NASCAR has quietly reinstated a significant mechanical advantage for its top-tier Cup Series organizations. This move is already sparking debate within the garage about competitive balance and the sport’s ongoing efforts to contain costs.
The sanctioning body has officially amended its rulebook to permit each organization to have one backup car with an engine already installed, a practice that was previously banned as a measure to control spending.
NASCAR’s New Rule for Backup Cars
This reversal comes after a season marked by relentless on-track turmoil. Teams have been forced to pull their backup cars out of the haulers numerous times due to crashes in practice and qualifying.
But without a pre-installed engine, the process became a brutal race against the clock. Crew members faced grueling, all-night workloads to prepare a functional car for Sunday, scrambling to install an engine from scratch in a high-pressure frenzy.
“NASCAR is allowing Cup organizations to have one of its backup cars to have an engine installed in it (one per organization). Previously, they were not installed as a cost-saving measure.” said Bob Pockrass, motorsports reporter for Fox News.
NASCAR is allowing Cup organizations to have one of its backup cars to have an engine installed in it (one per organization). Previously, they were not installed as a cost-saving measure.
— Bob Pockrass (@bobpockrass) November 15, 2025
However, people were quick to notice something about the reversal of the new rule. “So the poor teams gonna have to have an engine installed in case the rich teams wreck?” said a fan.
The new regulations, buried deep within Section 14 of the rulebook, aim to add structure to this chaotic process. NASCAR will now require teams to declare all their backup engines for an event beforehand.
In a significant twist, the total number of these backup engines is now capped. Section 14.7.1.J states that the maximum allowed will be “half of the total number of Teams in the Event supplied by the same engine builder,” with fractions rounded up. Crucially, all teams using that builder’s power must share from this single, limited pool.
This rule change, while presented as a logistical fix, inherently benefits the sport’s wealthiest and most prominent teams. Organizations fielding multiple cars can now have a ready-to-race backup for each entry, a luxury that comes with a steep price tag for smaller, single-car teams.
The pre-installed engine represents not just time savings but a massive tactical advantage, turning a potential all-night ordeal into a simple car swap.
Further complicating the logistics, the rule introduces a strict protocol for engines that are not pre-installed.
If a team’s backup car is not at the track or if it needs to use a different engine, that power plant must be presented to officials for inspection and sealing before it can leave the premises for installation.