When Dodge brought its Viper ACR to the production car party back in 2015, the automaker also brought a long a sheet filled with brand new track records. The ACR broke production-car lap records at 13 different tracks. These weren't rinky-dink little local circuits that you've never heard of, either. We're dealing with the likes of Mazda Raceway Laguna Seca, Road Atlanta, Virginia International Raceway, and more.
Today, Engineering Explained is here to break down the physics of how the Viper ACR was able to accomplish such a feat.
It all centers around serious grip and massive amounts of downforce. Sure, it's nice to have a V-10 that puts out 645 horsepower in a car that weighs less than 3,400 pounds. It's the grip and downforce, however, that helped the ACR push past other insanely quick production machines that have great power figures and even greater price tags. Our host Jason Fenske uses the incredible Ferrari 488 GTB for comparison.
Dodge fitted the ACR with an Extreme Aero package. This equips the Viper with an adjustable rear wing that is 6-feet wide, has 7.69 square feet of surface area, and produces an amazing 1,101 pounds of downforce at 150 mph. The front splitter has a detachable extension so you can drive it on the street without destroying it anytime you near the smallest of road imperfections. Dive planes on the front fenders push the car closer to the pavement as well.
The drawback of all that aero? The Viper moves like a brick through the air with a 0.54 coefficient of drag, and that limits its top speed to 177 mph. The Ferrari, on the other hand, can top 200 mph. Turn corners at speed, though, and the benefits are obvious, as Jason shows.
Be aware that this is a 21-minute video, and Jason dives deeply into the math. We highly recommend that you take the time to watch it, though, as you will understand more about how cars go fast around a track than you ever thought you might.