Red Bull and Renault's spell of dominance between 2010 and 2013 may have contributed to the power unit manufacturer's current struggles, according to the Viry firm's managing director Cyril Abiteboul.
The Frenchman suggested that such success may have obscured deficiencies in Renault's development and testing protocols, which are now coming to light.
Speaking ahead of the latest Grand Prix in Spain, in which both Red Bulls suffered issues in practice but went on to score points in the race, Abiteboul said: "On the dyno the engines are reliable, but when we come on track they are not.
"Obviously there is something wrong in our validation process, from dyno to track. There is something we need to investigate. It's just like aerodynamics, when the wind tunnel is not telling the truth; it's exactly the same in the engine world.
"Maybe we flattered ourselves on the back of very good results with Red Bull for years, to think that we are controlling everything. But maybe there was some form of beast in the shadows, hiding. And we need to hide that beast now."
Abiteboul also reiterated Renault's long-term commitment both to Red Bull and F1, adding: "We are living through a tough moment. [But] this marriage has all the reason in the world to last. So we have to do a better job on-track, but we also have to a better job off-track."
To watch the full interview with Cyril Abiteboul, click the video below:
