Red Bull Racing is set to be forced to make changes to the engine mapping of its cars for this weekend's Hungarian Grand Prix, AUTOSPORT has learned, with the FIA poised to issue a clarification in the next 48 hours on the matter.

Following the controversy at Hockenheim on Sunday, when Red Bull Racing was referred to the stewards to explain why its cars were operating with engine maps that had reduced torque in the mid rpm range, motor racing's governing body is now close to acting.

AUTOSPORT understands that the FIA is planning to issue an official clarification on the matter before action gets underway in Budapest on Friday.

This document is almost certain to make it clear that what Red Bull Racing was doing in Germany will no longer be deemed acceptable.

Sources suggest that the FIA will lay down specific limits on the variations of torque that can be used throughout the rev range - with Red Bull Racing believed to have been using much less than the maximum available torque in the middle rev range.

It is understood that the new limit could allow as little tolerance in torque as two per cent, which is believed to be well inside the variation shown on the engine map used by Red Bull Racing at the German GP.

By having a greater variation in its engine mapping, Red Bull Racing was able to both minimise wheelspin and also pump more gases through its engines, therefore helping the aerodynamic benefits that the outfit still gets through the use of exhaust flow at the rear of the car.

Although Formula 1 technical delegate Jo Bauer believed that Red Bull Racing's engine maps were in breach of the regulations in Germany, the race stewards did not agree - even though they also did not accept the team's explanations of what was happening.

Red Bull Racing team principal Christian Horner was keen to play down the matter at Hockenheim, suggesting that he never had any doubt his team was in compliance with the regulations.

"Unfortunately, when you have a quick car, it's inevitable that questions are asked," he said. "F1 is a competitive business.

"The rules are pretty black and white and having looked at the evidence, the data, they [the stewards] were fully satisfied. That's the nature of Formula 1 at the end of the day. Of course, you are always going to get other teams that are going to speculate."

Even if the FIA rule clarification does mean Red Bull Racing has to make changes to its engine maps, it should be a fairly simply matter for the team to revert to settings that it used without problem earlier in the campaign.