87 US AKI octane confirmed on the subaru of japan site (sorry its going open a PDF,...lots of stuff in the flyer though).
maybe it will automatically reflash for more hp/torque if you put higher octane in.
https://www.subaru.co.jp/press/file/...17_1129_02.pdf
73 liters ~ 19.28 gallons for the fuel tank capacity. (subaru did not give a conversion in the data below)
quoted text centered:
< Major Specifications of Ascent (US specs.) >
Body size (Overall length / width / height) 4,998 x 1,930 x 1,819*1 mm (196.8 x 76.0 x 71.6*1 in.) Wheelbase 2,890 mm (113.8 in.)
Minimum ground clearance 220 mm (8.7 in.)
Engine
2.4-liter Horizontally-Opposed four cylinder, DOHC, Direct injection turbo FA24 engine
Displacement 2,387cc Bore and stroke 94 x 86 mm Maximum output 260hp / 5,600rpm Maximum torque 277lb.-ft. / 2,000 - 4,800rpm
Fuel tank capacity 73 liter
Fuel type 87 AKI
Transmission High-torque Lineartronic*2 Drivetrain Symmetrical AWD Tire size 245/60 R18, 245/50 R20 Seating capacity 7 / 8
*1: Without roof rail: 1,766 mm (69.5 in.)
*2: Continuously variable transmission (CVT) with fully automatic electronic control