Renault's future in Formula One will hinge on upcoming dyno tests and whether or not the FIA allows in-season development next year, says chassis partner Red Bull.
For the second year in a row under the new V6 turbo engine regulations, Renault has struggled for performance compared to its rivals - a point perfectly illustrated by performance of Red Bull and Toro Rosso in Canada last weekend.
A loophole in this year's regulations means power units can be developed throughout the season using the FIA's token system, but that loophole is due to be closed off next year with the introduction of a homologation deadline of February 28, by which time all 25 development tokens for 2016 are due to be spent.
Reliability issues have put Renault's development on hold this year and it has spent just 20 of the 32 development tokens it was allocated for 2015. If next year's homologation deadline remains in place, it will have until February 28 to spend a further 37 tokens, which will make it a tough task to get BHP-value for each token spent. The February 28 deadline will also see 23% of the power unit frozen in the regulations, potentially locking in a deficit that Renault will not be able to recover from.
"From Renault's perspective [the deadline] is the worst thing because the engines are effectively frozen forever after," Red Bull boss Christian Horner said. "If you've missed it by February 28 then the scale of difference is unachievable in that time frame. Really, as these regulations are still relatively immature, it would make sense to allow, as we did this year, for development to happen in the season."
However, allowing in-season development will require the agreement of Mercedes, which is the most advanced in its token spend and currently has the most powerful engine. Horner urged his rivals to consider what is best for Formula One as Renault may be forced to pull out of the sport if the February 28 deadline remains in place.
"They don't have to [agree to in-season development] obviously, but the situation is that it's a precarious point in terms of Renault's commitment to the future. If you are effectively shutting that down in February, you are almost waving goodbye to Renault.
"I think they [Mercedes] need to have a bit of a grown-up think about it, and the FIA as well, to decide what is in the best interests of Formula One. If Formula One can afford to lose an engine manufacturer, then stick to February 28."
Renault is already working on its 2016 programme and upcoming tests in the next few weeks will be crucial for future competitiveness of the power unit.
"The frustrating thing with the power unit is that the lead times [for new parts] are just so long," Horner added. "There are some important tests going on in the next few weeks at Viry on the dyno and they will have a significant impact for the direction for next year. It's a big two weeks behind the scenes in Viry-Chatillon.
"Hopefully over time these engines will converge in performance. Ferrari has done a super job and thrown an awful lot of time, effort and resource at closing that gap, so it demonstrates that it is possible. I take heart from that and I'm just hopeful Renault can make the same commitment to bridge that gap."