Stock Car Science

Congrats! If you’re reading this, it means that they turned on the Large Hadron Collider without creating any black holes…yet.

If there’s one question I get when I speak it is: “If they were going to design a car from scratch, is the new car really the best they could do?” My favorite phrasing of this question is “If we can put a man on the moon, why can’t NASCAR build a car that can race? (Uh, how much money did that cost, how long did it take and how many people lost their lives in that endeavor?)

At this point in the season, I think everyone recognizes the big problems with the new car:

• The center of gravity of the new car is a couple of inches higher than in the old car. That exacerbates load transfer, which means that the car has overall less grip.
• NASCAR instituted a minimum and maximum height for the splitter. The old valence only had a minimum height. The new restriction reduces the front-end travel on the car, making it harder to get the car in the aerodynamically favorable “hound dog” (nose down tail up) position. The end result: less grip.
• The total aerodynamic downforce of the new car is less than the aerodynamic downforce of the old car–again, the end result being less grip.
• NASCAR tightly legislates body shape, precluding the teams from making the body asymmetric. An asymmetric body can help the car turn better. This removed one of the main tools teams had to get ahead, as very small changes to the body can produce big changes in aerogrip.
• The new car is much more ‘finicky’ (as Chad Knaus puts it) than the old car. We’ve seen a couple of examples where teams that are usually really good got to the track and "missed the setup". Even with three practices worth of tweaking, they could never get the car handling correctly.

These points have been well documented, so let’s put a moratorium on the cranky articles that do nothing more than complain about the car, or even complain that the right people aren’t complaining about the car. My father had a policy: If you can’t suggest something better, you don’t have the right to complain.

‘Better’ implies realistic, so all the calls to go back to the old car are banned under my moratorium as well. It just ain’t gonna happen. Can you imagine the teams scrapping two years of work–and inventory–and trying to buy back all those chassis from the ARCA teams?

Besides, most of the teams will tell you that they’ve learned a lot about the new car since the beginning of the year. Few teams bring back the same car to a track because they’ve made so many changes that the car from the first race–even a car that wonthe first race–wouldn’t be competitive.

There are two big components to my solutions. The first time. Teams used to have twenty races worth of data from which to determine set ups. This year, they have at most three races worth of data. It’s not entirely surprising that teams miss the setup sometimes. Every time I talk with engineers, they tell me how much more they understand about the car. That aspect is just going to work itself out with time; however, the narrowing of the ‘grey area’ is another matter. The primary ‘grey area’ teams used to have was manipulating the body shape. They don’t have that any more, so they have to focus on other (often less familiar) areas. Some crew chiefs complain that NASCAR is getting to be too much like a spec series, where everyone gets the exact same equipment. We’re pretty far from a spec series, but the series is definitely headed more toward that direction than I think most of us would like.

For what it’s worth, here are my suggestions for what NASCAR ought to be considering as they start to write the 2009 rule book. All of my suggestions end tied with one common thread,which is purposely making the box in which teams can work bigger.

• The CG has to be lowered. Teams are searching for even small changes in the weight distribution. Some teams are replacing metal dashboard panels with carbon fiber panels to save 6-9 lbs of weight that is located fairly high on the body. (This sort of defeats the idea of decreasing cost because carbon fiber is expensive.) A smart team would contact the Tegris people (the material from which the splitter is made). Milliken (the folks who make the splitter) recently launched a molded kayak made from Tegris that is strong and lightweight. The primary use of Tegris now is as sheet goods (cutting the splitter out of a flat piece), but Milliken has some really nice molding technology. Tegris will save weight without costing as much as carbon fiber. But these are small changes. Why not just make the car another 100 lbs heavier and let the teams put all of that extra weight on the left side of the car if they want. Yes, the cars would be a little less peppy (Not even NASCAR can outlaw F=ma), but if the handling improves, you’re going to get better racing and happier drivers.
• Give everyone the same basic engine block and cylinder head, but allow them a wider range of variation in how they can modify the components. Wait, you say–isn’t that moving into a spec series? I’m arguing it’s not because, although they’ll have the same basic components, I would give them a much larger box within which to work. For example, allow variation in bore dimensions (not volume, but aspect ratio) and a wider range of intake manifold geometries. I’m tired of the whining about how one manufacturer has an advantage because of their basic engine design. You shouldn’t be at a disadvantage because your manufacturer hasn’t gotten a new engine approved yet. Give all the teams the same basic components, enlarge the box and then let the engine guys do what they can to get as much horsepower as they can. There is nothing sacred about these engines: It’s not like the manufacturers pull a few off the production line and ship them off to Charlotte.
• Instead of mandating two or three rear-end gears, give the teams a continuous (and wider) range of gears to use. That will further broaden the box for the engine while keeping a limit on the rpm range.
• The car needs more downforce, so the aerodynamic issues have to be addressed. The NASCAR R and D center has a handful of engineers. Asking this small group of people to design a brand new race car and have it work perfectly is utterly unrealistic. On a major team, about 10% of the employees are engineers, which means over the last two years, there have been probably 350-450 engineers thinking really hard about how to make the car go fast. Some of those people are very smart aerodynamicists. NASCAR needs allow each team one participant, lock them in a room with the NASCAR R and D staff, sit them down around a table and let them propose how to change the car’s aerodynamics. They’ll bring a wealth of ideas and information. Give them as their goal coming up with an aerodynamic ‘box’. It would be a fun meeting to be at because different teams have been focusing on different aspects of aerodynamics. No one will want to reveal their closest-held secrets, but I bet a consensus of common issues would emerge that would improve the aerodynamic issues such as downforce and, most importantly, the effect of sideforce on turning and passing.
• A lot of people are calling for a return of the spoiler. The problem is that the higher greenhouse doesn’t let the air hit the old spoiler as well as it did in the old car. Don’t think NASCAR isn’t concerned about the wing. Notice that the Nationwide COT (NCOT) is keeping the spoiler, but the spoiler has a different shape. Since the NCOT uses the same chassis and presumably has the same height issues, here’s a chance for NASCAR to do some experimenting with spoiler shape. My rental car in Richmond had a wing in the back and I must say that not being able to see out the rear window is really annoying.
• If they’re going to reserve a room for the aero think tank, they might as well get suspension experts together as well and ask for ideas on how much they can increase the front travel without totally obviating all the work the teams have done with bump stops and chassis stops. Again, put reps from the different teams in the same room and let them say as much as they are willing to say in front of each other. If someone bright takes all of those ideas and puts them together to find the overlaps, they should end up with a box within which the engineers have plenty of room to experiment.

I’d like to close this week by thanking all the folks at Richmond: My hosts at VCU were terrific, especially Wanda, the administrative assistant in the History department who took care of all the logistics. I had a couple good meals and enjoyed myself greatly, even if my shoes still are a little damp. The people in Richmond–as in most places in the South–are very friendly, but especially so at the track. That’s a big difference from some places, where track security seems to enjoy telling people "no". The folks at RIR kept smiles on their faces, even as the rain moved in Friday afternoon and they realized they’d have to postpone the race. As fan-friendly as the larger tracks are, I really like the smaller tracks like Bristol, Richmond and Martinsville, where getting a dent in your fender doesn’t end your day. I look forward to returning to Richmond and getting to see a race there in the future.