The M-Sport-built Fiesta spent time in Ford's multi-million pound climatic chamber at its engine factory in Dunton, with the special focus of ensuring the Ford remained competitive during the high-altitude Rally Mexico earlier this year.
Loriaux says the Dunton work has led to benefits beyond the Guanajuato event.
"What we learned in the chamber at Dunton," said Loriaux, "helped us learn more and more about other things. We worked on the engine map before Mexico and while doing that we have understood more and more about the maps. That time in the chamber has really helped the engine work this year."
Loriaux added that the biggest step forward for Ford came with the new gear ratios which were introduced at the last event in Portugal.
"We have a longer first gear and slightly shorter sixth," said the Belgian. "First [gear] was really short, and we were just about never using it; effectively, instead of a six-speed gearbox, we only had a five-speed on the gravel.
"With the old car [the Focus RS WRC], where you had a flat power curve, it was okay, but this one is a bit more peaky, so the more gear you have the faster you are. We knew the ratios were a good step forward and that gave us good confidence."
Loriaux added that he was also sure the team had eradicated the misfire which plagued some of the Fiestas running on the Rally of Portugal, with the issue believed to be linked the heavy rain experienced on the Faro-based event.
Loriaux said: "A lot of people had a misfire and we think we have tracked it down, but I'm not going to count my chickens before they hatched and tell you how confident I am. The problem was probably water-related - it is a concern with the number of watersplashes in Argentina, but we fixed it."