Is the Subaru B4 turbo?
Not in the form of a current Subaru model. The B4 badge is not a modern turbo designation; turbocharged Subarus exist, but under WRX/WRX STI or Legacy GT lines rather than a standalone “B4 Turbo.”
Historically, the B4 label appeared in Japan as a body‑style/trim marker on four‑door sedans within Subaru’s Impreza and Legacy lines in the 1990s and early 2000s. While some B4-equipped cars were turbocharged, others were naturally aspirated. In today’s global market, Subaru’s turbo performance lineup is branded around WRX/WRX STI (and current turbo variants like the FA24-powered WRX), with no active product named “B4.” If you’re evaluating a specific vehicle, confirm its engine and trim from the VIN, brochures, or dealer documentation.
Understanding the B4 badge
The B4 designation is primarily a historical label tied to a four‑door sedan body style in Subaru’s Japanese market. It is not a stand-alone engine or performance name, and by itself does not guarantee turbocharging. Turbo variants did exist in some generations, but the presence of a B4 badge did not universally indicate a turbo engine.
Historical context
During the 1990s and early 2000s, Subaru offered both turbocharged and naturally aspirated variants on Impreza and Legacy sedans in Japan. The B4 tag appeared in marketing materials as a descriptor for certain sedan configurations rather than as a turbo badge.
Modern status
Today, Subaru communicates performance through WRX/WRX STI and, more recently, FA24‑powered WRX models. There is no current product named “B4,” so any B4 reference is historical or restricted to specific older markets and configurations.
Key points to keep in mind when assessing a B4 and any potential turbo status:
- The B4 tag is a historical body‑style/trim designation used on some Japanese market sedans, not a turbo badge.
- Turbocharging existed in some B4‑equipped cars, but many were naturally aspirated; the badge alone does not confirm turbo status.
- Current Subaru turbo models are branded WRX/WRX STI (and the FA24 WRX), with no ongoing “B4” model in production.
Conclusion: Use the specific model name (WRX, WRX STI, Legacy GT, etc.), year, and engine code to determine turbo status rather than relying on a B4 label alone.
How to verify if a B4 is turbo
- Inspect the engine bay for turbo components such as a turbocharger, intercooler, and associated piping.
- Check for external badges that indicate a turbocharged variant (e.g., WRX/WRX STI). Note that some B4 configurations might not carry obvious turbo branding.
- Look up the vehicle’s VIN or chassis code and cross‑check with the original brochure or dealer documentation to confirm engine type and trim.
- Review service records for mentions of turbo maintenance, boost settings, or related performance options.
- If in doubt, have a qualified mechanic perform a boost and compression test to confirm turbo presence and condition, including any aftermarket modifications.
Conclusion: A combination of visual inspection, official documentation, and expert diagnosis will provide the most reliable determination of whether a specific B4 is turbocharged.
Summary
The Subaru B4 is a historical, Japan‑market body/trim designation rather than a current turbo model. Turbocharged Subarus today are branded as WRX/WRX STI (and newer FA24‑powered variants), while the presence of a B4 badge alone does not guarantee a turbo engine. For any specific car, verify engine type and trim via the VIN, brochures, and service history to confirm whether it is turbocharged.
What does B4 mean on a Subaru?
It's a Subaru Legacy. B4 meaning Boxer 4WD.
Which Subaru models are turbo?
Subaru currently offers turbocharged models in the Ascent, Outback, and WRX. Older or region-specific turbocharged models include the Legacy XT and some Forester and Crosstrek trims.
You can watch this video to see a review of the turbocharged Subaru Outback: 59sCarGurusYouTube · Nov 20, 2025
Current turbocharged models
- Ascent: The Ascent comes standard with a turbocharged 2.4-liter engine.
- Outback: Turbocharged engines are available on specific Outback trims, often designated as "XT".
- WRX: The WRX is Subaru's high-performance car and comes standard with a turbocharger.
Past and regional turbocharged models
- Legacy XT: The Legacy XT was a turbo model, though its availability varies by model year.
- Forester: Some older Forester models, as well as some current versions in specific markets, have offered a turbo option.
- Crosstrek: At least one recent model year includes a turbo engine as standard on a specific trim in some regions.
- Subaru XT: An older, classic coupe that was available with a turbo engine.
What engine is in a Subaru B4?
2.0-liter boxer four
B4 Engine Structure
The B4 is powered by a 'phase 2' all-alloy DOHC, 16-valve, intercooled turbo 2.0-liter boxer four. According to official Subaru literature, there are several advantages to the boxer design.
Is the Subaru B4 a fast car?
Horsepower but regardless of the transmission. This car wasn't just fast it was quick the B4. RSK could hit 60 mph. In just 5.2 seconds with the manual transmission. And even with the automatic.
