Both Toro Rossos are set to start from the back of the grid for Sunday's US Grand Prix after taking on new power unit elements. Honda confirmed that Pierre Gasly's car has already been fitted with the new components, while Brendon Hartley will have them fitted following running on Friday.
Gasly has had a new internal combustion engine, turbocharger, MGU-K and MGU-H fitted to the car. Honda is hoping that this will be the last time in 2018 that it has to fit new parts to the Toro Rosso and take a grid penalty.
"Both drivers will have new power unit's this weekend: in the case of Pierre the new unit is already in the car," said Honda F1 boss Toyuharu Tanabe. "With Brendon, he will start the weekend with a previously used power unit and it will be replaced with a new unit on Friday night."
Two weeks ago, Honda introduced its brand new engine upgrade at the Japanese Grand Prix which saw an evident boost in performance. Despite missing out on points, Toro Rosso got both of its cars inside the top ten in qualifying.
"On both cars, the new units will feature minor modifications to the specification when compared to that used in the in the Japanese GP," Tanabe added. "After examining the power units used in Suzuka, we had some concerns so we decided to take these changes, which we believe is the best strategy for Toro Rosso Honda for the remainder of the season."
Bahrain International Circuit - Winter testing