Note: This is a continuing series for INDYCAR.com, with different guests, leading into each race weekend for the NTT INDYCAR SERIES, focusing on various technical challenges of each respective circuit.

The sixth round of the 2023 season for the NTT INDYCAR SERIES remains home for the crown jewel event of the year with the 107th Running of the Indianapolis 500 presented by Gainbridge on May 28.

The 2.5-mile superspeedway is 50 feet wide on the straightaways, while being 60 feet wide in each of the four turns. While there is no banking on the straightaways, the turns are banked at 9 degrees, 12 minutes. The symmetrical rectangular configuration of the oval has the front and back straights measured at 5/8 of a mile, while the short chutes are 1/8 of a mile and the turns are 1/4 of a mile.

The annual historical event features seven practice sessions (following the rained-out practice on Opening Day), which includes Fast Friday, when the turbocharger boost is increased as part of preparations for PPG Presents Armed Forces Qualifying. The first day of qualifying will comprise of all 34 entrants, with positions 13-30 locking in at the end of the day and deciding who will advance into Sunday’s top 12 to battle for the NTT P1 Award and the Last Chance bout to decide positions 31-33. Two of the six practices will take place after the field of 33 is set, with a pair of two-hour sessions taking place Monday, May 22 and on Miller Lite Carb Day, Friday, May 26. (Note: Coverage times for qualifying and the race listed below.)

While Scott Dixon stormed to the fastest pole in history last year with a four-lap average of 234.437 mph, the qualifying record is held by Arie Luyendyk, who delivered a scorching 236.986 mph four-lap run in 1996 on the second day of qualifying.

This week’s featured guest is Brad Goldberg, race engineer for Marcus Ericsson’s No. 8 Huski Ice Spritz Honda fielded by Chip Ganassi Racing (CGR). Goldberg helped guide the Swedish maestro to a thrilling victory in last year’s edition of “The Greatest Spectacle in Racing.”

Q: What is it like preparing for the Indianapolis 500?

Brad Goldberg: It's the biggest event of our year and the most attended. So, it's obviously the most important. Our season revolves around this race. You know, anybody can tell you who won the ‘500’ five, 10, 15 years ago, not necessarily the championship. This race team has two goals: The first one is win Indianapolis 500; the second one is win the championship. It is by far the most important, the most stressful, the most amount of time, put into getting the car prepared, ready, studying all the aero numbers, chassis setup items, stuff like that. So, it is the most thorough process we go through. It is the most amount of time we spend in terms of one particular race. It's stressful is the biggest thing. Every detail is incredibly important at this track.

Q: Some teams wait until the Month of May to run their Indy 500 car, while others ran them at the Open Test last month. For instance, this is the third consecutive year Helio Castroneves is running his Meyer Shank Racing car that won the 2021 Indy 500. What are the nuances of that, and what did you guys at CGR decide to do?

Goldberg: Yeah, that's a good question. There's no secrets. Everybody has an oval car, as far as I know. Yes, the car we're preparing is the ‘500’-winning car from last year. That was a new car for us last year. The first thing a car does when it comes into the shop is it gets measured, put together and then it goes into the body fit, which is what everybody's doing. It's why Helio's running his same car for three years in a row. It's why Andretti has their oval-only car. McLaren, same way. It's basically making all the body work, all the seams, fit as perfectly as you possibly can.

This place being so big and so fast, any sort of little bit of drag, any sort of bodywork or seam that is wider than it should be, can potentially slow you down. That's why teams put hours, and we're not talking like four or five hours, we're talking weeks, to get one of these cars prepared. So, when there's a mountain of work that goes behind that most people don’t even know about or see or hear about. But yes, it takes, to get the bodywork done for an Indianapolis 500 car, we're talking weeks. We're not talking eight hours, we're not talking a day. It's a copious amount of time, and that's why teams have these sort of cars. Again, we're just trying to make all seams, bodywork, sidepods, fitment, engine cover, all that stuff is incredibly important around here.

That's where like a lot of the details are and what makes this track so unique is this; It all matters, but this place, it matters more than every other place we go to. Everybody pretty much has their oval-only car. Generally speaking, you don't like to run it before the "500." For instance, Texas or whatever. One, the car going around the racetrack and there's dust in the air, there's sand on the racetrack, there's marbles that come off of the tires, little bits of rubber. Everybody's seen a car after the race, it looks like it went through a swarm of bugs or whatever. It's all just splattered rubber. All that takes a toll on the bodywork. It does. You have to repair it. You have to fix it. A little bitty tiny rock may chip the paint, well then you got to fix that.

Q: If it’s a microcosm of drag that develops?

Goldberg: Absolutely. So yeah, there's a lot of teams that don't even run their Indy 500 car until Indianapolis. For the same reasons. It's all just a matter of time protecting it because again, it goes back to your first question, this is the most important race of the year. So, you have to have everything as best and most prepared as you possibly can.

Q: From a general engineering point of view, what type of setup do you lean toward around the Indianapolis Motor Speedway oval?

Goldberg: Obviously, the most important part of the car is the aero. That also dictates where you want run the car setup-wise. So, once you figure out where that is, then you have to figure out what setup will allow you to actually stay in that area. This track is smooth, so it is always a matter of mechanical grip versus aero grip. There's a tradeoff there, for sure.

Q: Not quite as aggressive as Texas Motor Speedway, I would assume?

Goldberg: No, Texas is pretty rough. This place is not 100 percent smooth. There's bumps in Turn 3. You can see the cars go through there and years ago, when people ran dome skids, you could actually see the dust from there. We don't have those anymore. This is a flatter track with longer straights, so you want to get the most amount of drag out of the car as possible to go as fast as you possibly can down the straights, but you still have to turn hard left at the end of it. That's where the tricky bit comes in. That's where the aero versus mechanical tradeoff happens. You still have to have the grip to go hard left on a pretty flat track. Yes, it still has banking, but compared to a Texas or an Iowa or heck, even Turns 1 and 2 in Gateway (World Wide Technology Raceway). It's very flat. That's where you sort of have to have the car balanced out mechanically for grip. It is a nuance. It is a fickle mistress, if you want to say, because the track, the sun comes out, and the track temperature gets very hot. It gets very slick. You have to have some sort of aero to get around the corner. You can't solely rely on mechanical. So, finding out what levels of downforce you need to actually make it around the racetrack and then how do you make the car live in that area.

Q: How much of a fine line is it to get as close to the ground as possible without having it bottom out?

Goldberg: A car bottoming is friction. It is, it's no different than you taking your hand and sliding it across a table. It takes more force to slide it than if it had zero friction if your hand was just straight above it. You don't want the car to smash into the racetrack, especially on qualifying day. One, it upsets the balance of the car and two, it potentially could slow you down. So, that millimeter, even half-millimeter, makes a big difference. It's an interesting thing, you can actually hear the cars go across the Yard of Bricks, which isn't the same level as the asphalt. Bricks are rough. Exactly. Even that is a vital spot on the racetrack that you focus on to make sure the car is in the right area. That's why going across, I mean, you can hear them, you know. In the GMR GP when you had all the downforce on the car with road course wings and things like that, you can actually see the car go '"doink'" right across it. It's just part of the track. It's part of figuring out where it needs to be car setup-wise.

Q: How are the setups for four laps in qualifying different than what you run in the 500-Mile Race?

Goldberg: The setups are vastly different in terms of what you're trying to target. Race Day conditions, you're in a bunch of traffic, there's lots of cars on the track. The air is very turbulent from those cars on the track, and then trying to follow somebody that close when you are in an aero-dependent car, it creates its own set of challenges. It's very different than qualifying, when the car is on the edge, and you're trying to go as fast as you possibly can. I think there isn't an engineer in this paddock that wouldn't say the most stressful days of their racing year are Friday, Saturday, Sunday of qualifying.

Q: Not to mention the boost, right?

Goldberg: Yeah, exactly. At that moment, you got to understand the driver is putting 100 percent of their trust into the engineer. He is going out there and he is going into Turn 1 with the trust of holding their foot flat. He or she is trusting you that it sticks. There is bumping (long pause followed by laugh); it's a stressful day. I don't want to speak negative because anything can happen around this place. The Indianapolis Motor Speedway is a monster. It's an animal. Anything can happen, anything does happen around this place.

Q: And compared to the race?

Goldberg: The biggest thing in the race is traffic. And what I mean by that is, when you're behind somebody, you don't have any air on the front wing, so you got to get the car to turn.

Q: So, qualifying is more aero grip whereas you have to completely flip to mechanical for the race, maybe not 100 percent, but moving the needle that direction quite a bit?

Goldberg: Yes. And you're looking for that balance behind other cars to make sure your car can still navigate the corner and have the driver carry as much throttle as they can because, yeah, when you're behind somebody, when you're up behind somebody's gearbox, there's no air coming on your front wing, which means it's harder to turn the car so you have to get some sort of rotation out of the car without having the aero that you normally do have in qualifying. It's quite the opposite, in terms of you want to get the car to go as fast as it possibly can through the air. You're not worried about losing air on your front wing. You're the only car on the track. You don't have that challenge of not being able to rely so much on the front wing to rotate the car.

Q: If you were to tell a novice fan what area dramatically changes? Dampers, wing adjustments, etc.?

Goldberg: In general, because the aero configuration of the car is slightly different in qualifying because you do have the higher boost, with the higher boost your ride heights are even different because you're going faster.

Q: Plus, a lighter fuel load in qualifying?

Goldberg: Yeah, exactly. When you're going 235 mph, you have more air pushing down on the car than say 220 mph at the lower boost level. Even if you're the only car on the track, it's no different than an airplane.

Q: Would it be hundreds of pounds of difference even with just 15 pounds of difference?

Goldberg: For sure. It's like an airplane. An airplane has a stall speed that's within a couple miles an hour. An airplane just doesn't go "boop" up in the air. It needs a runway to take off. It's the same thing, an INDYCAR is the same way, where yes, the increase of speed does push the car down in the ground faster. Just like an airplane, the faster it goes, it creates more lift.

It's the exact same principle. It does change, and it goes back to that aero versus mechanical grip. You can't just pile on all the downforce and all the drag like you do in the race. You see people run Gurneys (Gurney flaps) in the race on the rear wing. Clearly, everybody saw what we ran last year because you do lose all that downforce behind somebody. You still need something to get around the racetrack. So, you have to put more downforce and more drag on the car because it's not free. You can't just say, "Oh, I'm going to put 200 pounds of downforce on the car and have zero pounds of drag." It doesn't exist. There's the tradeoff. So, you need some downforce to actually make it around the track. That goes back to that aero versus mechanical. Whether it's the race or qualifying, that balance is still very critical. What the difference is, is effectively how the air is and where it is on the car. Like, in the race when you're behind 10-15 cars, it's very turbulent. It's very low, and when you do have that many people in front of you or a car in front of you, you're not generating the same amount of downforce as you are when you're out front. You can't run your qualifying downforce in the race because you just will be that much less in traffic. And again, that goes back to that aero versus mechanical: You won't make it around the corner, so it gets a bit tough.

In terms of stress level, qualifying is always the hardest. It is always the hardest just because the car is so much on edge because of that. You're trying to get every ounce of speed out of the car as you possibly can and take every ounce of drag you can get off the car as you possibly can. So, because of that and you're putting the car so much on the edge to get that speed because that's where the speed is, it's a thin line. And again, the driver has complete trust in you that the car will make it around the corner.

Q: What does it take to make a car consistently quick over a full race stint?

Goldberg: A little bit of everything because as you go through a stint, the tires, you go through a phase where the tires are warming up. They're just not instantly hot. You see it on the out laps on road and street courses with the primary and the alternate compound. The out laps on the alternate compound are generally always faster than the ones on the primary because the tire takes time to warm up. It may take a handful of laps to get to its peak operating temperature, and then it sort of hits that peak operating temperature. And if you're out front and you're always pushing on the tire, those tire temps might be stable. But in traffic when you're lifting, the more you push the tire, the hotter it gets. That's why you see in practice teams doing like full-tank runs as we call them, where they all leave as a group, like all four this year, Ganassi cars leave together, and then they're joined by four Andretti cars. That's what doing, is trying to make a change on the car and then validate it through the tire life of a run.

Like you pointed out, your car may be great for the first 10 laps, but as the tires start to degrade, as they start to wear, your performance may get worse and worse and worse. So, you're trying to find that even-keel baseline because the driver in the car can adjust their bars, they can move the weight jacker, but that's it. If you need to make an air pressure adjustment, you have to wait until the next pit stop to do it. So, you're trying to find a window where the driver can adjust the car with the tools they have available during the stint and stay in that performance window that gives the driver the confidence in the car to push the edge.

Q: What is the notorious trouble spot?

Goldberg: It's almost changed. Turn 1 is still a very notorious trouble spot, but Turn 2 has started to become a very troublesome spot, too. I think you saw it in the race last year. It's more exposed from conditions. In Turn 1, you've got the stands blocking say, wind from the south or from the west. The stands sort of block that a little bit. But in Turn 2, it doesn't. It's wide open. Same with the track itself. Toward that five o'clock hour or whatever, Turn 1 starts to get shade on it, which helps cool the track down, especially on a bright sunny day. Those track temps can get up 120 degrees, like they were in the race last year. So, any little difference like that, any sort of nuance, plus Turn 2 being so exposed and then the track, everybody knows there's a bowl you fall into Turn 2, as well. That sort of upsets the car, dynamically, getting across that area, too. So, that's sort of become the troublesome spot just as much as Turn 1 has. Turn 1 is still its own animal. And you even saw in the race, it depends on the direction of the wind. You saw (Scott) McLaughlin get caught out in the wind in the race last year. Turn 3 is just like Turn 2, in terms of exposure of the elements. In a certain wind condition that becomes fairly critical, as well.

Q: There are some new aero elements for this year. What are they?

Goldberg: There's wickers that go on the lift-up flaps on the back of the car, on the underwing. There's Gurneys you can bolt on the back of that. The bargeboards, which is a little piece on the leading edge of the underwing. There's an inner one now, so you can possibly run two. You did have that at Texas. The underwing strake, so there's that little divider that goes down the middle of the underwing. There are two specs. There was what's called a Z30, which is a shorter one, which is meant for like short ovals and things like that, and well, speedways, too. And then there's a Z15, which was originally meant for road courses, which is a bit longer, that's now allowed at the racetrack (IMS). So, it's navigating all those new bits and how they interact because maybe it's the old strake with the two bargeboards or the new strake, the longer strake with no barge boards and then you put this flap Gurney on there. Well, maybe the flap Gurney doesn't like necessarily working with the long strake, and it might want the short strake. You have to figure that out. That combination of trying to find the best relationship of downforce to drag and how those all interact with each other.

Q: What is your interpretation of what those elements will do for the on-track action?

Goldberg: It is a wild card because all those elements, the new ones interact with each other, right? The front wing interacts with the underwing, interacts with the rear wing. So, it's finding how all of those new bits interact with each other to make it the best possible configuration aerodynamically. It always is a variable. You have to go through your test plan and navigate your way into what you think is the best combination, and you need to test it on track to validate it. When aero configurations change like this, it always does throw a new challenge in. A new challenge into figuring out does two plus two equal four in terms of how it all works.

Q: That’s a lot to figure out in knowing if your car is a sitting duck while leading or what have you?

Goldberg: Exactly. So, everything you do around Indianapolis has to be validated in and out of traffic, which is its own challenge. You may run on your own, and it feels great. Well, we know in the race conditions you have a lot of downforce to run in traffic. So, when you do get out on your own, it's way different. Yes, you have to validate everything in and out of traffic because it might feel great on your own, but then you get in traffic and it's not so great. But then it might feel great in traffic, and then you get out front of the pack and it's like, 'Oh wait, this isn't actually really good.' That's always the challenge around here is when they put new bits and pieces in the configuration pile, validating what is the best combination. Maybe the best combination is all of them on the car. It's trying to figure all that out.

Q: Some tracks, having tire rubber is crucial, at others its all about the track temperature?

Goldberg: When the track temp gets up, when it gets very hot, sunny day, that is the number one very like defining thing. You go back to Saturday qualifying last year; it was nice and cool in the morning. Winds were calm and there was some fast times ripped off, and then you got into the Saturday afternoon, it was kind of right around when Alex (Palou) started qualifying, you can just spot the track temp and you can kind of see ‘whoop’ (pointing up). Then the speeds never got high again. The track got slick, and again, you needed a certain amount of downforce to actually just make it around the track without having to lift in qualifying. That's where it gets challenging, but, for sure, ambient conditions are a huge, huge, huge factor around this place.

Q: And lastly, what type of setup does Marcus Ericsson prefer around IMS?

Goldberg: Stability in the car so it's doing sort of the same. What I mean by that is it's sort of doing the same thing throughout the corner, whether it's understeer all the way through the corner. He doesn't like (inconsistent combinations of) understeer, oversteer, understeer, oversteer or oversteer, understeer, understeer. He just wants sort of the same sort of balance all the way through the corner. And that's what I mean by stability. He'll call it consistency. Like: "OK, I can work with this. The car's doing one thing around the corner.”

The first day of PPG Presents Armed Forces Qualifying is Saturday, May 20, running from 11 a.m.-6 p.m. ET (Peacock, INDYCAR Radio Network, INDYCAR Live!). A two-hour window of coverage will also be featured on NBC, beginning at 2:30 p.m. ET.

On Sunday, May 21, the top 12 battle will start at 2 p.m. ET (Peacock, INDYCAR Radio Network, INDYCAR Live!). Then, the Last Chance and Firestone Fast Six is scheduled for 4 p.m. ET (NBC, Peacock, INDYCAR Radio Network, INDYCAR Live!).

A two-hour pre-race show for the 107th Running of the Indianapolis 500 presented by Gainbridge will begin at 9 a.m. ET on Peacock, with a preview also taking place at 10 a.m. ET via the INDYCAR Radio Network. Coverage for the race will start at 11 a.m. ET (NBC, NBC Universo, Peacock, INDYCAR Live!, INDYCAR Radio Network).