What matters at Phoenix: Pit stops, restarts will shape championship race

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What matters in today’s Cup race (3 p.m. ET on NBC and Peacock), and how will pit stops and restarts shape the championship picture? Let’s dive into the relevant analytics and trends at Phoenix Raceway:

All can be lost on a pit stop (or two, or three)

In 2020, Brad Keselowski and Jeremy Bullins brought an undefeated chassis to the season finale in Phoenix. They figured it was their best vessel for a shot at winning the series championship.

Their hunch was correct. The car ranked as the fastest of the race, based on timing and scoring data. But that wasn’t good enough. They finished second in large part because of their pit crew’s woeful effort on the day.

Keselowski’s over-the-wall crew cost him 13 positions on caution-flag pit stops. His final turn as the race’s leader ended after lap 195 — on pit road, not on the racetrack. His above-par passing out of those internally inflicted deficits still couldn’t overcome Chase Elliott, the eventual winner and champion.

This year’s crop of championship contenders fare among the best position-getters in a variety of statistical measures; however, Keselowski, himself a brilliant short-run performer, proved that track position near the front in this particular race is elusive. It’s a lesson that bears learning: Even the most adept climbers can’t reach the surface if they’re buried too deep.

In what is slated to be the final race of the five lug-nut era, it’s fitting that the championship could be decided — or most likely lost — on a pit stop. At first blush, it appears all four Championship 4 teams are in good shape. They each rank within the top five for median four-tire box time across the last nine playoff races:

The four pit crews are effectively close, separated by one-tenth of a second with Kyle Larson’s team enjoying the advantage. The remaining three are within, no kidding, one-thousandth of a second. One long pit stop, either by virtue of a mistake or adjustments meant to improve handling, will be costly, because it’s most likely that other competitors won’t err badly enough for a position to change hands.

And it’s not just errors — simply not having stops on par with the opposition will keep good cars out of the lead. Case in point, Denny Hamlin had the fastest car in the spring race at Phoenix, per its median lap time ranking, but 31 of his 33 laps led came before or during the competition caution. After Joey Logano passed him shortly after a restart, Hamlin was stymied as Logano’s pit crew reeled off three sub-13-second stops compared to one for Hamlin’s crew.

Despite having a faster car, Hamlin couldn’t corral Logano. Clean air, an advantage frequently defended on pit road, dictated the day’s green-flag runs.

Restarts will set the tone for all that comes after

Immediately following each caution-flag pit stop is a restart. And double-file restarts, which set the tone for subsequent green-flag runs, make for quite the show at Phoenix.

NASCAR, of course, has ensured this to be the case. For the spring race, the PJ1 traction compound was applied to the outer groove. The thinking was that it’d make the high line more effective and, possibly, the desired restart lane.

But that wasn’t the case. Within the top 14, drivers in the inside line defended position at a higher rate — 73.2% compared to the outside’s 46.4% clip. Those restarting from the inside groove have more width, thanks to the apron adjacent to the dogleg, something Keselowski demonstrated early in the race to nearly a heart-stopping degree:

More measured approaches also proved successful. Logano selected the inside groove as the leader three times — on laps 84, 99 and 200 — and retained the lead with each attempt. Up until the final restart on Lap 288, the car restarting from the inside of the front row had only been passed once, and the passer emerged from the inside of the second row, not the outside of the front row.

That’s what made Logano’s loss of the lead hard to swallow. Martin Truex Jr., from the outside of the front row, took advantage of the remaining grip from the traction compound to hold onto his car well enough in the center of the corner to swipe the lead:

It was a move of the kamikaze variety, to be sure, but involved some calculation. Truex’s execution was counter to those who previously utilized the outside groove. Instead of trying to out-duel Logano in the dogleg, he got back into the throttle on the dogleg’s exit before Logano did and stayed on the throttle longer going into the next corner.

“He drove in deep. I drove in deeper,” Truex said.

An elite restarter — he ranks second in position retention rate on restarts across all tracks — Truex was aware of his limitations, saddled with a restart spot he didn’t prefer.

“If I was the leader,” he said, “I probably would have chose the bottom as well.”

In lieu of PJ1, resin has been applied to the same high line around Phoenix for today’s race. Whether a driver is able to securely hold on to his car in the manner Truex did is unclear; what is a likelihood is the strength of the inside line, especially among leaders. It’s an inherent advantage to lead the race, but for some, it’s practically a requirement in advance of each restart:

Three of the Championship 4 — Truex, Larson and Elliott — are better restarters from the front row than they are in traffic. Truex and Larson, in particular, are downright deadly when seeing clean air at the start of a run, both retaining at least 85% of such attempts in playoff races.

But their rates fare worse when clean air is absent. Larson defends his restarting spot far less frequently, by over 20 percentage points. Truex’s gap is 17 percentage points. It’d behoove their teams to keep them at or near the front, helping to build a relatively impenetrable firewall on short runs.

Hamlin represents the outlier. In an odd twist, he’s been less successful at retaining front-row restarting spots, doing so at a 59.3% rate, but his defense when mired between the second and seventh rows is outstanding by comparison. In playoff races, he’s maintained his running position on 32 of 36 attempts. This suggests he’s the driver most impervious to further drops in the running order when he can’t depend on clean air. But good defense doesn’t necessarily translate to offense.

That’s why we’re likely to see title contenders driving in “deeper” as Truex succinctly put it. Ideal track position at Phoenix is elusive, at times fleeting, and the opportunities for gains are few and far between. Caution flags, which prompt pit cycles and restarts will create the very moments of vulnerability that have affected past races at the 1-mile facility.

Today, those moments will determine which of the four combatants hoists a championship trophy.

Appeal panel gives William Byron his 25 points back

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William Byron is back in a transfer spot after the National Motorsports Appeals Panel rescinded his 25-point penalty Thursday for spinning Denny Hamlin at Texas.

By getting those 25 points back, Byron enters Sunday’s elimination playoff race at the Charlotte Roval (2 p.m. ET on NBC) 14 points above the cutline.

Daniel Suarez is now in the final transfer spot to the Round of 8. He is 12 points ahead of Chase Briscoe and Austin Cindric. Christopher Bell is 45 points behind Suarez. Alex Bowman will not race this week as he continues to recover from concussion symptoms and has been eliminated from Cup title contention.

NASCAR did not penalize Byron after his incident with Hamlin because series officials did not see the contact. Two days later, NASCAR penalized Byron 25 points and fined him $50,000 for intentionally wrecking Hamlin.

The National Motorsports Appeals Panel stated that Byron violated the rule but amended the penalty to no loss of driver and owner points while increasing the fine to $100,000.

The panel did not give a reason for its decision. NASCAR cannot appeal the panel’s decision.

The panel consisted of Hunter Nickell, a former TV executive, Dale Pinilis, track operator of Bowman Gray Stadium and Kevin Whitaker, owner of Greenville-Pickens Speedway.

Here is the updated standings heading into Sunday’s race at the Roval:

Byron’s actions took place after the caution waved at Lap 269 for Martin Truex Jr.’s crash. As Hamlin slowed, Byron closed and hit him in the rear. 

Byron admitted after the race that the contact was intentional, although he didn’t mean to wreck Hamlin. Byron was upset with how Hamlin raced him on Lap 262. Byron felt Hamlin forced him into the wall as they exited Turn 2 side-by-side. Byron expressed his displeasure during the caution.

“I felt like he ran me out of race track off of (Turn) 2 and had really hard contact with the wall,” Byron said. “Felt like the toe link was definitely bent, luckily not fully broken. We were able to continue.

“A lot of times that kind of damage is going to ruin your race, especially that hard. I totally understand running somebody close and making a little bit of contact, but that was pretty massive.”

On the retaliatory hit, Byron said: “I didn’t mean to spin him out. That definitely wasn’t what I intended to do. I meant to bump him a little bit and show my displeasure and unfortunately, it happened the way it did. Obviously, when he was spinning out, I was like ‘I didn’t mean to do this,’ but I was definitely frustrated.”

Drivers for Drive for Diversity combine revealed

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The 13 drivers who will participate in the Advance Auto Part Drive for Diversity Combine were revealed Thursday and range in age from 13-19.

The NASCAR Drive for Diversity Development Program was created in 2004 to develop and train ethnically diverse and female drivers both on and off the track. Cup drivers Bubba Wallace, Daniel Suarez and Kyle Larson came through the program.

The 2020 and 2021 combines were canceled due to the impact of COVID-19.

“We are thrilled that we are in a position to return to an in-person evaluation for this year’s Advance Auto Parts Drive for Diversity Combine,” Rev Racing CEO Max Seigel said in a statement. “We are energized by the high-level of participating athletes and look forward to building the best driver class for 2023. As an organization, we have never been more positioned for success and future growth.”

The youngest drivers are Quinn Davis and Nathan Lyons, who are both 13 years old.

The group includes 17-year-old Andrés Pérez de Lara, who finished seventh in his ARCA Menards Series debut in the Sept. 15 race at Bristol Motor Speedway.

Also among those invited to the combine is 15-year old Katie Hettinger, who will make her ARCA Menards Series West debut Oct.. 14 at the Las Vegas Bullring. She’s also scheduled to compete in the ARCA West season finale Nov. 4 at Phoenix Raceway.

 

 

Name

Age Hometown
Justin Campbell 17 Griffin, Georgia
Quinn Davis 13 Sparta, Tennessee
Eloy Sebastián

López Falcón

17 Mexico City, Mexico
Katie Hettinger 15 Dryden, MI
Caleb Johnson 15 Denver, CO
Nathan Lyons 13 Concord, NC
Andrés Pérez de Lara 17 Mexico City, Mexico
Jaiden Reyna 16 Cornelius, NC
Jordon Riddick 17 Sellersburg, IN
Paige Rogers 19 New Haven, IN
Lavar Scott 19 Carney’s Point, NJ
Regina Sirvent 19 Mexico City, Mexico
Lucas Vera 15 Charlotte, NC

 

Dr. Diandra: Crashes: Causes and complications

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Two drivers have missed races this year after hard rear-end crashes. Kurt Busch has been out since an incident in qualifying at Pocono in July. Alex Bowman backed hard into a wall at Texas and will miss Sunday’s race at the Charlotte Roval (2 p.m. ET, NBC).

Other drivers have noted that the hits they’ve taken in the Next Gen car are among the hardest they’ve felt in a Cup car.

“When I crashed it (at Auto Club Speedway in practice), I thought the car was destroyed, and it barely backed the bumper off. It just felt like somebody hit you with a hammer,” Kevin Harvick told NBC Sports.

The three most crucial parameters in determining the severity of a crash are:

  • How much kinetic energy the car carries
  • How long the collision takes
  • The angle at which the car hits

Angle

The last of these factors requires trigonometry to explain properly. You can probably intuit, however, that a shallower hit is preferable to a head-on — or rear-on — hit.

A graphic show shallower (low-angle) hits and deeper (high-angle) hits
Click for a larger view

When the angle between the car and the wall is small, most of the driver’s momentum starts and remains in the direction parallel to the wall. The car experiences a small change in velocity.

The larger the angle, the larger the change in perpendicular speed and the more force experienced. NASCAR has noted that more crashes this season have had greater angles than in the past.

Busch and Bowman both had pretty large-angle hits, so we’ll skip the trig.

Energy — in pounds of TNT

A car’s kinetic energy depends on how much it weighs and how fast it’s going. But the relationship between kinetic energy and speed is not linear: It’s quadratic. That means going twice as fast gives you four times more kinetic energy.

The graph shows the kinetic energies of different kinds of race cars at different speeds. To give you an idea of how much energy we’re talking about, I expressed the kinetic energy in terms of equivalent pounds of TNT.

A vertical bar graph showing kinetic energies for different types of racecars and their energies

  • A Next Gen car going 180 mph has the same kinetic energy as is stored in almost three pounds of TNT.
  • Because IndyCars are about half the weight of NASCAR’s Next Gen car, an IndyCar has about half the kinetic energy of a Next Gen car when both travel at the same speed.
  • At 330 mph, Top Fuel drag racers carry the equivalent of six pounds of TNT in kinetic energy.

All of a car’s kinetic energy must be transformed to other types of energy when the car slows or stops. NASCAR states that more crashes are occurring at higher closing speeds, which means more kinetic energy.

Longer collisions > shorter collisions

That seems counterintuitive, doesn’t it? Who wants to be in a crash any longer than necessary?

But the longer a collision takes, the more time there is to transform kinetic energy.

A pitting car starts slowing down well below it reaches its pit box. The car’s kinetic energy is transformed into heat energy (brakes and rotors warming), light energy (glowing rotors), and even sound energy (tires squealing).

The same amount of kinetic energy must be transformed in a collision — but much faster. In addition to heat, light and sound, energy is transformed via the car spinning and parts deforming or breaking. (This video about Michael McDowell’s 2008 Texas qualifying crash goes into more detail.)

The force a collision produces depends on how long the car takes to stop. Compare the force from your seat belt when you slow down at a stop sign to what you feel if you have to suddenly slam on the brakes.

To give you an idea of how fast collisions can be, the initial wall impact in the crash that killed Dale Earnhardt Sr. lasted only eight-hundredths (0.08) of a second.

SAFER barriers use a car’s kinetic energy to move a heavy steel wall and crush pieces of energy-absorbing foam. That extracts energy from the car, plus the barrier extends the collision time.

The disadvantage is that a car with lower kinetic energy won’t move the barrier. Then it’s just like running into a solid wall.

That’s the same problem the Next Gen car seems to have.

Chassis stiffness: A Goldilocks problem

The Next Gen chassis is a five-piece, bolt-together car skeleton, as shown below.

A graphic showing the five parts of the Next Gen chassis.
Graphic courtesy of NASCAR. Click to enlarge.
The foam surrounding the outside of the rear bumper
The purple is energy-absorbing foam. Graphic courtesy of NASCAR. Click for a larger view.

That graphic doesn’t show another important safety feature: the energy absorbing foam that covers the outside of the bumpers. It’s purple in the next diagram.

All cars are designed so that the strongest part of the car surrounds the occupants. Race cars are no different.

The center section of the Next Gen chassis is made from stout steel tubing and sheet metal. Components become progressively weaker as you move away from the cockpit. The bumper, for example, is made of aluminum alloy rather than steel. The goal is transforming all the kinetic energy before it reaches the driver.

Because the Next Gen car issues are with rear impacts, I’ve expanded and highlighted the last two pieces of the chassis.

The rear clip and bumper, with the fuel cell and struts shaded

The bumper and the rear clip don’t break easily enough. The rear ends of Gen-6 cars were much more damaged than the Next Gen car after similar impacts.

If your initial thought is “Just weaken the struts,” you’ve got good instincts. However, there are two challenges.

I highlighted the first one in red: the fuel cell. About the only thing worse than a hard collision is a hard collision and a fire.

The other challenge is that a chassis is a holistic structure: It’s not like each piece does one thing independent of all the other pieces. Changing one element to help soften rear collisions might make other types of collisions harder.

Chassis are so complex that engineers must use finite-element-analysis computer programs to predict their behavior. These programs are analogous to (and just as complicated as) the computational fluid dynamics programs aerodynamicists use.

Progress takes time

An under-discussed complication was noted by John Patalak, managing director of safety engineering for NASCAR. He told NBC Sports’ Dustin Long in July that he was surprised by the rear-end crash stiffness.

The Next Gen car’s crash data looked similar to that from the Gen-6 car, but the data didn’t match the drivers’ experiences. Before addressing the car, his team had to understand the disparity in the two sets of data.

They performed a real-world crash test on a new configuration Wednesday. These tests are complex and expensive: You don’t do them until you’re pretty confident what you’ve changed will make a significant difference.

But even if the test goes exactly as predicted, they aren’t done.

Safety is a moving target.

And always will be.

NASCAR weekend schedule for Charlotte Motor Speedway Roval

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NASCAR Cup Series drivers race on the road for the final time this season Sunday, as the Charlotte Motor Speedway Roval course ends the playoffs’ Round of 12.

The 17-turn, 2.28-mile course incorporating the CMS oval and infield will determine the eight drivers who will advance to the next round of the playoffs. Chase Elliott won last Sunday at Talladega Superspeedway and is the only driver who has qualified for a spot in the Round of 8.

Entering Sunday’s race, Austin Cindric, William Byron, Christopher Bell and Alex Bowman are below the playoff cutline. Bowman will not qualify for the next round because he is sidelined by concussion-like symptoms.

The race (2 p.m ET) will be broadcast by NBC.

Charlotte Motor Speedway Roval (Cup and Xfinity)

Weekend weather

Friday: Sunny. High of 81 with a 6% chance of rain.

Saturday: Mixed clouds and sun. High of 67 with a 3% chance of rain.

Sunday: Sunny. High of 68 with a 3% chance of rain.

Friday, Oct. 7

(All times Eastern)

Garage open

  • 12 – 5 p.m. — Xfinity Series

Saturday, Oct. 8

Garage open

  • 7 a.m. – 2:30 p.m. — Cup Series
  • 8:30 a.m. — Xfinity Series

Track activity

  • 10 – 10:30 a.m. — Xfinity practice (NBC Sports App)
  • 10:30 – 11:30 a.m. — Xfinity qualifying (NBC Sports App)
  • 12 – 1 p.m. — Cup practice (NBC Sports App, USA Network coverage begins at 12:30 p.m.)
  • 1 – 2 p.m. — Cup qualifying (USA Network, NBC Sports App)
  • 3 p.m. — Xfinity race (67 laps, 155.44 miles; NBC, Peacock, Performance Racing Network, SiriusXM NASCAR Radio)

Sunday, Oct. 9

Garage open

  • 11 a.m. — Cup Series

Track activity

  • 2 p.m. — Cup race (109 laps, 252.88 miles; NBC, Performance Racing Network, SiriusXM NASCAR Radio)