Monday Morning Pit Box: Frenzy of Cautions Shape Fuel Strategy at Iowa

It took nearly six months, but the two-time reigning Daytona 500 champion is back in victory lane.

William Byron used a combination of speed and strategy, stretching his final tank of fuel a remarkable 144 laps to win the Iowa Corn 350 at Iowa Speedway on Sunday (Aug. 3). It’s just his second checkered flag of 2025 and the 15th of his Cup Series career in the No. 24 Hendrick Motorsports Chevrolet.

Similar to last week’s Brickyard 400, several different pit strategies formed as the race unfolded in the Heartland, and it all centered on fuel. Let’s break down the winning—and losing—pit strategies from Iowa.

Streak of Cautions Shakes Up Fuel Strategy

The Cup Series’ second visit to the 0.875-mile short track at Iowa could be best described as a tale of two races in one. During the first half of the 350-lap event, there were just two caution flags, one for the stage one break and the other for the first of two spins by Shane van Gisbergen. The second half took on an entirely different complexion with 10 yellow flags.

Byron made what turned out to be his final pit stop for tires and fuel on lap 206. At that point, with 144 laps to go, it seemed as though the No. 24 team would have to make another pit stop to make it to the end.

But as the old saying goes, cautions breed cautions. With each yellow flag, another handful of lead-lap cars came to the service of their pit crews. Consequently, fuel strategy split in multiple directions, as can be seen by the lap of the final pit stop for each of the top 10 finishers.

There was a 50-lap range in the final pit lap for the top 10, from Byron’s max fuel savings to Austin Dillon cracking the top 10 with fresher rubber at the end.

William Byron Wins Iowa Corn 350

Of note, Brad Keselowski had arguably the best car in the field, sweeping stages one and two but settling for third on 24-lap fresher tires than Byron.

“Just the way the yellows fall,” Keselowski said post-race about how the end of the race unfolded. “We had so many yellows there in stage three that it got the [No.] 24 and the [No.] 19 to where they could make it on fuel pitting way outside the window, and we just couldn’t get back by them.”

Getting back to Byron, Sunday’s victory proved to be a reversal of fortune from two previous fuel management races from earlier in the summer. At Michigan International Speedway in June, Byron led late before running out of fuel with four laps left and falling to 28th. In last week’s Brickyard 400, Byron’s tank ran dry during the final lap, sending him plummeting to 16th in the final running order.

While talking to NBC Sports post-race, Byron mentioned how those two races, while disappointing, turned out to be learning opportunities for himself and the No. 24 team.

“I think our calculations were a lot tighter, a lot more refined, so they were coaching me on what to do,” Byron said. “Inside the car, I’ve had to look at ‘okay, what can I do to save fuel when there’s nothing going on.’”

Iowa could prove to be a turning point for the Byron and the No. 24 team. With the win, Byron has retaken the regular season points lead, up 18 markers over Hendrick Motorsports teammate Chase Elliott. Between the speed of the car and crew chief Rudy Fugle calling the right strategy, Iowa truly was a total team effort for the No. 24 bunch.

Pit Road Police

Here is a summary of notable pit road penalties called during Sunday afternoon in the Hawkeye State:

• Ryan Preece and Alex Bowman, two drivers who entered Iowa hovering around the playoff cut line, both got tagged for speeding on pit road in lap 73. Both speeding infractions occurred on section 13 towards the end of the pit lane. Neither Preece nor Bowman seemed too fazed by the early speeding penalty as they both rebounded for top-10 finishes, with Preece placing fifth and Bowman bringing the car home seventh.
• On lap 224, Chris Buescher got sent to the tail of the field for an equipment interference penalty called on the No. 17 RFK Racing crew. It was a setback in an already rough day for Buescher, who finished 22nd. That result, coupled with Preece’s top five, reduced Buescher’s gap above the cut line from 42 points before the race to just 23 points with three regular season races left.
• Bubba Wallace, Erik Jones and Tyler Reddick all got hit with too many men over the wall penalties during the second half of the race.
• Ty Dillon got busted for speeding on lap 246, part of a turbulent day in Iowa that saw the younger Dillon brother finish four laps down in 35th.

Look Ahead to Next Week

The NASCAR Cup Series will make left and right hand turns next Sunday, Aug. 10, with the running of the Go Bowling at the Glen from Watkins Glen International in New York.

Like this week at Iowa, fuel mileage has been a factor in many past races at the Glen. Take, for example, Elliott’s first career Cup Series win in 2018, when driver No. 9 saved just enough fuel to hold off Martin Truex Jr. before running dry on the cooldown lap.

Also, with van Gisbergen having won three out of four road/street courses so far this season, don’t be surprised to see teams formulate strategies to try and counter the No. 88.

Andrew Stoddard

Andrew Stoddard joined Frontstretch in May of 2022 as an iRacing contributor. He is a graduate of Hampden-Sydney College, the University of Richmond, and VCU. He works as an athletic communications specialist at Eastern Mennonite University in Harrisonburg, Va.