The unveiling last Monday of Toyota’s new redesigned race car for 2017 got a little lost between Junior’s wedding and Carl Edwards’ surprise ‘stepping back’ from NASCAR. But every time a manufacturer redesigns and engine or a body, it opens up a giant task for NASCAR.

The Level Playing Field

A new race car is always a delicate proposition for NASCAR because they must ensure the vaunted ‘level playing field’ stays level, while addressing manufacturer concerns about fidelity to the look of the street car. Conspiracy theories aside, it does NASCAR no good to have one manufacturer run away with the series.

The History of Equal vs. Equivalent

In the 50’s and 60’s, the place to get an advantage in NASCAR was engines. As usually happens, the easy gains were made quickly. Once the low-hanging fruit was picked, competition ramped up to the point where people spent a lot of money to get tiny performance improvements. NASCAR addressed the problem by making engine rules to limit what teams could do to their engines and how much money they could spend.

Keeping engines approximately equal is relatively straightforward because there are easily quantifiable metrics like rpm, horsepower, and torque. You can run a couple engines from each manufacturer on a dyno in a short period of time and emerge with a couple of graphs that make everyone feel like no one is getting away with anything.

Aerodynamics

When NASCAR limited what they could do to their engines, teams turned in the mid 60’s to a new area: aerodynamics. The AeroWars of 1969-70 featured Chrysler vs. Ford and the era of the winged car.

This was the first big step in moving from stock cars to purpose-built race cars. And, as everything in NASCAR tends to do, it quickly got out of hand. The manufacturers produced limited editions so they could say that they were still racing ‘stock’ cars, but it quickly got out of hand and very expensive. In 1972, NASCAR made big changes to the rules governing car bodies and we went back to more reasonable facsimiles of stock cars.

That isn’t to say that teams didn’t keep putting a lot of effort into aerodynamics. They just had a smaller box to work in.

Not to suggest that engines are trivial, but aerodynamics is an entirely different beast in terms of complexity. I find aerodynamics one of the more difficult aspects of NASCAR to explain (and sometimes to understand) for two reasons.

1. It’s difficult to see what’s happening without the aid of a wind tunnel or complicated Computational Fluid Dynamics programs, neither of which the average person has readily accessible to them.
2. It’s very complicated. The differential equations governing even simple aerodynamics are pretty hairy-looking. When you start making all the additions to the theory to take things like turbulence into account, you are dealing with something that only people with Ph.D.-level experience can understand.

Aerodynamics is how air flows over a surface. When you’re dealing with a simple shape like a teardrop or a block, you can sort of see how things happen.

The surface of a racecar is an entirely different matter. It’s irregularly, curvy and three dimensional. It’s a series of shapes and how air flows over a shape depends on what shape it’s coming off. It is not unusual for a team to take a car into a wind tunnel and find that changing some panel by an eighth of an inch makes a huge change in the overall aerodynamics of the car. That’s why teams spend so much money on Computational Fluid Dynamics simulations and aerodynamicists.

Equal: The COT

By the mid-2000s, aerodynamics had gotten out of hand again. The Generation 4 car (aka the ‘Twisted Sister’) became an object of ridicule for looking like it had been in an accident before it even got on the track. But there were other considerations now: A renewed interest in safety, not only in terms of personal protection like HANS and belt design, but also in terms of what the car could do to protect the driver.

In 2008, NASCAR introduced the “Car of Tomorrow” (the Gen-5 car.) A primary reason for the redesign was a massively improved chassis that made a huge step forward in terms of safety. The chassis was standardized to the point where teams were given Autocad files and told not to change anything — or else.

That principle extended to the body. There were some tiny differences in styling, but on the track, the only way to tell if you were looking at a Chevy or a Ford was to look for the nameplate. Fans (who couldn’t see the new chassis) derided the new car, as did a number of drivers. Teams that tested to see if NASCAR was really serious about this ‘don’t modify the body’ thing learned that they, indeed, were. The Gen-5 car was a huge improvement in safety, but introduced new problems.

1. Manufacturers didn’t like that the cars looked the same. It was contrary to the whole point of their being in NASCAR.
2. Fans didn’t like that the cars looked the same.
3. The car’s aerodynamics made it very hard to pass, which impacted the quality of the racing.
4. The cars were less robust, so even a minor accident could throw a driver out of contention.

By 2010, the wing that had been introduced was scrapped and the spoiler re-instated. In 2012, they re-did the front splitter. The manufacturers really pushed to be allowed to include the styling details and cues from their street cars in the race cars.

Equal was not going to cut it.

Equivalent: Gen-6

Starting in the (then Nationwide not XFINITY) series, NASCAR brought back manufacturer identify and made the cars look more like their street counterparts.

That left no way for NASCAR to make the car’s aerodynamics ‘equal’. If the shapes are different, the aerodynamics are different. Measuring those differences is hard for two reasons.

1. Aerodynamics, as mentioned before, is complicated. A car has a complex surface and not even the smartest engineers can predict in advance exactly how a car will behave aerodynamically.
2. Aerodynamics is dependent on speed. As we’ve discussed before, the aerodynamic force changes with the speed squared. Two cars that have the same general aerodynamic behavior at 90 mph could have very different behavior at 150 mph. We’re talking hours and hours of measurement to completely characterize two cars aerodynamically.

So NASCAR, the manufacturers and the teams decided on a principle of equivalence. They came up with a few measurements that would give everyone baseline equivalence; for example, the amount of front and rear downforce. Different cars can generate that downforce in different places, but the magnitude of the downforce is the same.

I love the idea of equivalent. It gives teams more latitude to innovate. Sure, it’s a constrained box, but it’s a box. We didn’t have that in the Gen-5 car at all. Plus, you have to admit that today’s cars look much better than the COT did.

Toyota’s New Nose

I haven’t heard much talk about the fact that Toyota will show up at Daytona this year with a brand new car design. The 2017 NASCAR Toyota Camry race car is modeled on the 2018 production Camry, which will be available starting in August of this year. The two are compared in the picture at the very top of the blog.

The teams were much more involved in designing this car than they had been in the previous cars. Toyota Racing Development had taken the lead with consultation from Calty Design Research. This time, Toyota availed themselves of the best racing aerodynamicists, who work for the race teams. I understand that Joe Gibbs Racing made the first prototype (a top-secret project) and were very proud that it passed all of NASCAR’s compliance tests on its first attempt.

Toyota took an interesting tact: they made a conscious attempt to make the production car look more like the race car, not unlike what Chevrolet has done with the Corvette. If you wondered why the headlight covers disappeared from Corvettes, you have Corvette Racing to blame (or thank). They were an aerodynamic hindrance. As always, Toyota’s goal was maximizing downforce and minimizing drag.

So here’s a comparison of the 2013, 2015 and 2017 Toyota noses (from top to bottom). You can see the changes from 2013 to 2015 just in terms of the stylizing and cue from the production car. I like the head-on shots because you can really see the left-right asymmetry of the car.

You have to ignore the decals, because some of them give the illusion of shape, but they’re actually flat. The most noticeable difference (to me, anyway) is the styling on the sides of the hood, which looks very different from the 2015 to the 2017 model. I don’t know how it’s going to perform, but I think you have to admit that it’s a darn nice looking car — especially when you put it right next to the 2013 model.

Just for comparison, here’s the rear ends of the 2015 and the 2017. The 2017 is on top in this picture.

They’re not at the same angle, so it’s hard to make a lot of comparisons, but you can (again) see the asymmetry that is so important to cars turning left. It does, however, give you a graphic picture of how much the spoiler has shrunk!

Motortrend has a very nice article about the new racecar – and they have a picture of the inside of the car that gives a great view of the new digital dash. Look at all the carbon fiber…

If All Things are Equivalent…

Then the new nose shouldn’t make much difference, right? I mean, it matched all of NASCAR’s requirements for equivalence.

I wouldn’t go quite that far. When a designer designs a car, they are looking not just at that year, but toward the future. In the last two years, NASCAR has made a clear move toward lowering overall downforce. They’ve even stated their ultimate target. Toyota designed their new car knowing where the target was and where it will be moving.

Here’s the other thing: The holy grail in NASCAR right now are modifications that don’t become apparent until the car is at speed. Why? Because they are notoriously hard for NASCAR to police. We’ve seen this in rubber grommets at attachment points (now outlawed) that allow the rear of the car to skew out when the car is cornering — but which looks totally normal when standing still. So the car follows the letter of the law and passes inspection, but gets an advantage on the track.

Aerodynamics is the place to exploit this: There are shapes that might not give you much difference in numbers during a wind-tunnel test in which the car is head-on to the wind (i.e. unlike the car’s attitude while turning) and there are no other cars in the immediate vicinity.

So we won’t actually know whether Toyota’s new design gives them any advantage. The one thing I can say with certainty is that the other manufacturers are busy thinking about their redesigns and will be watching Toyota to see if they found anything that works — or doesn’t.