CONCORD, N.C. -- The Sprint Cup garage at Lowe's Motor Speedway was full of engineers during the Tuesday and Wednesday test sessions. Many wore collared shirts with pens in the pockets and had their faces buried in computers. Some looked like they'd just stepped out of a college course in robotic applications.
And then there was Greg Erwin.
The 38-year-old from Hatboro, Pa., was wearing a black T-shirt and black pants with enough dirt on the knees to make it clear he had been under a car and not sitting at a table all day. He had grease under his nails and about a day's worth of stubble on his face.
He defied the so-called "geek" image that often goes along with an engineering degree. Or as one crew member jokingly said, "He doesn't bake cakes."
"That's what makes him special," said Tony Gibson, the crew chief for Mark Martin at Dale Earnhardt Inc. "He understands his race car. He knows how to work on them as well as the engineering background.
"He's one of those guys that nobody realized how much talent he had until now."
Erwin's anonymity disappeared in the time it took Greg Biffle to win the first two races of the Chase and shoot to second in the standings, 10 points behind Roush Fenway Racing teammate Carl Edwards heading into Sunday's race at Kansas Speedway.
Erwin went from just another face in the garage to a rising star. He is drawing comparisons to Chad Knaus, routinely referred to as the best crew chief in the garage after helping Jimmie Johnson to the past two titles.
"He's a very underrated crew chief," said DEI vice president of competition Bobby Hutchens, who worked with Erwin at Richard Childress Racing. "He's also one of the topflight engineers in the garage.
"He's got all the tools to be as good as anybody. It's taken a little time for people to notice, but [the No. 16 team is] going to be a force in this Chase for sure and for some time to come."
Erwin was paired with Biffle in May 2007 after spending the previous two seasons with Robby Gordon. They won their first race together a year ago at Kansas, but drew little attention because Biffle wasn't in the Chase.
Now they are the hottest combination in the sport, feeling they can win wherever they show up. They were the fastest in two of the four test sessions at LMS.
"Give me a good car and I'm going to drive the crap out of it," Biffle said.
Such passion and aggressiveness make Biffle a perfect fit for his crew chief. It's the same personality that made Erwin one of the hardest-hitting outside linebackers/defensive ends at Hatboro Horsham High and later on the club team at Clemson University, despite being one of the smallest players.
"That was my thing," said Erwin, 5-foot-9 and 170 pounds. "I liked running into people."
Now he likes running by people -- with speed. He had the No. 16 car so dialed in the first Chase race at New Hampshire that Biffle said he was holding back until he shot past Johnson at the end.
Biffle was equally strong last weekend at Dover, pulling away to a 12-car victory after an intense battle with teammates Matt Kenseth and Edwards.
The results have made Biffle a contender to become the first person to win titles in the Cup, Nationwide and Truck series, and Erwin a household name.
"I'm not surprised at all," Gibson said. "Once [Erwin] sets his mind on something, once he starts attacking something, he won't stop until he gets it."
Gordon knocked on Erwin's door at 10 one evening in late 2004. He wanted to make one last pitch for Erwin to leave Richard Childress Racing and come to his one-car operation as crew chief.
"If you really want somebody, you've got to go after it," Gordon said.
Erwin thought long and hard about the decision, as he does most. He wasn't sure he wanted to be a crew chief because he was happy with the responsibilities as an engineer helping on seven-post research and the development program.
"That's probably why it took so long to take that thing," Erwin said. "I didn't necessarily think that was the direction for me at the time. After a little bit of soul-searching and a lot of discussions with the wife, I wound up taking it.
"I'm not sorry I did."
Although he'd spent his summers working with his father's race team and learning the mechanical side of racing, Erwin never envisioned being a crew chief when he graduated from Clemson in 1992. He took a job back home working for Ford in a complete nonracing environment.
Erwin may never have gotten into racing full-time at all had it not been for the 1993 plane crash that took the lives of NASCAR star Alan Kulwicki and Mark Brooks, the son of Hooters of America chairman Robert H. Brooks, whose company sponsored Kulwicki's car.
In memory of his son, the elder Brooks underwrote the Brooks Motorsports Institute at his alma mater, Clemson. Erwin was one of the first offered a spot in the program, which ultimately connected him with former NASCAR star Ricky Rudd, legendary owner Bud Moore and Billy Ingle.
At the end of the season Erwin moved to Team SABCO, which ultimately became Chip Ganassi Racing with Felix Sabates. He stayed there through the end of 2002, when he moved to RCR.
It was there that he first was paired with Gordon on the No. 31. Chris Andrews, who also works for Roush Fenway now, was the crew chief.
"I begged for Chris to be my crew chief and Greg to be my engineer," Gordon said. "I told these guys they're making me look very smart, but also very stupid because I let them both get away."
Gordon didn't let Erwin get away to Roush until the two became a mainstay in the top 35. They didn't miss a race in 2006.
"How do you say it?" Gordon said. "We haven't been able to find a guy to replace him since."
Erwin meets The Biff
Biffle wasn't happy when team owner Jack Roush decided to split him and crew chief Pat Tryson last season. He knew changes needed to be made, but more along the way the company structured its testing program than personnel.
"[I] felt we worked pretty well together," Biffle said.
Once Roush made it clear the change would be made, Biffle was given the choice of two replacements. One was Erwin, who this time had no reservations about making the move.
"I feel that this is one of the top crew-chief opportunities in the garage," Erwin said at the time he was hired. "If you could paint a picture of where you would like to go as a crew chief, to give it a shot to win and compete for a championship, this is it."
The two didn't contend for a title last season. They didn't even make the Chase, finishing 14th in points.
But they laid the foundation for this season, although that didn't become evident until the past two races.
Biffle believes Erwin's engineering background has been key.
Greg's biggest thing when he played football was he played with a lot of heart. He was always very passionate. He was ferocious.
-- Ray Erwin
"We understand each other," he said. "I understand the car really well and I understand the racetracks and I understand what this track is gonna do, and I can provide that information for him.
"That's probably something he hasn't had before is the knowledge of what I anticipate what we're gonna need come Sunday. So we get along really well together. We complement each other fairly well."
Some would say extraordinarily well, but it goes beyond setups and pit-road decisions. It has to do with a competitive passion that drives both to be the best.
"Greg's biggest thing when he played football was he played with a lot of heart," said Erwin's dad, Ray, who works for DEI. "He was always very passionate. He would come completely across the field and hit the biggest guy.
"He was ferocious. There's some guys there that will tell you for his size they haven't been hit so hard. There were some that didn't want to line up against him. He had no fear."
Not just in football, for which Erwin was the team captain, but also in wrestling, in which he typically went against opponents 30 pounds heavier, and in the classroom, where he stayed at the top of his class.
He was so successful that he received a nomination for the Air Force Academy, which he turned down for Clemson, where he would be on most football Saturdays if not for racing.
"I watch him now and he's the same way," the elder Erwin said.
But Erwin is showing a side that his father hasn't seen. It's a sense of confidence that borders on cockiness.
"Racing has put that into him," Ray said.
But Erwin is far from cocky. Although he's not surprised by the team's success, he's not looking past the next race, as Biffle did when he talked about having a spot reserved for the grandfather clock awarded to the winner at Martinsville four weeks from now.
"If that's working for him, that's good," Erwin said. "But the minute I start looking at Martinsville I'm going to forget something I needed to do for Kansas. I can't let that happen."
Erwin went so far as to have a few meetings this week with his crew to make sure they weren't getting ahead of themselves.
"Reminding them that as easy as it looks like it's coming now, it can go just as quickly," he said.
You have to search hard to find somebody who expects Biffle to go away in the Chase. You have to search even harder to find somebody who expects Erwin will let him go away.
"[Erwin's] just not that type of guy," Gibson said. "He deserves what he's getting. He may come across as confident, but that's what you have to be, no matter if it's football or baseball or whatever.
"I told his dad last week flying home, 'Hell, you just need to quit and move in and cut his grass and mooch off of him a little bit.' Greg's really, really good. He's got a huge future in front of him."
And maybe even a championship.
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org.