2015 Nissan Altima Aftermarket Parts

The 2015 Nissan Altima, a mid-size sedan renowned for its fuel efficiency and comfortable ride, offers a solid platform for aftermarket modification. While it’s not typically associated with high-performance customization like a sports car, a significant market exists for upgrades that enhance its aesthetics, handling, and even a bit of its performance. This guide explores common aftermarket parts available for the 2015 Altima, delving into their technical aspects and potential benefits. We'll steer clear of subjective opinions and focus on the "how" and "why" behind these modifications.

Engine and Performance Upgrades

While transforming the Altima into a track monster is unlikely, certain modifications can improve throttle response, engine efficiency, and overall driving experience. These mostly center around optimizing existing components rather than radical engine swaps.

Cold Air Intakes (CAI)

A cold air intake replaces the factory airbox and intake tube with a system designed to draw cooler air into the engine. The premise is simple: cooler air is denser, containing more oxygen per unit volume. More oxygen allows the engine to burn more fuel, theoretically resulting in increased horsepower.

Most CAI systems utilize a larger diameter intake tube, constructed from materials like aluminum or reinforced plastic, to reduce airflow restriction. The filter element is also typically larger and less restrictive than the stock paper filter. However, the "cold air" aspect is crucial. A poorly designed CAI that draws hot air from the engine bay can actually *reduce* performance. Look for CAIs with heat shields or those that position the filter away from heat sources. The Mass Air Flow (MAF) sensor is located within the intake tract, and its proper function is critical. Any discrepancies in intake diameter or airflow characteristics compared to the stock setup can trigger check engine lights and require recalibration (tuning).

Cat-Back Exhaust Systems

The exhaust system's primary role is to expel exhaust gases from the engine. A cat-back exhaust system replaces the exhaust components from the catalytic converter backward, typically including the mid-pipe, muffler, and tailpipe(s). These systems are often designed to reduce backpressure, allowing exhaust gases to flow more freely. Lower backpressure can improve engine efficiency and horsepower, particularly at higher RPMs.

Cat-back systems are usually constructed from stainless steel for increased durability and resistance to corrosion. They often feature larger diameter piping and less restrictive mufflers than the stock system. The muffler design greatly affects the exhaust note; chambered mufflers tend to be quieter, while straight-through mufflers produce a louder, more aggressive sound. It's crucial to ensure the cat-back system complies with local noise regulations. Installation is generally straightforward, involving bolting the new system onto the existing catalytic converter flange.

ECU Tuning

The Engine Control Unit (ECU) manages various engine parameters, including fuel injection, ignition timing, and throttle response. ECU tuning, or remapping, involves modifying the ECU's software to optimize these parameters for increased performance or fuel efficiency. While a simple CAI or exhaust upgrade may yield marginal gains, combining them with a proper ECU tune can unlock more significant improvements.

Tuning can be accomplished using handheld tuning devices or by a professional tuner who can custom-tune the ECU based on dyno testing. Tuning can adjust fuel-air ratios, advance ignition timing (within safe limits to prevent engine knocking), and optimize throttle mapping for a more responsive feel. It's critical to ensure the tuner has experience with the 2015 Altima's ECU and uses reliable tuning software. Incorrect tuning can lead to engine damage. Consider emission regulations as well; tuning for peak performance might violate local regulations.

Suspension and Handling Upgrades

Improving the Altima's handling characteristics often involves modifying the suspension system. These upgrades can enhance cornering ability, reduce body roll, and improve overall stability.

Lowering Springs

Lowering springs replace the factory coil springs with shorter, stiffer springs. This lowers the vehicle's ride height, reducing the center of gravity and improving handling. Lowering springs also typically increase spring rates, which means the suspension resists body roll more effectively.

Lowering springs are available in various lowering amounts (e.g., 1.0 inch, 1.5 inches). Lowering too much can negatively impact ride quality and lead to clearance issues with speed bumps and driveways. When installing lowering springs, it's generally recommended to also upgrade the shock absorbers to match the increased spring rate. Stock shocks may not be able to adequately control the stiffer springs, resulting in a bouncy ride and reduced handling performance. Alignment is essential after installing lowering springs.

Strut Tower Braces

A strut tower brace (or strut bar) is a metal bar that connects the two strut towers in the engine bay. Its purpose is to reduce chassis flex during cornering. When the car leans into a turn, the suspension exerts force on the strut towers, which can cause them to flex inward. This flex reduces the effectiveness of the suspension and can negatively affect handling.

The strut tower brace acts as a structural member, distributing the load between the strut towers and reducing flex. This results in improved steering response and more precise handling. Strut tower braces are generally easy to install, bolting directly to the strut towers. Their effectiveness is most noticeable in vehicles with softer chassis or those subjected to aggressive driving.

Sway Bars (Anti-Roll Bars)

Sway bars (also known as anti-roll bars) connect the left and right wheels on each axle. They resist body roll during cornering by transferring force from one wheel to the other. A stiffer sway bar will reduce body roll more effectively, improving handling.

Aftermarket sway bars are typically thicker and stiffer than the factory sway bars. Increasing the front sway bar stiffness will tend to reduce understeer, while increasing the rear sway bar stiffness will tend to reduce oversteer. It's important to choose sway bars that are properly matched to the vehicle's suspension setup and driving style. Overly stiff sway bars can make the car feel twitchy and unpredictable. Installation typically involves unbolting the existing sway bar and bolting in the new one, along with new bushings.

Braking System Upgrades

Enhancing the braking system can improve stopping power and braking feel, increasing safety and confidence behind the wheel.

Performance Brake Pads

Performance brake pads are designed to provide higher friction and better resistance to fade (loss of braking performance due to heat) compared to stock brake pads. They are typically made from different friction materials, such as semi-metallic, ceramic, or carbon-fiber compounds.

Performance brake pads can significantly improve stopping power, especially during repeated hard braking. They may also produce more brake dust and noise than stock pads. It's important to choose brake pads that are appropriate for the intended use. Track-day pads, for example, may not be suitable for daily driving due to excessive noise and poor cold-weather performance. Bedding-in the brake pads properly is crucial for optimal performance and longevity.

Stainless Steel Brake Lines

Stainless steel brake lines replace the factory rubber brake lines with lines that are reinforced with a stainless steel braid. Rubber brake lines can expand under pressure, leading to a spongy brake pedal feel and reduced braking performance.

Stainless steel brake lines resist expansion, providing a firmer, more responsive brake pedal. They also tend to be more durable and resistant to corrosion than rubber brake lines. Installation requires bleeding the brake system after installation to remove air bubbles. This upgrade primarily enhances brake feel rather than significantly increasing stopping power.

Aesthetic Upgrades

Numerous aftermarket parts can enhance the 2015 Altima's appearance, allowing owners to personalize their vehicles.

Wheels and Tires

Upgrading the wheels and tires is one of the most common aesthetic modifications. Aftermarket wheels are available in a wide variety of styles, sizes, and finishes. Selecting the correct wheel size and offset is crucial to avoid rubbing against the fenders or suspension components.

Tires play a significant role in both aesthetics and performance. Wider tires can improve grip and handling, while tires with different tread patterns can alter the vehicle's appearance. It's important to choose tires that are appropriate for the intended driving conditions and meet the vehicle's load and speed ratings.

Body Kits

Body kits consist of aerodynamic components that alter the vehicle's exterior appearance. These can include front spoilers, side skirts, rear diffusers, and rear wings. Body kits are typically made from fiberglass, polyurethane, or carbon fiber.

Proper installation of a body kit is critical. Poorly installed body kits can look out of place and may even damage the vehicle. Fitment issues are common with aftermarket body kits, so it's important to choose a reputable brand and have the kit professionally installed, if possible.

In conclusion, the aftermarket for the 2015 Nissan Altima offers a wide range of parts designed to enhance its performance, handling, and aesthetics. While it is not a performance car by nature, thoughtful modifications can improve the driving experience and personalize the vehicle to the owner's preferences. Careful research, proper installation, and consideration of local regulations are essential for successful and safe modifications.