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Encyclopedia > Engine tuning

Engine tuning is the adjustment, modification or design of internal combustion engines to yield optimal performance, either in terms of power output or economy. It has a long history, almost as long as the development of the car in general, originating with the development of early racing cars, and later, with the post-war hot-rod movement. Tuning can describe a wide variety of adjustments and modifications, from the routine adjustment of the carburetor and ignition system to significant engine overhauls. At the other end of the scale, performance tuning of an engine can involve revisiting some of the design decisions taken at quite an early stage in the development of the engine. Image File history File links Question_book-3. ... In music, tuning is the process of producing or preparing to produce a certain pitch in relation to another, usually at the unison but often at some other interval. ... A colorized automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... Car redirects here. ... Auto racing (also known as automobile racing or autosport) is a sport involving racing automobiles. ... This article does not cite any references or sources. ... Bendix-Technico (Stromberg) 1-barrel downdraft carburetor model BXUV-3, with nomenclature A carburetor (North American spelling) or carburettor (Commonwealth spelling), is a device that blends air and fuel for an internal combustion engine. ... The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ...


On older engines, setting the idling speed, mixture, carburetor balance, spark plug and distributor point gaps and ignition timing were both regular tasks on all engines and the final but essential steps in setting up a racing engine. On modern engines some or all of these tasks are automated, although they still require periodic calibration.

Contents

Engine Tune-up

A tune-up usually refers to the routine servicing of the engine to meet the manufacturer's specifications. Tune-ups are needed periodically as according to the manufacturer's recommendations to ensure an automobile runs as expected. Modern vehicles now often run over 160,000 km (or 10 years) without requiring a tune-up.[citation needed] A kilometre (American spelling: kilometer) (symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ...


Tune-ups may include the following:

The cylinder head from a GMC van. ... Bendix-Technico (Stromberg) 1-barrel downdraft carburetor model BXUV-3, with nomenclature A carburetor (North American spelling) or carburettor (Commonwealth spelling), is a device that blends air and fuel for an internal combustion engine. ... The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ... Breaker arm with contact points at the left. ... Distributor cap. ... Air filter in an Opel Astra car, top side=clean side Air filter in an Opel Astra car, bottom side=dust side Automotive air filter clogged with dust and debris. ... Emissions control may refer to: EMCON, a military state of readiness. ...

Chip tuning

Main article: Chip tuning

Modern engines are equipped with an engine management system which can be modified to different settings, producing different performance levels. Manufacturers often produce a few engines which are used in a wider range of models and platforms, and this allows the manufacturers to sell cars in various markets with different regulations without having to spend money developing and designing different engines to fit these regulations. This also allows for a single engine to be used by different brands, tuned to suit their particular market. Chip tuning refers to changing or modifying an EPROM chip in a cars or other vehicles electronic control unit (ECU) to achieve better performance, whether it be more power, cleaner emissions, or better fuel economy. ... In automotive electronics, an electronic control unit (ECU) is an embedded microcomputer that controls one or more of the electrical subsystems in a vehicle. ...


Performance tuning

Performance tuning focuses on tuning an engine for motor sport, although many such cars never compete but rather are built for show or leisure driving. In this context, the power output, torque, and responsiveness of the engine are of premium importance, but reliability and fuel economy are also relevant. In races, the engine must be strong enough to withstand the additional stress placed upon it, and so is often far stronger than any mass-produced design on which it may be based, and also that the vehicle must carry sufficient fuel. In particular, the transmission, driveshaft and any other load-bearing powertrain components may need be modified to withstand the load from increased power. Auto racing (also known as automobile racing or autosport) is a sport involving racing automobiles. ... “Gearbox” redirects here. ... This article is about the mechanical device. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...


In most cases, people are interested in increasing the power output of an engine. Many well tried and tested techniques have been devised to achieve this, but all essentially operate to increase the rate (and to a lesser extent efficiency) of combustion in a given engine. This is achieved by putting more fuel/air mixture into the engine, using a fuel with higher energy content, burning it more rapidly, and getting rid of the waste products more rapidly - this increases volumetric efficiency. In order to check the amount of the fuel/air mixture, air fuel ratio meters are often used. The weight of this fuel will affect the overall performance of the car, so fuel economy is a competitive advantage. This also means that the performance tuning of an engine should take place in the context of the development of the overall vehicle. Volumetric efficiency in internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. ... An air-fuel ratio meter is a meter that monitors the air-fuel ratio of an internal combustion engine. ...


The specific ways to increase power include:

  • Increasing the engine displacement by one or both of two methods: "Boring" - increasing the diameter of the cylinders and pistons, or by "stroking" - using a crankshaft with a longer stroke and longer connecting rods, in combination with pistons of shorter compression height (to maintain the original compression ratio).
  • Using larger or multiple carburetors, to create more fuel/air mixture to burn, and to get it into the engine more quickly. In modern engines, fuel injection is more often used, and may be modified in a similar manner.
  • Increasing the size of the valves in the engine, thus decreasing the restriction in the path of the fuel/air mixture entering, and the exhaust gases leaving the cylinder. Using multiple valves per cylinder results in the same thing - it is often more practical to have several small valves than have larger single valves.
  • Using larger bored, smoother, less contorted intake and exhaust manifolds. This helps maintain the velocity of gases. Similarly, the ports in the cylinder can be enlarged and smoothed to match. This is termed cylinder head porting, usually with the aid of an air flow bench for testing and verifying the efficiency of the modifications.
  • The larger bore may extend right through the complete exhaust system, using larger diameter piping and low back pressure mufflers, and through the intake system, with larger diameter airboxes and high-flow, high-efficiency air filters. Muffler modifications will change the sound of the car's engine, usually making it louder; for some tuners this is in itself a desirable property.
  • Increasing the valve opening height (lift), by changing the profiles of the camshaft or the lift (lever), ratio of the valve rockers (OHV engines), or cam followers (OHC engines).
  • Optimising the valve timing to improve burning efficiency - usually this increases power at one range of operating RPM at the expense of reducing it at others. For many applications this compromise is acceptable. Again this is usually achieved by a differently profiled camshaft. See also valve timing, variable valve timing.
  • Raising the compression ratio, which makes more efficient use of the cylinder pressure developed and leading to more rapid burning of fuel, by using larger compression height pistons or thinner head gasket, or by milling or "shaving" the cylinder head.
  • Forced Induction; adding a turbocharger or supercharger. The fuel/air mass entering the cylinders is increased by compressing the air first, usually mechanically. Further gains may be realized by cooling compressed (and thus heated) intake air with an air-to-air or air-to-water intercooler.
  • Using a fuel with higher energy content or by adding an oxidiser such as nitrous oxide.
  • Reducing losses to friction by machining moving parts to better tolerances than would be acceptable for production, or by replacing parts. A common example of this is, in OHV engines, replacing the production rocker arms with replacements incorporating roller bearings in the roller contacting the valve stem.
  • Reducing the mass of the "rotating mass", which comprises the crankshaft, connecting rods, and pistons. Doing so can improve throttle response due to lower inertia, as well as reduce overall vehicle weight.
  • Changing the tuning characteristics electronically, by changing the firmware of the engine management system (EMS). This chip tuning often works because modern engines are designed to give a great deal of raw power, which is then reduced by the engine management system to make the engine operate smoothly over a wider RPM range, with low emissions. By analogy with an operational amplifier, the EMS acts as a feedback loop around an engine with a great deal of open loop gain. Many modern engines are now of this type and amenable to this form of tuning. Naturally many other design parameters are sacrificed in the pursuit of power.

The choice of modification depends greatly on the degree of performance enhancement desired, budget, and the characteristics of the engine to be modified. Intake, exhaust, and chip upgrades are usually amongst the first modifications made as they are the cheapest, make reasonably general improvements (whereas a different camshaft, for instance, requires trading off performance at low engine speeds for improvements at high engine speeds), can often improve fuel economy, generally do not affect engine reliability much (because no moving parts are modified), and are in any case essential to take full advantage of any further upgrades. One complete cycle of a four cylinder, four stroke engine. ... Cylinder with piston in a steam engine A cylinder in the central working part of a reciprocating engine, the space in which a piston travels. ... For the American composer, see Walter Piston. ... Crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black) Continental engine marine crankshafts, 1942 Components of a typical, four stroke cycle, DOHC piston engine. ... Bold text The compression ratio is a single number that can be used to predict the performance of any engine (such as an internal-combustion engine or a Stirling Engine). ... Bendix-Technico (Stromberg) 1-barrel downdraft carburetor model BXUV-3, with nomenclature A carburetor (North American spelling) or carburettor (Commonwealth spelling), is a device that blends air and fuel for an internal combustion engine. ... // Multi Port Fuel injection is a means of metering fuel into an internal combustion engine. ... A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ... In automotive engineering, an engine is referred to as multi-valve (or multivalve) when each cylinder has more than two valves. ... Left side of a Ford Cologne V6 engine, clearly showing a (rusty) cast iron exhaust manifold - three exhaust ports into one pipe. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel. ... This article is about the engine piece. ... Air filter in an Opel Astra car, top side=clean side Air filter in an Opel Astra car, bottom side=dust side Automotive air filter clogged with dust and debris. ... For the fictional characters of the same name, see Camshaft (Transformers). ... For the Portuguese town and parish, see Lever, Portugal. ... OHV redirects here. ... Overhead cam (OHC) piston engines place the camshaft above the cylinder heads and drive the valves or lifters directly instead of using pushrods. ... rpm or RPM may mean: revolutions per minute RPM Package Manager (originally called Red Hat Package Manager) RPM (movie) RPM (band), a Brazilian rock band RPM (magazine), a former Canadian music industry magazine In firearms, Rounds Per Minute: how many shots an automatic weapon can fire in one minute On... Today Internal combustion engines in cars, trucks, motorcycles, construction machinery and many others, most commonly use a four-stroke cycle. ... Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. ... Bold text The compression ratio is a single number that can be used to predict the performance of any engine (such as an internal-combustion engine or a Stirling Engine). ... Different kinds of gaskets, #4 indicating a V4 head gasket. ... Endmills for a milling machine. ... The cylinder head from a GMC van. ... Forced induction is a term used to describe internal combustion engines that are not naturally aspirated. ... Air foil bearing-supported turbocharger cutaway made by Mohawk Innovative Technology Inc. ... A supercharger (also known as a blower) is an air compressor used to force more air (and hence more oxygen) into the combustion chamber(s) of an internal combustion engine than can be achieved at ambient atmospheric pressure (natural aspiration). ... An intercooler, or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through isochoric cooling. ... For other uses, see Nitrous oxide (disambiguation). ... For other uses, see Friction (disambiguation). ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ... In automotive electronics, an electronic control unit (ECU) is an embedded microcomputer that controls one or more of the electrical subsystems in a vehicle. ... Chip tuning refers to changing or modifying an EPROM chip in a cars or other vehicles electronic control unit (ECU) to achieve better performance, whether it be more power, cleaner emissions, or better fuel economy. ... rpm or RPM may mean: revolutions per minute RPM Package Manager (originally called Red Hat Package Manager) RPM (movie) RPM (band), a Brazilian rock band RPM (magazine), a former Canadian music industry magazine In firearms, Rounds Per Minute: how many shots an automatic weapon can fire in one minute On... Op-amp ICs (some single, some dual) in 8-pin dual in-line packages (DIPs) An operational amplifier, usually referred to as an op-amp for brevity, is a DC-coupled high-gain electronic voltage amplifier with differential inputs[1] and, usually, a single output. ...


Furthermore, tuners may also use analytical tools to help evaluate and predict the effect of modifications on the perfromance of the car.


Definitions

Overhaul

An engine Overhaul means putting the engine back to factory specifications. This generally involves new Piston rings, bearings and Gaskets. When done by a competent engine builder, you can be confident the engine will perform as new. Spring-loaded piston rings. ... A bearing is a component used to reduce friction in a machine. ... This article is about mechanical seals. ...


A top overhaul only covers the replacement of components inside the cylinder head without removing the engine from the vehicle, such as valve and rocker arm replacement. A full overhaul however covers the whole engine component replacement which requires the engine to be removed from the vehicle, such as replacing the connecting rods and crankshaft bearings. By comparison, a full overhaul service costs more than a top overhaul service. The cylinder head from a GMC van. ...


Rebuild

Rebuild is a marketing term with no fixed definition. It is often taken to mean a professional overhaul with certain parts replaced with new units whether needed or not. For example some rebuilders will always replace the pistons (which often are not replaced during an overhaul unless damaged).


Re-manufacture

Re-manufactured is a marketing term to mean an engine put together to match factory specifications e.g. "as new". Although often a buyer may take this to mean all-new parts are used, this is never the case. At the very least, the cylinder block will be used, as may most other parts. High-quality rebuilds will often include new pistons and line-boring of the crankshaft and camshaft bores. The cylinder block of a Ford I4 DOHC engine The cylinder block or engine block is a machined casting (or sometimes an assembly of modules) containing cylindrically bored holes for the pistons of a multi-cylinder reciprocating internal combustion engine, or for a similarly constructed device such as a pump. ...


Blueprinting

In engine blueprinting, all the specifications are double-checked. Usually this indicates closer-than-factory tolerances, with custom specifications appropriate for a street car or a race car. The goals usually are to:

  • Ensure the engine puts out the rated power (because not all mass-production engines put out the rated power) for its manufacturer's design

or

  • Eke more power out of a given engine design, by extra careful measurement and assembly
  • balancing of reprocating parts and rotating assemblies, to reduce engine vibrations thus achieving more power due to recover of power "lost" to vibrations

Ideally, blueprinting is performed on components removed from the production line before normal balancing and finishing. If finished components are blueprinted, there is the risk that the further removal of material will weaken the component. However, lightening components is generally an advantage in itself provided balance and adequate strength are both maintained, and more precise machining will in general strengthen a part by removing stress points, so in many cases performance tuners are able to work with finished components. Engine balance is the design, construction and tuning of an engine to run smoothly. ...


For example, an engine manufacturer may list a piston ring end-gap specification of 0.003 to 0.005 inches for general use in a consumer automobile application. For an endurance racing engine which runs hot, a "blueprinted" specification of 0.00045 to 0.00050 may be desired. For a drag-racing engine which runs only in short bursts, a tighter 0.00035 to .00040 inch tolerance may be used instead. Thus "Blueprint" can mean tighter or looser clearances, depending on the goal.


See also

Wikibooks
Wikibooks' [[wikibooks:|]] has more about this subject:
Reading spark plugs for racing

Image File history File links Wikibooks-logo-en. ... The power band of an engine refers to the range of operating speeds under which the engine is able to operate efficiently. ... Tuned Audi TT Car tuning is both an industry and a popular hobby, in which a car is modified in order to improve its performance and handling and better suit the owners driving style. ... Chip tuning refers to changing or modifying an EPROM chip in a cars or other vehicles electronic control unit (ECU) to achieve better performance, whether it be more power, cleaner emissions, or better fuel economy. ... A screen shot of Crome 1. ... A screen shot of Uberdata 1. ...

External Links

  • Tuner Plaza

  Results from FactBites:
 
Nitro Engine Tuning (3813 words)
The engine will be a little softer when accelerating from a standstill, but it’s the only way to ensure there is an adequate supply of fuel and oil when running at the upper end of the rpm range.
If the engine is able to idle steadily for a longer time, then it may start to lean out and heat up during a race and make it difficult to drive the car and keep the engine running.
Engine tuning is not a fl art; it just takes time to learn the particulars so you can maximize your power plant's performance.
Engine tuning - Wikipedia, the free encyclopedia (1206 words)
Engine tuning or engine building is the adjustment, modification or design of internal combustion engines to yield more performance, either in terms of power output or economy.
Performance tuning focusses on the tuning of an engine for motor sport, although many cars built by hobbyists never compete but are rather built for display at motor shows or the simple pleasure of owning and driving such a car.
Increasing the size of the valves in the engine, thus decreasing the restriction in the path of the fuel/air mixture entering, and the exhaust gases leaving the cylinder.
  More results at FactBites »

 
 

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