Pierre Gasly admits the speed Toro Rosso has lost on the straights is "crazy".
Gasly says that his team's straightline speed deficit with its Honda engine in comparison to their midfield rivals is "crazy".
The Frenchman will start today's British Grand Prix in 14th place.
Gasly is the only Toro Rosso driver to take part in the race following Brendon Hartley's crash in the final practice.
He admitted that the engine is holding Toro Rosso back, but was pleased with the performance of his car.
"The car was mega, but with the long straights at the moment it's crazy how much time we lose," Gasly said.
"We knew that on a track like this, with Turn 1 and 9 being flat-out we'll struggle.
"We're talking about nine tenths compared to Force India and Sauber, so yeah, very difficult to fight.
"But in the corners, looking at the GPS, we are faster and it looks pretty good, but just on the straights at the moment, we are really slow.
"Objectively we have no pace, not coming from the car, but from the engine."
Gasly revealed that getting onto the seventh row of the grid was a better result than he was expecting.
"We were actually surprised to go into the Q2 because we lost so much time in the straights since the beginning of the weekend," Gasly said.
"You cannot recover nine tenths in the corners.
"In the end it was a good day, but the race will be difficult.
"(The time loss is) only full throttle, straight steering, so in my case except getting ower in the car, there is not much more I can do."