Falling to fourth in the standings, Pat Symonds feels Williams’ rivals improved more than expected this season, especially with their engines.
Switching to Mercedes power as F1 made the move to V6 engines, Williams had, and still have, the best engine on the grid.
This helped them to third in the championship in 2014 and again in 2015, finishing behind Mercedes and Red Bull and then Mercedes and Ferrari.
This year, though, they are behind all three teams.
Symonds, Williams’ technical chief, reckons that is because of Ferrari and Renault’s improved power units.
Asked where it had gone astray, he told the official F1 website: “I think that most of our competitors improved more than we expected.
“We made the improvements that we more or less had expected to make. We probably didn’t set the targets high enough. Some of our competitors have improved a lot.
“But a huge factor also was that the power units got much more equal – and that is eroding some of the advantage that we had…
He also revealed that while Williams are putting efforts toward next year’s car, they are also pushing on with updates for their FW38 as they look to keep Force India at bay.
He said: “There are still people working on the current car; we still have upgrades that we will bring. We have a new floor that we are bringing to Hungary, a new wing in Monza – so there are still plenty of things coming. But sure, the majority of our people are working on next year’s car.”