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Day One of NASCAR’s short track package test a mixed bag

NASCAR Cup Series driver Kyle Larson (5) chases Kevin Harvick (4) through turn 1 and into 2 during the Cup Series Championship race at Phoenix Raceway in Avondale on Nov. 5, 2023.

There is still another full day of aero and tire testing remaining at Phoenix Raceway on Wednesday but NASCAR officials and a handful of participating teams feel as though they are making a degree of progress in some areas but less so in others.

That is effectively the very nature of a test session.

The biggest purpose of the test is to continue making strides towards improving the racing product on short tracks with the third-year, seventh-generation Cup Series car. While most everyone in the industry believes the big-track product is as compelling as ever, the competition on tracks a mile and shorter has been really hard to watch at times.

With that said, NASCAR officials, drivers and teams are generally on the same figurative page about the root causes and are working towards a solution together. These are the participating drivers this week:

  • Christopher Bell (No. 20 Joe Gibbs Racing Toyota)
  • Ryan Blaney (No. 12 Team Penske Ford)
  • Chris Buescher (No. 17 RFK Ford)
  • Erik Jones (No. 43 LEGACY Motor Club Toyota)
  • Corey LaJoie (No. 7 Spire Motorsports Chevrolet)
  • Kyle Larson (No. 5 Hendrick Motorsports Chevrolet)

For this week, the proposed solution includes a series front splitter and rear diffuser swaps paired with an aggressive Goodyear tire compound.

Ryan Blaney said he ran just short of 500 laps on Tuesday. The way these sessions work is that the first couple of runs are a baseline package, then a lunch break, and then the experimental options to see how they deviate from the baseline.

Dr. Eric Jacuzzi is NASCAR’s vice president of vehicle performance and the league’s head aerodynamicist.

“For us, I think it’s coming out of here with a direction on the tire and aero package, be it neutral, positive, and any other things we learn along the way,” Jacuzzi said in an interview captured by freelance reporter Cole Cusumano. “Tomorrow we’re (testing) mufflers to make sure we have nothing unexpected in (Los Angeles for the Clash the Coliseum).

“We got some cooling improvements along with those too to address driver concerns. There’s a lot to it that will determine what we do in the future moving forward.”

Only splitters and a ‘simplified’ rear diffuser was tested alongside the tire compounds on Tuesday with no plans to remove the diffuser entirely. This generation of Cup Series car is the first to feature a completely sealed underbody and some drivers and crew members have expressed a desire to start unsealing parts of it to improve short track races.

In the graphic below, the splitter is green and the diffuser and diffuser strakes are green, purple and hot pink respectively.

Newly crowned Cup Series champion Blaney said the first run with a new splitter made a massive difference to him.

“Yeah, big difference from how we unloaded in the fall with this car,” Blaney told Cusumano in a scrum. “Ran a couple hours on it and then changed splitters and big difference; massive in the way it drives. There was so much downforce taken away with that. It was big. My first laps, I radioed and said ‘this thing is way different.'”

This was the first run after taking off the baseline set-up.

“Yeah, I think so,” Blaney said. “It was a huge difference, which it should, because it’s a massive aero loss when you do that. The simple diffuser, wasn’t as big of a change as the splitter but it still something to feel. That front splitter was a huge change. Hopefully we can continue tweaking it a little bit and get it better.”

Meanwhile, Jones did not care for any of the aero changes but did like the tire compound.

“There was nothing I was really excited about with any of it,” Jones said. “Maybe some of the diffuser stuff, I liked for sure, at the end of the day.

“The tire stuff, I thought was really good. I think Goodyear got some good notes from that that can improve a lot of places. We’ll see how durability is today with the tire that everyone liked today because we’re going to give it a longer run and see what happens there, and pairing it with some different package stuff. That was good. Of all the tire tests, and this isn’t really a tire test, by far of my career, this was the biggest difference I’ve noticed.”

Drivers and crew chiefs have been pretty vocal about the car needing to have more horsepower than the current 670HP target.

NASCAR has been pretty vocal back that they believe it is too expensive, thus placing a power restricting tapered spacer on the current generation of powerplants that are capable of producing over 900HP.

While the test took place, several industry crew members still feel like this is going to be the only solution to create better racing on short tracks because the car just doesn’t have enough power to wear out the rear tires when getting back on throttle in corner exit.

A Stewart Haas Racing engine tuner and Denny Hamlin’s crew chief, respectively, offered opinions on why.

Matt Weaver is a Motorsports Insider for Sportsnaut. Follow him on Twitter.

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