Car tuning

Car tuning is a generalized term to refer to the act of improving the performance or appearance of a vehicle. For actual "tuning" in the sense of automobiles or vehicles, see engine tuning. As most vehicles leave the factory set up for average driver expectations and average conditions, tuning has become a way to personalize the characteristics of the vehicle to the owner's preference. For example, cars may be altered to provide better fuel economy, produce more power, or to provide better handling.

Car tuning is related to auto racing, although most performance cars never compete. Rather, they are built for the pleasure of owning and driving such a vehicle. Exterior modifications include changing the aerodynamic characteristics of the vehicle via side skirts, front and rear bumpers, spoilers, splitters, air vents and light weight wheels.

In the 1970s and 80s, many Japanese performance cars were never exported outside the Japanese domestic market. In the late 1980s and early 1990s, grey imports of Japanese performance cars, such as the Nissan Skyline , began to be privately imported into Western Europe and North America. In the United States, this was in direct contrast to the domestic car production around the same time, where there was a very small performance aftermarket for domestic compact and economy cars; the focus was instead on sporty cars such as the Ford Mustang and Chevrolet Corvette, or on classic muscle cars.

Because of their light weight and the increasing availability of low-cost tuning equipment, economy and compact cars exhibit high performance at a low cost in comparison to dedicated sports cars. As professional sporting and racing with such vehicles increased, so did recreational use of these vehicles. Drivers with little or no automotive, mechanical, or racing experience would modify their vehicles to emulate the more impressive versions of racing vehicles, with mixed results.

Engine tuning

Engine tuning is a significant element of car tuning. An experienced engine tuner can improve the output of stock motors with the simple adjustment of values in the vehicle's engine control or powertrain control module.

Although installing a supercharger or turbo may be mistaken for tuning, this is incorrect. Tuning is necessary after installation, but the two are only interrelated in that sense, no further. Installing a forced induction system to a vehicle is more related to the act of bolting on.

Some tuners will install devices which modify communications to the Engine Control Unit in order to obtain more power. Such devices provide the stock ECU with inaccurate data from sensors to modify engine output. This is often an inexpensive way to modify an OEM computer system used to tune lightly modified vehicles. This method is known as piggy-backing, or using the stock engine management along with a chip to provide the "inaccurate" data to fool the ECU into providing the correct amount of fuel and spark timing.

Today’s car and light truck engines are fully electronically controlled. That makes it very easy to enhance the performance of the engine through “Chip-Tuning”. This refers to modifying the programming of the computer chips which control the engine management. Chip tuning can be used for both gasoline and diesel engines that are equipped with an electronic motor management.

Other standalone engine management systems are available. These systems replace the factory computer with one that is user programmable. Using such a device a tuner can control all running aspects of an engine; reducing knock, correcting air fuel ratios, and advancing or retarding timing to 

obtain efficient power levels for their setup.

 

Suspension tuning

Suspension tuning involves modifying the springs, shock absorbers, swaybars, and other related components of a vehicle. Shorter springs offer greater stiffness and a lower center of gravity at the cost of proper suspension geometry. Stiffer shock absorbers improve the dynamic weight shifting during cornering and normally have shorter internals to stop them from bottoming out when shorter springs are used. Stiffer sway bars reduce body roll during cornering, thus improving the grip that the tires have on the surface by reducing suspension geometry changes caused by roll; this also improves handling response due to faster weight shifting (similar to stiffer springs.) The danger with overly stiff swaybars is the lifing of the inner wheel, which reduces its traction. Loss of traction less likely with softer bars. Other components that are sometimes added are strut bars, which improve the body stiffness and help better maintain the proper suspension geometry during cornering. On some cars certain braces, anti-roll bars, etc., can be retrofitted to base model cars from sports models.

For offroad vehicles, the emphasis is on lengthening the suspension travel and installing larger tires to increase ground clearance.

These suspension modifications are in contrast to Lowriders with hydraulic or pneumatic suspensions. Lowriders use another type of suspension tuning in which the height of each individual wheel can be rapidly adjusted by a system of rams which, in some cases, makes it possible to "bounce" the wheels completely clear of the ground.

Body tuning

Body tuning involves adding or modifying spoilers and a body kit in order to improve the aerodynamic performance of a vehicle. Through the generation of downforce, cornering speeds and tire adhesion can be improved, often at the expense of increased drag. To lighten the vehicle, bodywork components such as hoods and rear view mirrors may be replaced with lighter weight components.

Often, body modifications are done mainly to improve a vehicle's appearance, as in the case of non-functioning scoops, spoilers, wide arches or other aesthetic modification. Aftermarket spoilers or body kits rarely improve a car's performance. The majority, in fact, add weight and increase the drag coefficient of the vehicle, thus reducing its overall performance.

Increasing the wheel track width through spacers and wide body kits enhance the cars cornering ability. Lowering the center of gravity via suspension modifications is another aim of body tuning. Often, suspension tuners unfamiliar with spring dynamics will cut stock springs, producing a soft, bouncy ride. It is also common to lower the car too far beyond the optimal center of gravity purely for appearance.

Competition cars may have light weight windows, or the windows may be completely removed, as auto glass adds significant weight. Plastic windows are much more vulnerable to scratches which reduces service life.