Renault engine Renault will decide in September just how many customer teams it will be able to supply when Formula 1 switches to the new V6 turbo engines from 2014.

Amid some concern in the paddock about dramatic cost increases for teams because engine makers have to pass on the development costs of the new power units, sources have revealed that efforts are being made to ensure that the situation does not destabilize the sport.

Renault Sport F1's managing director Jean-Francois Caubet believes that a lifting of the current limitation of manufacturer to supply a maximum of three teams would be a big help, especially amid uncertainty about the number of teams independent suppliers PURE and Cosworth may reach deals with. That would leave the way open for Renault to supply up to six teams, which could mean that the costs of its deal may not be as high as those engine makers only supplying two or three teams like Mercedes-Benz and Ferrari.

With Renault due to dyno test its V6 for the first time this week, Caubet said: "Today we have four customers. I think we will keep four next year, as there is no way to change.

"The problem we have is that we need to choose what will be our strategy for 2014. We have two kinds of options: to focus on two teams or to choose a bigger figure. In any case, the decision will be taken in September this year because we need to decide what we do.

"What we first want to understand is what will be the position of the World Council about how many teams. That will be discussed next week. We are quite clear with Jean [Todt, FIA president] and we talked with Bernie [Ecclestone] that we need to have an open market, because under old rules it was right [to limit the number of teams] when there was Ferrari, us, Cosworth, Mercedes, Honda and BMW and Toyota. We told Jean that now, though, we need to have an open market, with no limitations for 2014."

Although engine and power train deals are expected to cost around $25 million for 2014 – which would be a big increase in costs for some teams – manufacturers are adamant that a glide path reduction in costs means that over a five-year period costs will be the same on average as they are now, at around $19 million for a top-line package.

"If you introduce a new engine it can cost more in the beginning, but it is a five-year period we are talking about," noted Mercedes-Benz motorsport boss Norbert Haug. "I think we can achieve comparable spending over a five-year period and that has to be the target."