http://www.motorsport.com/f1/news/magnu ... co-737960/
Magnussen said he has been impressed by his first feelings of the progress, even though he admitted it was hard to notice any straight line speed benefit from the cockpit.
"To be honest the engine feels nice to drive," he said. "The driveability is better than the old engine. More power too.
"But from the driving point of view it is difficult to feel how fast you are going on the straight. Whether you are going 330km/h or 333km/h, it is difficult to feel.
"But the engineers will have it on the data and they will tell us later on. But the main thing is the power unit is driveable so we can continue just working as normal.
He added: "This power unit is actually better than the old one and we haven't had much time to work on it. Straight away out of the box it has better driveability – and hopefully the power is a good step as well."