The NASCAR Next Gen car introduced in 2022 presented a breakthrough in the world of stock car racing. It moved away from a traditional 4-speed manual gearbox to feature a 5-speed sequential manual gearbox. With only the Cup Series getting to use this advanced technology, the lower tiers carried on with life using the 4-speed manual.
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Both transmissions are required to meet high standards of operation and comprise heavy-duty gears to withstand high power demands. But here’s a magnified look at the small differences between each. The Next Gen transmission was developed by Xtrac and is known as P1334. The transaxle utilizes a common bell housing that holds the clutch and the flywheel in a single unit.
The manufacturer reasoned that the decision to switch to a transaxle instead of the traditional mounted transmission was to allow the driver’s seat to be closer to the vehicle’s centerline. This is believed to improve driver safety while also offering a more balanced weight distribution. Xtrac has also stated that this setup would aid with future electrification plans.
Down below in the Xfinity Series, cars still use the traditional 4-speed manual. This transmission is durable and holds massive historical importance. Various companies such as Xtrac and Andrews manufacture these units, but they are all similar in architecture. They allow different gear ratios to adapt to different tracks, but the fourth gear is always a 1:1 ratio.
They also feature an internal oil pump to help with circulation throughout a race. One crucial difference between these two systems falls in the shift pattern. For the Next Gen cars, NASCAR got rid of the traditional H-pattern transmission. They still have a floor-mounted gearbox, but it only has two positions. Drivers push it forward to downshift and pull it back to upshift.
These new levers introduced a third position as well. They can be pulled up to engage in reverse. Like the 4-speed manuals, the 5-speed sequential transmission comes with a clutch pedal. However, they don’t come into much use during a race since drivers just match the upcoming gear to the engine’s RPM to shift.
Xtrac has posted a list of advantages that the transmission on the Next Gen offers in comparison to its counterpart. It is a relatively more cost-effective and reliable solution, it has active oil cooling ports, it has fixed gear ratios that reduce maintenance requirements, and so on.
