thanks to my350z for the info:
If you don’t know how an engine works please first read this: http://en.wikipedia.org/wiki/Gas_engine
You are viewing: What Does N/a Mean In Cars
I hope those that don’t understand F/I or N/A Engine find it helpful too.
Note: I did not write any of this. I found all of the below information at: http://en.wikipedia.org/wiki/Main_Page
-N/A is short for Naturally-Aspirated.
A naturally-aspirated engine (NA – aspiration meaning breathing) refers to an internal combustion engine (normally petrol or diesel powered) that is neither turbocharged nor supercharged. Most automobile gasoline(petrol) engines are naturally-aspirated, though turbochargers and superchargers have enjoyed periods of success, particularly in the late 1980s and the current 2000s era. However, most road-going diesel-engined vehicles use turbochargers, because naturally-aspirated diesels generally cannot offer suitable power:weight ratios to be acceptable in the modern car market.
Air or fuel-air mixture is forced into the cylinders by natural atmospheric pressure upon opening of the inlet valve or valves. The pressure within the cylinder is lowered by the action of the piston moving away from the valves (so as to expand the volume available for incoming air). In some cases the lowering of the cylinder pressure is enhanced by a combination of the speed of the exhaust gases leaving the cylinder and the closing of the exhaust valve at the appropriate time. A tuned exhaust can help with this but generally only works at a narrow range of engine speeds and hence is most useful in very high performance cars, aircraft and helicopters. Many NA engines today make use of Variable Length Intake Manifolds to harness Helmholtz Resonance, which has a mild forced induction effect but is not be considered true forced induction.
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Natural aspiration gives less power than either turbo or supercharged engines of same engine displacement but is cheaper to produce and generally operates with better fuel efficiency. In drag racing, naturally-aspirated vehicles are vehicles that do not run a blower, a turbo, nor use nitrous oxide.
Many racing series specify NA engines to limit power and speed. NASCAR, Indycar, and Formula One are all in this category. Naturally-aspirated engines have been mandated in Formula One since 1989, in order to curb the excessive powers being developed by engines with superchargers or turbochargers.
-F/I is short for Forced induction.
Forced induction is a term used to describe internal combustion engines that are not naturally aspirated. Instead, a gas compressor is added to the air intake, thereby increasing the quantity of air or fuel-air mixture available for combustion.
Forced induction can be used to increase the power of an engine, its efficiency, or both, without much extra weight. Pressurizing the intake of combustion ingredients increases the effective capacity of the engine without an increase in physical size. The forced induction approach has the advantage that the intake pressure may be regulated according to the engine speed, thus providing power from extra capacity at high speed, but without wasting fuel at lower speeds.
The two different forced induction technologies in common use are superchargers and turbochargers. They differ mainly in the power source for the compressor.
-Supercharger (SC):
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A supercharger (also known as a blower, a positive displacement pump or a centrifugal pumper) is a gas compressor used to pump air into the cylinders of an internal combustion engine. The additional mass of oxygen that is forced into the cylinders allows the engine to burn more fuel, which improves the volumetric efficiency of the engine and makes it more powerful. A supercharger is powered mechanically by belt- or chain-drive from the engine’s crankshaft. It is similar in purpose to the closely related turbocharger, but a turbocharger is powered by the flow of the engine’s exhaust gases driving a turbine. Superchargers may absorb as much as a third of the total crankshaft power of the engine, and in many applications are less efficient than turbochargers. In applications where a massive amount of power is more important than any other consideration, such as top-fuel dragsters and vehicles used in tractor pulling competitions, superchargers are extremely common.
In cars, the device is used to increase the “effective displacement” and volumetric efficiency of an engine, and is often referred to as a blower. By pushing the air into the cylinders, it is as if the engine had larger valves and cylinders, resulting in a “larger” engine that weighs less. Turbochargers are more commonly used in this role because they use otherwise “wasted” energy instead of using up power from the crank, but the supercharger reacts more quickly to power application and thus outaccelerates a car with the same amount of boost being provided by a turbo.
In 1900 Gottlieb Daimler (of Daimler-Benz / Daimler-Chrysler fame) became the first person to patent a forced-induction system for internal combustion engines. His first superchargers were based on a twin-rotor air-pump design first patented by American Francis Roots in 1860. This design is the basis for the modern Roots type supercharger.
It wasn’t long after its invention before the supercharger was applied to custom racing cars, with the first supercharged production vehicles being built by Mercedes and Bentley in the 1920s. Since then superchargers (as well as turbochargers) have been widely applied to racing and production cars, although their complexity and cost has largely relegated the supercharger to the world of pricey performance cars.
Boosting has made something of a comeback in recent years due largely to the increased quality of the alloys and machining of modern engines. Boosting used to be an effective way to dramatically shorten an engine’s life but, today, there is considerable overdesign possible with modern materials and boosting is no longer a serious reliability concern. For this reason boosting is commonly used in smaller cars, where the added weight of the supercharger is smaller than the weight of a larger engine delivering the same amount of power. This also results in better gas mileage, as mileage is often a function of the overall weight of the car and that is based, to some degree, on the weight of the engine, gas mileage can also be saved with a turbo because the engine does not have to have as much displacement therefore not needing to inject as much petrol in the the cylinders. Nevertheless, adding boost to a car will often void the drivetrain warranty. Also, improperly installed or excessive boost will greatly reduce life expectancy of the engine as well as the transmission (which may not have been designed to cope with additional torque).
There are three types commonly used in today’s automotive world: Roots type supercharger, twin-screw type supercharger, and Centrifugal type supercharger.
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Source: https://t-tees.com
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