ESPN's Tim Brewer answers your questions

We know NASCAR fans have a lot of questions from watching Sprint Cup races, so we went to one of our experts for some answers.

ESPN analyst and former championship crew chief Tim Brewer has many years of experience from working on NASCAR teams and has offered to share his knowledge and connections.

ESPN.com's NASCAR Icons gathered some of your questions earlier this week and Brewer obliged with the following answers:

Wouldn't it be easier to change a battery with the "quick-connect" if it was located under the hood [like a regular car] instead of under the wheel well?

Brewer: Yes it would be a lot easier, but it's not as safe. If it were on the right front corner, on impact it would probably burst the battery. So therefore all crew chiefs like the weight really low and over to the left side. And we always locate them on the left side of the car for the weight balance as well as it's a lot safer for them to be encased in a steel container beneath the car away from the driver.

It only takes about 30 seconds to change a battery because we have cam locks that holds the lid on the battery box, use a screwdriver to open the steel container, grab ahold of the handle on the back of the battery, pull it out and it unplugs with a quick-disconnect. Then we simply align the quick-disconnect and push the new battery back in there. And it takes no time to change them at all and the teams do rehearse that quite often.

A lot of guys have two batteries in the cars that you simply flip the switch from battery A to battery B. That's the quickest method of changing them, but some guys don't use but one battery and it's a really large battery. Other guys use two small batteries.

Not necessarily NASCAR [different tracks, different situations] but generally speaking, is it better on the brakes to brake lightly for a longer distance, or harder for a shorter distance?
Springfield, Mo.

Brewer: Depends where you're at. At Martinsville I'm a big fan of get on the brake, brake the car hard, get off the brake, let the car roll through the corner because you don't build up as much heat in the brake rotor, the car turns better through the center of the corner and you don't have the air pressure buildup in the tires that change the handling characteristics of the car. So I'm a big fan of get on the brake, get off, let the car roll.

Now, at Daytona and Talladega you will see the guys hold the gas wide open and basically reach over with their left foot and control the speed of the car especially in a draft. So it's whatever the driver feels comfortable doing. But you see a lot of brake dust on the wheels of these cars because the drivers always want to keep the momentum up at Daytona and Talladega, which you don't need brakes for the corners but you need to adjust your speed in the draft.

I've noticed from watching IndyCar and F1 races that the crew receives a lot of information from on-board computers. Is any of that used in NASCAR? If so, why is there so much importance given to communication between driver and crew chief?

Robb Angier,

Brewer: In the first place when you've got IndyCar and Formula One races they rely a lot on computers during the event to convey information. NASCAR does not allow on-board computers or information to be gathered by the driver and conveyed to the crew during the race. So we have to basically convey all the information to the driver that we want him to know through the radio communications.

Not to mention it's very, very expensive and NASCAR is trying to kind of cut back on some of those things. Believe it or not some of those steering wheels in F1 cars, they've got $100,000 price tags on them. They've got so much information, the crew chief can send them a message without repeating it on airwaves. He can basically send it to the steering wheel and the driver can literally read it right there.

They let us use any method of instrumentation for the car that we want to in testing. But they will not allow it on the cars during a race. And that's an effort of cost controlling the event as well as when you look at a lot of technology you can also contain traction control with that particular application. And NASCAR doesn't want anything to do with that because, it's like fuel injection systems, any time you've got computers on board the race cars people are very, very creative in manipulating a lot of things on the race cars. And NASCAR just does not simply allow computers on board the cars in competition.

Are fuel gauges illegal in NASCAR? I realize that a convention gauge would not work, but my idea is to mount the tank on four load cells. The registered weight could then be converted to gallons, or left in pounds.
Roger Wolf,
Birdsboro, Pa.

Brewer: And that's a great idea, but NASCAR doesn't allow anything to be information -gathering devices on the car during a race. Years ago we used to use a fuel-flow gauge that sat in front of the driver. And when you came into the pit stop we would put 22 gallons of fuel in the car and as the race went on when the driver got down to about 21.2 or 21.3 gallons he would start watching that fuel pressure that we were allowed to have in the car. But NASCAR does not allow you to have any kind of information on board the car.

In my years we've always measured the gallons and measured the weight of the fuel that we actually put in the car and we would do a fuel consumption run [meaning fill the car as full up with fuel as we could possibly get it, let the guy go out and run say 10 laps and we would get accurate fuel consumption information].

The crew chiefs are not guessing, believe me. They know exactly how far they can go. And the trick is being able to get every ounce of fuel out of the fuel cell.

So it's not that complex of a system, you just have to work the system to your advantage with gearing, carburetion, etc. It's not a defined science, but it's really an accurate deal when it comes to crew chiefs and engine tuners.