LONDON, England - Jenson Button thinks GP2, Formula 1's second-tier support series, will be close for pace as F1's new V6 engines 'slow' cars in 2014.As the sport's all-new energy-recovery and V6 turbo-powered era kicked off at Jerez in January 2014, drivers were impressed by the torque but concerned that the big reduction in downforce had slowed the cars too much through corners.The initial lap time gap compared to the Jerez test the previous year was a disastrous 10 seconds but McLaren rookie Kevin Magnussen ultimately reduced the gap to less than six.'WE'LL BE QUICKER'Button asserted that GP2, with unchanged technical specifications, would come close in 2014. Button said: "They will be a lot closer on certain circuits. We'll be quicker, but not that much quicker."However he believed F1 would embark on a steep and speedy development curve with the clean-sheet regulations and that the Jerez cars will be substantially faster by the time the season opened in Australia in March 2014.Button added: "Three races in there will be another chunk in terms of lap times. By the end of the year we might not be that far off (2013 pace), maybe a couple of seconds, which will be pretty good when we get a real handle on where we are."Some of the extra lap time, Button explained, was due to Pirelli's new, harder and more durable tyres: "We think they are a half-second slower."