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BMW N55B30 specs: 3.0L (182 ci) 6-cylinder, 84 x 89.6 mm (3.3071 x 3.5276 in) bore and stroke, 10.2:1 compression. Rated 300-349 hp, 2011–2019.
The BMW N55B30 is undersquare — the 3.5276" stroke exceeds the 3.3071" bore by 6.3% — a layout that trades peak RPM for leverage and torque low in the range. The 3.5276" stroke puts mean piston speed at 4,000 ft/min around 6,800 RPM, which is where a production bottom end is generally considered at its limit. Each of the 6 cylinders displaces 30.3 ci (497 cc).
10.2:1 is in the range that usually runs on pump premium.
It is one of 7 engines in the BMW 182ci family, all of them 182 ci — the differences between them are in compression, heads and rating, not displacement. 29 factory variants share these dimensions, rated from 300 to 349 hp across 2011–2019.
| Displacement | 182 ci / 3 L |
|---|---|
| Bore | 3.3071" |
| Stroke | 3.5276" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 10.2:1 |
| Bore/stroke ratio | 0.937 |
| Fuel type | gas |
|---|---|
| Advertised HP | 300–349 hp |
| Years | 2011–2019 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2011 | N55B30 net | 300 @ 5800 | 300 lb-ft @ 1300 | 10.2:1 |
| 2012 | N55B30 net | 300 @ 5800 | 300 lb-ft @ 1300 | 10.2:1 |
| 2012 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2013 | N55B30 net | 300 @ 5800 | 300 lb-ft @ 1300 | 10.2:1 |
| 2013 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2014 | N55B30 net | 300 @ 5800 | 300 lb-ft @ 1300 | 10.2:1 |
| 2014 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2015 | N55B30 net | 300 @ 5800 | 300 lb-ft @ 1300 | 10.2:1 |
| 2015 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2016 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2017 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2018 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
| 2019 | N55B30 net | 315 @ 5800 | 330 lb-ft @ 1300 | 10.2:1 |
Factory specification sheet.
| Bore/stroke character | 0.937 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,528 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 30.3 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 |
|---|---|---|
| 2011 | — | N55B30 |
| 2011 | 300 hp | N55B30 |
| 2012 | — | N55B30 |
| 2012 | 300 hp | N55B30 |
| 2012 | 315 hp | N55B30 |
| 2012 | 335 hp | N55B30 |
| 2013 | — | N55B30 |
| 2013 | 300 hp | N55B30 |
| 2013 | 315 hp | N55B30 |
| 2013 | 335 hp | N55B30 |
| 2013 | 349 hp | N55B30 |
| 2014 | — | N55B30 |
| 2014 | 300 hp | N55B30 |
| 2014 | 315 hp | N55B30 |
| 2014 | 335 hp | N55B30 |
| 2014 | 349 hp | N55B30 |
| 2015 | — | N55B30 |
| 2015 | 300 hp | N55B30 |
| 2015 | 315 hp | N55B30 |
| 2015 | 335 hp | N55B30 |
| 2015 | 349 hp | N55B30 |
| 2016 | — | N55B30 |
| 2016 | 315 hp | N55B30 |
| 2016 | 335 hp | N55B30 |
| 2017 | — | N55B30 |
| 2017 | 315 hp | N55B30 |
| 2018 | — | N55B30 |
| 2018 | 315 hp | N55B30 |
| 2019 | 315 hp | N55B30 |
8 factory vehicles, 2011–2019. Each year opens that model's engine table.