Martin Whitmarsh is hoping a last-minute upgrade for McLaren’s struggling MP4-26 will bring the 2011 car onto the pace this weekend in Australia.
Lewis Hamilton recently admitted the car is at least a second too slow, but on Monday team boss Whitmarsh said some radical changes have been implemented based on the disappointing results from winter testing.
He described the changes as "dramatic", following reports McLaren has accepted its ultra-radical exhaust system was too complicated.
Whitmarsh said the MP4-26 will also have a new floor in Melbourne.
"I think we in particular had a very extreme (exhaust) solution but it was not, in my opinion, delivering sufficient benefit for its complexity," he told reporters during a media teleconference.
"Frankly, some of our solutions weren’t reliable and that’s why I think we had to go back a little bit," added Whitmarsh.
He said he is hopeful the changes will make the car more than a second faster than in recent tests.
"There’s some risk, but I think it was the right thing to do and we’re hopeful the risk comes off and the car is a lot more competitive in Australia," said the Briton.