Red Bull is perfecting a "system" that is mimicking the effects of banned traction control, Germany's Auto Motor und Sport reported on Thursday.
The magazine said the complex electronic mapping system, although entirely legal, is able to put Renault's V8 engine down to just four-cylinders under certain circumstances.
"I am sure for the races to come that we will be able to enhance the system even further -- to profit even more," world champion Sebastian Vettel told F1's official website.
He told reporters: "Other people will never figure out how we've done it."
"The last time I was able to put the pedal down that quick was back in 2007 or 2008, when we had traction control," he said.
"They are using something different compared to the other teams but something that is completely ok," he is quoted by the BBC.
Red Bull boss Christian Horner, however, admitted the rumours were frustrating.
"So we're running traction control through the ECUs which are supplied by McLaren and approved by the FIA?" he bristled at reporters.
"You'd have to be pretty stupid," added Horner.