How to Install and Adjust a Rally Suspension for a Subaru Impreza WRX STI?

A Subaru Impreza WRX STI is not just a car, it’s a symbol of speed, power, and precision. Whether you’re using yours for an adrenaline-pumping rally race or just enjoying the thrill of a spirited drive, the right setup can make all the difference. One of the key components of a successful rally car setup is the suspension. It’s the interface between the car and the treacherous gravel roads or the winding tarmac. A well-tuned suspension can provide a significant edge in a rally setup, providing better handling, reducing roll, and ensuring optimum performance. Today, we’re going to show you how to install and adjust a rally suspension on your Subaru Impreza WRX STI.

The Basics of Suspension Setup

Before you dive into the installation process, understanding the basic principles of suspension setup is essential. The suspension setup includes several components – the springs, shock absorbers, sway bars, and tires. All these work together to keep the car in balance, manage weight distribution, and absorb shock from the road surface, especially in a rally scenario where the surface is often gravel or uneven.

Dans le meme genre : Can a Custom Carbon Fiber Spoiler Improve Downforce on a McLaren 570S Without Adding Weight?


The springs are crucial because they absorb the energy from road impact. They come in different stiffness levels. A stiffer spring will make the car feel more responsive and agile, but it might also make the ride feel harsher, especially on rough terrains.


The shock absorbers, or simply shocks, work in tandem with the springs. They control the motion of the springs and dampen the oscillations caused by road impact.

En parallèle : What’s the Optimal Angle for a Rear Wing on a Porsche 718 Cayman for Circuit Racing?

Sway Bars

Sway bars or anti-roll bars are used to reduce body roll during cornering. They distribute the force evenly to both sides of the car.


Tires, although not technically part of the suspension, play a vital role in handling. The type of tires you use and their pressure can affect the car’s grip and handling characteristics.

Choosing and Installing the Right Components

After understanding the components, it’s time to choose the right ones for your WRX STI. This will depend on factors like the type of rally you’re participating in and your driving style.

Choosing the Springs and Shocks

For a rally suspension, you will need to use specialized springs and shocks. The stock suspension of the WRX STI, which is designed more for road use, may not be suitable for the harsh conditions of rally driving.

You may want to consider a suspension kit that includes both springs and shocks. These are designed to work together and can offer better performance than mixing and matching different components.

Choosing the Sway Bars

Selecting the right sway bars for your WRX STI can significantly increase your car’s cornering ability. In a rally, getting the car around corners quickly and efficiently is crucial.

Choosing the Tires

When selecting tires, consider the type of surface you’ll be driving on. For a gravel rally, you might need a tire with a more aggressive tread pattern.

Installing the Suspension

The process of installing the suspension will involve replacing the stock springs and shocks with your chosen set. You will also need to install the sway bars and adjust them to the correct stiffness. This process is intricate and requires careful attention to detail.

Adjusting the Suspension

After installing the suspension, you will need to adjust it to suit your driving style and the conditions you’ll be racing in. This process includes setting the ride height, adjusting the damping, and fine tuning the sway bars.

Setting the Ride Height

The ride height is the distance between the bottom of the car and the road. A lower ride height can provide better handling and less roll, but it also reduces the car’s ability to absorb shocks from rough surfaces.

Adjusting the Damping

Damping is the process of controlling the oscillations of the springs. This can be adjusted by changing the settings on the shocks.

Tuning the Sway Bars

The sway bars can also be tuned to match your driving style. A stiffer set up can reduce roll, but it might also make the car less forgiving in the corners.

Remember, there’s no ‘one-size-fits-all’ setup for a rally car. It’s a process of trial and error to find the perfect balance for your Subaru Impreza WRX STI. With the right suspension, and the knowledge to adjust it, you will be well on your way to owning the rallyx circuit. Happy racing!

Dealing with Specific Suspension Challenges

Rally racing, particularly gravel rally, is not a walk in the park for your Subaru Impreza WRX STI. It places enormous pressure on the suspension components. Here we will focus on the various challenges you’re likely to encounter, and how to use the right suspension setup to mitigate them.

Weight Transfer

During acceleration, braking, or turning, the weight of your WRX STI shifts from one area to another. This is known as weight transfer. It can have a significant impact on the vehicle’s balance and behavior. The stiffer your springs, the less drastic the weight transfer will be. However, bear in mind that stiffer springs can make the ride harsher on rough surfaces.

Spring Rates

In a gravel rally, your vehicle will experience a lot of vertical movement. This is where spring rates come into play. A higher spring rate translates to a stiffer spring, which reduces body roll and improves cornering. But remember, it’s all about finding a balance as a too stiff setup can lead to poor traction on uneven surfaces.

Lower Mounts and Top Mounts

Lower mounts and top mounts are part of your WRX STI’s shock absorbers. They connect the shocks to the vehicle. In many aftermarket suspensions, such as the KSport Gravel, these components are adjustable, giving you the option to modify the ride height and damping without changing the spring rate.

Street Tires vs. Rally Tires

The choice between street tires and rally tires can be crucial for a rally event. Street tires might not provide the necessary grip on a gravel surface. Rally tires, on the other hand, are designed specifically for the demands of rally racing, offering better grip and handling characteristics.

Useful Tips and Conclusion

To wrap up, let’s look at some valuable tips from seasoned rally drivers and forum members who have been in the trenches of rally racing.

Trial and Error

Don’t be discouraged if your first setup doesn’t deliver the desired results. It takes time, patience, and a lot of trial and error to find the optimum suspension configuration for your Subaru WRX.

Post Installation Check

After installing and adjusting your suspension, it’s crucial to test your vehicle on a similar surface to the one you’ll be racing on. This allows you to get a clear picture of how your car will behave during the actual race.

Regular Maintenance

Just like any other mechanical component, your suspension needs regular maintenance to maintain peak performance. This includes inspecting and replacing worn-out parts as needed.

Seek Professional Help

If you’re unsure, seek professional help. Installing and adjusting a rally suspension is a complex task that requires specific knowledge and skills. A professional can provide guidance and ensure the job is done correctly.

In conclusion, upgrading and fine-tuning your Subaru Impreza WRX STI’s suspension system for rally racing is an intricate process that demands a thorough understanding of the role of each suspension component. By keeping in mind the factors discussed above like weight transfer, spring rates, using the right tires, and the role of lower and top mounts, you will be well-equipped to handle the demands of gravel rally. Always remember, there’s no one-size-fits-all setup, and the key to success is continuous learning and adaptation. Happy Rallying!