Jenson Button believes McLaren can expect a snowball effect in performance as it ups the power from its Honda engine.
McLaren has spent the first two races at the back of the grid, running its power unit at lower state of tune in order to gain mileage and make up for lost time during testing. The team is hoping to up the power of the Honda engine at each race and Button believes that will bring more performance on an increasing scale as the car becomes more fuel efficient.
"As soon as we can extract more power from areas and not have to turn things down we will hopefully find more than we expected in terms of power and lap time," he said.
"There is one engine that has more power than the others [Mercedes], there is one that is close to it [Ferrari] and there is another one that is quite a long way away from it [Renault] ... and then there's us.
"The biggest problem is that if you have a power deficit it is a [negative] snowball effect. We are all allowed to use the same amount of fuel, we spend more time at full throttle than the Mercedes so we use more fuel, which means you have to save more fuel, which means you are going even slower.
"It's a very difficult situation but we all knew that when the formula started and it was designed, so we can't really complain too much about it."
McLaren racing director Eric Boullier said the team made a big step between Australia and Malaysia.
"When you have more efficiency your first aim is to have more power and good aero efficiency - that is the only way to make sure your fuel consumption is down. The efficiency itself is also the engine. We have done a massive gain already compared to where we were in Australia and we are back in the normal fuel consumption now."