Former Red Bull team boss Giancarlo Minardi, who initiated the speculation, was watching the Singapore race from the sidelines and claims the Renault engine in Vettel's car was making a "sound similar to the sound made by the engine when the traction control system was used in previous seasons."
Former champion and Mercedes-Benz driver Lewis Hamilton made statements that line up with Minardi's accusation, and says that Vettel is at full throttle "at least 20 meters before anyone else," and that the last time he could do that was when the cars were running traction control in 2007 and 2008.
Vettel responded lightheartedly, saying he believes Red Bull has a better engine-control system than its rivals, and that the first time it worked was during the Singapore race.
Former champion and rival Fernando Alonso brushed off the speculation, saying the Red Bull car has been making the sound since winter testing and that it has passed every tech inspection this year. Mercedes driver Nico Rosberg, who was in second place pursuing Vettel at Singapore, also denied the speculations, attributing Vettel's quicker pace to struggles in his own car, which was hampered by rubber in his front wing, costing him 1.7 to 1.9 seconds per lap.