Why the Indy 500 is “fascinating puzzle” according to ex-F1 engineer David Brown

The 33 cars that will participate in the Greatest Spectacle in Racing on Sunday have already undergone countless hours of work in shops and at the Indianapolis Motor Speedway in an attempt to become the next Indy 500 champion. But what does a technical director look for when setting up a car to perform at its best on this unique 2.5-mile oval track?

Motorsport.com sat down with David Brown, who joined Juncos Hollinger Racing last December, to understand how an IndyCar organization navigates the Month of May and the forces involved in taming a car that goes almost 240 mph. Racing for Juncos are Conor Daly and Sting Ray Robb.

Brown has decades of motorsport experience. He spent nearly 15 years in Formula 1 with Williams, where he engineered Nigel Mansell’s and Alain Prost’s World Championship seasons, and worked also with McLaren and Jordan.

Yet, he is fascinated by the Indianapolis 500. “The more you get involved, the more you understand why people become obsessed with the Indy 500,” Brown says.

David Brown, Juncos Hollinger Racing

Photo by: Juncos Hollinger Racing

From a technical standpoint, what does the car need to be fast in the Indianapolis 500?

“It’s a juggle between drag, balance and efficiency. So it’s easy to watch the race from the outside and think it’s just about running minimum wing and minimum drag. But the problem is that you can’t, because you will be too slow in the corners. Even though the cars still look fast in the corners, if you lift and you lose momentum, and you have to keep the revs up. So all these little tiny things join together to give you the [car’s] overall performance. So you’re looking for low drag, but you need downforce, which means you also need efficiency, which is a combination of the two. You need high power, which is good because we have a Chevy engine, which is very good engine.

“But also you need to get that power onto the road, which means you need to be very efficient in your transmission. So it’s another combined factor. You also need to be able to stay full throttle, which is the downforce side of it. So you’re maximising the output of your engine and your transmission.

“And then in traffic, you need to be able to respond with the correct gear ratio selection. So everybody runs fourth, fifth and sixth gear very, very close together. So you can do laps with a tow, for example, at sixth gear. But when you’re in traffic, you might need to be fourth gear, and a very small gap, so you’re almost imperceptible. You see the driver’s hand move and the engine note changes just a little, because you’ve made a 70 rpm rev change to the engine by changing gear.

“So all these tiny things come into focus then, and that’s just producing the lap time. I mean, you’ve got pit stops, which are absolutely vital. You have a car which has got the wheels like this for rubbing on the oval, braking at maximum deceleration into the pit lane, even though the outside of the tyre is completely cold and blah, blah, blah, blah. And the car’s got a weight jacker, which is the cross weight is all on one side of the car. So when you come to stop the car in the pit lane, you often see people locking wheels and stuff.

“The idea is that, you know, you can’t make mistakes by having the wrong brake bias and the wrong weight jacker position when you come into the pit lane, because otherwise you risk, apart from the fact that you will slide all over the place and scare all the people in the first pits, you risk crashing the car coming into the pit lane and ruining your race. So there are so many little details. It’s a fascinating puzzle to put together.

Conor Daly, Juncos Hollinger Racing

Photo by: Action Sports Photography

It’s clear you’re passionate about it. Of course, you have a lot of experience with other forms of motorsports, especially Formula 1. How would you compare the Indy 500 to everything else you’ve done in your career?

“It’s very individual. It’s very unusual. I mean, I’ve done Le Mans and Monaco and Daytona and everything in between, you know, all the sort of long races and 20 years of Formula 1 and stuff. And it’s just… it’s like looking at a face through a screen, right, you know, it’s there and you sort of recognize it, but nothing is exactly the same. And so you have to adjust your perception when you get involved in it.

“And I did get involved in this race 20 odd years ago, but only on the sort of periphery. But it’s been a lot of learning for me. But it’s fascinating. I often talk about race engineering and engineering and racing cars. You know, these people who spin plates on a stick? You see the guy running around. He has 20 of these things going. He’s running. It’s just like that. That’s exactly what you’re doing. So you have to make sure that all the plates are still spinning.”

Having all these days of practice means there’s a lot of data to analyze. How does Juncos Racing process all of that?

“Well, it’s interesting you should say that, because on paper, yes, we’ve got lots of time. But in fact, we are always running as long as we possibly can in every session because of the challenges of qualifying and the importance of qualifying, and the fact that the configuration of the car is so different for qualifying.

“We have really two separate areas. We have the race preparation and the qualifying preparation. And the car, of course, is a similar car, but its final aero configuration and so on is quite different for qualifying — and the power. We get extra boost. Everybody gets extra boost for qualifying and all that sort of stuff. So we arrive here having done lots of simulation.

”We did the Open Test, which is two days. So we arrived here with some idea of what challenges we were going to face. And we have a list of just like with any other challenge in life, you have a list of things that you want to try and you want answers to. And we start off with the most important ones and we work towards the least important ones.

“Of course, it’s never as linear and as obvious and as straightforward as you would hope. So always extra things comes up. You either learn something that sets you off in a slightly different direction to your advantage or you learn something that isn’t working well and you have to go another route in order to compensate.

“And there is, as you say, a lot of data. We have three engineers directly working on each car. Plus two other senior engineers, myself and Will (Phillips), who’s the senior engineer on the other car. We get a lot of support from GM because we’re a GM engine team. So they have engineers as well who are looking at the data. So in running the two cars, we’ve probably got, including the GM people, probably 10 or 11 people looking at data, which is a lot. But we generate a lot of data. It’s huge.

How do you divide your time during practice between qualifying and the race?

“We ran Tuesday, Wednesday, Thursday. So I think we ran three days of practice, which was race practice. But we did also do some running on our own to try and practice a little bit of qualifying. So maybe a third of a day. And then the day before qualifying was just practising for qualifying. And then you have qualifying itself. Because we narrowly missed getting into the top 12 by 0.06 of a mile an hour, some tiny margin. And of course, everything is tiny margins because it’s IndyCar and it’s Indianapolis. So we didn’t have to run on Sunday. But today (May 19th) we’ve got two hours of practice and then we have carb day on Friday, that’s another couple of hours, and that’s it, that’s the race. It doesn’t take long to whip through all that time.

“Even though it’s such a short lap, the conditions are constantly changing. So not only the atmospheric conditions, because, you know, of the wind and the temperature and the ambient pressure and humidity and stuff, all of which makes a difference. If the wind changes and we have to change the downforce level, if the temperature changes, we have to change the wing settings to compensate for the temperature.

“By the time you covered all that stuff, you really are running all the time. I mean, today we want to do long runs, some 30 lap runs, just like the race to look at the tyres and look at the performance and look at the handling as over the length of it as the fuel load comes down and the tyres degrade, for example. But Carb Day is it’s pretty late to make big changes by the time you get to Carb Day really. You’re just sort of checking everything, making sure, just doing the tiny little sort of polishing, if you like, of the performance. But today is quite an important day. It’s only two hours and it’s going to go ‘boom!’.

How does a car’s setup differ between qualifying and racing?

“For us, it’s mainly been aero. I mean, some people have made some more mechanical changes, but if you have a car which you really like from a mechanical point of view. And so a good car mechanically, is a car which you can run a range of aero balances on an aero components and it’s still the same. So we think our car is comfortable for the drivers. So we made mainly aero changes, but very few mechanical changes.”

Sting Ray Robb, Juncos Hollinger Racing

Photo by: Penske Entertainment

How easy is it to fall off the window with the setup by making a slight change?

“Very easy. Yeah. I mean, every time we make a change, we measure how the car is before we make the change and then measure afterwards, which means literally if we change the front wing angle in the pit lane, we measure the front wing angle in the pit lane, even though we’ve done it half an hour before. We measure it and we change it, we measure it again. So we’re dealing with, what did we make the other day? We made a wing angle change of 0.15 of a degree. Complete madness, 0.15 degrees like this, but because it makes such a huge difference because at 230 miles an hour, the forces are enormous. And if you’ve got an imbalance, everything is magnified.”

It’s funny that you mentioned that because I heard Conor Daily say that he didn’t feel right with the car during the Open Test. He said that he wasn’t comfortable, and you changed the front wing. Despite the fact that it was supposed to be the same front wing, it kind of changed the whole balance of the car. That’s how tricky and small the margins are.

“Yes, we ended up actually having to select by running them on the car to check all the wings because the circumstances it’s not really very easy to model because the expectation is every wing is the same. But in fact, every wing is different. And so we have some tests which we do on the wings statically to measure how stiff they are and how robust they are. So we measure vertically and in torsion and all those things like everybody else does. And we do some other tests as well. And when we select the wings from our stock, which we have a primary wing and a secondary wing for each car, and then we run them on the track just to be sure, because as you say, if if it’s slightly imbalanced, then it’s over. You know, it’s going to be a very, very long day.”

Which tool is the most important for adjusting the car setup in the Indy 500? Can you pick just one, or is that not possible?

“Well, the nice thing and the fascinating thing is the racing car is like those models of chemicals, those balls with balls and everything is connected. So every time you make a change to one part of the setup, then something else is going to move as well. And it’s just because it’s a racing car. That’s the way racing cars are, which makes it interesting, but it makes it difficult to define which is going to predominate. It would be obvious to say, ‘oh, the aero is very important’. Yeah, it is. But so the mechanical side, because that controls the ride heights and the ride heights define the aero. So is everything is connected. And so you can use the mechanical side to change the aero properties of the car, for example. So they’re tied together. The obvious thing is we change the wings a lot, but we also change the suspension as well. You know, some people run different wheelbases depending on whether they’re racing and qualifying. Quite big changes, but we didn’t because we quite like our car like it is. So we just changed some fewer components.”

Juncos has had fast cars at the Indy 500 for the last couple of years, but they’ve had inexperienced drivers for this specific event. How much did Conor’s IMS experience change the car?

“I think that one of the things that Conor brings because of his experience, he’ll drive the car, he’ll come in and say, ‘this is how I want the car to feel or this is not how I want the car to feel. It’s OK for one lap, but if I get into traffic, it does this and it moves too much’. He will make comments like, ‘Yes, I know what it feels like now. And my experience tells me that in the race, it’s going to feel like X, which is either good or bad.’ And that brings a huge plus to us, a huge advantage.”

You have the hybrid unit for the first time this year for the Indy 500. Was it difficult to learn how to use it?

“Yes, I think we, along with most people, have worked with it enough now to know what we want to do with it in the race. You saw in different strategies in qualifying, it’s not going to be like that in the race because you will use the hybrid in a completely different way because it’s a totally different environment in the race. But most people have been using it long enough to have experience of how to use it properly. So, yeah, it’s just another piece to add into the puzzle, if you like.”

Do you think it could be a deciding factor in the race?

“Well, I’m sure if you get it wrong. The thing is that everybody has it, right? So it’s like making the engines bigger. Everybody will just go faster. But you can get it wrong. And so if somebody gets it wrong or, you know, the driver doesn’t press the button at the right time, that will become an influence. But if everybody does everything perfectly, nothing will change. But of course, that applies to everything, pit stops, etc.”