The Forced Performance FP Blue 58mm Turbo for Subaru: Your Guide to Streetable Max-Effort Power

You’ve conquered Stage 2. The downpipe roar, the aggressive tune, the newfound pull—it was exhilarating. But now, the itch is back. The stock VF turbo, even at its limit, feels like a leash. You’re not dreaming of a drag-only monster; you’re building a devastatingly fast street car, a daily driver that can humble much more expensive machinery. This is the crossroads where the FP Blue 58mm turbo Subaru community thrives. According to countless dyno sheets and track slips, this turbo represents one of the most potent and reliable paths to a genuine 400-450 wheel horsepower on the EJ257 and EJ255 platforms, a benchmark that transforms the character of the car entirely.

Table of Contents

• What is the FP Blue Turbo? The 58mm Powerhouse
• FP Blue Turbo Specs and Technical Deep Dive
• FP Blue STI Horsepower and Real-World Performance
• What Supporting Mods Are Required for the FP Blue?
• FP Blue Turbo Install and Tuning Considerations
• FP Blue vs. The Competition: FP Green, Blouch, and More
• Is the FP Blue a Good Turbo for a Daily-Driven Subaru?
• FP Blue Turbo Cost and Investment Breakdown
• Frequently Asked Questions (FAQ)
• Final Verdict: Is the FP Blue 58mm Turbo Right for You?

What is the FP Blue Turbo? The 58mm Powerhouse

The Forced Performance FP Blue is not just another turbocharger; it's a calculated evolution designed for a specific purpose. It sits squarely in the "streetable max-effort" category, a term enthusiasts use for a turbo that delivers a massive power increase without the crippling lag of a full-race setup. Think of it as the perfect bridge between the responsive but limited stock VF series and the laggy, high-strung giant turbos used for all-out competition.

The heart of the matter is the compressor wheel. The "58mm turbo Subaru" designation refers to the inducer diameter of the compressor wheel—58 millimeters. This size is the sweet spot for moving a massive volume of air, enough for over 400 whp, while still being able to spool respectably on the 2.5-liter EJ engine. Forced Performance is a legendary name in the turbo world, known for their robust engineering and real-world testing, which gives the FP Blue turbo review community a high level of confidence in the product.

A Legacy of Forced Performance Turbo Upgrades

Forced Performance cut its teeth in the Mitsubishi Evolution world, creating legendary turbos that dominated tracks worldwide. They brought that same engineering philosophy to the Subaru market. The FP Blue is a direct response to enthusiasts demanding a turbo that could deliver on the promise of 400+ whp without requiring a built engine in every single case, though it is highly recommended.

FP Blue Turbo Specs and Technical Deep Dive

Let's get into the numbers that define this turbo. Understanding the specs is key to knowing why it performs the way it does.

• Compressor Wheel: 58mm inducer, 76mm exducer (The "58mm" in FP Blue 58mm turbo Subaru)
• Turbine Wheel: FP's proprietary 8-blade, 49.2mm inducer design (based on the Mitsubishi TD05H turbine family but enhanced for flow)
• Bearing System: This is a critical point. Is the FP Blue a ball bearing turbo? Yes. It uses a genuine journal bearing system. While many high-end turbos use ball bearings for reduced friction and faster spool, FP's journal bearing design is renowned for its extreme durability and ability to handle high boost and back-pressure, making it a favorite for high-power, high-stress applications.
• Housing Options: Typically available with a 10.5cm² or 11.5cm² turbine housing (for Subaru IWG internal wastegate applications). The 10.5cm² will spool faster, while the 11.5cm² can offer more top-end power on built motors.
• Flow Rating: Approximately 65 lb/min, which is the airflow capacity that puts it solidly in the 400-450 whp range.

FP Blue STI Horsepower and Real-World Performance

This is the section everyone reads first. What is the horsepower potential of the FP Blue turbo on a Subaru STI? The answer depends heavily on fuel and supporting mods, but the range is well-established.

How much boost can the FP Blue turbo handle reliably? The turbo itself is capable of boost levels north of 28-30 psi, but the practical limit is often the engine. On a stock-block EJ257, pushing beyond 24-25 psi, even on E85, is flirting with danger. The consensus is that FP Blue STI horsepower figures are safest and most reliable in the 400-450 whp range, which requires a manageable 24-26 psi on E85.

How does the spool time of the FP Blue compare to the stock STI turbo? This is the trade-off. Expect full boost (around 22-24 psi) to arrive between 3800-4200 RPM, depending on the turbine housing and tune. The stock VF turbo might hit peak boost by 3000-3200 RPM. The lag is noticeable but far from unbearable. The payoff is an avalanche of power that the stock turbo simply cannot replicate past 5000 RPM. In a real-world 1/4 mile time or 60-130 mph scenario, a well-tuned FP Blue car can achieve low 11-second passes and 60-130 mph times in the 8-9 second range, a massive improvement over a Stage 2 car.

What Supporting Mods Are Required for the FP Blue?

You cannot simply bolt on an FP Blue turbo upgrade and go. It demands a suite of supporting modifications to feed it, control it, and ensure the engine survives the experience. This is not a "bolt-on" turbo in the traditional sense; it's the centerpiece of a new powertrain level.

Mandatory Supporting Modifications:

• Fueling: A high-flow in-tank fuel pump (like a Walbro 450 or AEM 340) is the bare minimum. You will need aftermarket fuel injectors in the 1000cc to 1300cc range. For E85, these injectors and a flex fuel kit are non-negotiable.
• Exhaust: A full turbo-back exhaust with a high-flow catted or catless downpipe is required. The stock downpipe is a massive restriction.
• Intake and Intercooling: A high-flow intake is needed. More critically, can the FP Blue be used with the stock Subaru intercooler? Absolutely not. You must upgrade to a larger top-mount intercooler (TMIC) or a front-mount intercooler (FMIC). The stock unit will be a severe heat soak bottleneck, leading to power loss and dangerous knock. Consider an upgrade like the HKS Top Mount Intercooler Kit for a balanced setup.
• Engine Internals: Can you run an FP Blue on a stock Subaru EJ257 block? Technically, yes, at lower boost levels on pump gas. But it is a ticking time bomb. For reliability and to actually use the turbo's potential, forged internals (pistons, rods, crank) are highly, highly recommended. The stock hypereutectic pistons are the weak link.
• Clutch: The stock clutch will surrender immediately. A performance clutch like the ACT Xtreme Duty Clutch Kit is essential to handle the torque.
• Engine Management: A professional, custom tune from a proven Subaru tuner is mandatory. An off-the-shelf map will not work.

FP Blue Turbo Install and Tuning Considerations

The FP Blue turbo install process is similar to any other turbo replacement on an EJ engine. It's a labor-intensive job that involves removing the intercooler, downpipe, and various coolant and oil lines. For a competent DIY mechanic, it's a weekend project. For most, it's a job for a reputable performance shop.

Key installation notes include ensuring a fresh oil feed line and verifying the oil restrictor is correctly sized (FP provides guidance). The turbo requires a specific break-in procedure, typically involving a few hundred miles of gentle driving before the full boost tune is applied.

Does the FP Blue require a custom tune, and what powerband can I expect? Yes, a custom tune is 100% required. The tune is what unlocks the turbo's potential and keeps the engine safe. Your tuner will map out the boost, timing, and fuel curves. The powerband is characterized by a strong ramp-up starting around 3000 RPM, with a ferocious pull from 4000 RPM all the way to the 7000+ RPM redline. It's a top-end power monster compared to the stock turbo.

FP Blue vs. The Competition: FP Green, Blouch, and More

No turbo exists in a vacuum. The FP Blue vs FP Green debate is a classic, as is the comparison to Blouch's offerings.

FP Blue vs. FP Green: What's the difference and which one is better for my goals? The FP Green uses a slightly larger 60mm compressor wheel. The difference? The Green will make more peak power (especially on a built motor) but spool 300-500 RPM later. The Blue is the better choice for a street car where transient response and mid-range punch are prized. The Green is for the enthusiast who lives at the track and doesn't mind the lag for a higher power ceiling. The Blouch Dom 1.5XTR vs FP Blue comparison is incredibly close. Both are fantastic 58mm turbo Subaru options with nearly identical performance. The choice often comes down to tuner preference, availability, and specific bearing/housing options.

Is the FP Blue a Good Turbo for a Daily-Driven Subaru?

This is a nuanced question. Is the FP Blue a good turbo for a daily-driven Subaru? If your definition of "daily" includes a tolerance for more lag in stop-and-go traffic and a thirst for premium fuel or E85, then yes, it can be an exhilarating daily. The car will be perfectly tractable and well-mannered under normal driving conditions. However, the increased stress on the drivetrain and the need for a more aggressive clutch can detract from the stock refinement. For a pure, comfort-focused daily driver, it's overkill. For an enthusiast's daily that doubles as a weekend warrior, it's nearly perfect.

FP Blue Turbo Cost and Investment Breakdown

Understanding the FP Blue turbo cost is about looking at the total system, not just the part itself.

• FP Blue Turbocharger: ~$1,800 - $2,200
• Supporting Mods (Fuel Pump, Injectors, TMIC/FMIC, etc.): ~$2,000 - $3,500
• Clutch: ~$800 - $1,500
• Professional Installation (if not DIY): ~$800 - $1,500
• Custom Tune: ~$500 - $800
• Potential Engine Build (Highly Recommended): ~$5,000 - $8,000+

The all-in cost for a reliable, well-executed FP Blue 58mm turbo Subaru build, including a conservative built short-block, can easily reach $10,000+. This is a serious investment for a serious power goal.

Frequently Asked Questions (FAQ)

Final Verdict: Is the FP Blue 58mm Turbo Right for You?

The Forced Performance FP Blue 58mm turbo is not for the faint of heart or the thin of wallet. It is a purpose-built tool for the enthusiast who has outgrown the beginner and intermediate stages of Subaru modification. It demands respect, a comprehensive parts list, and a expert tuner's touch.

If your goal is a street-driven Subaru that delivers a true 400-450+ wheel horsepower with a brutal, top-end charge that pulls harder the higher you rev, the FP Blue 58mm turbo Subaru package is arguably one of the best choices on the market. It strikes a nearly perfect balance between spool and power, earning its reputation as the premier "streetable max-effort" turbo. For those ready to take the leap, the performance payoff is immense.

Before you begin your build, ensure you have all the necessary supporting components. You can browse our selection of supporting mods, from engine components to exhaust parts and cooling systems, to ensure your project is a success.

Disclaimer: This article is for informational purposes only. Modifying your vehicle's engine and powertrain can void warranties and carries inherent risks. Always consult with a licensed and experienced automotive performance professional before undertaking any modifications. The publisher is not responsible for any damage or issues resulting from the use of this information.