Tony Stewart's sudden jump from struggling regular season form - in which he only just managed to make the post-season shootout for the title - to sudden unstoppable juggernaut with four wins in nine Chase races has been little short of phenomenal. And a large part of the credit surely has to go to Stewart's crew chief, Darian Grubb.

It's remarkable then that given Stewart could clinch the title this weekend, it's looking more and more likely that he and Grubb will be splitting up despite the late-season success.

Asked in a media teleconference whether he would still be crew chief for the #14 in 2012, Grubb was notably evasive: "We'll leave that to after Sunday and figure out what's going to happen there. Our goal is to win the championship and we'll decide everything else after that."

Rumours that Grubb was leaving the #14 crew started during the middle of the year, when little seemed to be going right for Stewart on the track while Stewart's team mate Ryan Newman seemed to be faring much better. Stewart, as co-owner of the Stewart-Haas Racing team, was overtly critical of his team's performance for much of this period and speculation began early that this had led to friction between him and Grubb, although performance has done a one-eighty since those dark midsummer days.

So what was it that has transformed the season for the #14?

"We haven't changed anything in the game plan and they way we've been approaching every week. We've been doing the same job since the start of the season," insisted Grubb. "A lot of things just stacked up to where we've had the good data we've needed to have for the last ten races and being able to apply that to the racetrack. Everybody's just digging in a little deeper and working a little bit harder trying to find whatever's left out there for performance."

Grubb was a key hire for Stewart when setting up his own race team in 2009. With SHR relying on a technical alliance with Hendrick Motorsports, Stewart opted to lure Grubb away from Hendrick Motorsports because of his familiarity with the equipment. Grubb insisted that his relationship with Stewart remained still strong three seasons later - although his answer hinted that it might not necessarily be a particularly harmonious one.

"We've gotten to be pretty good friends on and off the racetrack. We've spent a lot of time together. We know each other a little better than we should at times," he added. "We eat, sleep, and live together pretty much half the time at the racetrack, and try to accomplish on the racetrack.

"It's a tough dynamic, kind of a love-hate brother relationship at times," he said. "When you feel each of you needs to do something, but it's the best of times when you can go out there and make things work and get on top of the victory stage and take those pictures with the trophy."

If Grubb does stand down as Stewart's crew chief it's still possible he would stay within the SHR organisation, which has a number of key roles to fill before the start of next season - including a crew chief for the high-profile #10 car that Danica Patrick will be running for the team in ten Sprint Cup races next season, beginning with February's season opener at Daytona.

But before any of that, there is one more race to get through this weekend at Homestead-Miami. Only two drivers are now in the running for the Sprint Cup title: Stewart, and Carl Edwards who is just 3pts ahead in the standings, making it neck-and-neck.

Despite how close it is going in, Grubb insisted that they were approaching it as 'business as usual': "Just trying to do the same thing we've been doing the last half of the season," he said. "Just going out there for maximum points. We know if we win the race, that's our goal. We can't finish any worse than second. That's what we do. We go out there for the win."

Even if they don't win the title, they are assured of second place in the championship which will be their best performance yet since the team was set up - Stewart finished sixth in 2009 and seventh in 2010.

"There is really no pressure. We feel like we've already accomplished what we need to accomplish, but bringing the trophy home would definitely put the icing on the cake," said the day's master of understatement.

Danica crew chief fined

NASCAR issued a penalty to Danica Patrick's crew chief Tony Eury Jr. following the weekend's Nationwide Series race at Phoenix, after the #7 JR Motorsports car was found to be in violation of the 2011 NASCAR Nationwide Series rule book.

Eury was fined $10,000 and put on NASCAR probation until March 28, 2012 for the rule breach. Patrick herself was not penalised.

An improperly attached weight meant that the car was in violation of sections 12-1 (actions detrimental to stock car racing), 12-4-J (any determination by NASCAR officials that the race equipment used in the event does not conform to NASCAR rules) and 20A-2.3A (improperly attached weight) of the rules.