How to Increase Horsepower in a Subaru Crosstrek

Want more power from your Subaru Crosstrek? You’re not alone. With the right modifications—like ECU tuning, cold air intakes, and exhaust upgrades—you can safely increase horsepower without sacrificing reliability. This guide covers everything you need to know to unlock your Crosstrek’s hidden potential.

If you’re driving a Subaru Crosstrek and feeling like it could use a little more pep in its step, you’re not alone. The Crosstrek is a fantastic all-around vehicle—rugged, reliable, and great on gas. But let’s be honest: its factory horsepower, especially on the naturally aspirated 2.0L and 2.5L engines, leaves something to be desired for enthusiasts who crave a more thrilling drive. Whether you’re navigating mountain passes, towing a small trailer, or just want to feel more confident merging onto the highway, increasing horsepower can make a world of difference.

The good news? You don’t need to trade in your Crosstrek for a sports car to enjoy more power. With smart, well-planned modifications, you can safely and effectively boost your Crosstrek’s performance. From simple bolt-on upgrades to advanced tuning, there are plenty of ways to squeeze more horsepower out of your Subaru. And the best part? Many of these mods can be done at home with basic tools—or with help from a trusted mechanic.

In this guide, we’ll walk you through the most effective and practical ways to increase horsepower in your Subaru Crosstrek. Whether you drive a naturally aspirated model or one of the newer turbocharged versions (like the 2018+ Crosstrek with the FA24F engine), we’ve got you covered. We’ll explain how each modification works, what kind of power gains to expect, and how to keep your Crosstrek running smoothly and reliably. Let’s get started!

Key Takeaways

• ECU tuning is the most effective way to increase horsepower: A custom or off-the-shelf tune can add 15–30+ HP by optimizing fuel, timing, and boost (on turbo models).
• Upgrade the cold air intake for better airflow: Replacing the stock airbox with a high-flow intake improves engine breathing and can add 5–10 HP.
• Install a performance exhaust system: A cat-back or turbo-back exhaust reduces backpressure, enhancing power and sound.
• Consider a turbo upgrade for significant gains: On turbocharged Crosstreks (2018+), a larger turbo or hybrid turbo can dramatically boost output.
• Use high-octane fuel to support tuning: Premium fuel (91+ octane) prevents knock and allows for more aggressive tuning.
• Maintain your vehicle regularly: Clean fuel injectors, fresh spark plugs, and proper oil changes ensure mods work at peak efficiency.
• Balance performance with reliability: Avoid extreme mods unless you’re prepared for increased maintenance and potential warranty issues.

Understanding Your Subaru Crosstrek’s Engine

Before diving into mods, it’s important to understand what you’re working with. The Subaru Crosstrek has evolved over the years, and its engine options play a big role in how—and how much—you can increase horsepower.

Engine Options in the Crosstrek

The Crosstrek has been offered with a few different engines since its debut in 2013. The most common are:

– 2.0L Naturally Aspirated Flat-4 (FB20): Found in 2013–2017 models, this engine produces around 148–152 horsepower. It’s reliable and fuel-efficient but lacks the low-end torque and high-RPM excitement some drivers want.
– 2.5L Naturally Aspirated Flat-4 (FB25): Available in later non-turbo models (2018–2023), this engine bumps output to about 182 horsepower. It’s a solid improvement but still not a performance powerhouse.
– 2.4L Turbocharged Flat-4 (FA24F): Introduced in the 2018 Crosstrek and standard in the 2024 model, this turbo engine delivers 182 horsepower and 176 lb-ft of torque. While the horsepower number looks similar to the 2.5L, the turbo provides much better low-end torque and responsiveness.

Knowing your engine type is crucial because it determines which mods will work best. Naturally aspirated engines respond well to airflow and tuning improvements, while turbocharged models can benefit from boost upgrades and more aggressive tuning.

Stock Limitations and Bottlenecks

Even with a turbo, the Crosstrek isn’t built for high-performance out of the box. Subaru prioritizes fuel economy, emissions compliance, and reliability—which means the engine is often tuned conservatively. This leaves plenty of room for improvement.

Common bottlenecks include:
– Restrictive factory air intake
– Narrow exhaust system with a small catalytic converter
– Conservative ECU (engine control unit) tuning
– Limited cooling capacity under sustained load

By addressing these limitations, you can unlock hidden power. But remember: every mod should be done with care. Overdoing it can lead to engine knock, overheating, or even premature failure.

ECU Tuning: The Fastest Way to Gain Horsepower

If you’re serious about increasing horsepower in your Subaru Crosstrek, ECU tuning should be at the top of your list. This is the single most effective modification you can make—especially on turbocharged models.

How ECU Tuning Works

The ECU (also called the PCM or engine computer) controls nearly every aspect of engine operation: fuel delivery, ignition timing, throttle response, and boost pressure (on turbo models). Factory settings are designed to meet emissions standards, ensure reliability across various climates, and protect the engine under all conditions. That means they’re often dialed back.

A performance tune reprograms the ECU to optimize these parameters for power and efficiency. On a turbo Crosstrek, a good tune can increase boost pressure, advance ignition timing, and enrich the air-fuel mixture—all of which translate to more horsepower.

Types of Tuning

There are two main types of ECU tuning:

– Off-the-Shelf (OTS) Tunes: Pre-written tunes from companies like Cobb, OpenFlash, or Accessport. These are plug-and-play and designed for common mod combinations. They’re affordable ($300–$600) and easy to install, but not customized to your specific vehicle.
– Custom Tunes: Created by a professional tuner using dyno testing and real-time data. These are more expensive ($500–$1,000+) but offer the best performance and safety, especially if you’ve made multiple mods.

For most drivers, a quality OTS tune is a great starting point. But if you’re adding a turbo, intercooler, or other major components, a custom tune is worth the investment.

Real-World Gains

On a stock 2.4L turbo Crosstrek, a well-done tune can add 20–30 horsepower and 25–40 lb-ft of torque. That’s a noticeable improvement in acceleration and responsiveness. On a naturally aspirated model, gains are smaller—typically 5–10 HP—but still worthwhile when combined with other mods.

Important Considerations

– Always use high-octane fuel (91+ octane) with a performance tune to prevent engine knock.
– Monitor engine parameters (like AFR and boost) with a gauge or OBD2 scanner.
– Avoid “cheap” tunes from unknown sources—they can damage your engine.

Upgrade the Air Intake System

Your engine needs air to make power—and the stock air intake on the Crosstrek is designed more for quiet operation and emissions than performance. Upgrading to a cold air intake (CAI) is one of the easiest and most cost-effective ways to increase horsepower.

How a Cold Air Intake Works

The factory intake pulls air from inside the engine bay, where temperatures are high. Hot air is less dense, which means fewer oxygen molecules for combustion—and less power. A cold air intake relocates the air filter outside the engine bay, drawing in cooler, denser air from the fender or bumper area.

Additionally, performance intakes use larger-diameter tubing and high-flow filters (like oiled cotton or synthetic media) to reduce restriction. This improves airflow and allows the engine to breathe easier.

Types of Intake Systems

– Short Ram Intake: Replaces the stock airbox but keeps the filter inside the engine bay. Easier to install but less effective than a true CAI.
– Cold Air Intake (CAI): Routes the filter to a cooler location (often behind the bumper or in the fender well). Offers the best performance gains.
– Ram Air Intake: Uses the vehicle’s motion to force air into the engine. Rare on the Crosstrek but possible with custom fabrication.

For most Crosstrek owners, a quality CAI from brands like Perrin, Injen, or AEM is the best choice.

Expected Gains and Sound

A cold air intake typically adds 5–10 horsepower, depending on the engine and other mods. While that might not sound like much, the improvement in throttle response and engine sound is immediate and satisfying. You’ll hear a deeper, more aggressive intake roar under acceleration—especially on turbo models.

Installation Tips

– Follow the manufacturer’s instructions carefully.
– Reconnect all sensors (like the MAF sensor) properly.
– Re-tune your ECU after installation, especially if you’re using a performance tune. The ECU needs to adjust for the increased airflow.

Improve Exhaust Flow with a Performance Exhaust

Just as your engine needs to breathe in, it also needs to breathe out. The stock exhaust system on the Crosstrek is restrictive, with narrow piping and a small catalytic converter. Upgrading to a performance exhaust reduces backpressure, allowing exhaust gases to exit more freely—which can increase horsepower and improve sound.

Types of Exhaust Upgrades

– Cat-Back Exhaust: Replaces everything from the catalytic converter back (muffler, resonator, piping). This is the most popular and street-legal option. It improves flow and sound without affecting emissions.
– Turbo-Back Exhaust (Turbo Models Only): Replaces the downpipe (from the turbo to the catalytic converter) and the rest of the system. This offers greater gains but may require a tune and could affect emissions compliance.
– Header/Manifold Upgrade: Replaces the exhaust manifold with equal-length or high-flow headers. More complex and expensive, but beneficial for high-performance builds.

For most drivers, a quality cat-back system is the best balance of performance, sound, and legality.

Expected Gains

A cat-back exhaust typically adds 5–15 horsepower, depending on the design and engine. On a turbo Crosstrek, gains can be higher due to reduced backpressure. The sound is deeper and more aggressive—think sporty growl instead of a whisper.

Popular Brands and Options

Look for systems from reputable brands like:
– Borla
– MagnaFlow
– Cobb
– Invidia
– Perrin

Many offer stainless steel construction, mandrel-bent piping, and drone-free designs for a refined driving experience.

Installation and Legal Notes

– Cat-back systems are generally legal in all 50 states.
– Turbo-back systems may require a tune and could trigger emissions issues in strict states (like California).
– Always check local laws before modifying your exhaust.

Boost Power with a Turbo Upgrade (Turbo Models Only)

If you drive a 2018 or newer Crosstrek with the 2.4L turbo engine, you have a major advantage: forced induction. This means you can significantly increase horsepower by upgrading the turbocharger.

How Turbo Upgrades Work

The factory turbo on the FA24F engine is designed for reliability and fuel economy. It produces around 12–14 psi of boost. By installing a larger or more efficient turbo (or a hybrid turbo), you can increase boost pressure and airflow, resulting in substantial power gains.

Types of Turbo Upgrades

– Hybrid Turbo: A modified version of the stock turbo with upgraded compressor and turbine wheels. Offers better flow and response without requiring major changes.
– Full Turbo Upgrade: Replaces the entire turbo with a larger unit (e.g., from Garrett or BorgWarner). Requires supporting mods like a larger intercooler, fuel system upgrades, and a custom tune.
– Boost Controller: An electronic device that allows you to manually adjust boost pressure. Can be used with the stock turbo for moderate gains.

Realistic Gains

– Hybrid turbo: +30–50 HP
– Full turbo upgrade: +70–100+ HP (with supporting mods)

These gains are impressive, but they come with trade-offs: increased cost, complexity, and potential reliability concerns.

Supporting Mods Are Essential

Upgrading the turbo isn’t a standalone mod. You’ll also need:
– High-flow fuel injectors
– Upgraded fuel pump
– Larger intercooler
– Custom ECU tune
– Possibly upgraded engine internals (for extreme builds)

This is a serious project—best left to experienced builders or professional shops.

Other Performance Enhancements

Beyond the big three (tuning, intake, exhaust), there are several other ways to squeeze more power from your Crosstrek.

Upgrade the Intercooler (Turbo Models)

The intercooler cools compressed air from the turbo before it enters the engine. Cooler air is denser and more powerful. A larger or more efficient intercooler (like a front-mount or top-mount upgrade) can reduce intake temperatures and prevent heat soak—especially during repeated hard driving.

Use High-Octane Fuel

Higher-octane fuel (91 or 93) resists detonation, allowing for more aggressive timing and boost. If you’re tuning your Crosstrek, premium fuel isn’t optional—it’s essential.

Install a Performance Throttle Body

A larger throttle body improves airflow into the engine. Gains are modest (3–5 HP), but it can improve throttle response.

Upgrade Spark Plugs and Ignition Coils

High-performance spark plugs (like iridium or platinum) and upgraded coils ensure a strong, consistent spark—especially under boost. This supports tuning and prevents misfires.

Reduce Weight

While not a direct horsepower increase, shedding unnecessary weight (like spare tires, rear seats, or heavy accessories) improves power-to-weight ratio. Every pound removed is like adding a tiny bit of horsepower.

Maintaining Reliability While Increasing Power

It’s easy to get excited about mods—but don’t forget that more power means more stress on your engine and drivetrain. To keep your Crosstrek running strong, follow these tips:

– Follow a strict maintenance schedule: Change oil every 3,000–5,000 miles (especially with a tune or turbo).
– Monitor engine parameters: Use an OBD2 gauge to watch for knock, high EGTs, or lean conditions.
– Avoid excessive boost on stock internals: The FA24F can handle moderate increases, but pushing beyond 20 psi may require forged pistons and rods.
– Don’t skip the tune: Never install performance parts without a proper tune. The ECU needs to adapt.

Conclusion

Increasing horsepower in your Subaru Crosstrek is absolutely possible—and more accessible than ever. Whether you drive a naturally aspirated model or a turbocharged version, there are proven, reliable ways to unlock more power and improve your driving experience.

Start with the basics: a quality ECU tune, cold air intake, and performance exhaust. These mods offer the best balance of cost, ease, and results. If you’re driving a turbo Crosstrek and ready for more, consider a turbo upgrade—but be prepared for the supporting mods and costs.

Remember, the goal isn’t just more horsepower—it’s a better, more enjoyable Crosstrek. With the right approach, you can have both performance and reliability. So go ahead, give your Subaru the power it deserves. Your Crosstrek will thank you with every thrilling acceleration.

Frequently Asked Questions

Can I increase horsepower on a naturally aspirated Subaru Crosstrek?

Yes, you can. While gains are smaller than on turbo models, modifications like ECU tuning, cold air intake, and performance exhaust can add 10–15 horsepower combined. Focus on improving airflow and optimizing engine management.

Is it safe to tune my Crosstrek’s ECU?

Yes, if done correctly. Use reputable tuning platforms like Cobb Accessport or OpenFlash, and always use high-octane fuel. Avoid cheap or untested tunes, and consider a custom tune if you’ve made multiple mods.

Will modifying my Crosstrek void the warranty?

It depends. Modifications that directly cause a failure may void related warranty claims. However, the Magnuson-Moss Warranty Act protects you—dealers can’t void your entire warranty just because you added a cold air intake.

How much horsepower can I realistically add to a stock Crosstrek?

On a turbo Crosstrek, 20–30 HP with a tune, intake, and exhaust. On a naturally aspirated model, expect 10–15 HP total. Larger gains require internal engine work or turbo upgrades.

Do I need to retune after installing a cold air intake?

Yes, especially if you’re using a performance tune. The ECU needs to adjust for increased airflow. Most tuners offer revised maps for common intake systems.

Can I install performance mods myself?

Many bolt-on mods (intake, exhaust, throttle body) can be done at home with basic tools. Tuning and turbo upgrades are best left to professionals. Always follow instructions and safety guidelines.