After the excitement and intensity of Melbourne, the Formula 1 circus rolls into Malaysia, where the tropical climate and searing temperatures will push the new-generation cars far closer to the limit than the Australian season-opener.
The morning's session focused on correlating the performance of several new components - including a distinctive new nose-box - with the figures indicated by aero research back at MTC. During the morning session, Kevin suffered a brief setback when a sensor on his power unit detected overheating and switched the engine into 'limp-home' mode. Although he only made it into the pitlane, the marshals and mechanics pushed him back to the garage, where he was quickly turned around before the end of the session.
In the afternoon, neither driver felt encouraged by the changes made to the car, and both struggled on their long runs. With slightly cooler temperatures forecast for the rest of the weekend, and conditions that should therefore be kinder to tyres, both drivers are making progress during qualifying and the race.
Jenson Button: "We're finding it tough out there today - especially in the heat. We're not as strong as we'd like to be in high-speed corners - and, when you have downforce issues, they're further amplified by the hot weather. So our long runs were tricky - in terms of both tyre degradation and outright pace.
"We're now going through the data, but the upgrades we brought here seem to be giving us something - so that's encouraging - but there's a lot of work still to be done.
"I'm sure people are getting excited about individual lap-times, but they don't count for too much around here because you can usually overtake. It's the long runs that you need to analyse, and that's where we're finding it a bit more difficult."
Kevin Magnussen: "I've never driven a car in these sorts of temperatures - so I learned a lot today. As I say, the track temperatures are so hot here that the tyres are really suffering - but it's the same for everyone, so we need to try and get on top of things before tomorrow's sessions. I'm going to try and set the car up in order to protect the rears.
"There's always something you can improve, and we've currently got a lot to think about and a lot of data to sift through tonight. For me, overheating the rears is my biggest problem - the tyres are behaving very differently from how they did in Australia - so that'll be my focus. Still, I'm convinced we can make some useful changes to the car overnight."
Eric Boullier, Racing Director: "This morning's session was an important one for us, because it gave us the first opportunity to carry out on-track correlation of our new nose-box.
"Initial impressions were positive. Both Jenson and Kevin were immediately able to put in competitive lap-times this morning, and both guys also reported that our car felt good in high-speed and low-speed corners alike.
"This afternoon was a little trickier. The changes we'd introduced between the two sessions didn't make the improvements we'd been hoping for, and we're aware that we've still got a lot of work ahead of us tonight to get our cars into a stronger position for tomorrow.
"Still, today is only the first of three days of running. Moreover, I know how hard our engineers will be pushing tonight, and consequently I think we can make up some ground in terms of competitiveness relative to our nearest rivals before qualifying."
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