NASCAR tests six-speed sequential gearbox in 2021 Next Gen car

Independent suspension, bigger wheels, wider tires, new aero, and more

The NASCAR Next Gen car is on the way for 2021, the current series now helping test a raft of modernizing updates to some components that can trace their roots back to the early 20th century. As Jalopnik notes, prime among them is a six-speed sequential transmission in transaxle configuration. Right now, NASCAR Cup cars use a four-speed H-pattern – the same Andrews A431 gearbox available in the Hendrick Motorsports Track Attack track-day cars. Bozi Tatarevic did some sleuthing for a report in Hagerty that pegged a modified Xtrac P1293 transaxle as the likely culprit. The same model is the spec gearbox for Australia's Supercars Championship, where it offers six gears in a compact package weighing less than 140 pounds, a max torque rating of 495 pound-feet, and plenty of adjustment and gear-swapping options.

The present H-pattern shifter traces it roots back to a Borg-Warner unit from the 1930s. The Xtrac transmission, beyond helping NASCAR put another wheel in the 21st century, could help teams save money through not needing as many gearsets for the variety of ovals and road courses the series visits each year.

Assuming the Next Gen car goes with transaxle arrangement, that means the current solid-rear has to die, too. NASCAR has already confirmed an independent rear suspension, thought to be a coilover setup, and it's suspected the front suspension will go independent as well. Fans could see larger wheels and wider tires. The Gen 7 cars testing now have 18-inch wheels, up from 15 inches, on wider, lower-profile tires that have increased from 10 inches wide (28/10-15) on the Gen 6 car to 14.3 inches (365/35 R18).

Aerodynamically, the test cars have used a stepped front splitter, placed new vents in the hood, added redesigned side skirts, and bolted on a large rear diffuser. Beyond the track, there's wind tunnel work to get the rear diffuser to create more downforce, and new roof flaps and diffuser treatments to increase lift-off speed. The Gen 7 car at the second test also featured exhausts exiting from the bodywork ahead of the rear wheels.

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Out west at @ismraceway Day 2 testing the Next Gen Car. Here is a behind the scenes look of what I know so far!

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The testing regimen started at Richmond, a short track with lower speeds, then to Phoenix, where cars run higher speeds and loads, and on to Homestead in Miami, the next step up in speed, aero load, and a variety of racing lines through the banking. The drivers used during testing — Austin Dillon, Joey Logano, and Erik Jones — have made positive assessments but are still getting their footing after running Gen 6 cars since 2013. Logano said the Next Gen car "doesn’t come back until the driver steers the car back — it doesn’t fix itself. And that puts it more in the driver’s hands. And I like that piece. It’s going to be challenging, but I think you’ll see more mistakes on the race track which makes, in my opinion, better racing, and more passing opportunities."

Jones echoed those comments in Miami, saying, "We have a lot of sideforce in our cars now and there is a lot to lean on — when you get loose the car kind of corrects itself and straightens itself out. This car doesn’t really have any of that. The quarter panels are so short and there’s no offset in the car — it’s very symmetrical — so there’s not a lot to lean on in this car. I think a lot of the aero changes they’ve done are going to help as far as racing goes, especially racing in a pack. ... I think as far as development goes, there is going to be a lot more mechanical grip available than what we currently have."

The series' SVP of racing innovation said there'll be a Phase 3 prototype "which will take all of the lessons learned from the tests we’ve previously had. Once that is built, we’ll probably start using this car as a ‘second car’ to start simulating cars in traffic to see what we can learn from that." The next test happens in March after the race at Auto Club Speedway in Fontana, California. Assuming all goes to plan with the Next Gen car for 2021, NASCAR is pushing to go full hybrid for the 2022 season.

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