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BMW N74B66 specs: 6.6L (402 ci) 12-cylinder, 89 x 88.3 mm (3.5039 x 3.4764 in) bore and stroke, 10:1 compression. Rated 600-601 hp, 2017–2022.
The BMW N74B66 is close to square: 3.5039" bore against 3.4764" stroke, within 0.8%, which splits the difference between a high-revving layout and a torque layout. The 3.4764" stroke puts mean piston speed at 4,000 ft/min around 6,900 RPM, which is where a production bottom end is generally considered at its limit. Each of the 12 cylinders displaces 33.5 ci (549 cc).
10:1 is in the range that usually runs on pump premium.
6 factory variants share these dimensions, rated from 600 to 601 hp across 2017–2022.
| Displacement | 402 ci / 6.6 L |
|---|---|
| Bore | 3.5039" |
| Stroke | 3.4764" |
| Cylinders | 12 |
| Compression ratio | 10:1 * |
| Bore/stroke ratio | 1.008 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Advertised HP | 600–601 hp |
| Years | 2017–2022 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2017 | N74B66 net | 600 @ 5500 | 590 lb-ft @ 1550 | — |
| 2020 | N74B66 net | 600 @ 5500 | 590 lb-ft @ 1550 | — |
| 2022 | N74B66 net | 600 @ 5500 | 590 lb-ft @ 1550 | — |
Factory specification sheet.
| Bore/stroke character | 1.008 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,476 ft/min — conservative for a street engine |
| Displacement per cylinder | 33.5 ci |
| Static compression | 10:1 — 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 |
|---|---|---|
| 2017 | 600–601 hp | N74B66 |
| 2018 | 601 hp | N74B66 |
| 2019 | 601 hp | N74B66 |
| 2020 | 600 hp | N74B66 |
| 2021 | 601 hp | N74B66 |
| 2022 | 600 hp | N74B66 |
1 factory vehicle, 2017–2022. Each year opens that model's engine table.