Heavily popular in much of Europe to the point they would sometimes outpace gasoline engines, diesel powerplants exists as a niche item in North America. Large-scale interest in diesel powerplants in North America was a by-product of high gasoline prices in 2008. Although gas prices have dropped from impairing highs, many auto companies were still committed to offer diesel engine options. Attached to building small, affordable cars, Japanese auto brand Mazda created an uproar in 2012 when they pledged to include a diesel engine as part of their upcoming Mazda6 sedan and CX-5 crossover vehicle for North American consumers. Part of Mazda’s campaign to convince American and Canadian audiences to the effectiveness of their so-called SkyActiv-D engine took place in sports car racing. After three years, there have been signs Mazda’s diesel marketing tool is running out of momentum. Since May, it has been rumoured the SpeedSource team fielding Mazda’s diesel-powered prototype effor...