Adrian Sutil has predicted the 2014 F1-spec cars will be at least four seconds a lap quicker by the end of this year.

Pre-season testing commenced this week at Jerez in Spain with rookie Kevin Magnussen topping the combined times in his McLaren on a 1 minute 23.276 seconds. That was, however, a long way off the marker set by Felipe Massa and Ferrari some twelve months ago, when the Brazilian managed a 1m 17.879s in the corresponding test.

Asked if the cars are too slow now and if F1 has lost the thrill it had in 2013, Sutil said the drop-off was only to be expected - given all the changes, including of course, most notably, the switch from V8 engines to turbo-charged V6s.

"It [the new car] is not boring to drive," he told reporters including Crash.net following the Jerez test. "You have got to do a lot of work to keep it on the circuit. It is just very low grip and the car is always moving around. But it is just a question of time. We have seen over many years with new regulations once it gets going the teams pick up seconds every month or every two months and the cars improve. So, I expect a gain of at least four seconds by the end of the season. There will be a huge step and then hopefully F1 will be fast enough again."

Sutil struggled to get the heat into the rear tyres during testing at Jerez and he added that this could definitely be a factor during 2014.

"Yes, in cold races for sure - it will be a big problem," remarked the Sauber pilot. "We have lost the blowing effect and now we really see how much we relied on that. It had a big effect and now it is gone. Also we now have a single wing in the rear. There is so much load missing. The traction has gone down by a big, big step.

"The car is quite tricky on power and the lack of grip and the lack of traction is huge compared to last year. It caught me again today on an installation lap in second or third gear [and that was why I spun]."

Sauber ran with a 'basic' version of its 2014 car at Jerez - to the extend Sutil said the test was more a 'roll-out' for them [see separate story, HERE] - and he added that, not unsurprisingly, the C33 will look very different by the time the sport heads to Australia for the opening event in March.

"For us compared to here it will be a huge step because we have no spec on the car," he confirmed. "During the season, as I said, for sure, I hope [we will gain] a few seconds always in the right direction, but at the moment that is an estimation. We have to work as fast as possible and see how quick we can improve."

"If the parts had been finished we would have had them on the car here," he explained. "It is just what we decided. We felt it is better to concentrate a little bit more on the development in the wind tunnel and in the factory to maximise the performance. The car was finished very late. But I don't think it is a bad approach and we shouldn't be that worried.

"There was enough work for us to do anyway and we will have the right spec on the car in Bahrain [for the next test]."