How to Calculate Engine Displacement
Engine displacement is the total volume swept by all pistons in one complete engine cycle. The formula is: Displacement = (π/4) x Bore² x Stroke x Number of Cylinders. Bore is the cylinder diameter, and stroke is the distance the piston travels from top dead center to bottom dead center.
Displacement Unit Conversions
| From | To | Multiply By |
|---|---|---|
| Cubic inches | Liters | 0.016387 |
| Cubic inches | CC | 16.387 |
| Liters | Cubic inches | 61.024 |
| CC | Liters | 0.001 |
Bore vs Stroke: What It Means
The bore-to-stroke ratio determines the engine's character. Oversquareengines (bore > stroke) breathe better at high RPM and favor horsepower — common in performance cars and motorcycles. Undersquareengines (stroke > bore) produce more torque at lower RPM — common in trucks and diesel engines. Square engines (bore = stroke) balance both traits.
Common Bore and Stroke Specifications
| Engine | Bore | Stroke | B/S Ratio | Type |
|---|---|---|---|---|
| Chevy LS1 (5.7L) | 3.898" | 3.622" | 1.08 | Oversquare |
| Ford Coyote (5.0L) | 3.630" | 3.650" | 0.99 | Square |
| Cummins 6.7L | 4.21" | 4.88" | 0.86 | Undersquare |
| Honda K20 (2.0L) | 3.386" | 3.386" | 1.00 | Square |
| Chevy 454 (7.4L) | 4.251" | 4.000" | 1.06 | Oversquare |
FAQ
Does more displacement mean more power?
Not necessarily. Displacement sets the engine's potential to make power, but factors like compression ratio, camshaft profile, forced induction (turbo/supercharger), and engine management all play a role. A turbo 2.0L can make more power than a naturally aspirated 5.0L.
Why do some cars list displacement in liters and others in cubic inches?
It's a regional convention. US muscle cars and trucks traditionally use cubic inches (350, 454, 302). Modern vehicles and imports use liters (2.0L, 3.6L, 5.0L). Both measure the same thing — total swept volume of all cylinders.
Can I increase displacement without changing the block?
Yes. Boring the cylinders (increasing bore) or installing a stroker crankshaft (increasing stroke) both increase displacement. A stroker kit is the most common approach — for example, a Chevy 350 can become a 383 with a longer-stroke crank and matching rods and pistons.