Gary Paffett reckons this year's cars will be "a lot more difficult to drive" as they have "a lot less" downforce.
Although the McLaren test driver has yet to put this year's MP4-29 through its paces out on track, he has been in action in the simulator.
Getting a feel for the changes, which mandate the use of only a single exhaust pipe that cannot be used to influence aerodynamics, Paffett says drivers will need to adapt their style to the new regulations.
"It is going to be exciting, the cars are very different to what we have had for the last few years," he said in an interview with Sky Sports Online.
"The downforce level in particular is a lot less than we have had - in the past the FIA have tried to reduce that, but this year they seem to have successfully done that.
"The cars are a lot more difficult to drive, especially with the different power unit and the amount of torque that the turbo engines produce - even the medium to high speed corners are difficult without the blown downforce we have had in the last few years.
"The cars are definitely a lot more difficult to drive, so it is going to be exciting to see how the drivers get on with it."
He added: "They are definitely going to have to change. I have worked in the simulator a long time on these cars and when I swapped back and forth from the (MP4-) 29 to the 28, you do have to change your style, the way you drive the car.
"Working with Jenson (Button) as well, the first time he came to drive the car I spent a bit of time talking him through it and you could physically see him having to think about how to drive the car.
"So the drivers are going to have to think about it and try and think how to get the best out of it because it is not just how the car handles and the balance of the car, but the way to use the tyres and use the fuel and all of the devices we have on the car now as well with regards to the KERS and everything else, it takes a lot more thought from the driver this year."
As for the possibility of a McLaren fight back in the wake of a podium-less 2013 campaign, Paffett is confident the team has resolved their issues.
"I think if we had fully identified it we would have been a lot more competitive at the end of the year," he said.
"We accepted that we made mistakes and there are areas of the car we know were problematic, but I think the problem was some of the areas were too big to fix during the season.
"So I am pretty sure we have a good idea of where we went wrong, but you can never say for sure until you build another car that you know exactly how it went wrong, but we have an idea of what we are doing with this year's car.
"It is a different car totally anyway, we have learnt from last year's car areas we need to avoid going down, but it is a different car anyway - it is a different challenge and it is a challenge for everybody. We certainly feel it is a bit of a fresh start for everybody and we are pushing very hard to make sure we get on top of it from the start.
"However, you can set your targets, but we are never going to know where we are until we get out testing and in the first race - because it is such a big regulation change, you really don't know where you need to be.
"The lap times in the simulator mean nothing as you don't know what everyone else is doing and with such a big change in the design of the car for this year, until we get to the first race, I don't think we are really going to know where we are."
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