|NASCAR tested a low-downforce aero package at Darlington, Sept. 5, 2015.|
Credit: Charlotte Bray for Skirts and Scuffs
In 2015, NASCAR introduced a high-downforce, lower-horsepower package. Drivers and fans alike have been vocal in their criticism of the racing produced by this rules package. A high spoiler, large splitter and large radiator pan create racing where aerodynamics play the larger part in how cars handle. Drivers feel the package takes the driving out of their hands, and complain they simply cannot pass each other as in years past.
"You just can't pass people," has been a common refrain during post-race interviews this year.
Clean air is king, and if you're mired in the middle of the field, your greatest hope of passing is on restarts. Because of the lower horsepower and high downforce, drivers are forced to be on the throttle almost constantly. The cars are slower on straights and faster in the corners, and extremely aero-sensitive. The cars are too easy to drive, almost driving themselves. Drivers want to race, not chase each other around the track with little hope of advancing.
Fans criticize the racing as unexciting. They want more passing, more lead changes and better finishes.
|A shortened spoiler and smaller splitter characterize the low-downforce package.|
Credit: Charlotte Bray for Skirts and Scuffs
They got their wish.
After months of collaboration with teams, drivers, manufacturers and Goodyear, NASCAR has come up with a rules package that promises to put control of the cars back in the drivers' hands. Cars will be harder to drive, with less grip and more throttle-break changes. Additionally, the 2016 base rules package provides an opportunity for Goodyear to safely develop track-specific tires to complement aerodynamic effects for optimal racing.
The base rules package does not include the individual track specifications (e.g. tire compounds and drivetrain rules) which will be released at a later date.
Below are the rules package specifics per NASCAR.com:
All tracks except superspeedways (Daytona, Talladega)
- 3.5-in. high rear spoiler (down from 6 in.)
- 0.25-in. front splitter leading edge (down from 2 in.)
- 33-in. wide radiator pan (down from 38 in.)
- Rear gear ratios adjusted to maintain 9,000 RPM maximum engine speed
- 1.38 third gear ratio for tracks smaller than 1.25 miles
- Engine roller lifters replace solid lifters (adds ~10 horsepower)
- Restrictor plate reduced from 29/32 in. to 57/64 in.
- Standardized radiator / oil cooler (effective July Daytona race)
- Digital dash in all vehicles (previously optional)
- Fire suppression system activation cable routed to dash or right-hand side leg board
- Right-hand side double NACA duct to cool drivers at tracks where side window is used
- Seat belt restraint systems must meet SFI 16.6 specifications
Downforce changes explained
Rear Spoiler: The rear spoiler redirects air flowing over the car, reducing lift. The higher the spoiler, the more air is redirected, and thus more downforce. A shorter spoiler provides less downforce on the rear tires, leaving them with less grip on the racing surface.
Front Splitter: The front splitter affects downforce by "splitting" the air pressure at the front of the car. The air hitting the bumper becomes high pressure, and the air under the car becomes an area of low pressure. This pushes the front end of the car toward the track, creating more downforce and thus traction. The more a splitter extends from the bumper, the more downforce is created. The smaller splitter will reduce that front downforce on the front tires.
Radiator Pan: The radiator pan, or splitter extension panel, is a flat piece of metal which lies under the radiator right behind the splitter. When the air flows under the splitter, it continues straight past the smooth radiator pan, increasing the low air pressure under the car and further pulling the car closer to the racing surface. One negative effect of the radiator pan is that, during an accident where the car goes airborne, more lift is created (the opposite of what happens when the car is right side up) and can cause a more dangerous wreck, much as Austin Dillon's No. 3 car did at the July 2015 Daytona race. The narrower radiator pan will allow more "choppy" air to flow under the car, reducing downforce and the risk of a dangerously airborne car.
What are NACA ducts?
NACA ducts are low-drag inlets which allow air to enter the cockpit of the car. After the Darlington and Kentucky tests of the new aero package, drivers advised NASCAR that their cockpits were exceedingly hot -- some interiors reached temperatures of more than 160°. By increasing the number of NACA ducts on the right-side window at tracks where one is installed, NASCAR expects more air to flow into the cockpits to help keep the drivers cooler.
If Darlington and Kentucky's races are any indication, the racing next year should be more exciting, with more passing and closer finishes. Cars will be less grippy and more apt to slide around the track. Drivers will have to use every bit of their skill and concentration to keep their noses pointed in the direction they want to go. Ultimately, that's what any driver or race fan wants to see: their favorite drivers going all out, working for just one more position and with their eyes on the checkered flag.