Hey car enthusiasts! Ever dreamed of taking your ride off the beaten path and conquering the rally stages? Well, buckle up because we're diving headfirst into the exhilarating world of a 2017 Subaru WRX STI rally build. This isn't just about slapping on some stickers and calling it a day, folks. We're talking about a serious transformation, turning a street-legal beast into a machine built to handle the brutal demands of rally racing. This article is your ultimate guide, covering everything from the essential modifications to the nitty-gritty details that separate a weekend warrior from a true rally contender. Ready to get your hands dirty? Let's jump in!

The Heart of the Beast: Engine and Powertrain Upgrades

First things first, you can't go rallying without a robust engine and a powertrain that can handle the punishment. The 2017 Subaru WRX STI comes with a solid foundation, its legendary 2.5-liter turbocharged and intercooled Boxer engine. But to truly rally-proof this machine, we need to dial things up a notch, right? The very first thing to consider is engine management. A quality engine management system (EMS), such as those from Cobb Tuning or Link, is crucial. This system lets you fine-tune the engine's performance, optimizing it for rally conditions. Think about the high altitudes and varying terrains you will be facing. The EMS helps keep your engine running at its peak, regardless of the challenges. Then, the internal components should be upgraded. Consider stronger pistons, connecting rods, and a performance crankshaft. These upgrades will ensure your engine can handle the relentless stress of rally racing. The stock components are generally pretty good, but they may become the weak link with increased power and the demands of constant high-RPM operation. A new and upgraded turbocharger is a must-have. Something like a Garrett GTX series or a Blouch Dominator will provide more power and better response, allowing you to quickly accelerate out of corners and maintain speed on those demanding stages. We must also upgrade the intercooler to keep the intake temperatures down. A larger, more efficient intercooler will reduce the risk of power-robbing heat soak. A front-mount intercooler (FMIC) is the best way to go, though it requires some modification to the front bumper. The STI's six-speed manual transmission is already pretty robust, but consider upgrading the clutch to handle the increased power and aggressive driving. A performance clutch kit with a sprung hub will provide better grip and durability. The differentials also need attention. Upgrading the front and rear differentials with limited-slip differentials (LSDs) will significantly improve traction, especially on loose surfaces. The STI already has a great center differential. It is also good to check the condition of the center differential and consider upgrading it to a more robust unit if you intend to run higher power levels. Finally, don't forget the exhaust system. A high-flow exhaust system, including a downpipe and cat-back exhaust, will improve exhaust flow, allowing the engine to breathe better and produce more power. Make sure it's constructed with durable materials to withstand the rough conditions of rally racing. The entire powertrain must work in unison to effectively transmit power to the wheels and conquer the rally stages!

Suspension: The Key to Control and Durability

Alright, guys, let's talk about the unsung hero of a rally car: the suspension! This is where the rubber meets the road, or rather, the dirt, gravel, and everything in between. The suspension system must be able to absorb impacts, maintain control, and keep the tires firmly planted on the ground, no matter the terrain. A stock STI suspension is good for the street, but it won't cut it for rally racing. The stock suspension just isn't built to withstand the constant pounding and abuse. First, we'll need to install rally-specific coilovers. These coilovers are designed to handle the harsh conditions of rally racing. Look for brands like Ohlins, Bilstein, or RalliTEK. These coilovers are usually adjustable for ride height, compression, and rebound, allowing you to fine-tune the suspension for different stages and conditions. The suspension travel is also critical. Rally cars need much longer suspension travel than street cars to absorb bumps and jumps. This increased travel allows the wheels to move up and down freely, keeping the tires in contact with the ground. This helps maintain control. Then, we need to focus on the chassis. The STI's chassis is pretty stiff from the factory, but for rally racing, we want to make sure the chassis can handle the additional stresses. We can add a roll cage. A roll cage is a must-have safety feature in any rally car. It protects the driver and co-driver in the event of a rollover. A professionally installed roll cage that meets FIA or similar regulations is highly recommended. Strengthened subframes are also a good idea. Consider upgrading the subframes and adding bracing to further stiffen the chassis. These upgrades will help to prevent the chassis from twisting and flexing under stress. The bushings must be replaced. Replace the stock rubber bushings with polyurethane or spherical bushings. This will reduce flex and improve the suspension's responsiveness. The sway bars must be upgraded. Stiffer sway bars will reduce body roll and improve handling. Adjustable sway bars will allow you to fine-tune the car's balance. Finally, you can't forget about the tires and wheels. Choose rally-specific wheels designed to withstand the harsh conditions of rally racing. Rally wheels are usually stronger and more durable than street wheels. Choose rally-specific tires with a suitable tread pattern for the type of terrain you'll be racing on. Tires are very important, so choose wisely!

Protecting Your Investment: Safety and Chassis Reinforcement

Safety, safety, safety, folks! Rally racing is inherently dangerous, and ensuring the safety of the driver and co-driver is absolutely paramount. Let's delve into the crucial safety features and chassis reinforcements that transform a street car into a rally-ready machine. First up, we have the all-important roll cage. As previously mentioned, a professionally installed roll cage is non-negotiable. It's the backbone of your safety system, protecting occupants in the event of a rollover or severe impact. Choose a cage that meets FIA or similar motorsport regulations. This ensures it's built to withstand the forces of a crash. Next, let's talk about seats and harnesses. Upgrade to FIA-approved racing seats. These seats provide superior support and protection compared to the stock seats. Install a multi-point harness. A five- or six-point harness will keep you securely in place during high-speed maneuvers and impacts. Make sure the harnesses are properly mounted to the roll cage or chassis. Fire suppression is also critical. Install a fire suppression system. This system should include nozzles in the engine bay, passenger compartment, and fuel tank area. Choose a system that's easy to activate and can quickly extinguish a fire. The chassis must be reinforced. Weld in additional gussets and reinforcement plates at key stress points. This will increase the chassis's rigidity and prevent it from twisting or flexing under the strain of rally racing. Consider a skid plate. A robust skid plate is essential for protecting the underside of your car from rocks, roots, and other hazards. The skid plate should cover the engine, transmission, and fuel tank. You can install rock sliders. Rock sliders protect the sides of your car from damage. Install a fuel cell or fuel tank protection. If you're running a fuel cell, ensure it's securely mounted and protected. If you're using the stock fuel tank, consider adding additional protection. The 2017 Subaru WRX STI's body panels and exterior components need some protection. Install a front bumper guard, brush guard, and rear bumper guard to protect the front, rear, and sides of your car from impact damage. Mud flaps are also important. Rally-style mud flaps help to prevent rocks and debris from damaging the bodywork. Consider adding a roof scoop. A roof scoop can improve airflow to the engine and intercooler, especially in dusty conditions. Finally, we need to address the interior. Remove all unnecessary interior trim and components to save weight and simplify the car. Install a rally computer. A rally computer can provide valuable information, such as speed, distance, and time splits. Consider adding a communication system. Install a radio communication system so the driver and co-driver can communicate effectively. Proper preparation and attention to detail in these areas can significantly improve safety and give you peace of mind as you tackle the rally stages.

Interior: Cockpit Transformation for Rally Racing

Let's move inside the 2017 Subaru WRX STI, because the interior of a rally car is a far cry from a typical street car's cabin. It's all about functionality, safety, and creating a workspace optimized for the driver and co-driver to tackle the challenges of rally racing. First and foremost, let's talk about the seats and harnesses. The factory seats have to go, replaced with purpose-built racing seats. These seats need to provide exceptional support, keeping the driver and co-driver firmly planted during high-speed maneuvers. Select seats that meet FIA safety standards. Pair those seats with a multi-point harness system. These harnesses are crucial for keeping you secure in the event of an accident. The stock seat belts simply won't cut it. Make sure the harnesses are properly installed and anchored to the roll cage or chassis for maximum safety. The driver and co-driver's visibility is critical. Remove all unnecessary interior trim and components to reduce weight and simplify the car. This also makes it easier to access and inspect the chassis and roll cage. Install a rally computer and gauges. A rally computer is an invaluable tool, providing vital information such as speed, distance, and time splits. Add auxiliary gauges to monitor critical engine parameters like oil pressure, water temperature, and boost. Easy access to controls is essential. Relocate any essential controls, like the ignition switch and light switches, to a more accessible location for the driver and co-driver. Install a hydraulic handbrake. A hydraulic handbrake is essential for initiating slides and controlling the car in tight corners. Mount it in a location that's easily accessible by the driver. Communication is key for rally racing. Install a high-quality intercom system for clear and reliable communication between the driver and co-driver. Consider installing a radio communication system for communication with your team. Weight reduction is critical. Remove all unnecessary items from the interior. This includes the rear seats, carpet, sound deadening material, and anything else that's not essential for racing. Interior protection is very important. Cover the interior surfaces with durable and easy-to-clean materials, like aluminum or carbon fiber. This will help to protect the interior from damage and make it easier to clean. Keep it simple and organized. Keep the interior as simple and organized as possible, so that everything is within easy reach of the driver and co-driver. The interior must be a functional workspace designed for the specific demands of rally racing!

Wheels and Tires: The Grip Factor

Wheels and tires are the direct link between your 2017 Subaru WRX STI and the rally course. The choice of wheels and tires can significantly impact grip, handling, and overall performance. Selecting the right combination is a critical decision. For wheels, you'll need rally-specific wheels. These are designed to withstand the harsh conditions of off-road racing. They are typically stronger and more durable than street wheels. Look for wheels made from high-strength alloys like forged aluminum. This will provide the necessary durability and reduce unsprung weight. The wheel size is also important. The most common wheel size is 15 or 16 inches for rally racing. This allows for a larger tire sidewall, which provides better impact absorption and off-road performance. The wheel offset will also impact handling. Choose an offset that positions the wheels correctly within the wheel arches. Consider the bolt pattern. Ensure that the wheels fit your STI's bolt pattern. The most important choice is for the tires. Rally tires are designed to provide maximum grip on loose surfaces like gravel, dirt, and mud. There are different types of rally tires available, depending on the type of rally racing. Gravel tires are designed for dry and loose surfaces. Mud tires are designed for wet and muddy conditions. All-terrain tires are a good compromise for mixed conditions. Consider the tire size. Choose the correct tire size that's compatible with your wheels and rally regulations. Make sure the tires have sufficient sidewall height to absorb impacts and prevent wheel damage. Tire pressure is crucial for rally racing. Adjust the tire pressure based on the course conditions and the type of rally tires you're using. Lower tire pressures will provide more grip on loose surfaces. Check the tires before the race. Inspect the tires regularly for damage and wear. Replace worn or damaged tires before each race. Wheels and tires are the foundation of your rally car's performance. By choosing the right combination, you can maximize grip, handling, and overall performance on the rally course!

The Finishing Touches: Rally-Specific Accessories and Modifications

As we approach the finish line of our 2017 Subaru WRX STI rally build, let's explore those final touches. These accessories and modifications can make a world of difference. First off, a proper lighting setup. Rally stages often run in low-light conditions, so a robust lighting setup is essential. Install a set of auxiliary lights, such as a light bar or driving lights, to improve visibility. Consider a roof-mounted light bar for maximum illumination. A sump guard is important. A sump guard is a must-have for protecting the engine's oil pan from damage. Choose a heavy-duty sump guard made from thick steel or aluminum. This will provide maximum protection from rocks and other hazards. Install a fire extinguisher. Mount a fire extinguisher within easy reach of the driver and co-driver. A larger capacity extinguisher is recommended. The car exterior must have the correct protection. Install a front bumper guard. Protect the front bumper from rocks and debris. Consider adding a brush guard to protect the front of the car from impacts. Install a rear bumper guard. Protect the rear bumper from impacts. Mud flaps are also important. Rally-style mud flaps help to prevent rocks and debris from damaging the bodywork. Consider adding a roof scoop. This can improve airflow to the engine and intercooler. Interior modifications are important. Install a rally computer, which provides crucial information. Consider a communication system. Install a radio communication system for the driver and co-driver. Make sure that the car meets all rally regulations. The finishing touches are what elevate a good build to a great one. These seemingly small details can have a big impact on your performance and your overall experience. With these modifications in place, your 2017 Subaru WRX STI is ready to take on the challenges of rally racing!