Best Jump Starter for a Subaru EJ25 / FA24 (WRX / Outback / Forester)

The Subaru EJ25 and its FA24 successor are flat-four boxer engines that power most modern Subarus. EJ25 ran from 1996 through 2019 in Outback, Forester, Legacy, and Impreza, and remained in the WRX through 2021. FA24 took over in the 2022 WRX. Subaru owners ask about jump starters because the small footprint of the boxer engine puts the battery in unusual locations, and because WRX owners specifically run aftermarket audio and lighting that drains batteries faster than stock.

The Quick Answer

The Fanttik T8 APEX is the right portable jump starter for any EJ25 or FA24 Subaru. Cranking current on the boxer four runs 350-500A typical, climbing to 700A in cold weather. The T8 APEX's 2,000A peak provides 3-4× margin. is useful because Subaru owners disproportionately drive in weather where jump-starting happens in rain or snow.

Where the EJ25 and FA24 Live

The EJ25 in normally aspirated form powered Outback, Forester, Legacy, Impreza, and Crosstrek through 2019. Turbocharged EJ25 variants (EJ255, EJ257) powered the WRX and STI from 2002 to 2021. The FA24 dual-injection turbocharged flat-four took over WRX duties in 2022. Older EJ22 and EJ20 variants share the basic architecture and crank similarly.

The Specs You Need to Know

Why Subaru Battery Location Matters

The boxer-four engine sits low and wide in the engine bay, which pushes the battery to one side of the engine compartment — typically driver-side on US-spec cars, with a tray that's narrower than a typical inline engine's battery box. Aftermarket batteries that are physically larger don't fit. The T8 APEX clamps reach Subaru batteries without trouble; the consideration is just that there's less working room around the terminals than on a half-ton truck.

How to Jump an EJ25 or FA24 Subaru

1. Open the hood. The battery is on the driver side near the strut tower on most Subarus.
2. Red clamp to positive. The terminal is tight to the strut tower — a small adjustment to the clamp angle helps.
3. Black clamp to chassis ground or to a clean unpainted bolt on the strut tower.
4. Wait for the green light. EJ25 and FA24 cranking is reliable; force-start rare.
5. Crank. The engine should fire within 2 seconds.
6. Drive for 20+ minutes. WRX and STI owners with aftermarket loads should drive longer to fully recover.

What to Watch Out For

• WRX and STI owners running aftermarket audio amps, light bars, or air-suspension compressors often have parasitic-draw problems that flatten batteries in 5-7 days of inactivity. A jump fixes the symptom; the parasitic load needs diagnosis.
• 2018+ Subaru models with EyeSight require a brief calibration cycle after a battery has been fully disconnected. Jump-starting does not reset EyeSight, but a fully dead battery sometimes does.
• The FA24 in the 2022+ WRX has more sensitive ECM behavior around low-voltage starts. If the battery is below 11.5V resting, expect a longer crank than on the older EJ engines.

FAQ

Q: Will the T8 APEX work on a turbo STI?
A: Yes. The EJ257 STI pulls more current than a base EJ25, but still well inside the T8 APEX's range.

Q: How does the FA24 compare to the EJ25 for cranking?
A: Similar. The FA24 has slightly tighter low-voltage start behavior but the actual crank current is comparable to a turbo EJ25.

Q: Can the T8 APEX jump a Subaru with a fully dead battery (under 9V)?
A: Yes, in force-start mode. The pack delivers current bypassing the auto-detect that would otherwise refuse to engage.

Verdict

The Fanttik T8 APEX 2000A Jump Starter is the right portable jump starter for any EJ25 or FA24 Subaru. WRX, STI, Outback, Forester, Impreza — one pack covers the whole Subaru lineup.

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