are usually modified (if necessary) so that the heights of the brake and accelerator pedals are closely matched when the brake is sufficiently depressed, and the pedals are not too far apart to permit easy use of heel-and-toe.
The name stems from pre-WW2 vehicles where the accelerator pedal was in the centre (between the clutch on the left and the foot brake to the right). The brake was able to be operated with the heel whilst the accelerator pedal could be simultaneously pressed with the toe. The technique is carried out in modern cars by operating the brake with the toe area, while rocking the foot across to the right to operate the throttle with the right side of the foot. With practice, it becomes possible to smoothly and independently operate both pedals with one foot.
As the power band of most race cars is found high in the rev range, this technique can also be used to ensure that engine rpm does not drop below the power band of the car while under braking, by allowing a lower gear to keep the engine in the desired rev range. The importance of this is to avoid delay between the driver accelerating after the corner and when the car responds. This is especially true in turbocharged cars where not only is it important to maintain the required rev range for strong positive boost, but the 'blipping' of the accelerator can also be used to maintain turbine speeds and thus avoid turbo lag. This technique ensures that maximum power can be reached the instant the brake pedal is released and the accelerator fully depressed.
Rowing is the technique of downshifting more than one gear along with the heel-and-toe technique to provide engine braking and smoother deceleration/braking while in the intermediate gears. This provides for maximum braking when going from a top gear to a much lower gear, and optimal engine rpm for exiting the corner.[ citation needed ]
Double-clutching is a method of shifting gears used primarily for vehicles with an unsynchronized manual transmission, such as commercial trucks and specialty vehicles. While double clutching is not necessary in a vehicle that has a synchronized manual transmission, the technique can be advantageous for smoothly downshifting in order to accelerate and, when done correctly, it prevents wear on the synchronizers which normally equalize transmission input and output speeds to allow downshifting.
Left-foot braking is the technique of using the left foot to operate the brake pedal in an automobile, leaving the right foot dedicated to the throttle pedal. It contrasts with the practice of using the left foot to operate the clutch pedal, leaving the right foot to share the duties of controlling both brake and gas pedals.
Cruise control is a system that automatically controls the speed of an automobile. The system is a servomechanism that takes over the car's throttle to maintain a steady speed set by the driver.
A manual transmission (MT), also known as manual gearbox, standard transmission, or stick shift, is a multi-speed motor vehicle transmission system, where gear changes require the driver to manually select the gears by operating a gear stick and clutch.
In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated.
A semi-automatic transmission is a multiple-speed transmission where part of its operation is automated, but the driver's input is still required to launch the vehicle from a standstill and to manually change gears. Semi-automatic transmissions were almost exclusively used in motorcycles and are based on conventional manual transmissions or sequential manual transmissions, but use an automatic clutch system. But some semi-automatic transmissions have also been based on standard hydraulic automatic transmissions with torque converters and planetary gearsets.
Engine braking occurs when the retarding forces within an internal combustion engine are used to slow down a motor vehicle, as opposed to using additional external braking mechanisms such as friction brakes or magnetic brakes.
Dynaflow was the trademarked name for a type of automatic transmission developed and built by General Motors Buick Motor Division from late 1947 to mid-1963. The Dynaflow, which was introduced for the 1948 model year only as an option on Roadmaster models, received some severe early testing in the M18 Hellcat tank destroyer, which were built in Buick's Flint Assembly plant during World War II. It was also used in the 1951 Le Sabre concept car.
A direct-shift gearbox is an electronically controlled, dual-clutch, multiple-shaft, automatic gearbox, in either a transaxle or traditional transmission layout, with automated clutch operation, and with fully-automatic or semi-manual gear selection. The first dual-clutch transmissions were derived from Porsche in-house development for the Porsche 962 in the 1980s.
A transmission control unit (TCU), also known as a transmission control module (TCM), or a gearbox control unit (GCU), is a type of automotive ECU that is used to control electronic automatic transmissions. Similar systems are used in conjunction with various semi-automatic transmissions, purely for clutch automation and actuation. A TCU in a modern automatic transmission generally uses sensors from the vehicle, as well as data provided by the engine control unit (ECU), to calculate how and when to change gears in the vehicle for optimum performance, fuel economy and shift quality.
The Scandinavian flick is a technique used predominantly in ice racing and rallying. The technique induces oversteer using weight transfer to carry a vehicle through a turn while simultaneously reducing speed.
Clutch control refers to the act of controlling the speed of a vehicle with a manual transmission by partially engaging the clutch plate, using the clutch pedal instead of the accelerator pedal. The purpose of a clutch is in part to allow such control; in particular, a clutch provides transfer of torque between shafts spinning at different speeds. In the extreme, clutch control is used in performance driving, such as starting from a dead stop with the engine producing maximum torque at high RPM.
A wheelspin occurs when the force delivered to the tire tread exceeds that of available tread-to-surface friction and one or more tires lose traction. This leads the wheels to "spin" and causes the driver to lose control over the tires that no longer have grip on the road surface. Wheelspin can also be done intentionally such as in drifting or doing a burnout.
The Turboglide is a Chevrolet constant torque, continuously variable automatic transmission first offered as an option on Chevrolet V8 passenger cars for 1957. It consisted of a turbine-driven planetary gearbox with a 'switch pitch' dual-pitch torque converter stator. It had a die-cast aluminum transmission case, like Packard's Ultramatic of 1956. Turboglide cost about $50 more than the Powerglide 2-speed automatic. It was available in all V8-powered 1957-1961 Chevrolet models except the Corvette. General Motors produced 646,000 of these transmissions during its production.
A line lock is a device that allows the front brakes to lock independently of the rear brakes via a switch. The device is an electric solenoid that controls a valve which allows the brakes to be controlled individually. This allows the front brakes to be locked and the rear brakes to be open, and allows the driver to spin the rear wheels without wasting the rear brakes. This method is referred to as line lock and is popular among enthusiasts who like to do burnouts.
Sudden unintended acceleration (SUA) is the unintended, unexpected, uncontrolled acceleration of a vehicle, often accompanied by an apparent loss of braking effectiveness. Such problems may be caused by driver error, mechanical or electrical problems, or some combination of these factors. The US National Highway Traffic Safety Administration estimates 16,000 accidents per year in the United States occur when drivers intend to apply the brake but mistakenly apply the accelerator.
Synchronized downshift rev-matching system is a technology invented by Nissan for use on the Nissan 370Z. In combination with the Electronic Control Unit (ECU) and various sensors, the engine electronically blips the throttle for the driver during both downshifts and upshifts to allow for better and smoother shifting, and improved handling.
A MultiMode manual transmission is a type of automated manual transmission offered by Toyota. It uses a traditional manual gearbox with a computer-controlled clutch actuated by permanent magnet motors. Multimode Manual Transmission is available in the Aygo, Yaris, Corolla, Corolla Verso, Mark X and Auris in Europe, and should not be confused with Multimode Automatic Transmission, which is offered in the North American market by Toyota.
A motorcycle transmission is a transmission created specifically for motorcycle applications. They may also be found in use on other light vehicles such as motor tricycles and quadbikes, go-karts, offroad buggies, auto rickshaws, mowers, and other utility vehicles, microcars, and even some superlight racing cars.
Car controls are the components in automobiles and other powered road vehicles, such as trucks and buses, used for driving and parking.