* Displacement: This is the volume of the cylinders, typically measured in liters (L) or cubic inches (cu in). By this metric, the Wärtsilä-Sulzer RTA96-C marine engine with a 25,480-liter (1,550 cu in) displacement is the largest piston engine ever built. However, this engine is diesel, not gasoline.
* Power Output: The Wärtsilä-Sulzer RTA96-C also holds the record for the most powerful piston engine, with a maximum output of 108,920 hp (81,000 kW). However, there might be other gasoline engines with higher power outputs but are not widely publicized.
* Physical Size: This is difficult to measure, as engines come in many shapes and configurations. The Wärtsilä-Sulzer RTA96-C is certainly among the largest in terms of physical dimensions, but there might be other engines that are wider or taller.
Considering gasoline engines specifically:
* The largest gasoline engine in terms of displacement is the 7.0-liter (426 cu in) V8 found in the Dodge Challenger SRT Hellcat Redeye. This is a massive engine by car standards, but pales in comparison to the aforementioned marine engine.
* In terms of power output, there are several high-performance gasoline engines that produce upwards of 1,000 hp, like the Koenigsegg Jesko's 1,600 hp 5.0-liter V8. However, these engines are still relatively small in terms of displacement.
Therefore, it's difficult to definitively say which gasoline engine is the "biggest" without defining the specific criteria used to measure size.
