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Toyota B48B20 specs: 2.0L (121.9 ci) 4-cylinder, 82 x 94.6 mm (3.2283 x 3.7244 in) bore and stroke, 10.2:1 compression. Rated 255 hp, 2021–2024.
The Toyota B48B20 is undersquare — the 3.7244" stroke exceeds the 3.2283" bore by 13.3% — a layout that trades peak RPM for leverage and torque low in the range. The 3.7244" stroke puts mean piston speed at 4,000 ft/min around 6,450 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 30.5 ci (499 cc).
10.2:1 is in the range that usually runs on pump premium.
It is one of 4 engines in the BMW B48/B58 (Supra) family, the smallest at 121.9 ci. 4 factory variants share these dimensions, rated at 255 hp across 2021–2024.
| Displacement | 121.9 ci / 2 L |
|---|---|
| Bore | 3.2283" |
| Stroke | 3.7244" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 10.2:1 |
| Bore/stroke ratio | 0.867 |
| Fuel type | gas |
|---|---|
| Advertised HP | 255 hp |
| Years | 2021–2024 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2021 | B48B20 net | 255 @ 5000 | 295 lb-ft @ 1550 | 10.2:1 |
| 2022 | B48B20 net | 255 @ 5000 | 295 lb-ft @ 1550 | 10.2:1 |
| 2023 | B48B20 net | 255 @ 5000 | 295 lb-ft @ 1550 | 10.2:1 |
| 2024 | B48B20 net | 255 @ 5000 | 295 lb-ft @ 1550 | 10.2:1 |
Factory specification sheet.
| Bore/stroke character | 0.867 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,724 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 30.5 ci |
| Static compression | 10.2:1 — in the range that usually runs on pump premium |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2021 | 255 hp | B48B20 |
| 2022 | 255 hp | B48B20 |
| 2023 | 255 hp | B48B20 |
| 2024 | 255 hp | B48B20 |
1 factory vehicle, 2021–2024. Each year opens that model's engine table.