Renault boss Cyril Abiteboul says that the "clock is ticking" regarding the announcement of the 2021 engine regulations.
The plans from FIA and Liberty Media to switch to simplified power unit format with no MGU-H were announced as early as last October.
However, they dealt a severe blow when four existing manufacturers said that they'd rather stick with the current regulations, but some other alterations to make the sport more entertaining.
"The clock is ticking if we want it to have a completely different engine for 2021," Abiteboul told Motorsport.
"Certainly summer break this year would be the red line. I think it's no secret that two of the main drivers for that change of regulation were a) the possibility of a new entrant and b) the situation at Red Bull.
"Red Bull Racing and Toro Rosso were massively driving the change because it was clear to them that, independently from our situation, they had to think about their own situation.
"So now that a) Red Bull has found a new partner in Honda and b) there do not seem to be new entrants, I think the necessity of radical change to the engine regulation has lowered."
Abiteboul reveals that all of the current manufacturers are agreed on the target.
"I think we are talking about details right now but I think in general we agree on the target, we agree it is better to keep the existing platform, and we agree that we can make a better job with the existing platform," Abiteboul added.
"In our opinion, we still accept the fact that we need to improve the power unit for other reasons, mainly for the show, for the race, for the customer teams, for the manufacturers in terms of cost also.
"We accept all of those objectives, and I think, and frankly we praise that, the focus is how we can make change to the existing platform, to make it better, to make it deliver against those targets that we continue to agree."