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Mazda MZR 2.5 specs: 2.5L (152 ci) 4-cylinder, 89 x 100 mm (3.5039 x 3.9370 in) bore and stroke, 9.7:1 compression. Rated 167 hp, 2010–2013.
The Mazda MZR 2.5 is undersquare — the 3.937" stroke exceeds the 3.5039" bore by 11.0% — a layout that trades peak RPM for leverage and torque low in the range. The 3.937" stroke puts mean piston speed at 4,000 ft/min around 6,100 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 38.0 ci (623 cc).
9.7:1 on aluminum heads is in the range that usually runs on pump premium; aluminum sheds heat faster than iron, which makes the same number a little more forgiving.
It is one of 19 engines in the Skyactiv-G family, sitting between the 91.3 ci and 201.4 ci members. 4 factory variants share these dimensions, rated at 167 hp across 2010–2013.
| Displacement | 152 ci / 2.5 L |
|---|---|
| Bore | 3.5039" |
| Stroke | 3.937" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9.7:1 |
| Bore/stroke ratio | 0.89 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Redline | 6,200 rpm (factory limit) |
| Advertised HP | 167 hp |
| Years | 2010–2013 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2010 | MZR 2.5 net | 167 @ 6000 | 168 lb-ft @ 4000 | 9.7:1 |
| 2011 | MZR 2.5 net | 167 @ 6000 | 168 lb-ft @ 4000 | 9.7:1 |
| 2012 | MZR 2.5 net | 167 @ 6000 | 168 lb-ft @ 4000 | 9.7:1 |
| 2013 | MZR 2.5 net | 167 @ 6000 | 168 lb-ft @ 4000 | 9.7:1 |
Factory specification sheet.
| Bore/stroke character | 0.890 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,937 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 38.0 ci |
| Static compression | 9.7:1 — 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 |
|---|---|---|
| 2010 | 167 hp | MZR 2.5 |
| 2011 | 167 hp | MZR 2.5 |
| 2012 | 167 hp | MZR 2.5 |
| 2013 | 167 hp | MZR 2.5 |
1 factory vehicle, 2010–2013. Each year opens that model's engine table.