Horsepower-more or less

Many questions arise as to horsepower, such as does propane produce more or less than gas? No doubt there are a lot of opinions on this, so let’s try to answer this.

Chances are you’ve heard about horsepower. Just about every car or truck ad on TV mentions it, people talking about their cars bandy the word about, and even most lawn mowers have a big sticker on them to tell you the horsepower rating.


Susan Roush-McClenaghan, shown here with Jim Coker, won the season opener for the National Mustang Racing Association (NMRA) on March 6 at Bradenton (Fla.) Motorsports Park. Roush- McClenaghan, daughter of Roush Fenway Racing co-owner Jack Roush, edged Zak Harty to score the victory, her fourth career win with a propane-powered Ford Mustang. Harty beat McClenaghan off the starting line, but McClenaghan’s Heritage Propane Ford overpowered her rival to win the 17th Annual Nitto Tire NMRA Spring Break Shootout.
PHOTO COURTESY OF JIM COKER.

Fuel certainly has an important factor when it comes to combustion engines. A combustion engine is a device that converts the chemical energy stored in a fuel into heat energy, and then converts a portion of that heat energy into mechanical work. When you think of power in a fuel, you must consider two things, octane and Btu (British thermal unit).

The compression ratio of your engine determines the octane rating of the gas you must use in a car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So, a high-performance engine has a higher compression ratio and requires higher-octane fuel. The advantage of a high-compression ratio is that it gives your engine a higher horsepower rating for a given engine weight – that is what makes the engine high-performance. The racing industry looks to high octane for performance.

A Btu is the amount of heat energy needed to raise the temperature of 1 pound of water by 1 degree Fahrenheit. This is the standard measurement used to state the amount of energy that a fuel has, as well as the amount of output of any heat-generating device.

Susan Roush, who drag-races a propane-powered Mustang, says their comparisons to racing fuel has shown – and proven – that propane performs equal to racing fuel. LPG, which has propane as its primary constituent, has the advantages of producing lower emissions and offering more energy per unit mass while having a higher octane rating than gasoline. In addition, through the use of LPG we can continue to work away from dependence on foreign companies to supply domestic energy. One of the key benefits of the Roush LPG system is that vehicle operation and performance is virtually transparent as compared to that of the base gasoline vehicle. One of the reasons for this is the fact that there is no loss in engine performance with the Roush LPG system.

Onyx Environmental Solutions, who certifies engines on propane, has stated that propane horsepower is equal to that of gasoline. Of course, everything is relative to when and how propane is set up on the engine, according to Jeremy Hahne at Onyx.

Billy Levell of Turf Mangers says that his mowers perform better with propane than with gasoline as fuel.

So, when it comes to horsepower, more or less, you be the judge, but don’t prejudge.

Jim Coker is director of Metro Lawn, www.gogreenmetrolawn.com.