LAS VEGAS --- Hail, rain and strong winds pushed Monday's test session at Las Vegas Motor Speedway into the night. Even if it was nearly impossible to see the cars along the backstretch, teams were in a frenzy to gain as much information as possible on NASCAR's new full-time race car.

The Car of Tomorrow has created a new set of challenges in the Sprint Cup Series. Until everyone has a better understanding of it, teams are willing to work sunrise to sunset.

Most teams have learned to accept the new car. It's wider and taller than a traditional stock car. The bigger car not only has additional safety features, it's supposed to reduce the dependency on aerodynamics to enhance competition.

Now teams have shifted their attention to finding speed. So far, that's proven to be a difficult assignment.

"You know, the car itself is the 800-pound gorilla now, you know, in the room," Dale Earnhardt Jr. said. "That's just going to take a while for us to science it out and understand."

One of the car's benefits is it's supposed to level the playing field. There's no real difference between a Ford, Chevrolet, Dodge or Toyota.

That sameness is also its biggest curse.

"The problem is, the cars are too equal," Carl Edwards said. "We found out last year you could be 23rd on the track, running the same speed as the leader. Everyone's running the same speed. The cars are so equal it's really hard to pass."

Rules also restrict the way teams can adjust their cars. Crew chiefs Chad Knaus and Steve Letarte were both suspended for six races last year for expanding their front fenders by a fraction of an inch. Teams now realize the only way to find speed is adjusting the front bumper or with shock absorbers and springs.

"You're trying things and you're trying to answer questions," Jeff Gordon said. "The bottom line is you're always trying to find speed and ways to go faster."

The challenge is to be fast when the tires are worn. That's where teams said the new car seems to level out.

"The only true way you know who's good and who's not is to look at five and 10 and 20 lap runs of a team or a car," Gordon said. "So you do have to be careful. We focus on our own program. At the end of the day, I feel like we were a tenth (of a second) or two off. But we're trying a lot of things. I feel like the speed is going to come and I feel real good about it. Guys can put up a great first lap, but if they fall off after five laps they fall off.

"This car punches a big hole. When it does that, it's going to be tough to ride in right behind the guy in front of you. But the side-by-side seems to be excellent. The draft that you get down the straightaway is really good. I'm hoping that those things create some great passing and overtaking and great racing. That's my hope. I'm optimistic about it.

"You're going to see everyone progress every race as each year goes by."

Kyle Busch was one of the fastest drivers during the test at Daytona International Speedway, and he continued to be quick at Las Vegas.

"They're all important, but this one, California and probably Atlanta, the one we had last fall, are the most important tests," he said. "We've been trying hard on these cars to get more grip in them. We are still learning and trying to make it better."