Some crew chiefs will say privately that drivers know just enough about the race car to be dangerous.
What may surprise you is most drivers agree. Usually they don't know enough to make much of a difference.
"It matters a whole lot less now," Mark Martin said of a driver's car knowledge. "There are so many layers of information and technology today."
Back in the day, it wasn't unusual to see a NASCAR driver grab a wrench and slide under the car. He knew as much as or more about every part on his machine as anyone on the team.
Times have changed. Leave the technical aspects of the job to the experts -- engineers, engine builders, fabricators and crew chiefs, etc.
Nevertheless, the prevailing logic is the more a driver knows about how the cars works, the better chance he has of winning races.
So can the driver help the team make the car better?
"In this day and age, I don't think so," Tony Stewart said. "I don't have a mechanical background, just for the record. These engineers and crew chiefs now have to almost be as smart as the guys that launch the space shuttle."
But Sprint Cup drivers, including Stewart, sometimes try to persuade the crew chief to go a different direction on making the car better. However, the crew chief's guess usually is better than the driver's.
"I've worked on race cars a long time," Stewart said. "But my father [Nelson] is almost disappointed. I'm almost the letdown to the family gene. I can do just enough stuff to screw up a race car."
Kyle Busch feels differently. He grew up in Las Vegas working on race cars with his brother, Kurt, and dad, Tom. That was 10 years ago, but Kyle has tried to keep himself current with the key aspects of making these cars faster.
"The technology has evolved," Kyle Busch said at Texas. "Things always change, so you have to think of the different dynamic of what all those do.
"Now it's evolved to the bump stops [which help cushion the suspension] with our Cup cars. What's the repercussion of getting down on the bump stop? Will it be harder on the tire? Will there be more camber? All that kind of stuff."
Busch, who owns a Camping World Truck Series team, believes he can speak the technical language needed to help his engineers and crew chief Dave Rogers.
"I think it helps a little bit," Busch said. "You learn all that stuff so you can give better information back to the crew chief of what you feel the car is doing."
All drivers do that, telling the crew chief if the car is too loose entering the turn or too tight coming off the turn, etc. But it doesn't help much unless the driver knows what needs to change to make the car faster, based on his driving strengths.
"I have the best knowledge of what I'm feeling," Busch said. "Dave doesn't know exactly what I'm feeling in the car, so I know what a track bar does, what a wedge does, what air pressure does.
"When they ask me about a change, they're like, 'Let's do wedge.' I'm like, 'No, that's not really going to help with what I'm needing.'''
However, Busch admits he doesn't always know the best adjustment.
"Sometimes Dave can look at the timing and scoring and say we're two-tenths off from where we need to be," Busch said. "I can say, 'Yeah man, I just need half a round of wedge.'
"And he's like, 'Dude, we need something a lot more than that. We're going to have to take a big swing at this thing to get it right.' You have to work back and forth. We work together on those decisions."
Working together helps, but after 30 years of NASCAR racing, Martin realizes new technology has made his input less of a factor than it once was.
"So much of it is based on simulation," Martin said at Texas. "Years ago, you told them specifically, 'Raise the panhard bar. Put a rubber in the right rear. It needs a smaller bar.'
"You don't do that anymore and you can't do that anymore. And crew chiefs can't do that anymore without the [computers] and the engineer. There are a lot of layers to it. People work specifically on one area instead of one guy that works it all."
Kevin Harvick has seen a huge difference in the importance of a driver's technical input since he started Cup racing 10 years ago.
"It's a lot less than it used to be," Harvick said. "I am a little bit slower than I used to be about being able to say I think we need to do this or that."
Harvick and other drivers still get angry during a race when all that data doesn't pay off in a fast race car.
"The biggest thing now is to go off the feel as opposed to what needs to be tighter or looser," Harvick said. "A lot of these simulation programs have been developed off what you feel. It's all about tendencies and characteristics your engineers learn."
Rather than study the mechanical aspects of the car, Denny Hamlin watches video of previous events to see how he can change things for the better.
Harvick also believes it's more important today for a driver to remember what happened in previous races to try to improve.
"Sometimes I will have to go back and watch the race," Harvick said. "But usually by the time I leave RCR on Monday, everything is pretty fresh and you have a mental image in your mind of where all the bumps and cracks and crevices are at a particular racetrack.
"Every Monday we talk about the characteristics. There are little things that you run through in your mind: What helped you, what hurt you, and you try to get a visual in your mind before you get to the racetrack."
No matter how much a driver knows about the car and how he conveys his knowledge, there's only so much he can do to change things during a race.
In the end, most drivers just want the guys at the shop to give them a good-handling car and an engine with plenty of horsepower.
"Everybody's got horsepower," Martin said. "I want some luck."
Terry Blount is a senior writer for ESPN.com. His book, "The Blount Report: NASCAR's Most Overrated and Underrated Drivers, Cars, Teams, and Tracks," was published by Triumph Books and is available in bookstores. Click here to order a copy. Blount can be reached at email@example.com.