Long-time Arctic Cat riders have correctly pointed out that the new Arctic Cat 800 and 1000 laydown 2-stroke engines are not the first Arctic Cat power plants featuring two spark plugs per cylinder. This feature was also found on some of the Kawasaki-built engines from the early to mid-1970s, but for very different reasons.
Thirty-plus years ago Arctic Cat used the technology to reduce fouling because of the inadequate magneto ignition systems used at the time. Today, ignition systems are far more powerful, and plug fouling is far less frequent and, for all practical purposes, a faded memory.
Improving the fuel efficiency and reducing the engine emissions was the catalyst behind Arctic Cat’s redevelopment of twin-plug technology for the release of the big bore engines in 2007. At lower rpm, there is less turbulence of the fuel/air mixture in engines like the 800 and 1000.
Less mixture turbulence in the combustion chamber results in incomplete burning of the mixture, which means less than ideal fuel economy. By using two spark plugs that fire simultaneously, engineers achieved more complete combustion at low rpm (there is minimal effect at higher rpm because of the greater mixture turbulence). The latest system also incorporates sequential firing, with all of the ignition’s spark energy going to the pair of plugs (and cylinder) that needs it.
Dual sparkplugs per cylinder were just one of the technologies Arctic Cat employed to reduce emissions and improve fuel economy. With tighter emission regulations now only two model years away, look for this trend to continue.