Williams finance director Alan Kinch has revealed that Formula 1 costs escalated on the back of the move from V8 engines to V6 power units.
In an attempt to reduce costs, F1 switched from 2.4l V8 units to the more economically friendly 1.6-litre turbo-charged V6 hybrid units at the start of the 2014 season.
The change didn't go down well with a lot of people, but it played into Williams' hands as it co-incided with their switch from Renault engines to Mercedes with the German manufacturer one step ahead of their rivals.
The Grove squad went on to finish the 2014 campaign third in the Constructors' Championship, but they still posted a financial loss of £34.3million.
Kinch, though, says the engine change played a major role in those results as the costs doubled.
"Costs went up by about £20m and the reasons for that were three-fold," Kinch told the Independent. "The first one and the most significant one of all of them was the increase in costs in the power unit.
"So, moving from the traditional V8 engine to the new V6 hybrid essentially doubled the costs of the power unit and that was the biggest chunk."
Kirch added that engine expenses are unlikely to increase as the team "have got a long-term contract with Mercedes – I wouldn’t say it is at a fixed rate but it is at a stable rate year on year".