Formula 1's governing body, the FIA, has issued a new technical directive which could spell the end of the so-called 'party' engine modes in qualifying.
Though not 100% the reason for their additional performance over a single lap, Mercedes and Ferrari are known to burn on some occasions almost three times the amount of oil than their rivals at Renault and Honda, with the current limit set at 0.6 litres per 100km.
To be safe, the German manufacturer also reduced their quantity oil burning, which is one reason so believe explains why Ferrari has been closer in qualifying this season but still both have an advantage over the Renault-powered Red Bull.
Now though, the FIA has imposed fresh restrictions on the use of oil as fuel in qualifying which could end the practice altogether.
"We wish to clarify that in order to allow the FIA to monitor oil consumption during the qualifying practice session in a precise and timely manner, no oil may be added to the car nor may any auxiliary oil tank (AOT) be activated," a directive from technical delegate Jo Bauer read.
Also: "There may be no oil transfer between an AOT and any part of the engine lubrication system," it added.
The next two races in Spain and Monaco are on layouts which traditionally favour a better chassis over engines, although the Canadian GP in Montreal will likely be the first true test of whether this change has any effect.