Crew chief Bruce Cook answers your questions

ESPN.com's NASCAR Icons took some readers' questions and went to Germain Racing's Nationwide series crew chief Bruce Cook for the answers.

Cook has worked in racing for 20 years and is the crew chief for the No. 7 Toyota driven by Mike Wallace in the Nationwide series this season.

You can also hear Cook during ESPN2's coverage of the Nationwide series race Friday [8 p.m. ET start] at Daytona International Speedway when Wallace will be the in-race reporter.

Here are your questions and Cook's answers:

What is the purpose of the small strake/fin that extends down the driver side of the car along the roof line onto the rear glass. I thought it was an aero surface for left-turning ovals but it was on the Cup cars at Sonoma. What's going on with the left side air that's not happening with the right side air? Thanks.
Chris C.,
Fairfax, Va.

Cook: Chris, the piece is actually called a shark fin and there's one on each side of the car. It adds aero stability.

When the car turns sideways, either in yaw through the corners or from spinning out, the shark fin adds stability to turn the car back to straight. The shark fin is bigger on speedway cars because the cars are more affected by aerodynamics and they travel a lot faster.

I hear crew chiefs ordering a change of as little as a quarter pound of air in the tires. Tell the truth, you're just trying to make your job sound more difficult than it really is. A quarter pound can't really change the handling of a car, can it?
Ben Plantz,
Delavan, Wisc.

Cook: Ben, actually a quarter pound of air is worth 25 pounds of spring rate in a tire, which presents a significant change in tire that the driver can feel.

A quarter pound of air is also worth a pound and a half of buildup in a long green-flag run. That can have a huge effect on a tire by the end of a green flag run -- 150 pounds of spring-rate difference.

Now that Toyota has made its mark in NASCAR, how soon do you think it will be before the other foreign car makers throw their hats in the mix?
David Fabi,
Yonkers N.Y.

Cook: David, I've not heard of any talk in the garage about anyone new joining the field.

With that said, I would guess it would be four to five years out before any new carmakers joined the NASCAR ranks, given the time it would take for research and development.