Modifying cars is a common practice for nearly every car owner, if not all, whether it is for cosmetic reasons, enhancing the sound, or improving performance.
This explains why even cars of the same make and model often differ once their owners take them from the dealership.
A frequent motivation for modifications is to optimize engine performance. Consequently, car owners often seek budget-friendly aftermarket parts that still provide good value in terms of performance.
Below is a list of 10 of the most popular engine modifications that car enthusiasts can consider. The list includes a range of options, from the least expensive performance parts to those that are more complex and costly.
The prices mentioned reflect only the cost of the parts themselves and do not include labor costs.
10. Spark Plugs – $25 To $50
Unlike most parts on this list, spark plugs are typically replaced at regular intervals to ensure the proper ignition of the air-fuel mixture in the engine’s combustion chamber.
While some spark plugs may wear out after only 30,000 miles, others can last up to 50,000 miles or more.
Though spark plugs might seem simple, they serve several important functions: some people upgrade their plugs to improve fuel efficiency, while others opt for high-performance spark plugs that are better suited for tuning, as these spark plugs ignite combustion more effectively.
The main downside of this upgrade is the possibility of incorrectly installing a spark plug; however, if installed properly, this is one of the simplest and most affordable engine modifications.
Horsepower gain: Minimal, but improved efficiency and acceleration.
9. Fuel Injectors – $150 To $300
Fuel injectors play a critical role by injecting fuel to create the air-fuel mixture that is ignited by the spark plugs. Like spark plugs, fuel injectors also have a lifespan and typically need to be replaced after about 50,000 to 80,000 miles.
Upgrading the fuel injectors becomes essential when substantial modifications are made to the engine, such as installing a larger, less restrictive intake system or a free-flow exhaust pipe.
Changing fuel injectors and even the fuel pump are considered “supporting modifications” as they ensure the effectiveness of other upgrades.
Tuners usually opt for larger injectors that deliver more fuel. However, it is important to select the correct size and type of injector for the vehicle. Installing the wrong injector can lead to an overly rich air-fuel mixture.
Horsepower gain: Around 5hp to 10hp.
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8. Cold Air Intake – $400 To $600
Upgrading to a high-quality, less restrictive air filter can improve an engine’s responsiveness for as little as $70 to $120.
However, mechanics generally advise against this due to the risk of heat soak, a condition where the intake draws in warm air, which is detrimental to engine performance.
To avoid this issue, many tuners opt for a cold air intake system, as it ensures that the air being supplied to the engine is cooler and more condensed, ultimately improving horsepower.
Car enthusiasts should ensure that the intake kit is compatible with their vehicle’s specifications. An improperly fitted intake can lead to dust or other particles entering the engine block, potentially causing significant damage.
Additionally, an intake that is too large may result in a loss of power.
Horsepower increase: Varies, typically between 2hp to 30hp, depending on the vehicle and the quality of the intake.
7. Radiator/Cooling System Upgrade – $200 To $1,000
Many car owners choose to upgrade to aluminum radiators. While copper radiators offer better heat transfer, aluminum is stronger, more durable, and resists corrosion better over time.
Though a cooling system upgrade does not directly impact horsepower, it enables drivers to add modifications without risking engine overheating or damage.
In addition to upgrading the radiator, other parts of the cooling system, such as the thermostat, cooling hoses, and water pump, may also need to be upgraded as supporting modifications. Selecting the right coolant is crucial as well.
Upgraded radiators tend to be more expensive, especially those with multiple cores or those designed to provide superior cooling benefits.
6. Exhaust Upgrade (Catback Or Full Exhaust) – $400 To $2,500
Mufflers are designed to reduce engine noise, but in doing so, they also restrict the flow of exhaust gases from the engine.
This limitation leads many tuners to pursue one of the most common and noticeable upgrades: a new exhaust system.
There are several ways to upgrade a vehicle’s exhaust system, but most experts agree that the best power gains come from installing a cat-back system, which involves replacing all exhaust components located after the catalytic converter.
A cat-back system provides increased power by eliminating restrictions to the exhaust flow, resulting in reduced back pressure and improved engine efficiency.
However, the trade-off is higher noise levels, and there is a risk that the vehicle may no longer comply with street-legal noise regulations.
Horsepower gain: Around 10hp to 20hp, depending on the materials used.
5. Racing Clutch Kit – $400 To $1,700
While many consider the clutch assembly separate from the engine, it plays a crucial role for those seeking to increase horsepower.
The clutch connects the flywheel to the transmission, ensuring that power is transferred efficiently to the wheels.
Although a clutch does not directly impact horsepower, a high-quality clutch kit minimizes power loss during transfer.
Additionally, stock clutch kits can only handle a certain level of power; exceeding this threshold may result in severe damage to the clutch or even the entire transmission.
It’s essential to choose the right aftermarket clutch kit for the vehicle. Does it need a heavy-duty clutch for towing or hauling, or a lightweight, aggressive clutch for racing or track use?
In either case, the drivability will be affected, especially for manual transmissions, so careful consideration and planning are necessary before making a decision.
4. Forged Pistons – $750 To $1,500
Stock or cast pistons are not inherently bad, but when an engine is pushed to its limits, upgrading the car’s stock internals is highly recommended.
Almost all racing setups use forged pistons because they can withstand more power and higher RPMs without deteriorating over time due to heat.
This is why many aftermarket companies offer forged internals, such as crankshafts, pistons, and connecting rods these parts need to be strong and durable to handle the added power, especially considering that a thin layer of oil is all that prevents metal-to-metal contact.
When it comes to crankshafts and connecting rods, it’s also a good idea to upgrade these components if you’re aiming to safely produce more power.
However, for street applications, many stock crankshafts are capable of handling a small power increase without issue.
Horsepower gain: None, but supports a higher compression ratio, which is facilitated by upgraded cams.
3. Aftermarket Camshaft – $1,300 To $1,700
Camshafts are responsible for opening the engine’s valves, allowing air to enter a cylinder or exhaust gases to exit.
While stock camshafts are designed to last for a long time, OEM parts may not be able to support significant increases in horsepower.
Larger and more robust camshafts not only open valves wider and for a longer duration but also enable car owners to maintain higher RPMs without worrying as much about wear.
Upgrading camshafts requires mechanical expertise, so such modifications are often best left to professional mechanics.
An incorrect camshaft setup can lead to timing issues or rocker arm clearance problems, both of which can severely impact engine performance.
Horsepower gain: 10hp to 20hp.
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2. Turbocharger/Supercharger – $600 to $2,000
How can you add around 100 more horsepower to your car? The quickest answer would be forced induction, which involves installing a turbocharger or supercharger into the engine.
For cars that are already turbocharged, upgrading to a larger turbine can also provide significant gains.
For naturally aspirated cars, adding a turbocharger might introduce some delay in throttle response at cruising speeds, a phenomenon known as turbo lag.
However, the increase in horsepower and torque once the turbo spools is so significant that many car owners are willing to live with the lag and focus on improving their driving techniques.
One potential issue with turbocharging is introducing more power than the car’s engine can handle. There are numerous videos online showing the consequences of applying excessive boost.
While turbochargers and superchargers are great upgrades, they should only be used if the engine can safely handle the increased power.
This typically means ensuring that all of the aforementioned upgrades are made before adding forced induction.
Horsepower gain: 50hp to 150hp (or more, depending on the setup).
1. ECU Remap – $400 To $2,000
Upgrading cars is often referred to as “tuning,” and for good reason: the electronic control unit (ECU) of a car, which governs many aspects of the engine such as the air-fuel ratio, timing, spark plug ignition, and other variables, must be tuned by experts to achieve optimal performance.
In simple terms, the power gains from the upgrades made to a vehicle would not be fully realized if the ECU is not properly tuned.
Remapping adjusts how much fuel is injected at different power bands and determines when the spark plug will trigger combustion.
However, remapping is only applicable to modern vehicles or those equipped with electronic fuel injection, as opposed to carbureted engines.
Additionally, remapping is not inexpensive: tuners typically charge a significant fee for using specialized software, a dynamometer (which measures horsepower and torque), and the expertise they have gained over time.
It’s important to proceed with caution, as remapping can void the car’s warranty.
Horsepower gain: Around 20hp to 50hp, but essential for achieving a smooth ride and optimal performance.