Yuki Tsunoda says the important upgrade package introduced by AlphaTauri at Silverstone has so far not lived up to its expectations.
To address its AT04's chronic lack of downforce and poor straight line speed, AlphaTauri has revamped the car's floor, floor fences, floor edge and has altered the diffuser.
The team also mounted on its contender a new engine cover, rear wing and beam wing, while it has made changes to the rear suspension.
But the effects of those changes were no where to be seen in Friday's practice sessions, with Tsunoda and team mate Nyck de Vries concluding their day at the bottom of the timesheet.
"So far, it’s not looking good," admitted Tsunoda. "The result is no good so far.
"We can't see the results that we are improving massively. We feel definitely a couple of gains in some places but some places we didn’t improve that we expected.
"So, we have to look through it deeply."
©AlphaTauri
Tsunoda dismissed Pirelli's new tyre construction as a factor in the revised car's underperformance, while AlphaTauri chief race engineer Jonathan Eddolls suggested that there was still a lot of set-up work to be conducted on the new-spec machine.
"Analysis showed that the update is actually working well," he said.
"We made further changes to the car in FP2, but it’s fair to say we didn't hit the sweet spot with either car in terms of balance on the soft tyre short runs, lacking front end, which is a lap time killer here.
"High track temperatures exacerbated the front tyre overheating which resulted in a lack of front grip, so we think there is a step of lap time to come with better balance."
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