Oct.10 (GMM) An engineer working for the team's engine supplier Renault has dismissed reports Red Bull may be cheating its way to a fourth title.

Recent reports have cast doubt on the superior traction and odd tones of Sebastian Vettel's RB9 as the German cruises to yet another championship victory.

But Ricardo Penteado, a Brazilian engineer for Renault, said claims of illegal traction control are clearly wide of the mark.

"Everything is checked by the FIA," he told Brazil's O Estado de S.Paulo newspaper. "The electronic control unit is distributed by the FIA itself, to ensure that all the (electronic) programmes are in compliance with the rules.

"It would be foolish to try to do something illegal," Penteado insists. "It would end your credibility, the team would be excluded -- it makes no sense."

A member of the currently Renault-powered Williams team, who won titles with Adrian Newey-penned cars, also dismisses the notion Red Bull is doing something illegal.

"I know their designer (Newey) well," the unnamed team member told the newspaper.

"He has a group studying each area of the regulations in detail, in order to take advantage of anything that could give some additional speed.

"I just think that is what we are seeing now," he added.

Another well-placed insider, the renowned F1 technical illustrator Giorgio Piola, thinks Newey simply found a higher and smarter gear in the second half of the 2013 campaign.

"The Newey car that debuted at Spa, when the winning streak began, was very different to the previous version," said Italian Piola.

"Wings, floor, how it uses the exhaust gases, this new version of the RB9 was designed for the characteristics of the new Pirelli tyres.

"They (the Pirelli tyres) are very different from the earlier ones, but the other (teams) only made subtle adjustments to their cars," Piola added.