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 formaul plots as a curve and not linear but does not apply to Max/High Performance engines like motorcycles.
Chat with our AI personalities
There is not a direct conversion between engine displacement (cc) and horsepower (hp) as it depends on various factors such as engine design, efficiency, and tuning. However, as a general rule of thumb, a 208cc engine typically produces around 5-7 hp.
1 HP is about 15-17cc.
Therefore, 208cc is probably about 12HP. (208/17=12.2)
That is, using 17cc to 1HP, since there are many variables such as engine condition and design which can affect HP. So, I used 17cc since it is the more conservative conversion factor.
Look for the HP in the manufacturer's specs for the claimed value, but use my method for a ballpark figure.
1 hp is equal to 0.746 kW.
51 kW is equal to approximately 68.4 horsepower (hp).
1 horsepower (hp) is approximately equal to 0.7457 kilowatts (kW).
One hp is approximately 756 watts.
One horsepower (HP) is equivalent to approximately 0.746 kilowatts, so 100 HP is equal to around 74.6 kilowatts.