Start with a worn 50cc lawn mower engine and build your way up to a roaring 28-cylinder radial. Idle Engine Simulator is a relaxing engine tycoon game: rev your engine, bolt on better parts, tune it on the dyno and keep earning cash even while you are away. Every engine has a power target and an efficiency target. Upgrade it part by part, find what is holding it back, and certify it at the redline to unlock the next build. Mopeds, dirt bikes, V-twins, inline-4s, flat-4s, straight-6s, V8s, V12s, W16s and giant radials: 24 engines, each one animated piston by piston, with an engine note to match. BUILD • Tap and hold to rev your engine all the way to the redline • Upgrade intake, exhaust, ignition, fuel, cooling and boost parts • Badges show what holds you back: bottleneck, overheating, knock or misfire • Certify each engine for power and efficiency, then build the next one TUNE • Dial in air/fuel, spark advance and cam timing by hand • Choose piston crowns, engine shapes ...