Many drivers are gearheads who get under their vehicles weekly to adjust, upgrade, modify and fine-tune. The most popular car modifications are done to increase power, but some are also focused on increasing fuel economy.

The top 10 modifications are also the stuff of real mechanics; they are not just for looks or for a passing fad. There are no ridiculous wings, spinning rims or horrendous body kits in honest-to-goodness car modifications. Most of these are also not for the novice or those on a tight budget. They are for true car fanatics who are really into slinging wrenches to get the most out of their vehicles.

Easy Car Modifications

Most car modifications that are easy are really just for looks or to fit a personal preference. However, there are some modifications that can be completed by someone who is just wading into gearhead territory.

— Computer Chip or Module Upgrade

Auto manufacturers program a vehicle’s computer for average driving. This is akin to the factory settings on a computer where many users end up customizing those settings to their own unique needs.

A chip or module upgrade for a vehicle is no different. A programmer module is attached to the diagnostics plug that is located around the driver’s knees. The module then adjusts the car’s computer to different specifications. This modulator allows for increased performance such through increasing fuel or oxygen to the engine. It is also necessary to allow for other modifications that the original settings won’t recognize. Modules or tuners cost around $200.

Moderately Difficult Car Modifications

Most modifications to a car require a certain level of expertise if you want to complete them yourself. They can be potentially dangerous or hazardous to the vehicle and the modifier if not done correctly.

Exhaust System

The purpose of any exhaust system is to exhale the smoke created by the gas burned in the engine, but most people don’t know that there is more to it than that. The back pressure created by the gases can help or hurt any engine. Most of the components a driver would replace or modify on an engine are moderately complicated adjustments. Modifying the muffler is relatively simple, however.

Correctly modifying the exhaust manifold – also called a header, pipes, or the catalytic converter- will result in increased air and efficiency from your car’s engine. The result could be an increase in horsepower or energy efficiency depending upon the modification you choose. Exhaust system modifications can cost from a few hundred to a few thousand dollars, depending on the type of modifications and the cost of the parts.

Nitrous Oxide Injection

This modification, referred to as NOS, is meant to add short bursts of increased power and speed to any engine. It is an easy install, but is also easy to mess up. The gas Nitrous Oxide is introduced into the engine by a switch, greatly increasing fuel combustion. This increased fuel combustion in turn increases your engine’s output for a short period of time. It is a pretty standard modification found on street racers and cars of drivers who want to have an extra punch every now and then. There are some drawbacks, however.

Nitrous Oxide will exacerbate any problems with your engine, increasing the chance of breakdown. The gas is also only sold by certified dealers, so it could be a hassle to have the tanks tested, certified and refilled again and again. Furthermore, it is an extremely flammable mixture. Nevertheless, it is a very popular car modification that costs around $200 to $500.

Cold Air Intake

Your car’s engine needs two things to run: fuel and air. Increasing the air flow to the engine will result in more power. A cold air intake system delivers outside air, which is cooler than the air in the engine, into the combustion chamber. This colder air allows for more oxygen and thus more combustion, creating more power.

Adding a cold air intake system is easier and less expensive than other systems that increase airflow. It also creates an increase in fuel efficiency, boosting your vehicle’s miles per gallon ratio. Air intake systems can cost from a few hundred dollars to $500.

High Performance Electronic Ignition

The ignition system is what provides the spark that ignites the fuel and air mixture in the combustion chamber. Factory ignition settings are made to work with the fuel and air combination created from factory parts.

When you start to modify your car to increase air flow or fuel flow, it can create a fuel to air ratio that is not as easily ignited with the original ignition system. A high performance electronic ignition system will work more efficiently with different fuel to air ratios, increasing the efficiency and power of your engine. They cost between $200 to $500.

Difficult Car Modifications

The lions’ share of car modifications are difficult and time-consuming. They require the expertise of those with oil under their fingernails and high octane running in their veins; they do it because they love it. Serious damage can be done to an engine if these modifications are done incorrectly. Many of these modifications can only be perfected through trial and error, so they can also cost a lot of money.

Forced Induction

Forced induction, called a turbocharger or a supercharger, uses a similar concept to cold air intake systems.  The amount of air that enters the engine is increased. One of the differences is that the air is forced into the engine, rather than just using natural aspiration through gravity. This compresses the oxygenated air, so more is pushed into the combustion chamber to mix with the fuel. More horsepower is created when the oxygen and fuel ignite.

Turbochargers and superchargers create more power and efficiency, but they can also increase fuel consumption.  Prices for turbochargers range from $2,500 to $3,500; superchargers are more expensive at $5,000 to $8,000.

Cam Shaft

In basic terms, the cam shaft controls the length of time the cylinders in your vehicle’s engine are open. Modifying the cam shaft can increase the amount of time the valves are open. This allows for more air and fuel to enter the combustion chamber. The more air and fuel compressed in the chamber, the more horsepower your engine creates.

Modifications to the cylinder head, such as a cam shaft modification, result in the most increase in power. This modification can also be done to increase fuel economy however such modifications are really at an expert level due to time and difficulty considerations. The tools and parts are also in the expensive range, costing several thousand dollars.

Factory Heads Replacement

Modifying your car’s factory heads or replacing them with performance heads is aimed at increasing air flow. It increases the oxygen in the combustion shaft. The increased oxygen creates a more forceful combustion reaction, which gives your vehicle more power or fuel economy.

One example is cylinder head porting. This means either removing any unneeded metal from the port that might restrict or obstruct airflow or actually making the port larger. Again, Custom-Cars.us points out that this is an involved process that includes a lot of trial and error. It also takes a lot of money, figuring into the thousands for all of the tools and equipment needed.

Oversized Cylinders

Installing oversized cylinders is part of cylinder head modification, and the aim is to increase airflow. Bigger cylinders allow more air. Generally, this modification is done in addition to other modifications to realize more power or gas mileage from your engine.

Stroker Crank

This modification allows for more displacement by increasing how far your engine’s piston travels up and down because the crank is larger. Compression and combustion space is increased because the engine is larger and the combustion chamber holds more air and fuel, resulting in more power and uses much more gas.

All of these modifications require machining of parts and a very extensive amount of knowledge. Although same may sound pretty easy you really should only ever let an expert handle any modifications to your car. You also need to chat with your auto insurance company before making any modification since the slightest change can often void your auto insurance policy. Most car insurance companies do allow some modifications but without prior notice you will be driving a car that is different from the one they agreed to insure and that is enough reason to deny any claim.