Air suspension systems, once predominantly used in the trucking industry, have now made their way into various sectors, including commercial and consumer vehicles. From motorcycles to everyday commuter cars, these systems have become increasingly popular due to advancements in technology.
Gone are the days of bulky, slow, and imprecise systems. Modern air suspension systems utilize fast and precise technology, equipped with advanced electronics that control ride height and air pressure in the bags. This results in a smoother and more controlled driving experience.
Your car’s suspension is a critical aspect of its performance, affecting both comfort and safety. Traditional shock absorbers and coil springs help manage road forces, but they have limitations. Factors like changes in weight, speed, and direction challenge their capabilities.
Air suspension systems replace coil springs with air springs, which are essentially tough rubber and plastic bags inflated to specific pressures and heights. However, these systems go beyond simple replacement. With features like onboard air compressors, sensors, and electronic controls, modern air suspension systems offer significant advantages over traditional metal springs. These include rapid adjustments, the ability to adapt to different driving conditions, and enhanced load-bearing capacity.
Air Suspension System Components
Early air suspension systems were basic, with air bags replacing coil springs. These bags were inflated using an external compressor through a valve on the bag. As technology evolved, more components were added to enhance control and functionality. However, modern air suspension systems share similar core components across different brands, with variations mainly in controls and ease of installation.
Air bags have remained largely unchanged over time, typically made of a composite material of rubber and polyurethane. This material provides durability, airtightness, resistance to abrasion from road debris, and protection against corrosion from salt and chemicals.
There are three main types of air bags:
- Double-convoluted bag: Shaped like an hourglass, providing some lateral flexibility.
- Tapered sleeve: Designed to fit in tight spaces and offer adjustability in ride height.
- Rolling sleeve: Designed for specific applications, with differences in ride height and spring control depending on the vehicle and its use.
Most modern air suspension systems include an onboard compressor, an electric pump that delivers air to the bags through compressed air lines. The compressor is typically mounted on the vehicle’s frame or in the trunk, often with an attached drier. The drier removes moisture from the outside air before it enters the system, preventing damage caused by moisture accumulation.
Some systems rely solely on the compressor to adjust pressure, while more advanced setups include an air tank for maintaining pressure and ensuring smooth transitions between pressures. Compressors can be activated manually or automatically, controlled by the driver or through an electronic system, or a combination of both.
Solenoids, Valves and Lines
Certainly, an air suspension system involves more than just air bags. Here are the components that contribute to its operation:
- Lines: These carry compressed air to the air bags. Typically made of rubber or polyurethane, they run along the vehicle’s frame. Custom steel lines are an option for a cleaner appearance and enhanced durability.
- Valves: These control the flow of air into different parts of the system. In modern systems, valves are crucial for directing and regulating air flow. Early systems had two-way setups, where air was shared between left and right bags, leading to body roll. Today’s systems use valves to counteract this, improving handling.
- Solenoids: Found in electronically-controlled systems, solenoids manage air filling and venting in each air bag. They open or close in response to system adjustments, altering air levels in the bags.
- Electronic Control Module: This module oversees electronic systems. It can have basic control functions or more advanced features, monitoring pressure and ride height in real time. Inputs from sensors, like ride-height sensors, inform the module’s decisions, toggling the compressor as needed. Electronic advancements drive innovation in air suspension systems, with future changes likely in this area. These systems typically operate independently from the vehicle’s onboard modules and communications.
Air Suspension Kits
Upgrading a car’s suspension system from its factory shock absorbers and coil springs requires careful consideration and expertise to maintain the vehicle’s ride quality and handling. Selecting the right suspension kit can be overwhelming due to the multitude of manufacturers and components available, varying in quantity and quality.
Since air suspension kits only replace coil springs, many companies offer complete suspension overhaul kits. These kits replace everything from tie rods to control arms and shocks with high-quality components, optimizing the benefits of an air suspension system.
Basic kits typically include air bags to replace coil springs, a compressor, and air lines. However, these basic kits often result in heavy body roll due to their two-way system. Higher-priced kits offer better components, providing more control and adjustability.
Choosing a suspension kit requires careful consideration based on the desired outcome. For example, a classic car owner looking to lower their suspension for show purposes would need a different system than a pickup truck driver seeking improved load capacity and control while hauling heavy materials. Similarly, a racing driver’s needs would differ from those of a touring car driver.
Advanced kits use a four-way system controlled by an advanced controller. Each air bag is independently controlled but linked by the electronic controller for dynamic and static control. Consumers must also understand the difference between pressure-based and ride-height-based systems.
Pressure-based systems monitor air pressure in the bag, suitable for presetting a pressure to lower a low-rider at a show. However, incorporating ride-height sensors into the system offers enhanced functionality. Ride-height systems monitor how much a car raises and lowers while adjusting the pressure to achieve each level. This is beneficial for both performance and practical applications, such as maintaining suspension height when carrying heavy loads in a pickup truck.
Air Suspension System Installation
The biggest problem people faced in installing their new system was that they never read the instructions. Proper installation of complex systems is possible, but it requires reading and following the instructions. However, it’s important to note that installation should only be attempted by those with some knowledge of working on cars, especially suspension systems, and access to the necessary tools and facilities to do the job safely and correctly.
It is estimated that installing a muscle car bolt-on kits would take around 12 to 15 hours for the undercar suspension components and an additional 10 hours for the compressor system. Adding a leveling system could add another five to six hours. Investing time in proper installation can save money in the long run by ensuring all components work correctly and are set up to prevent common issues like chafing, which often leads to air leaks.
To maintain airtightness, it’s crucial for installers to take precautions outlined in the instructions, such as using sealer tape on threaded connections and routing lines away from potential chafing points. Estimated that 90 to 95 percent of leaks could be prevented by following these guidelines.
During installation, attention should also be paid to ensuring proper clearance for the air bags to avoid rubbing against the vehicle or coming into contact with hot components like exhaust pipes. With careful and diligent installation, an air suspension system can last for over a decade.
Additionally, tuning is an important aspect of installation. Many companies recommend replacing the car’s shocks when switching from coil springs to air bags, as shocks are designed to work in conjunction with springs. This relatively simple change adds another layer of tuning to the project but ensures optimal performance of the system.
While air suspension systems may seem complex and intimidating, they can provide impressive aesthetics and performance when installed and tuned correctly.