Subaru CB engine

The CB engine was first introduced in August 2020 with the second-generation Levorg. According to Subaru, CB stands for Concentration/Compact Boxer. It is the fourth-generation boxer engine family from Subaru. Compared to the preceding FB series, the CB is shorter; the bore pitch (centerline to centerline spacing between adjacent cylinders) has decreased from and the overall crank length has decreased from . For the first time in a Subaru engine, the centerlines of the cylinder bores do not intersect with the crankshaft axis; instead, there is a crank offset of . This offset reduces friction during the piston downstroke. Overall thermal efficiency is 40% due to the adoption of lean-burn combustion with an excess air ratio (λ) of 2. The third generation FB/FA connecting rods are split diagonally (also called an offset or asymmetrical connecting rod) to allow a longer piston stroke without increasing the width of the engine, but the horizontally-split connecting rods are stronger. ==CB18==

The first engine in the series is designated CB18, a 1.8 litre dual overhead cam 16-valve engine featuring dual AVCS with gasoline direct injection and a turbocharger. Compared to the FB16 used in the previous generation of the Levorg, the CB18 offers decreased fuel consumption ( for the CB18 and for the FB16, both using the JC08 mode) and increased torque ( for the CB18 and for the FB16). In addition, the CB18 achieves its peak torque at a lower engine speed. The CB18 engine is also fitted to the Subaru Legacy Outback for the Japanese market. In April 2022, Subaru had to suspend production of Forester, Outback and Levorg after it discovered a sensor in CB18 engine malfunctioned. ;CB18 specifications: • Displacement: DOHC, turbocharged • Bore × stroke: • Compression ratio: 10.4:1 • Power: at 5,200–5,600 RPM • Torque: at 1,600–3,600 RPM ;CB18 applications: • 2021–present JDM Subaru Levorg (VN5) • 2021–present JDM Subaru Forester (SK5) • 2021–present JDM Subaru Legacy Outback (BT5) • 2025– JDM Subaru Forester (SL5) ==References==