Week in and week out, whenever there is a snooze-fest of a NASCAR race, there is a section which always blames a lack of horsepower and/or the aero package that the car ran for that particular race. The problem is that if you map the fan survey which is regularly run by The Athletic Auto's correspondant Jeff Gluck and his totally officially unofficial scientifically unscientific question of "Was Such-And-Such a good race?" then what you find is that whether or not something was a good race has no mapping whatsoever to the amount of horsepower, the particular aero package that weekend, the size of the speedway, whether it was a superspeedway, short-track, or road course; in fact as far as I can make out, there is near enough no correlation with anything to determine if a given race will be good or not.
In a series like NASCAR, where the teams are very much bound inside a tightly controlled box by the rule book, any advantage that anyone can find comes at a premium. However, it all appears to be chasing down the very edges of performance such as manipulating 1% items of aero, which is why Joey Logano tried driving with a webbed glove to block out window drag, or why Joe Gibbs Racing put down 30 layers of tape underneath the livery wrap.
The thing that nobody can address is that a NASCAR Cup car is very wide for the length. They are very hefty hecka-chonks that just don't rotate through any of the three axes of rotation all that well. While this means that they are stable, it also means that they don't pitch much and don't turn through corners all that well.
Speaking as someone who can only manipulate numbers and who can not actually perform the experiment, my suspicion is that the ideal ratio of Wheelbase to Width, is the Golden Ratio. The Golden Ratio is (1+√5)/2, which is about 1.618033. A lot longer than this and cars will not turn very well hence why dragsters are long and skinny, and a lot shorter than this and paradoxically cars also do not turn very well due to the fact that turning a car is essentially operating a lever through the yaw axis.
In terms of what horsepower and the aero package actually do when it comes to how good the racing is, the reason why I think that they are most irrelevant is that even with a 1000 horsepower car, that power is still only being applied linearly and at best is only going to break the mechanical grip of tyres on the road. The aero package which is designed to suck a car to the track, only really applies vectored suck forced downwards relative to the axis of pitch in the car.
When it comes to what makes racing 'good' or not, then I suspect that the overriding aspect of a car's basic geometry by means of the axis of yaw, is in fact the single most critical aspect. Cars that are twitchy, are mostly twitchy through the yaw axis and while the three axes of pitch, roll and yaw all come into play when driving a car but only yaw is important when it comes to turning a vehicle through a corner. Granted that pitch and roll will affect the ability of the wheels to attach themselves to the road surface but how well a car turns through a corner, is the subject of loads and loads of dark arts which apart from camber, castor, toe, rubber compound, et cetera, is mostly determined by yaw.
A NASCAR Cup Car which has had the base dimensions baked in ever since the 1981 season has the following dimensions.
NASCAR Cup Car: Wheelbase/Width.
110.0' / 78.6' = 1.399
A W/W ratio of only 1.399 is actually stubbier than my wee ickle Mazda 2 DJ. What this means is that a NASCAR Cup Car is a hefty chonky boi, which doesn't turn particularly well; which is expressed in the fact that they aren't exactly the fastest thing around road courses and street circuits.
So what's the solution?
The obvious thing that I can think of is simply to make the cars narrower. The closest that you can get to the Golden Ratio is 66 inches wide but that might look a bit silly. Seeing as the Ford Falcon from 1960-2016 was within a quarter percent of 110.0 inches by 72 inches, then that seems to me to be about right. A 72 inch wide car is like about the upper limit as that gives you a W/W radio of 1.52.
The second obvious thing that I can think of is to make the tyres narrower. A NASCAR Cup Car sits on tyres that are 365mm wide. A V8Supercar tyre, which is a tyre for a similar application but which turns far more easily, is only 280mm wide. That's roughly a whole palm width wide. While that doesn't seem like a lot, rotating a wider tyre through its own axis of yaw is also harder than rotating a narrower tyre through its own axis of yaw; in addition to rotating the whole car.
The third thing that I would do is to increase the ride height relative to the road. This would also help to remove some of the mechanical grip by removing a lot of the vectored suck force which happens because a big thing is clearing the air away.
By doing all of this, lap speeds would blow out and get worse but the cars would be far more nervous than they are currently. If the aim is to actually provide good racing, then making the cars more directionally unstable and making them dance more is surely the way to go. However, in making the cars more directionally unstable I would give back part of what I took away.
When Chrysler shut down its missile division in 1968, it found that it had a bunch of engineers left over. Rather than waste them, it immediately employed them to attack the problem of going motor racing the Superspeedways. The result was the Dodge Charger Daytona and the Plymouth Road Runner. Both of these cars had almost comically large fins which provided directional stability and kept them pointed in a straight line.
Of course the idea of putting fins on a racecar had been known about since the 1930s. In the 1950s Jaguar made use of the existence of a driver in an open cockpit and put a giant fin behind the driver on their D-Type. Even though the 1955 Le Mans 24 Hour Race was marred with tragedy and Mercedes-Benz withdrew their cars, they were still being pushed by the Jaguars all the way. When in 1956 Mercedes-Benz didn't show up, Jaguar D-Types basically had no competition.
Practically every car with any kind of aerodynamic attachment has end plates on the ends of their wings and modern Le Mans prototypes still have fins. Even NASCAR Gen-1 cars for a while had fins by default and it is reported that cars like the 1959 Plymouth Fury where the fins were quite pronounced, were pleasant to drive. If I was Grand Poohbah and Lord High Everything Else, then I'd think about putting big fins on the back of NASCAR Cup cars again. I'd also likely use the same kind of generic body from which the second division Xfinity series cars could come from and where Truck series trucks would come from.
I have seen enough races over the years to know that when you have drivers pushing and bumping each other, that no human however superhuman they think that they are, can possibly understand or react to forces that they can not see. Quite often small taps, especially caused when a pusher is pushing a pusher, result in the car at the front of the train wiggling, then the driver trying to correct and overcorrect the steering; then in the space of microseconds, we have ten to twenty cars torn up for no good reason at all. At 200mph at car is moving at more than 293 feet per second. By putting big fins on the back, at least there'd be a tendency for the cars to want to continue to travel straight and true; which given the current aero kits which want to pull a car downwards, does not happen. Remember, forces are vectored; which means that they have both magnitude and direction.
And I think that fins look cool.
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