Red Bull-Honda will soon benefit from an updated fuel mix.
This week, team boss Christian Horner said some of Ferrari's current engine advantage is because of a "juicy" fuel supplied by Shell.
But Red Bull's partner ExxonMobil is working hard to match that.
Technical advisor Dario Izzo admitted that Red Bull has been using the same fuel since the start of the year.
"Normally it changes more often, but this year it was neither possible nor necessary," he told La Gazzetta dello Sport.
"Honda is working in a very structured way, so that we did not have to make any major changes."
But he says the plans for an updated fuel will bring more horsepower to Red Bull-Honda.
"We will be bringing the update towards the end of this season," said Izzo. "Hopefully it will bring more performance.
"We also see it as a test towards the 2020 season," he added.
