Why There's No Easy Way to Make a Race Car Fast
In all of my research about car suspension, I have talked about advantages and disadvantages of various configurations and designs. And if one thing can be better, couldn't there be a best? Surely there is some absolutely ideal setup, one that makes a car as fast as possible? Well, even when you dive into the world of motorsports, where faster is always better, you find that there's no one clear answer, and it has as much to do with psychology as it does physics.
We all love watching heroic moments of oversteer in racing, and the saying "loose is fast" is not just a line from Days of Thunder, but something of a truism in motorsports. On a 2021 episode of Red Bull F1's podcast, Talking Bull, Adrian Newey said Max Verstappen's "ability to live with a car where the rear end moves around a little bit is exceptional." At various points in his career, this trait has been suggested as a reason for why he's so damn fast. Driver coach extraordinaire and Speed Secrets author Ross Bentley explains why a somewhat oversteer-y car can be a good thing.
"When you have a little oversteer, the car is helping you do what you want it to do, it's helping you change that direction or rotate the car through the corner. So that's generally why it is faster," he says. "In many cases, not all, but in many cases the way to deal with a car that oversteers a little bit is to add a tiny bit more throttle. The way to deal with understeer is to get out of the throttle. Which, last time I looked, more throttle makes you go faster, less throttle makes you go slower."
Of course, dealing with a "loose" or "free" car like this is difficult. "If you get a car that is slightly loose and a driver loses confidence because of that it will be slower," Bentley says. "Now, if that exact same car is slightly loose and the driver doesn't lose confidence but can actually use that to their advantage, it will go faster."
Jeff Braun, a longtime race engineer who currently works in sports prototypes, brings the discussion back to the tire-grip curve. Plotted out, this looks like a bell curve with lateral force (usually in pounds or newtons) on the Y axis, and slip angle—the difference in angle between where the tire is pointed and where it's going—on the X axis. As lateral forces and slip angle increase, so too does grip. Once you reach the peak of the curve, however, grip falls off sharply. (Note that this curve is ever-changing.) He says the best drivers in the world live between 2% above and below the peak of grip, averaging out to operating at the maximum level over the course of a lap, stint, or race. "If you drive an 'uncomfortable' car, it's because you're pushing it hard enough to get to that part of the tire curve where it's uncomfortable, because you're falling off the peak of that curve," he says. "The pros live there. The amateur guy, weekend guy, doesn't live there because he's not skilled enough to drive 2% over the curve and catch it. He crashes."
The human here is the most important variable. Computer simulation can help an engineer determine the fastest possible setup for a race car, but even with a 99.99-percent accurate correlation between the sim and real-world conditions, can the driver hang on?
Braun remembers working with Dallara in the Nineties in the early days of the Indy Racing League (IRL). The engineers, new to the Indy 500, wondered why when all the data they had indicated that the cars should've been faster in turn one, drivers kept lifting. Braun remembers asking the engineers if they knew what entering turn one at 230 mph felt like. No, they said, and thus, they all began a project of using torque sensors on the steering shaft to try and better understand the driver psychology.
"We learned that what the driver feels as the limit can be much different than the actual limit of the car," Braun says. "So some of those adjustments we're making to try to get 'more grip' or 'make the car go faster' are to get the driver better able to feel where he is on that [tire-grip] curve." That led to tailoring setups to increase what Dallara called the "perceived limit" rather than the actual limit of grip. Beyond that, they started looking into driver ergonomics, to help make the person in the cockpit more comfortable getting speed out of the car.
Even still, a top-tier driver is never fully comfortable. "They'll say, 'Well, I just sailed it in there and dealt with whatever happened when I got there,'" Braun says. "You go, 'Really? You could've crashed that thing, rolled it over and burst into flames.' "Yeah, but I knew I could fix whatever happened once I got into the corner." And that's where those world class guys live every day, every lap, every corner."
"The very best are stupidly optimistic, I can't remember the phrase I used, but it was something like, but intelligently pessimistic," Bentley says. "They always think 'There's a way I'm going to do this,' but they're always afraid that somebody's going to do it better, so they're going to work harder to get there." Braun says this work takes the form of the driver finding the car's limits—perceived or otherwise—the engineer making those limits higher, and the process repeating itself ad infinitum. "They've had to save their life eight times in the last two laps, but that's where they live," he notes.
The psychological aspects of race-car setup also have much to do with how long a driver will be out on track. You can give a car an edgy, nervous setup that might provide excellent one- or two-lap pace, perfect for qualifying, but it could be too much for a driver, even the best of the best, to manage for an entire race. Then you have to think about tires again, that edgy setup might cause a dramatic loss of grip after those one-or-two heroic laps. That won't do for an actual race. And then there's the length of the race itself. Is it an hour-and-a-half sprint or a 24-hour enduro where the tires have to last a long time. Endurance racing might provide the biggest challenge for a race engineer. They have to create a setup that's fast, but not too tough on the tires, and easy to manage for a driver out on track for two or three hours at a stretch. Then, endurance-racing teams often feature drivers of varying skill levels.
Typically with these engineering stories, I'm guided by a fairly simple question. In this case it's "How do you make a race car fast?"
"There's no answer, you can't just look it up on Wikipedia or anything. And that's what I love about race engineering," Braun says. "It's working with your driver or drivers, to try to come up with the best compromise—because it's always going to be a compromise—and to compromise between peak lap time, versus stint length, versus drivability, versus, 'Okay, let's give the guy a really fast car, but man, for 24 hours he's liable to get it wrong once, because it's so twitchy and crash into things.'
"Do that, and then in sports car racing, you throw in, 'Okay, that's our world class driver. Now we have to give this thing to a bronze-rated driver. A good semi-pro, decidedly not a pro, and he's got to deal with it too.' How's that going to go?"
Braun says ultimately, a good driver-engineer pairing is like a great football coach-quarterback pairing. Both sides need to understand the technical aspects of what's happening, but perhaps more important is the specific game they're playing. In an ideal world, they're on the same wavelength, they understand each other intuitively.
Essentially to answer my original question, you need degrees in physics, mechanical engineering, and psychology. I told you it was complicated.
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