Next Gen: Auto Club offers strong data on repairs, adjustments

Dec 05, 2023

NASCAR Cup Series

By Bozi Tatarevic

NASCAR.com

Published:

4 Minute Read

Editor's note: Bozi Tatarevic is a professional racing mechanic and pit crew member. He will provide technical analysis for NASCAR.com throughout the 2022 season.

Sunday's WISE Power 400 at Auto Club Speedway was an eventful race as drivers figured out the handling and cooling limits of the Next Gen car on the surface of the 2-mile oval. We saw some of those challenges and how much harder this car is to drive in practice as well as the race. Multiple cars spun from lift-off oversteer while cooling challenges started to show themselves for some teams in the early stages.

Lift-off oversteer is a condition where load transfer happens from the rear to the front tires of a car as the throttle is lifted, which causes the rear tires to lose traction and the tail of the car to snap around. This is also often referred to as the car snapping loose. It was something we saw starting in the practice sessions with multiple cars spinning and some ending up in the wall. One such case was the No. 4 Ford of Kevin Harvick which ended up hitting the wall with its right corner.

The Stewart-Haas Racing crew examined the damage on the car and decided to repair it instead of going to a backup. They were able to unbolt the deck lid and the composite rear bumper and quarter panels to find that the rear bumper assembly had taken most of the damage. Since the Next Car has modular chassis and body components, they were able to unbolt that rear bumper assembly and bolt a spare one and then reinstall the bodywork back over it. This would have required a backup car in the past as the chassis supports in the rear required cutting and welding for repair versus bolting on a new one with the redesigned car.

In all honesty all of that part went really well.

Last year would have been 1 week in the chassis shop, 2 days in heavy fab, 6 days on a body plate, 2 days in finish fab, 2 days in the body shop, a day in the scan room, 40 runs in the Hawkeye. https://t.co/Hc5YR5evlN

— Rodney Childers (@RodneyChilders4) February 27, 2022

Crew chief Rodney Childers took to Twitter to share feedback from their repair experience and stated that the repair process went well and shared that the at-track repair that the team completed on this car would have taken almost two weeks of work at the shop last year. According to Childers, it would have had to visit their chassis and shops for repair and welding of the damaged chassis components and sheet metal work on that body. Vinyl was re-applied once the composite body panels were bolted back on and Harvick went on to finish seventh in the race after having to start at the rear due to those repairs.

While Harvick had a fairly smooth start to his race after his initial troubles in practice, we saw the first yellow flag of the race come out as Kyle Busch lost traction with his No. 18 Camry when he touched one of the seams on the racing surface. As he was bringing his car back to pit road, we heard that his engine temperatures were hot and that was likely a combination of the new cooling configuration and possible debris on the track limiting some of that cooling.

The radiator duct assembly has a grille at the front and most teams run a secondary screen inside the duct before it reaches the radiator to trap debris. That duct now leads to the radiator and oil cooler which are sandwiched together and then a snorkel from that assembly leads to the engine air intake. This type of configuration discourages teams from taping the grille or trying to obstruct it in some other way because it could potentially reduce airflow to the engine intake, therefore, reducing power.

The way that teams can control how much air passes through the radiator now is with a blocker plate that can be installed behind the radiator to throttle some of that airflow. If a team chooses to use a radiator blocker plate then it must use a piece that is 0.062 inches thick with identical circular holes to allow the air to pass through. Teams can tune how much air passes by the size of these holes if the blocker plate is installed.

The likely scenario that we saw in the Kyle Busch incident, and a few others that complained of overheating, is that those cars likely had a throttle plate installed which would limit a certain amount of airflow. That combined with sandy debris we saw at Auto Club limited airflow to the radiator enough to cause engine temperatures to rise. Teams attempted to resolve some of this by clearing the grille area during pit stops but that is the limit of what can be done in race conditions because the blocker plates cannot be removed during the race and they are not allowed to be adjustable.

Auto Club was definitely a track for collecting data on repairs and adjustments and we’re likely to see improvements based on that information as teams head into Las Vegas Motor Speedway this week.