I updated the original article November 2014 here: cc to torque to hp Conversion Update!
Well they changed the rules on us again. Five years ago the power output of every snowblower sold here in the United States was measured in hp or horsepower.
Two years ago they changed the rules and started selling snowthrowers with the power measured in gross torque. Of course no one understood what this meant and even though companies like Briggs & Stratton tried to explain it, it still didn’t make much sense.
So we just started to get used to measuring an engine’s output in torque and now most of the snow blower manufacturers are dropping the torque measurement and only giving us engine size in cc’s.
I spent a great deal of time researching this and I’m not going to spend time trying to explain why the engine manufactures have changed their terminology. Instead I’m just going to show you a formula you can use to figure it out yourself.
Here’s the formula I used from the Briggs & Stratton website (rpm x torque / 5,252) The engine manufacturer’s used 3600 rpm most of the time to rate the engine’s horsepower so I will use that number in the formula. I also used the torque ratings from the Briggs & Stratton website for their motors to keep this chart simple. Other manufactures (like Powermore) may have different torque ratings for their motors. If you are trying to get exact hp measurements you should research the torque ratings for the specific brand.
Here is a simple chart of approximate cc to torque to horsepower conversions. It’s not exact, but it will give you a better idea of how big the new engines are. I used 3600 rpm in the formula for this comparison.
179 cc = 5 hp
205 cc = 8 to 9 Gross Torque = 5.5 to 6.5 hp
250 cc = 11 to 11.5 Gross Torque = 7 to 8 hp
305 cc = 13.5 to 14.5 Gross Torque = 9 to 10 hp
342 cc = 15.5 to 16.5 Gross Torque = 11 to 12 hp
389 to 420cc = 18 ft lbs = 13 to 15 hp
To me cc’s is not a good comparison from one motor to another. It is also not a good comparison from one manufacture to another. For example, a 190cc Briggs & Stratton side valve motor will not have the same power as a Honda 190cc overhead valve motor. cc’s won’t give you a good measurement of what the engine is capable of. True, an overhead valve motor from a specific manufacture should have more power with more cc’s but there are a lot of other factors that go into determining how much power is available for you to use.
The true power of a motor is determined by engine type, (overhead valve/side valve) carburetor, (naturally aspirated/fuel injected/turbo) rpm you use it at, (2750/3100/3650) and many other factors.
I hope this helps.