Aston Martin chose to halt continuous minor upgrades after the Miami Grand Prix to focus resources on long-term goals, causing them to fall behind advancing rivals.
"When you design in a rush, weight is the first thing that suffers because you don't have the time to thoroughly optimise everything," said Newey.
The team is now preparing to introduce a major development configuration to address these shortcomings at the upcoming Hungarian Grand Prix, scheduled for July 24-26.
"Aerodynamically, we also took a bold direction – which was largely pushed by me – without the luxury of exploring multiple concepts in depth because time was against us.
I wouldn't say the direction we've taken is fundamentally wrong, but it has thrown up challenges we didn't anticipate," said Newey.
The upcoming modification package will feature a re-homologated and crash-tested forward chassis alongside an altered front suspension configuration aimed at reducing weight.
"The main structural elements remain the same – the chassis and gearbox architecture don't fundamentally change – but we've taken weight out of both, which required re-homologating and crash testing the forward chassis.
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The front suspension is also revised," said Newey.
