Car Engine Tuning Parts Buying Guide

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Car Engine Tuning Parts Buying Guide

Engine tuning has been an integral part of maintaining or improving the performance of an internal combustion engine throughout its history. In the early years, regular tune-ups were required to keep the engine functioning as intended. Modern engines do not require this calibration as frequently as their older counterparts did, but it is still a part of regular maintenance. Engines can also be tuned to improve a particular aspect of their performance: power, fuel efficiency, or durability. The term "engine tuning" usually refers to this type of performance enhancement. However, improving one factor may cause deterioration in another. For example, tuning an engine for more power usually results in lower fuel economy.

Engine tuning may involve the modification or replacement of car engine tuning parts or, in the case of more modern vehicles, changing the settings of the Engine Control Unit (ECU). Buyers considering parts to tune car engines should know how engine tuning works, what the different options available are, and the parts and tools needed to do the job.

Different Types of Engine Tuning

The word "tuning" is used to describe a range of adjustments and modification carried out on an engine. This can include everything from routine adjustments of fuel injection systems to complete engine overhauls. In modern engines, many of the routine maintenance tasks are performed automatically, with periodic calibration.

Engine Tune-Up

Tune-ups are regular maintenance tasks needed to keep an engine running as expected. They are based on manufacturers' recommendations and may include the following tasks:

Tightening cylinder head bolts
Adjusting carburettor idle speed and the air-fuel mixture
  • Inspecting the ignition system and replacing components as required
  • Replacing filters
  • Inspecting emission controls
  • Adjusting the valve train

Today's engines require a comparatively small number of tune-ups during their lifetime. Most manufacturers recommend a tune-up once every 30,000 miles or two years, whichever comes first.

Chip Tuning

Chip tuning originally referred to changing an engine's erasable programmable read-only memory (ROM) chip in the electronic control unit (ECU). Today the term is often used to describe ECU tuning that does not involve physically changing the chip. Modern ECUs can be tuned through a standard interface, by simply updating their software. An ECU in a modern engine controls spark timing, fuel injection, poppet valve timing, boost control, and other non-engine controls.

Performance Tuning

Performance tuning usually focuses on getting the most power out of an engine for the purpose of motorsport. However, many car engines undergo performance tuning even if they are not going to be used in competitive racing. If engines are tuned for improved fuel efficiency, it is sometimes called "economy tuning". When engines are tuned for greater power, other parts of the car may need to be changed to handle the increased stress. These include the transmission, driveshaft, and other powertrain components. Most methods of performance tuning are simply an attempt to increase the rate of combustion in the engine.

When to Tune a Car Engine

If an engine is being tuned for power or economy enhancements, it can be tuned anytime. Tune-ups, on the other hand, need to be carried out at regular intervals. These intervals are usually specified by manufacturers in terms of distance or years, whichever comes first. However, there are times when a car engine needs a tune-up even if it is not time for one. The following symptoms are signs that an engine requires a tune-up:

  • The car stalls often
  • Engine runs rough when idling or accelerating
  • The car is increasingly harder to start

How to Tune a Car Engine

In early engines, performance tuning was possible by changing or modifying parts of the engine. Modern engines however, are usually detuned through the ECU by manufacturers. This helps the cars meet emission standards and provides smoother performance since engine limits are not reached. As a result, simply tweaking ECU settings can result in improved performance.

Physical Changes to the Engine

Even with modern car engines, physical changes to parts of the engine can greatly enhance aspects of their performance. Depending largely on what type of performance enhancement is required, users have several alternative methods. Some of the ways to increase the power of an engine are described below.

Desired Result



Increased engine displacement



Increased cylinder volume

Greater movement of the cylinder

More controllable air-fuel mixture

Larger carburettors

Multiple carburettors

Engine runs smoother

Less restrictions in air-fuel mixture path

Increase size of poppet valves

Increase number of valves

More space for air-fuel mixture to enter and leave cylinders

Maintain velocity of gases

Cylinder head porting

Smoother flow of engine gases

Improved burning efficiency

Use camshaft with different profile

Optimised valve timing

Better burning efficiency

Increased air-fuel mixture intake

Add a turbocharger or supercharger

Cool intake air with an intercooler

Compressed air increases air-fuel mixture intake

Increased power

Reduced friction loss

Machine parts to lower tolerance

Smoother movement of engine parts

Reduced "rotating mass"

Replace steel parts with alloy equivalents

Increased throttle response

Lower underbonnet temperature

Install thermal insulation

Lower intake temperature

More power

Changes to parts of a vehicle other than the engine can also enhance performance. Changes to exhaust systems, for example, have a direct impact on engine performance. Physical changes to an engine also require ECU remapping in modern engines to fully realise performance gains.

Modifying ECU Settings

Engines with ECUs can be tuned by modifying the software of the ECU. This is called "remapping" the ECU. The most common way this is done is with plug in modules or an "on board diagnostics flash tool". Some ECUs can support several different maps, allowing drivers to choose the type of engine performance. Two types of maps are available from tuners: library files, and custom remapping. Custom remapping is done by a professional tuner who begins with the original file in the ECU. Only the settings that need to be changed are touched. Other manufacturer settings, including software updates, security features, and bug fixes, are left as they are.

On the other hand, remapping with a library file is not customised in any way. The original ECU file is overwritten completely with no regard for features or updates that may be critical to the operation of the engine. Though performance gains may be achieved, there is a high probability of the engine becoming buggy. In some cases, the ECU may freeze and become inaccessible. Buyers should opt for custom remapping even if it is more expensive than remapping with library files.

Another way to tune this type of engine is to add an external tuning box. External boxes have the advantage of allowing owners to quickly return their cars to standard configuration by simply removing them.

The Parts and Equipment Involved in Car Engine Tuning

Different parts of an engine may be changed or modified when it undergoes performance tuning. If an engine is tuned for higher performance, parts of the powertrain may need to be replaced if they cannot handle the increased power of the engine. Special tools and accessories are available for tuning and maintaining car engines.

Type of Part

Name of Part, Tool, or Accessory

Engine parts

Spark plugs

Air filter

Ignition wires and cables

Distributor rotor cap


Valve rockers

Cam followers


Poppet valves

Alloy "rotating mass"; crankshaft, connecting rods, pistons, and flywheel

Heat shields and thermal barrier coating

Powertrain parts



ECU modification

ECU maps

Plug-in chip module

Tools and accessories

Spark plug tool

Spark plug gapping tool

Torque wrenches

Air-fuel ratio meter

On board diagnostics flash tool

Compressed air

Air flow bench

Milling machine

Not all parts are changed when an engine is tuned. In fact, most times only the ECU settings need remapping. However, even modern car engines can benefit from performance replacements.

Buying Car Engine Tuning Parts on eBay

Buyers looking for car engine tuning parts can choose from an extensive collection of engine parts, tools, and accessories on eBay. Buyers can use the search bar available on the eBay homepage and other pages on the site to quickly locate an item. If search results are too extensive, buyers can obtain more relevant results by adding specific keywords to the search phrase. For example, a search for "Ford Escort oversize piston" lists only the Ford Escort oversize pistons currently available on eBay.

Buyers can ask seller's any questions they may have regarding an item's condition and compatibility before deciding to purchase a part. Buyers must review a seller's exchange and return policy before committing to a purchase. This is important in case an item is defective or does not meet expectations. Buyers can also avoid postage costs by choosing a seller located nearby and arranging a local pick-up, if the seller is comfortable with such an arrangement.


Tuning an engine is essential to maintaining or improving its performance. Early engines required regular tune-ups to keep them running well. Modern engines perform many of these tasks automatically, but still require calibration. Tuning can also improve or change the characteristics of an engine. This type of tuning is called "performance" or "economy" tuning, depending on the purpose of the tuning. Most tuning is meant to enhance the engine's power output. Performance tuning in modern cars can be achieved by "remapping" the engine control unit (ECU). Buyers should avoid remapping the ECU with library files since this can degrade engine performance, or even make the ECU unusable.

Physical changes to the engine were once the only way of improving the performance of an engine. Replacing or modifying engine parts is still one of the best ways to improve engine performance. Different parts of an engine may be changed or modified depending on the end result desired. Buyers looking for car engine tuning parts online can choose from a wide range on eBay.

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