Connor Zilisch: Phoenix Dogleg Delivers a 10G Hit Every Lap

Phoenix’s dogleg has a number now. Connor Zilisch, the 20-year-old rookie driving the No. 88 Chevrolet for Trackhouse Racing in his first full Cup season, told SiriusXM NASCAR Radio on Wednesday what his mouthpiece measured during Sunday’s race at Phoenix Raceway: “Yeah, I certainly have it in, and basically every time you go down there, it’s a 10G hit. It depends on how many times you run it. You get a lot of just 10G hits that don’t feel great.” The full account comes from MotorBiscuit, with Heavy carrying the same quotes.

What exactly measured the 10G?

A mouthpiece. A team at the Wake Forest University School of Medicine built the sensor to record head motion and impacts, and Cup drivers have been wearing it since the 2023 season, per MotorBiscuit. It records linear and rotational G-forces, giving teams a read on what drivers actually absorb inside the car.

This is the same kind of data program that already changed a racetrack once. After drivers’ mouthpieces logged nearly 1,000 impact events in the Bus Stop at Watkins Glen in 2023, that section was reconfigured with smoother curbing. That precedent is why Zilisch’s numbers matter beyond one radio hit. NASCAR now has a data point, from a current driver, tying a specific corner to repeated high-G head impacts. The question is what the sanctioning body does with it before the 2027 season.

What is the dogleg, and why do drivers keep running it?

It is a bend on the Phoenix frontstretch, just past the start/finish line. Drivers cut low across the flat apron below it, ground that used to be grass, then climb back up onto the banked racing surface. The flat-to-banked transition is what does the damage, and it is also what makes the racing. The low line opens passing on restarts and side-by-side battles, and the dogleg is why Phoenix races the way it does.

Zilisch learned about the transition the hard way in the spring, when a qualifying run through the dogleg knocked his helmet crooked on his head. “I went into one and two, basically blind,” he said. Teams do not even practice the line, to protect the underside of the car. He has since made sure his helmet is set up correctly, but the physics did not change.

What could change at Phoenix?

Zilisch is honest about being stuck in the middle. “I struggle to want to let them change it,” he said. “But at the same time, you’ve got to do what’s safest for the drivers.” The dogleg is the passing zone; take it away and the racing suffers. His preferred direction is softer rather than removed: “I certainly think NASCAR could add turf and make it easier for us as drivers, and ease the burden of having to run the dogleg when you’re two or three wide or restarts or whatever it might be.”

The idea list since Sunday’s race, per On3 as cited by MotorBiscuit, runs from adding turf to enforcing a double-yellow-line rule that would keep cars out of the low line entirely. Zilisch’s bottom line: “Regardless, I’m sure NASCAR will make the right decision on that, and I just hope it doesn’t affect the racing at the racetrack because, you know, I feel like the dogleg is what allows for passing and helps kind of make the racing a little better.”

Why does this land hardest right now?

Because Phoenix has been a safety conversation all season, and this site has covered it. NASCAR is already letting teams change brakes at Phoenix after a season of wall hits, and the track produced two of the year’s flashpoints: Riley Herbst dumping Michael McDowell in stage one and Kyle Larson’s crash that cut his points lead from 49 to five. The dogleg data is the third Phoenix safety item of the year, and the first one measured in Gs. Zilisch’s Sunday confrontation with Zane Smith on the cool-down lap came on the same track, in the same weekend, for different reasons.

What happens next?

Nothing is decided. NASCAR faces a 2027 choice between turf, a double-yellow line, or leaving the dogleg alone, and the Glen precedent says data like Zilisch’s can force the issue. If another driver publishes sensor numbers, or if NASCAR announces a Phoenix change, this page updates.