ESPN's Ray Evernham answers your questions

NASCAR Icons readers filled the mailbag with questions for ESPN analyst Ray Evernham and he responded to some of the best ones below.

Evernham, who is co-owner of Gillett Evernham Motorsports, started out racing modifieds before making his name as a crew chief. He won three NASCAR Cup championships and 47 races with Jeff Gordon and Hendrick Motorsports in the 1990s before venturing into ownership in 2000.

Kasey Kahne, Patrick Carpentier and Elliott Sadler drive Dodges for Gillett Evernham in the Sprint Cup series this season.

Here are your questions and Evernham's answers:

With all the automotive technology today, NASCAR has not evolved in two areas, computer-controlled engines and non-carbureted engines, why? Often I hear NASCAR talk about running stock cars as manufactured by Detroit automakers. Not so. Detroit has not made a carbureted stock car in many years.
Wayne Koehn,
Atwater Calif.

Evernham: NASCAR still controls that area very tightly. They feel like they can better inspect a carbureted engine than a computer-controlled engine. With an electronically controlled engine they believe that we'd have too much room to make changes. And until they come up with a way that they can inspect and control the rules surrounding computer-controlled engines, electronic fuel injections and mapping systems and things like that they're not going to approve it. Eventually I believe it's going to have to happen.

I think the other reason that they do that is because they want more in the driver's control rather than the engineer's control. And if you have to do it with a carburetor it makes the driver use his foot a little bit more carefully.

Mr. Evernham: One of the best books I've ever read was "The Physics of NASCAR." It's obvious Diandra Leslie-Pelecky learned a great deal during her time with the No. 19 team. What did you and the team learn from her and what changes to the GEM approach to car building and setups came out of her time with the team? Cheers!
Kenny Solomon,
Pembroke Pines, Fla.

Evernham: She was certainly a casual observer. And we didn't pick her brain too badly, but basically racing's all about the laws of physics ... period. Even though you don't think they obey the laws of physics every week, they do.

And everything that we basically do from the internal combustion engine, to aerodynamics, to mechanical grip still comes down to the laws of physics ... weight transfer, acceleration, de-acceleration, all those things. Working with Leslie gave a clearer sense of formula and reality to our engineers. And again everything that we do in motorsports, whether it's pit stops or the actual racing itself, it still is about the laws of physics -- movement and things like that.

Has the entire exhaust system on the cars been mandated by NASCAR? Or is there room there to experiment, on the chance of finding a few hp?
Kevin Wilson,
Peterborough, Ontario

Evernham: They have mandated some of it, but there is some room to experiment with the size and shape of your headers, the length of your tailpipes. NASCAR has mandated some of the shapes and length of tailpipes but there is still room to experiment in the exhaust area with the headers, primarily the length of the primary tubes and the secondary tubes and how you arrange your collectors [how all the pipes mold in together]. There is not a lot of room but certainly some because every engine wants something a little bit different. There are engines that require, when we go to a short track, running a smaller primary or a bigger primary depending on the power band that you want.

Hey Ray. You have said before that when Bill Elliott decides to run his last race, he will do it in the No. 9. With Bill Elliott's career winding down, I was wondering if Elliott really is going to be able to run the No. 9 in his last race?
Nick Kroplin,
Huber Heights, Ohio

Evernham: Well, Bill's just got to tell us when that is. I thought he did it at Homestead in 2003. But he keeps popping up.

Certainly now there's more people that would have to be involved in that decision with George Gillett being a partner and the folks at Budweiser now being on board we'd love to provide Bill Elliott the opportunity when he's ready, when he's really ready to run his last race because I think he's somewhat retired three or four times now.

So until he's ready to run his last race he's got to let us know. But then it's something that certainly I would love to do. I think that the fans would like it and Bill's been a big part of Gillett Evernham Motorsports, so if it was all possible we'd like to work that out.