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Chevrolet LWN specs: 170 ci (2.8L) 4-cylinder, 3.701 x 3.937 in (94 x 100 mm) bore and stroke, 16.5:1 compression. Rated 181 hp, 2016–2022.
The Chevrolet Duramax (LWN) is undersquare — the 3.937" stroke exceeds the 3.701" bore by 6.0% — 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 42.5 ci (696 cc).
At 16.5:1 this is a compression-ignition engine: the ratio is the heat source that lights the fuel, not a knock limit to be managed.
It is one of 17 engines in the Duramax family, the smallest at 170 ci. 12 factory variants share these dimensions, rated at 181 hp across 2016–2022.
| Displacement | 170 ci / 2.8 L |
|---|---|
| Bore | 3.701" |
| Stroke | 3.937" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 16.5:1 |
| Bore/stroke ratio | 0.94 |
| Block material | cast iron |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | diesel |
| Advertised HP | 181 hp |
| Years | 2016–2022 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2016 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
| 2017 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
| 2018 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
| 2019 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
| 2020 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
| 2021 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
| 2022 | LWN net | 181 @ 3400 * | 369 lb-ft @ 2000 * | — |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 0.940 — 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 | 42.5 ci |
| Static compression | 16.5:1 — 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 |
|---|---|---|
| 2016 | 181 hp | LWN |
| 2017 | 181 hp | LWN |
| 2017 | 181 hp | LWN |
| 2018 | 181 hp | LWN |
| 2018 | 181 hp | LWN |
| 2019 | 181 hp | LWN |
| 2020 | 181 hp | LWN |
| 2020 | 181 hp | LWN |
| 2021 | 181 hp | LWN |
| 2021 | 181 hp | LWN |
| 2022 | 181 hp | LWN |
| 2022 | 181 hp | LWN |
4 factory vehicles, 2016–2022. Each year opens that model's engine table.