Spec G25-660 Turbo Kit + Custom Tune — 2022+ Subaru WRX VB

The G25-660 is an ideal turbo upgrade for VB WRX owners targeting 450 wheel horsepower and up while maintaining strong response, excellent street manners, and a broad usable powerband.

I run this exact turbo configuration on my personal VB WRX, so the boost-response figures below are based on real-world use rather than estimates from a compressor map.

The G25-660 provides substantially more airflow than the factory turbo without pushing the powerband excessively high in the RPM range. It is an excellent match for a street-driven VB WRX that needs enough airflow to make serious power while retaining quick response between shifts.

The G25-660 offers a well-rounded balance of:

• Suitable for builds targeting 450 WHP and up — see the updated estimated wheel-output readings from my personal car on 93 octane + water-methanol injection (WMI) below.

• Strong street response

• Excellent transient response

• Broad usable powerband

• Progressive boost delivery

• Strong midrange and top-end performance

• Better high-RPM airflow than the factory turbo

Actual power will depend on fuel, boost pressure, tuning, engine condition, supporting modifications, elevation, and drivetrain configuration.

The factory VB WRX turbo produces a sharp surge of torque at low RPM. While this makes the car feel responsive, the sudden torque spike can place substantial stress on the transmission and drivetrain.

The G25-660 builds boost more progressively and carries power farther into the upper RPM range.

This smoother delivery reduces the harsh low-RPM torque hit of the factory turbo while providing stronger performance throughout most of the usable powerband. Instead of hitting hard and falling off, the G25-660 continues pulling toward redline.

The following boost-response figures were recorded using this turbo configuration on my personal VB WRX.

Exact spool will vary depending on exhaust configuration, boost target, tuning, gear, fuel, elevation, and supporting modifications.

• 1st gear: Approximately 18 psi

• 2nd gear: Full boost by approximately 4,000 rpm

• 3rd gear: Full boost by approximately 3,000 rpm

This is where the G25-660 performs especially well:

• 1st gear: Approximately 18 psi

• 2nd gear: Full boost immediately after the shift

• 3rd gear: Full boost immediately after the shift

Although initial spool takes slightly longer during an isolated low-RPM pull, the turbo retains shaft speed extremely well between gear changes.

Once the turbo is operating within its intended range, boost returns immediately after each shift and the car continues pulling hard through the remaining gears.

The biggest advantage of the G25-660 is its transient response.

A turbo should not be judged only by the RPM at which it reaches full boost during one isolated pull. How quickly it recovers after a gear change is equally important during real-world acceleration.

The G25-660 carries rotating energy exceptionally well between shifts. Once it is spooled, it remains responsive and quickly returns to full boost after each gear change.

The result is:

• Immediate boost recovery between gears

• Strong acceleration through consecutive pulls

• Minimal waiting for the turbo to respool

• A wide and usable street powerband

• Strong performance through the factory redline

• Continued pulling power at higher engine speeds

My personal setup is operated to approximately 7,000 rpm, where the turbo continues to pull strongly.

• GropeTuned Spec G25-660 turbocharger

• All turbo mounting studs

• Required oil and coolant hoses

• Turbo gaskets

• Complete mounting hardware

• Everything required for a direct swap onto a 2022+ Subaru WRX

Ready to bolt on, tune, and make power.

Professional tuning and appropriate supporting modifications are required before operating the vehicle under boost.

The updated analytical log comes from my personal VB WRX with the following configuration:

• 93-octane gasoline + water-methanol injection (WMI)

• GropeTuned Spec G25-660 turbocharger

• Stock exhaust headers

• Upgraded turbo inlet

• Aftermarket intake

• Front-mount intercooler

• Downpipe

• Upgraded intake manifold

Default matched package: this turbo is paired with a full WRX E-tune built around the selected turbo and your supporting mods.

The calibration in this kit is built around your car. These extend what it can do:

• Flex Fuel Tune Add-On — ethanol-aware fuelling, timing and boost that scale with what is actually in the tank
• Speed Density Tune Add-On — MAP-based load calculation, for when the intake tract no longer suits the MAF
• Ask about a Teach-As-We-Go upgrade — this kit already includes tuning; contact me about the teaching upgrade before purchasing a separate tune

• 62mm High-Flow Throttle Body — less restriction at the last turn into the manifold
• BRZ Intake Manifold Adapter Kit — the BRZ-style manifold conversion for the 2022+ VB

A bigger hot side puts more heat into the bay. We make the shielding for it.

• 3-Layer Heat Wrapping Service — send us your header or J-pipe and we build it
• Ultimate Heat Wrap Bundle — materials and the welder to build it yourself

Updated reference from my personal VB WRX with the GropeTuned Spec G25-660 on 93 octane + water-methanol injection (WMI): the analytical log estimates 429.20 wheel HP and 495.30 lb-ft at 4,564 RPM, and 474.32 wheel HP and 401.76 lb-ft at 6,222 RPM. These are selected log readings, not confirmed peak figures or a measured hub-dyno result. Results vary with vehicle, fuel, hardware, conditions, and calibration.

Not a guarantee. Results vary with vehicle, fuel, supporting hardware, ambient conditions and calibration.