3/14/2021 NASCAR Cup and Xfinity Series Phoenix Preview

This is a new series in analyzing data pertinent to a race weekend to predict who will be successful among the three national NASCAR series. We’ll use speed score, retention ratings, splits, and other tools available at rrel.ca. It remains to be seen if said metrics can predict winners, but anecdotally they’ve been good at predicting success. This weekend brings the Cup and Xfinity Series to Phoenix Raceway for the spring Phoenix race.

Cup Series

In 2020, Joey Logano won the spring race. Chase Elliott ran the fastest lap and finished second to Kevin Harvick in speed score by a decent margin, with Logano and Ryan Blaney rounding out the top of the class. It was a very good race for Penske in pure speed terms, with their three drivers and Matt DiBenedetto in the affiliated Wood Brothers car all in the top seven fastest. Those metrics measure pure speed, and most of the speed was found at the beginning of the race. Looking to complete-race numbers like net retention, Logano finished a strong fourth behind Harvick in first (by a mile), Elliott, and Brad Keselowski. Harvick deserved the win but couldn’t pass Logano off a late restart. I don’t think it’s important, but given his success thus far this year, perhaps it’s worth mentioning: Kyle Larson had the third fastest lap. He’s since changed teams.

Elliott won the fall race to take home the championship. He was fourth in speed score to Logano, Hamlin, and Keselowski. Logano and Hamlin were far and away tops in both speed score and net retention. Elliott had the fastest lap. As mentioned, this was the championship race, which means there were a ton of distortions and desperations. Most of the fast laps came late. From a speed point of view, Harvick was a non-factor.

You can look at last season too. Whether you look at short tracks or the 750 HP package, Logano was easily fastest over the course of the season. Same is true of the playoffs. Given that and Elliott’s general performance at Phoenix last year, they are the the Rrel.ca picks for this race. Don’t be surprised if Keselowski does well.


Brandon Jones won the spring race last year; his performance was fine but unexceptional in a race dominated by Kyle Busch. Jones was fourth in net retention, but well off Justin Allgaier, who led amongst series regulars. The same can be said of speed score. The only two drivers worth calling out as it pertains to this year are Allgaier, who was generally fastest amongst regulars, and Noah Gragson, who was second fastest and ran his best laps late.

Austin Cindric won the fall race to win the Xfinity Series championship. This was a deserved win for Cindric, as he led retention score, just above Allgaier, and was second in speed score, just trailing Allgaier. Cindric had the highest median lap speed by a good margin. Gragson, who finished second, was third in speed score but well off in retention. Jones replicated his performance from the spring race with very similar scores in both metrics, leading to a third place finish.

It’s difficult to judge whether Cindric’s improved performance between the races was luck driven / natural variance, or if it was development. I’m almost inclined to conclude the former, as his performance was fairly weak in the playoffs. But given his strength all year and at beginning of 2021, that downturn was likely luck driven itself. That being said, the Rrel.ca pick is Justin Allgaier. He was consistently great at Phoenix and easily fastest at short tracks in 2020. Without any data on comparable tracks in 2021, it’s hard to pick otherwise. Noah Gragson should perform well too.

Justin Barber - March 12, 2021, 9:39 p.m. - © 2022