The formula that works best only applies to the small newer normally aspirated (carbureted) 4 cycle engines. The ratios change slightly worse with altitude and slightly better with fuel injection and tuning. Most American mowers and the newer 4 cycle outboard motors fit into one of these two formulas: Typical new carbureted engine well tuned: 1 x HP per each 25 cc Fuel injected: 1 x HP per each 22 cc Notes:-Most engines are tuned down to a lower HP for better engine life. -It is common for the same cc engine to be built in 3 different HP versions with the highest rated being the maximized HP per cc version. That is how you see price and HP changes on the same cc engine made by the same company. -Some of the newest (2008 and newer) engines from Japan perform slightly better. A typical 150cc motor should equate to between 3.5 - 6 HP+ depending on tuning with 5 HP being the adv.
The actual formula plots as a curve and is not linear and also does not apply to Max/High Performance engines like motorcycles.
If you mean HP=Horsepower, and CC= Cubic centimeters then HP does have anything to do with CC's. Cc's are the size of the displacement of the engine. HP is the amount of power the engine produces.
how much cc's is a 6.5 hp engine
3.3 HP
There is absolutely NO relationship between HP and cc. Cc is simply the 'swept volume' of the engine. Horsepower has NOTHING to do with cc.
roughly 342 cc's to a 12 hp engine
CC (cubic centimeter) is a measurement of displacement used to identify the size of the combustion chambers in an engine. HP (horse power) is a measurement of power the engine can produce. CC and HP are not the same.
I understand that a 250 cc engine is around a 15 hp motor, so a 277 cc engine calculates about 16.5hp. there is no direct conversion between cc and hp because cc is a volume and hp is a energy.
7.5 hp
350 to 400 cc
The hp is not determined from the cc. However there is a relationship between hp and engine volume (CC). For most engines the larger the volume, the greater the hp (this doesn't always hold true however).
Number of cc's alone does not tell you HP of an engine.
76cc