![sun 800 tester-001](https://upload.wikimedia.org/wikipedia/commons/e/e6/Sun_800_tester-001.jpg)
Engine tuning is the adjustment or modification of the
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
or
Engine Control Unit
An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by re ...
(ECU) to yield optimal performance and increase the engine's power output, economy, or durability. These goals may be mutually exclusive; an engine may be de-tuned with respect to output power in exchange for better economy or longer engine life due to lessened stress on engine components.
Tuning can include a wide variety of adjustments and modifications, such as the routine adjustment of the
carburetor
A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meteri ...
and
ignition system
An ignition system generates a spark or heats an electrode to a high temperature to ignite a fuel-air mixture in spark ignition internal combustion engines, oil-fired and gas-fired boilers, rocket engines, etc. The widest application for spark i ...
to significant engine overhauls. Performance tuning of an engine can involve revising some of the design decisions taken during the development of the engine.
Setting the idle speed,
air-fuel ratio, carburetor balance, spark plug and distributor point gaps, and ignition timing were regular maintenance tasks for older engines and are the final but essential steps in setting up a racing engine. On modern engines equipped with electronic ignition and fuel injection, some or all of these tasks are automated but they still require periodic calibration.
Engine tune-up
The term "tune-up" usually denotes the routine servicing of the engine to meet the manufacturer's specifications. Tune-ups are needed periodically according to the manufacturer's recommendations to ensure the vehicle runs as expected. Modern automobile engines typically require a small number of tune-ups over the course of an approximate or a 10-year, lifespan. This can be attributed to improvements in the production process in which imperfections and errors reduced by computer automation, and significant improvement in the quality of consumables such as the availability of
synthetic engine oil.
Tune-ups may include the following:
* Adjustment of the carburetor
idle speed
Idling refers to running a vehicle's engine when the vehicle is not in motion. This commonly occurs when drivers are stopped at a red light, waiting while parked outside a business or residence, or otherwise stationary with the engine running. Wh ...
and the
air-fuel mixture,
* Inspection and possible replacement of ignition system components like
spark plugs
A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air ...
,
contact breaker
A contact breaker (or "points") is a type of electrical switch, found in the ignition systems of spark-ignition internal combustion engines. The switch is automatically operated by a cam driven by the engine. The timing of operation of the switch ...
points,
distributor
A distributor is an enclosed rotating switch used in spark-ignition internal combustion engines that have mechanically timed ignition. The distributor's main function is to route high voltage current from the ignition coil to the spark plugs ...
cap and distributor
rotor
Rotor may refer to:
Science and technology
Engineering
*Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator
* Helicopter rotor, the rotary wing(s) of a rotorcraft ...
,
* Replacement of the
air filter
A particulate air filter is a device composed of fibrous, or porous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may als ...
and other filters,
* Inspection of
emission controls,
*
Valvetrain
A valvetrain or valve train is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) ...
adjustment.
The term "
Italian tuneup
Italian tuneup is a slang automotive term for attempting to restore engine performance by driving a car at high engine speed (RPM) and load.
The term originated from Italian mechanics in the 1950s using this practice to burn off carbon deposits fr ...
" denotes the driving of a performance car, such as a
Ferrari
Ferrari S.p.A. (; ) is an Italian luxury sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari (1898–1988) in 1939 from the Alfa Romeo racing division as ''Auto Avio Costruzioni'', the company built its first car in ...
, by mechanics finishing the tune-up to burn out any built-up carbon.
Chip tuning
Modern engines are equipped with an
engine management system (EMS)/Engine Control Unit (ECU) that can be adjusted to different settings, producing different performance levels. Manufacturers often produce a few engines that are used in a wider range of models and platforms. This allows the manufacturers to sell automobiles in various markets with different regulations without having to spend money developing and designing different engines to fit these regulations. This also allows a single engine tuned to suit the particular buyer's market to be used by several brands.
Remapping
Remapping is the simplest form of stage one engine tuning; it is performed mostly on
turbocharged
In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...
vehicles containing a modern
Engine Control Unit
An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by re ...
(ECU). Almost all modern vehicles have an ECU, primarily supplied by
Bosch or
Delphi Technologies
Delphi Technologies was an independent automotive company from 2017 to 2020, when it was acquired by BorgWarner Inc.
Delphi Technologies was formed in 2017 when Delphi Automotive, formerly a division of General Motors, renamed itself Aptiv and ...
. The ECU has
firmware
In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...
that controls the various parameters under which the engine runs. These parameters include achieving the appropriate balance between fuel consumption, power, torque, fuel emissions, reliability and service intervals. In seeking this balance many factory firmwares do not prioritise power or torque, which means it is possible to increase the performance of the engine by remapping the ECU.
Many manufacturers build one engine and use several firmware versions, known as maps, to achieve different power levels to differentiate vehicles that essentially have an identical engine. This gives users an opportunity to unlock more power from the engine with a few changes to the factory software by reading and editing the factory firmware from the ECU using specialist tools plugged into the
on-board diagnostics (OBD) port. The tools can be connected to the OBD port on any car to read the
factory file that is saved on the ECU. Software to read specific types of factory files is available.
Parameters of factory files such as fuel injection, boost pressure, rail pressure, fuel pump pressure and ignition timing, are adjusted to safe limits that are set by an expert so the unlocked performance does not compromise the car's safe levels of reliability, fuel consumption and emissions. The map may be customized for city use, for on-track performance, or for an overall map giving power throughout the band in a linear manner. Once adjusted, the edited file is written back to the ECU with the same tools used for the initial reading, after which the engine is tested for performance, smoke levels, and any problems. Fine-tuning is done according to the feedback, producing a better-performing and more efficient engine.
Remapping may increase the temperature of
exhaust fumes
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an ...
.
Performance tuning
Performance tuning is the tuning of an engine for
motorsport
Motorsport, motorsports or motor sport is a global term used to encompass the group of competitive sporting events which primarily involve the use of motorized vehicles. The terminology can also be used to describe forms of competition of two ...
s. Many such automobiles may never compete but are built for show or leisure driving. In this context, the power output,
torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
, and responsiveness of the engine are of premium importance, but reliability and
fuel efficiency
Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, wh ...
are also relevant. In races, the engine must be strong enough to withstand the additional stress placed upon it and the automobile must carry sufficient fuel, so it is often far stronger and has higher performance than the mass-produced design on which it may be based. The
transmission,
driveshaft
A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connec ...
and other load-transmitting
powertrain
A drivetrain (also frequently spelled as drive train or sometimes drive-train) is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components o ...
components may need to be modified to withstand the load from the increased power.
There are many techniques that can be used to increase the power and/or efficiency of an engine. This can be achieved by modifying the
air-fuel mixture drawn into the engine, modifying the static or dynamic
compression ratio
The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values.
A fundamental specification for such engines, it is measured two ways: the stati ...
of the engine, modifying the fuel used (e.g. higher
octane
Octane is a hydrocarbon and an alkane with the chemical formula , and the condensed structural formula . Octane has many structural isomers that differ by the amount and location of branching in the carbon chain. One of these isomers, 2,2,4-Tri ...
, different fuel types or chemistries), injection of
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
or methanol, modifying the timing and dwell of ignition events, and compressing the intake air.
Air fuel ratio meters are used to accurately measure the amount of fuel in the mixture. Fuel weight will affect the performance of the car, so fuel economy (thus efficiency) is a competitive advantage.
Ways to increase power include:
* Increasing the
engine displacement
Engine displacement is the measure of the cylinder volume swept by all of the pistons of a piston engine, excluding the combustion chambers. It is commonly used as an expression of an engine's size, and by extension as a loose indicator of the ...
by one or both of two methods: "
boring" - increasing the diameter of the
cylinder
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base.
A cylinder may also be defined as an infin ...
s and
piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tig ...
s, or by "stroking" - using a
crankshaft
A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...
with a greater throw.
* Using larger or multiple carburetors to create a more controllable air/fuel mixture to burn and to get it into the engine more smoothly.
Fuel injection
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines.
All comp ...
is more often used in modern engines, and may be modified in a similar manner.
* Increasing the size of the
poppet valve
A poppet valve (also called mushroom valve) is a valve typically used to control the timing and quantity of gas or vapor flow into an engine.
It consists of a hole or open-ended chamber, usually round or oval in cross-section, and a plug, usual ...
s in the engine, thus decreasing the restriction in the path of the fuel–air mixture entering the cylinder and the exhaust gases leaving it. Using
multiple valves per cylinder results in the same effect, though it is often more difficult to fit several small valves than to have larger, single valves due to the
valve gear
The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. It can also serve as a reversing ...
required. It can also be difficult to find space for one large valve in the inlet and a large valve on the outlet side, and sometimes a large exhaust valve and two smaller inlet valves are fitted.
* Using larger bored, smoother, less-contorted
inlet manifold
In automotive engineering, an inlet manifold or intake manifold (in American English) is the part of an engine that supplies the fuel/air mixture to the cylinders. The word '' manifold'' comes from the Old English word ''manigfeald'' (from th ...
and
exhaust manifold
In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word ''manifold'' comes from the Old English word ''manigfeald'' (from the Anglo-Saxon ''manig'' anyand ''feald'' old and refe ...
s helps maintain the velocity of gases. The ports in the
cylinder head
In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber.
In sidevalve engines, the head is a simple sheet of metal; whereas in more modern ov ...
can be enlarged and smoothed to match. This is termed
cylinder head porting
Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve their air flow. Cylinder heads, as manufactured, are usually suboptimal for racing applications due to being design ...
. Manifolds with sharp turns force the air–fuel mix to separate at high velocities because fuel is denser than air.
* The larger bore may extend through the
exhaust system
An exhaust system is used to guide reaction exhaust gases away from a controlled combustion inside an engine or stove. The entire system conveys burnt gases from the engine and includes one or more exhaust pipes. Depending on the overall syste ...
using large-diameter piping and low
back pressure
Back pressure (or backpressure) is a resistance or force opposing the desired flow of fluid through pipes, leading to friction loss and pressure drop. The term ''back pressure'' is a misnomer, as pressure is a scalar quantity, so it has a magnit ...
muffler
A muffler (North American and Australian English) or silencer (British English) is a device for reducing the noise emitted by the exhaust of an internal combustion engine—especially a noise-deadening device forming part of the exhaust sys ...
s, and through the
intake system with larger diameter
airbox
An airbox is an empty chamber on the inlet of most combustion engines. It collects air from outside and feeds it to the intake hoses of each cylinder.
Older engines drew air directly from the surroundings into each individual carburetor. Modern ...
es and high-flow, high-efficiency
air filter
A particulate air filter is a device composed of fibrous, or porous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may als ...
s. Muffler modifications will change the sound of the engine, usually making it louder.
* Increasing the
valve opening height (lift) by changing the profiles of the cams on the
camshaft
A camshaft is a shaft that contains a row of pointed cams, in order to convert rotational motion to reciprocating motion. Camshafts are used in piston engines (to operate the intake and exhaust valves), mechanically controlled ignition systems ...
or the
lever
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is div ...
(lift) ratio of the valve rockers in
overhead valve
An overhead valve (OHV) engine, sometimes called a ''pushrod engine'', is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with earlier flathead engines, where the valves were located be ...
(OHV) engines, or
cam follower
In mechanical engineering, a cam follower, also known as a track follower, is a specialized type of roller or needle bearing designed to follow cam lobe profiles. Cam followers come in a vast array of different configurations, however the most de ...
s in
overhead cam
An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...
(OHC) engines.
* Optimizing the valve timing to improve burning efficiency; this usually increases power at one range of operating
RPM
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines.
Standards
ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...
at the expense of reducing it at others. This can usually be achieved by fitting a differently profiled camshaft.
* Raising the
compression ratio
The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values.
A fundamental specification for such engines, it is measured two ways: the stati ...
by reducing the size of the combustion chamber, 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
In an internal combustion engine, a head gasket provides the seal between the engine block and cylinder head(s).
Its purpose is to seal the combustion gases within the cylinders and to avoid coolant or engine oil leaking into the cylinders. Leak ...
s or by using a
milling machine
Milling is the process of machining using rotary cutters to remove material by advancing a cutter into a workpiece. This may be done by varying direction on one or several axes, cutter head speed, and pressure. Milling covers a wide variety of d ...
to "shave" the
cylinder head
In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber.
In sidevalve engines, the head is a simple sheet of metal; whereas in more modern ov ...
. High compression ratios can cause
engine knock
In spark ignition internal combustion engines, knocking (also knock, detonation, spark knock, pinging or pinking) occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignite ...
unless
high-octane fuel
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating ...
s are used.
*
Forced Induction
In an internal combustion engine, forced induction is where turbocharging or supercharging is used to increase the density of the intake air. Engines without forced induction are classified as naturally aspirated.
Operating principle Overvi ...
; adding a
turbocharger
In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...
or a
supercharger
In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement.
The current categorisation is that a supercharger is a form of forced induct ...
. The air/fuel mix entering the cylinders is increased by compressing the air. Further gains may be realized by cooling the compressed intake air (compressing air makes it hotter) with an
air-to-air or
air-to-water intercooler.
* Using a fuel with higher energy content and by adding an
oxidizer
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxid ...
such as
nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a ...
.
* Using a fuel with better knock suppression characteristics (race fuel, E85, methanol, alcohol) to increase timing advance.
* Reducing losses to friction by machining moving parts to lower tolerances than would be acceptable for production, or by replacing parts. This is done In overhead valve engines by replacing the production rocker arms with replacements incorporating roller bearings in the roller contacting the valve stem.
* Reducing the rotating mass comprised by the
crankshaft
A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...
,
connecting rods
A connecting rod, also called a 'con rod', is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the cranksha ...
,
piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tig ...
s, and
flywheel
A flywheel is a mechanical device which uses the conservation of angular momentum to store rotational energy; a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, ass ...
to improve throttle response due to lower rotational inertia and reduce the vehicle's weight by using parts made from alloy instead of steel.
* Changing the tuning characteristics electronically, by changing the
firmware
In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...
of the
EMS. This ''
chip tuning
Chip tuning is changing or modifying an erasable programmable read only memory chip in an automobile's or other vehicle's electronic control unitECU to achieve superior performance, whether it be more power, cleaner emissions, or better fuel ef ...
'' often works because modern engines are designed to produce more power than required, which is then reduced by the EMS to make the engine operate smoothly over a wider
RPM
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines.
Standards
ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...
range, with low emissions. This is called de-tuning and produces long-lasting engines and the ability to increase power output later for facelift models. Recently emissions have played a large part in de-tuning, and engines will often be de-tuned to produce a particular carbon output for tax reasons.
* Lowering the underbonnet temperature to lower the engine intake temperature, thus increasing the power. This is often done by installing thermal insulation – normally a heatshield,
thermal barrier coating
Thermal barrier coatings (TBCs) are advanced materials systems usually applied to metallic surfaces operating at elevated temperatures, such as gas turbine or aero-engine parts, as a form of exhaust heat management. These 100 μm to 2 mm ...
or other type of
exhaust heat management – on or around the exhaust manifold. This ensures more heat is diverted from the under-bonnet area.
* Changing the location of the air intake, moving it away from the exhaust and radiator systems to decrease intake temperatures. The intake can be relocated to areas that have
higher air pressure due to aerodynamic effects, resulting in effects similar to
forced induction
In an internal combustion engine, forced induction is where turbocharging or supercharging is used to increase the density of the intake air. Engines without forced induction are classified as naturally aspirated.
Operating principle Overvi ...
.
The choice of modification depends on the degree of performance enhancement desired, budget, and the characteristics of the engine to be modified. Intake, exhaust, and chip upgrades are usually among the first modifications made because they are the cheapest and make reasonably general improvements. A change of camshaft, for instance, requires a compromise between smoothness at low engine speeds and improvements at high engine speeds.
Definitions
Overhaul
An overhauled engine is one that has been removed, disassembled, cleaned, inspected, repaired as necessary and tested using
factory service manual
Factory service manuals (FSM) are the manuals provided by manufacturers which cover the servicing, maintenance, and repair of their products. They are not designed for the general public, however they are created by manufacturers for use at their ...
approved procedures. The procedure generally involves
honing, new
piston ring
A piston ring is a metallic split ring that is attached to the outer diameter of a piston in an internal combustion engine or steam engine.
The main functions of piston rings in engines are:
# Sealing the combustion chamber so that there is min ...
s,
bearings,
gasket
Some seals and gaskets
A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...
s and oil seals. The engine may be overhauled to 'new limits' or 'service limits', or a combination of the two using used parts, new
original equipment manufacturer
An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional or ...
(OEM) parts, or new
aftermarket parts. The engine's previous operating history is maintained and it is returned with zero hours since major overhaul.
Aftermarket part manufacturers are often the OEM part-suppliers to major engine manufacturers.
A "top overhaul" is composed of the replacement of components inside the cylinder head without removing the engine from the vehicle, such as valve and rocker arm replacement. It may include a "
valve job A valve job is an operation which is performed on any four stroke cycle, internal combustion engine, the purpose of which is to resurface the mating surfaces of the poppet valves and their respective valve seats that control the intake and exhaust ...
". A "major overhaul" is composed of the whole engine assembly, which requires the engine to be removed from the vehicle and transferred to an engine stand. A major overhaul costs more than a top overhaul.
"New limits" are the factory service manual's approved fits and tolerances to which a new engine is manufactured. This may be accomplished by using "standard" or approved "undersized" and "oversized" tolerances. "Service limits" are the factory service manual's allowable wear fits and tolerances that a new-limits part may deteriorate to and still be a usable component. This may also be accomplished using "standard" and approved "undersized" and "oversized" tolerances.
Remanufactured
Remanufacturing means an engine assembled to match factory specifications. A buyer may sometimes take this to mean all-new parts are used, this is not always the case. At least the
cylinder block will be used. High-quality rebuilds will often include the fitting of new pistons and the line-boring of the crankshaft and camshaft bores. Remanufactured engines are engines that have been damaged, they are sent to machine shops to be remanufactured to the manufacturers specifications. Remanufactured engines are often known as Reman engines.
Blueprinting
Blueprint
A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets. Introduced by Sir John Herschel in 1842, the process allowed rapid and accurate production of an unlimited number ...
ing an engine means to build it to exact design specifications, limits and tolerances created by its OEM engineers or other users, such as high-performance racing or heavy duty industrial equipment.
Because few have the capability to actually blueprint, and because of the monetary incentive of claiming one has performed the work, many people have come to believe ''blueprinting'' only means that all the specifications are double-checked. Serious efforts at blueprinting result in better-than-factory tolerances, possibly with custom specifications appropriate for the application. Common goals include engine re-manufacturing to achieve the rated power for its manufacturer's design and rebuilding the engine to make it more power from a given design than otherwise intended. Blueprinted components allow for a more exact
balancing of reciprocating parts and rotating assemblies so less power is lost through excessive engine vibrations and other mechanical inefficiencies.
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 them. Reducing the weight of components is generally an advantage provided balance and adequate strength are both maintained, and more-precise machining will generally strengthen a part by removing stress points. In many cases performance tuners are able to work with finished components.
History
Engine tuning originated with the development of early racing cars and the post-war
hot-rod
Hot rods are typically American cars that might be old, classic, or modern and that have been rebuilt or modified with large engines optimised for speed and acceleration. One definition is: "a car that's been stripped down, souped up and made ...
movement.
Tools
The 'Igniscope' electronic ignition tester was produced by
English Electric
N.º UIC: 9094 110 1449-3 (Takargo Rail)
The English Electric Company Limited (EE) was a British industrial manufacturer formed after the Armistice of 11 November 1918, armistice of World War I by amalgamating five businesses which, during th ...
during the 1940s, originally as 'type UED' for military use during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. The post-war version, the 'type ZWA' electronic ignition tester, was advertised as "the first of its kind, employing an entirely new technique".
The Igniscope used a
cathode ray tube
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms ( oscilloscope), pictu ...
, giving an entirely visual method of diagnosis. It was invented by
D. Napier & Son, a subsidiary of English Electric. The Igniscope was capable of diagnosing latent and actual faults in both
coil and
magneto
A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, ...
ignition systems, including poor battery supply bonding, points and condenser problems, distributor failure and spark-plug gap. One feature was a "loading" control that made latent faults more visible.
The UED manual includes the spark plug
firing order
The firing order of an internal combustion engine is the sequence of ignition for the cylinders.
In a spark ignition (e.g. gasoline/petrol) engine, the firing order corresponds to the order in which the spark plugs are operated. In a diesel engi ...
of tanks and cars used by the British armed forces.
[Manual for the "Igniscope" UED tester, Appendix 1]
See also
*
Car tuning
Car tuning is the modification of a car to optimise it for a different set of performance requirements from those it was originally designed to meet. Most commonly this is higher engine performance and dynamic handling characteristics but cars ...
References
{{DEFAULTSORT:Engine Tuning
Tuning
Tuning can refer to:
Common uses
* Tuning, the process of tuning a tuned amplifier or other electronic component
* Musical tuning, musical systems of tuning, and the act of tuning an instrument or voice
** Guitar tunings
** Piano tuning, adjusti ...
cs:Tuning
lt:Tiuningas