Analysis: Education, awareness hallmarks of elite NASCAR restarters


The first restart of NASCAR’s choose-rule era saw four of the first five cars in the running order select a launching point from Michigan International Speedway’s outside line, its statistically preferred groove. One of them — Kurt Busch — relinquished a fifth-place spot, traditionally the inside of the third row, for the eighth-place spot, the outside of the fourth row.

He promptly made his choice appear wise, gaining four spots — a positional net of +1 — while simultaneously justifying the existence of the choose rule, previously a feature of youth races on quarter-mile tracks, among others in short track racing. This invited others to attempt the same bid — Kyle Busch, Martin Truex Jr., Christopher Bell and Erik Jones would follow suit that day in dumping top-five spots for that magical eighth-place springboard.

Kurt Busch as the choose zone’s pied piper is fitting. Potentially the best restarter since the 2009 inception of the double-file format, he ranked first or second in position retention on non-preferred groove restarts in 2013-15, 2018 and 2020. His knack for scoring positions out of the non-preferred groove is a talent only he seems to carry from year to year, rules package to rules package. From 2013-16, he netted 27 positions from the lesser of the two grooves, while all other full-time drivers during that span registered net negatives. On a Lap 236 restart last season in Darlington’s Southern 500, he launched from the fifth row’s inside line — the non-preferred spot from which occupants saw a 12.5% success rate in defending position — and not only bucked the race’s pronounced statistical trend, but also gained one spot.

Busch is a mercurial soul, but thoughtful about his craft, studious of restarts. He watches videos of himself and his competitors so that he can plot his pounce on the fly.

“When you drive down into Turn 1, you have to have a plan already in place on those restarts and you have to anticipate what others are thinking and what they’re doing,” Busch told NBC Sports. “Sometimes you’re on four fresh tires and then sometimes there’s restarts where you just did fuel only or two tires. You have to absorb your car’s handling and be able to know what it’s going to give you when you land down in Turn 1.”

Watch Busch on successive restart attempts and you’ll notice he rarely does the same thing twice. His unpredictability is an asset, but it’s a spontaneity influenced by reflection. Depending on the drivers around him, their positioning and their habits — repetitious restarters tend to be poor restarters — he’ll flip the script. A defensive position might allow a chance at some offense, offensive spots might require defense and calm restarts may demand a touch of chaos.

“It’s like if you’re in football and you’re the quarterback,” Busch said. “Up at the line, changing the play call because he sees how the defense is lined up or he sees the cornerback not on top of his receiver as close as he had been.

“You find those small windows, those little openings, and that’s done off of tape review, it’s done off of experience. And it’s that feel of that next dimension that you have to apply to have a competitive edge over the next guy.”

Anyone who’s viewed Busch’s 2013 restart in Atlanta knows the depths of his capability. A clogged launch and some nifty maneuvering while working the gears created the setting for one of the most memorable restarts in NASCAR history:

He’s more than a GIF-maker, though. Each of his last two wins — Kentucky in 2019 and Las Vegas last year — required a late-race restart savvy, for which he was happy to oblige. He’s the current bar other non-preferred groove restarters are attempting to clear:

Defending a non-preferred groove position is a predominately fruitless endeavor. Occupants in that groove see an average disadvantage of 35 percentage points to their peers with preferred spots. Last year, Busch was one of two drivers to successfully defend position on more than 50% of his attempts from inside the top 14.

The other is Ryan Blaney, seemingly a natural. Since his Cup Series debut, he’s managed good restarting numbers, a rare attribute among drivers under 30 who score the bulk of their track position on long runs.

“If you can’t go forward on the restart, you better make sure that you’re at least staying where you’re at,” Blaney told NBC Sports. “You can’t just give up spots. That’s kind of the mentality I’ve always had. I’ve always tried to be good at timing restarts and runs.

“I think I’ve been doing it ever since late models, because those guys were so on it on restarts. If you weren’t paying attention, they took advantage of you. I was really young when I started in PASS (the Pro All-Stars Series, a late model series in the Southeast) and those guys had many years on them. I learned from an early age to be an aggressor on restarts, and I think it carried over to where I am now.”

Blaney’s elite restarting acumen is a foundational attribute made more valuable in the era of stage racing and competition cautions, guaranteeing at least three opportunities for a wholesale position shuffle. He views the vulnerable two-lap windows following each restart for what they are: Open invitations to seize track position.

“It’s one of the easiest places to pass people,” Blaney said. “One of the easiest is pit road, the other is restarts.”

Most drivers don’t experience the easy assimilation Blaney did. Matt DiBenedetto, for one, forced himself to study video over the last few years — his favorite subjects are Truex and Kevin Harvick — to make up for the lack of experience restarting next to stock car racing’s elites. For sure, it was a big chasm to close: He made just 15 restart attempts from inside the top 14 across 2017-18 while driving for GoFas Racing.

He’s now one of the best preferred groove restarters in the series, ranking third last year in position retention:

DiBenedetto credits knowledge accrued over time for his rapid improvement but cautions against sticking with the most pragmatic game plan.

“There’s a point where you can take in good information and use it to your advantage and be aware of certain things,” DiBenedetto told NBC Sports. “Like the basics of Michigan, you can try to drive down to the bottom but you better make sure you’re clear on exit, or if it’s Pocono, you know once you get off Turn 1, man, if you’re stuck on the bottom down the backstretch, the whole train on the outside is going to drive by you.

“That’s what’s helpful study material but you also don’t want to overanalyze certain things. You want to take those things into account but also be ready for different situations, like at the last second, there’s a hole up the middle. If I shoot there, I won’t have to let off the gas, you know, and I can keep my momentum and kind of hope that it works out.”

DiBenedetto’s education as a restarter was on display last year in Darlington, when he correctly assessed the low probability for positional gain and quickly retreated to safe mode. That his move mirrored that of Harvick, one of his admitted muses, was a fun coincidence:

His 43.21% retention rate from the non-preferred groove ranked eighth in the series last season, a sure sign of a well-rounded restarter.

“It’s a really, really tough balance,” he said. “You have to be so aggressive, but you also can’t be wadding your stuff up.”

The differences in retention rates from one driver to the next are slim, separated anecdotally by situational awareness. Drivers are consistently searching for better intel, leading to bigger gains. To wit, the best all-around restarter last year, Truex, made a spotter change specifically to improve his positional gain on 550-hp tracks. Seemingly, it’s a move akin to Stephen Curry changing shooting coaches, desiring to enhance an already accurate 3-point field goal percentage. But any improvement for Truex could assist in better finishes, if not more wins. His +0.64 positional net per preferred groove attempt was low given how other top position defenders performed last year. It’s an area for improvement that’s realistic and firmly within his control.

Control is the prevailing theme among the good restarters. Calculation amid perceived chaos is what’s winning them spots, the result of their experiences and individual efforts to improve.

There’s far more thought put to these hectic moments than meets the eye and it’s what is separating the great restarters from the rest of the herd.

Harrison Burton looks for progress in second year in Cup


Harrison Burton made the first start of his NASCAR Cup Series partnership with the Wood Brothers in the bright lights of Los Angeles.

Burton and the Woods teamed last season as Burton jumped into full-time Cup racing after two full seasons (and four wins) in the Xfinity Series. Their first race was the Clash at the Coliseum, and it was a good start — Burton qualified for the feature and finished 12th on the lead lap.

Then things headed downhill. Crashes at Daytona and Auto Club Speedway left Burton with finishes of 39th and 33rd, respectively. After the first five races of the year, he had four finishes of 25th or worse.

Now, Season Two, and there are higher expectations. Much higher.

MORE: Drivers to watch in Clash at the Coliseum

“The start of last year was really, really rough,” Burton told NBC Sports. “It kind of put us in a hole. We got into the wreck in the 500 and crashed at Fontana. Things kind of stack up on you, and all of a sudden you’re buried in points and it’s hard to make it back up.

“But, at the end of the year, three of the last four weekends were big for us (three consecutive top-20 finishes). We need to build off that and try to get out of the West Coast swing and have a clean group of those races. That’s really important. We need to get our average finish up in the first four to five races and not put ourselves in a hole we can’t get out of, and then go from there.”

The Wood Brothers team typically brings strong cars to the Daytona 500, the season’s first point race. Trevor Bayne scored the team’s latest win in stock car racing’s biggest event in 2011.

“We ran well in the 500 last year until I was upside down,” Burton said. “We had a fast car and qualified well and finished third in our duel. Then in the second Daytona race we put ourselves in good position late, so we were in contention in both Daytona races. The speed was there, and the cars drove well.”

The team’s primary goal is to make the playoffs, Burton said. “And we want to be a contender,” he said. “Cup races are so hard. First, you have to contend. Having a good average finish is really important. If you average around 17th or 18th all year, you can kind of point your way into the playoffs, and doing that is on our minds for sure.”

MORE: Power Rankings: 10 historic moments in the Clash

Burton looks for a strong start in Sunday’s Clash, which will present teams with a mix of the old and the new. Drivers got the experience of racing inside the Los Angeles Memorial Coliseum last year, and notes from that race will be useful, but the racing surface will be all new again.

“Every repave has a different tendency,” Burton said. “We’ll see how close it is to last time and how different. Obviously, there is experience on that track, but still it’s a completely new surface, so it’s going to be a mixture of old and new. There’s some knowledge we can build off of, but we kind of have to go into the weekend with that knowledge as tentative because we don’t know if the track is going to be different.”

Burton heads for Los Angeles with a win already under his belt this year. He and teammate Zane Smith, last year’s NASCAR Craftsman Truck Series champion, won last Friday’s International Motor Sports Association’s Michelin Pilot Challenge Series race on the Daytona International Speedway road course.

Burton drove the finishing laps in the four-hour race. He was third with about 50 minutes to go but moved in front with 22 minutes left when leader Elliott Skeer parked. Burton outran second-place Spencer Pumpelly by .688 of a second for the win.

“I thought we could run well,” Burton said. “After the test we did, we were really fast, so I was pretty excited. But apparently there is a lot of sandbagging that goes on there, so I wasn’t sure where we were. We had to have some things go right for us, and they did.”





Dr. Diandra: Muffling racecars won’t change fan experience


Last week, NASCAR tested the muffler that will be used for Sunday’s Clash at the Coliseum.

“Heresy,” some fans cried. They argued that it is against the laws of man and nature to muffle racecars. That noise is an integral part of the fan experience. That you’re not supposed to be able to have conversations during races.


The cars will be plenty loud.

Loud is fast

Engines produce power by combusting fuel and air in their cylinders. Each combustion produces high-pressure gases that push the piston up. The same gases make a loud popping sound when they escape the cylinder and finally the exhaust.

At 8,000 rpm, an eight-cylinder engine performs about 520 combustions every second. The faster an engine runs, the more combustions per second and the higher the frequency of the tailpipe noise.

That’s why NASCAR engines sound like grizzly bears and F1 engines, which run at higher speeds, sound more like angry mosquitoes.

Maximum horsepower requires getting the spent gases out of the cylinder as quickly as possible so the next combustion reaction can start. And that’s the problem with mufflers, from a racing perspective.

Mufflers on street cars bounce sound waves from the engine around a metal can. The waves interfere with each other, which decreases the overall volume coming from the exhaust.

Mufflers can also mitigate noise by directing the exhaust through a sound-absorbing material. Borla, the sole-source supplier for this weekend’s muffler, makes commercial racing mufflers that feature a robust sound-absorbing material superior to the commonly used fiberglass.

Both methods slow the exhaust gases — the first more than the second. The ideal racing muffler diminishes sound with minimal horsepower reduction.


Sound-level measurements come in decibels (dB), a unit named after Alexander Graham, not Christopher — and apparently by someone who wasn’t the best speller.

But decibels don’t tell the whole story. Sound intensity decreases with distance, so you need to specify how far away the sound source was.

The easiest way to explain the decibel scale is to relate it to real-world noises, as I’ve done below.

A bar chart showing representative sound levels expressed in decibels.

  • Zero dB is the threshold of human hearing.
  • A whisper you can just barely make out is about 20 dB.
  • Most everyday noises are in the 60 dB to 100 dB range but are sometimes louder.
  • Exposure to 130 dBs can be painful.
  • A 150-dB sound can cause permanent hearing damage in a very short time.

Ringing in your ears the day after a rock concert was a badge of honor in high school. Older me wishes I had been a little smarter.

Hair cells — not to be confused with ear hair — facilitate hearing. Sound bends these hair-shaped cells, and the cells convert sound into electrical signals that the brain interprets. Loud sounds can bend these cells so much that they break.

Unlike animals such as sharks, zebrafish — and even the lowly chicken — humans cannot grow new hair cells. Once your hearing is damaged, you can’t get it back.

How loud are racecars?

A noise mitigation study for the proposed Nashville Fairgrounds track measured a single Next Gen car at COTA generating 112 dB on a straightaway at 100 feet.

A 2008 study measured the sound level inside a Gen-6 car to be an average of 114 dB. The study also compared sound in the stands, the infield and the pits.

Let’s add those numbers to our graph.

A bar chart showing representative sound levels expressed in decibels, including sound measurements from the Gen-6 and Next Gen cars

  • The Next Gen car at 100 feet is about the same loudness as a person screaming at top volume 1 inch from your ear.
  • The Next Gen car at 100 feet is just a bit quieter than sitting inside the Gen-6 car.
  • Bristol reached peak sound levels loud enough to cause permanent hearing damage.

The graph data suggests that inside the Next Gen car should be around 10 times louder than inside the Gen-6. Some drivers made new earmolds to cope with the additional noise in the cockpit.

Because of the way sound works, the numbers don’t add like you’d expect them to. A Next Gen car might be 112 dB, but two Next Gen cars are more like 115 dB. A full field would be only 5-7 dB louder.

The mufflers won’t muffle much

NASCAR expects a six to 10-dB reduction in sound with mufflers. A 10-dB reduction would make the Next Gen car about as loud as the Gen-6 car was.

Another way of looking at it: Good earplugs reduce sound levels by 25 to 30 dB. Wearing earplugs just barely gets you into the range of being able to hold a conversation if you stand very close to each other and you both shout.

You won’t notice the change in sound inside the track.

You also won’t notice a change in speed this weekend, despite a drop of 30-40 horsepower. The Next Gen car takes around 14 seconds to traverse the L.A. Coliseum’s quarter-mile track. That means cars won’t be going much faster than typical expressway speeds.

If you’re headed out to the track this weekend — despite the mufflers — bring earplugs or over-the-ear headsets. This is especially important for children, as their hearing is more easily damaged.

Joe Gibbs Racing adds young racers to Xfinity program


Connor Mosack, 23, and Joe Graf Jr., 24, each will drive select races in the No. 19 Xfinity Series car for Joe Gibbs Racing this season.

Mosack, who has a 20-race Xfinity schedule with Sam Hunt Racing this year, will run three races for JGR: Chicago street course (July 1), Pocono (July 22) and Road America (July 29) while also competing in six ARCA Menards Series races for JGR, including Feb. 18 at Daytona.

Graf, who has a 28-race Xfinity schedule with RSS Racing this year, will run five races in the No. 19 Xfinity car for JGR: Auto Club Speedway (Feb. 25), Las Vegas (March 4), Richmond (April 1), New Hampshire (July 15) and Kansas (Sept. 9).

“I made my Xfinity Series debut with JGR last June at Portland and from the moment I made my first lap in their racecar, I realized why they’ve been so successful,” Mosack said in a statement. “Their equipment was second to none and the resources they had in terms of people and their knowledge was incredible.

“Jason Ratcliff was my crew chief at Portland and he’s got a ton of experience. I was able to learn from him before we even went to the track. Just in our time in the simulator, we made some great changes. So, to be back with him for three Xfinity races is going to be really valuable.

“And when it comes to JGR’s ARCA program, it’s the class of the field. After having to race against JGR cars, I’m really looking forward to racing with a JGR car. No matter what track they were on, they were always up front competing for wins. To have that chance in 2023 is pretty special, and I aim to make the most of it.”

Said Graf in a statement about his opportunity with JGR: “Running five races with JGR is a fantastic opportunity for myself and for my marketing partners. I think I can learn a lot from JGR and showcase my skills I’ve been growing in the series in the past three years. 2023 is shaping up to be a great year and I’m pumped to get started with the No. 19 group.”

Ryan Truex has previously been announced as the driver of the No. 19 Xfinity Series car in six races this season for JGR. The remaining drivers for the car will be announced at a later date.

Mosack didn’t start racing until he was 18 years old. He went on to win five Legends car championships before moving to Late Model stock cars in 2019. He graduated from High Point University in 2021 with a degree in business entrepreneurship. Mosack’s first Xfinity Series race with Sam Hunt Racing this season will be March 11 at Phoenix Raceway.


NASCAR weekend schedule for Los Angeles Memorial Coliseum


NASCAR’s winter break ends this weekend as Cup Series drivers return to the track for Sunday’s Clash at the Coliseum in Los Angeles.

The second Clash at the LA Memorial Coliseum has been expanded to 27 (from 23) drivers for the 150-lap main event. Qualifying, heat races and two “last chance” races will set the field.

MORE: Drivers to watch in the Clash

Joey Logano won last year’s Clash, the perfect start to a season that ended with him holding the Cup championship trophy.

Los Angeles Memorial Coliseum (Cup)

Weekend weather

Saturday: Mostly sunny. High of 71.

Sunday: Partly cloudy. High of 66.

Saturday, Feb. 4

(All times Eastern)

Garage open

  • 2 – 11:30 p.m. — Cup Series

Track activity

  • 6 – 8 p.m. — Cup Series practice (FS1, Motor Racing Network, SiriusXM NASCAR Radio)
  • 8:35 – 9:30 p.m. — Cup Series qualifying (FS1, MRN, SiriusXM NASCAR Radio)

Sunday, Feb. 5

Garage open

  • 11 a.m. – 12:30 a.m. Monday — Cup Series

Track activity

  • 5 – 5:45 p.m. — Four Heat races (25 laps; Fox, Motor Racing Network, SiriusXM NASCAR Radio)
  • 6:10 – 6:35 p.m. — Two Last chance qualifying races (50 laps; Fox, MRN, SiriusXM NASCAR Radio)
  • 8 p.m. — Feature race (150 laps; Fox, MRN, SiriusXM NASCAR Radio)