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Lexus 1UR-FSE specs: 4.6L (281.2 ci) 8-cylinder, 94 x 83 mm (3.7008 x 3.2677 in) bore and stroke, 11.8:1 compression. Rated 342-386 hp, 2007–2017.
The Lexus 1UR-FSE is oversquare — the 3.7008" bore exceeds the 3.2677" stroke by 13.3% — a layout that favors airflow and RPM over leverage at the crank. The 3.2677" stroke does not reach 4,000 ft/min of mean piston speed until about 7,350 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 35.2 ci (576 cc).
11.8:1 on aluminum heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 13 engines in the UR family, sitting between the 281 ci and 346 ci members. 15 factory variants share these dimensions, rated from 342 to 386 hp across 2007–2017.
| Displacement | 281.2 ci / 4.6 L |
|---|---|
| Bore | 3.7008" |
| Stroke | 3.2677" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 11.8:1 |
| Bore/stroke ratio | 1.133 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 342–386 hp |
| Years | 2007–2017 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2007 | 1UR-FSE net | 380 @ 6400 | 367 lb-ft @ 4100 | 11.8:1 |
| 2008 | 1UR-FSE net | 342 @ 6200 | 339 lb-ft @ 3600 | 11.8:1 |
| 2008 | 1UR-FSE net | 380 @ 6400 | 367 lb-ft @ 4100 | 11.8:1 |
| 2009 | 1UR-FSE net | 342 @ 6200 | 339 lb-ft @ 3600 | 11.8:1 |
| 2009 | 1UR-FSE net | 380 @ 6400 | 367 lb-ft @ 4100 | 11.8:1 |
| 2010 | 1UR-FSE net | 342 @ 6200 | 339 lb-ft @ 3600 | 11.8:1 |
| 2010 | 1UR-FSE net | 380 @ 6400 | 367 lb-ft @ 4100 | 11.8:1 |
| 2011 | 1UR-FSE net | 342 @ 6200 | 339 lb-ft @ 3600 | 11.8:1 |
| 2011 | 1UR-FSE net | 380 @ 6400 | 367 lb-ft @ 4100 | 11.8:1 |
| 2012 | 1UR-FSE net | 380 @ 6400 | 367 lb-ft @ 4100 | 11.8:1 |
| 2013 | 1UR-FSE net | 386 @ 6400 | 367 lb-ft @ 4100 | — |
| 2014 | 1UR-FSE net | 386 @ 6400 | 367 lb-ft @ 4100 | — |
| 2015 | 1UR-FSE net | 386 @ 6400 | 367 lb-ft @ 4100 | — |
Factory specification sheet.
| Bore/stroke character | 1.133 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,268 ft/min — conservative for a street engine |
| Displacement per cylinder | 35.1 ci |
| Static compression | 11.8:1 — high enough that pump premium or better is normally required |
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 |
|---|---|---|
| 2007 | 380 hp | 1UR-FSE |
| 2008 | 342 hp | 1UR-FSE |
| 2008 | 380 hp | 1UR-FSE |
| 2009 | 342 hp | 1UR-FSE |
| 2009 | 380 hp | 1UR-FSE |
| 2010 | 342 hp | 1UR-FSE |
| 2010 | 380 hp | 1UR-FSE |
| 2011 | 342 hp | 1UR-FSE |
| 2011 | 380 hp | 1UR-FSE |
| 2012 | 380 hp | 1UR-FSE |
| 2013 | 386 hp | 1UR-FSE |
| 2014 | 386 hp | 1UR-FSE |
| 2015 | 386 hp | 1UR-FSE |
| 2016 | 386 hp | 1UR-FSE |
| 2017 | 386 hp | 1UR-FSE |
2 factory vehicles, 2007–2017. Each year opens that model's engine table.