2017 Subaru WRX STI: Rally Build Breakdown

So, you're thinking about turning your 2017 Subaru WRX STI into a rally monster? Awesome! This guide will walk you through the key steps and considerations for building a competitive and reliable rally car. Whether you're dreaming of tearing up forest trails or just want a seriously capable weekend warrior, understanding the process is crucial. Building a rally car is no small feat; it requires careful planning, serious mechanical skills, and, let's be honest, a good chunk of change. But the thrill of piloting your own rally-prepped machine is an experience unlike any other. We'll break down everything from selecting the right parts to reinforcing the chassis, tuning the engine, and ensuring your car meets safety regulations. So buckle up, because we're diving deep into the world of Subaru rally builds!

Planning Your Rally Build

Before you even think about touching a wrench, planning is the most important stage. Think about what kind of rallying you want to do. Are you aiming for local club events, regional competitions, or something even bigger? This will heavily influence your budget and the level of modification needed. Then, you need to create a detailed budget. Rally builds can quickly spiral out of control, so it’s crucial to have a realistic estimate of all costs involved, including parts, labor, safety equipment, entry fees, and transportation. Don't forget to factor in unexpected expenses – because there will always be unexpected expenses. Research the specific regulations for the rally events you plan to enter. Different series have different rules regarding vehicle modifications, safety equipment, and eligibility. Make sure your build complies with all requirements to avoid disqualification. With that said, you should consider forming a team. Rallying is rarely a solo endeavor. Having a reliable team of mechanics, navigators, and support crew is essential for success. It would be best if you started networking with experienced rally teams and individuals. Their insights and advice can be invaluable, and they may even be able to offer assistance during the build process or at events. Sourcing a clean and well-maintained 2017 Subaru WRX STI is critical. Look for a car with minimal rust and a healthy engine and transmission. A solid foundation will save you time and money in the long run. Finally, you should document everything. Keep meticulous records of all modifications, parts used, and expenses incurred. This documentation will be helpful for troubleshooting, maintenance, and potential resale value.

Chassis Reinforcement and Safety

Okay, time to get serious about chassis reinforcement and safety. This is where you turn a regular car into a rally-ready fortress. A roll cage is non-negotiable. It's the single most important safety feature in a rally car, protecting the occupants in the event of a rollover. A professionally installed, FIA-approved roll cage is highly recommended. Seam welding strengthens the chassis by welding all the seams where individual panels are joined. This significantly increases rigidity and reduces the risk of cracking or fatigue under the stresses of rallying. Consider adding strut tower braces to further stiffen the chassis and improve handling. These braces connect the strut towers, reducing flex and maintaining suspension geometry. Then, install underbody protection. Rally stages are notoriously rough on the underside of a car. Skid plates made from heavy-duty steel or aluminum protect the engine, transmission, and fuel tank from rocks and other obstacles. Rock sliders protect the sills of the car from damage when traversing rough terrain. These are typically welded to the chassis for maximum strength. Heavy-duty mud flaps are essential for protecting the car and following vehicles from flying debris. They also help maintain visibility in wet or muddy conditions. Inside the car, install racing seats and harnesses. These provide superior support and restraint compared to the stock seats, keeping the driver and co-driver securely in place. A fire suppression system is critical for extinguishing fires quickly and effectively. Both manually activated and automatically activated systems are available. Consider a plumbed-in system that targets the engine bay and cabin. Install an intercom system for clear communication between the driver and co-driver, especially in noisy environments. This is essential for accurate navigation and timing. Finally, you should install window nets to prevent arms from flailing outside the vehicle.

Suspension and Brakes

Now let's talk about suspension and brakes, the heart of your rally car's handling and stopping power. Upgrading these components is crucial for tackling the demanding conditions of rally stages. Rally-specific suspension systems are designed to withstand the abuse of rough terrain and provide optimal handling. Look for adjustable dampers that allow you to fine-tune the suspension to different stage conditions. These springs are stiffer than stock springs and are designed to handle the increased loads and stresses of rallying. Consider adjustable spring perches to fine-tune ride height. Strengthen your suspension components by upgrading to reinforced control arms, trailing arms, and sway bar links. These components are less likely to bend or break under stress. Then, you should upgrade to larger, more powerful brakes for improved stopping power and heat dissipation. Look for slotted or drilled rotors to improve cooling and reduce brake fade. Rally brake pads are designed to provide consistent performance under extreme conditions. Choose pads that are appropriate for the type of rallying you'll be doing. Steel braided brake lines improve brake pedal feel and reduce brake fade by minimizing expansion under pressure. An adjustable brake bias valve allows you to fine-tune the front-to-rear brake balance to optimize handling. Consider a hydraulic handbrake for initiating drifts and controlling the car in tight corners. Make sure to upgrade your wheel studs for added strength and reliability. Longer studs may be required to accommodate thicker wheels or spacers. Choosing the right wheels and tires is critical for rally performance. Look for strong, lightweight wheels that can withstand the abuse of rally stages. Rally tires are designed to provide optimal grip on various surfaces, including gravel, dirt, and mud. Choose tires that are appropriate for the specific conditions you'll be facing.

Engine and Drivetrain

Time to dive into the engine and drivetrain – the powerhouse that propels your rally car through challenging stages. Extracting more power and ensuring reliability are the primary goals here. The 2017 WRX STI already has a potent engine, but some modifications can further enhance its performance. A cold air intake improves airflow to the engine, increasing horsepower and torque. Install a turbocharger to boost performance and reliability. A cat-back exhaust system reduces backpressure, improving exhaust flow and increasing power. A professional ECU tune can optimize engine performance for rally conditions. This can improve throttle response, increase horsepower and torque, and enhance reliability. Consider upgrading the fuel injectors and fuel pump to support increased power levels. Install an oil cooler to keep the engine oil temperature within acceptable limits. This is especially important in hot conditions or during extended periods of high-speed driving. A larger radiator improves cooling capacity and prevents overheating. You should reinforce the engine mounts to reduce engine movement under hard acceleration and braking. This can improve drivetrain responsiveness and prevent damage to other components. Upgrade the clutch to a high-performance unit that can handle the increased power and torque. A short shifter reduces shift throw and improves shift speed. Strengthen the transmission by upgrading to stronger gears and shafts. This is especially important if you're planning to run high power levels. Install a limited-slip differential (LSD) to improve traction and handling. An LSD distributes power more evenly to the wheels, reducing wheel spin and improving cornering ability. Strengthen the driveshaft and axles to handle the increased power and torque. These components are prone to failure under the stresses of rallying. Install a transmission cooler to keep the transmission fluid temperature within acceptable limits. This is especially important in hot conditions or during extended periods of high-speed driving.

Interior and Navigation

Let's get the inside of your rally car dialed in! Interior and navigation are key for both performance and safety. You need to be comfortable, have all the necessary information at your fingertips, and be able to communicate effectively with your co-driver. Start by stripping out any unnecessary weight from the interior, such as the rear seats, carpets, and sound deadening material. This can improve acceleration, braking, and handling. Then, install a rally computer for precise navigation and timing. Rally computers typically display information such as distance, speed, and time, and can be programmed with stage notes. A GPS system can be used to track your position on the stage and provide real-time navigation assistance. Mount a compass to provide a reliable backup navigation tool in case of GPS failure. An intercom system is essential for clear communication between the driver and co-driver, especially in noisy environments. The driver and co-driver will need rally helmets that are designed to provide maximum protection and communication capabilities. Install a data logger to record various parameters, such as engine speed, throttle position, and brake pressure. This data can be used to analyze performance and identify areas for improvement. A rearview mirror is important for keeping an eye on other vehicles on the stage. Consider mounting additional lighting inside the car for improved visibility in dark conditions. You should also consider installing a first-aid kit for dealing with minor injuries. A tool kit is essential for making repairs and adjustments to the car during the rally. Store spare parts, such as tires, brake pads, and fluids, in the service area for quick replacement. Finally, you should make sure all equipment is securely mounted to prevent it from becoming a hazard in the event of a crash.

Testing and Tuning

Almost there! Now comes the crucial step of testing and tuning. This is where you fine-tune your rally car to extract maximum performance and ensure reliability. Before hitting the rally stages, it's essential to test your car in a controlled environment. A gravel road or rallycross course is ideal for simulating rally conditions. Start by checking all the basic functions of the car, such as the engine, transmission, brakes, and suspension. Then, gradually increase the speed and intensity of your driving to identify any weaknesses or problems. Monitor the engine temperature, oil pressure, and other vital signs to ensure that the car is running properly. You should also use a data logger to record various parameters, such as engine speed, throttle position, and brake pressure. This data can be used to analyze performance and identify areas for improvement. Experiment with different suspension settings to find the optimal setup for different types of terrain. Adjust the brake bias to optimize handling and stopping power. Fine-tune the engine tuning to maximize horsepower and torque. Then, practice driving with your co-driver to develop a strong working relationship and refine your navigation skills. Pay attention to any noises, vibrations, or other unusual sensations that may indicate a problem. Address any issues promptly to prevent them from escalating into more serious problems. Finally, you should make sure that the car complies with all safety regulations before competing in a rally event.

Maintaining Your Rally Car

Okay, your rally car is built, tested, and ready to race! But the work doesn't stop there. Maintaining your rally car is absolutely crucial for ensuring its longevity and performance. After each rally event, thoroughly inspect the entire car for damage or wear. Pay close attention to the suspension, brakes, tires, and underbody. Replace any worn or damaged parts immediately. Change the engine oil, transmission fluid, and differential fluid regularly. Use high-quality fluids that are designed for racing conditions. Inspect the brake pads and rotors regularly and replace them as needed. Bleed the brakes to remove any air bubbles from the system. Check the tires for wear and damage. Rotate the tires regularly to ensure even wear. Inspect the suspension components for damage or wear. Replace any worn or damaged components immediately. Check the alignment regularly to ensure optimal handling. Inspect the roll cage for damage or cracks. Repair any damage immediately. Clean the car thoroughly after each event. Remove any mud, dirt, or debris from the underbody, suspension, and engine bay. Lubricate all moving parts regularly. Store the car in a dry, protected environment when not in use. Perform regular maintenance tasks, such as checking the fluid levels, tire pressure, and battery condition. Keep a detailed log of all maintenance and repairs. This will help you track the car's performance and identify any potential problems. Finally, you should follow the manufacturer's recommendations for maintenance intervals and procedures.