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Sim Testing

Off Track with Hinch and Rossi Apr 01, 2025 21 min

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About this episode

Dive into the world of racing simulators with Alexander Rossi as he breaks down what a sim day looks like for an IndyCar driver. From the importance of sim testing in modern motorsports to the challenges of replicating real driving conditions, Rossi shares insights on tire modeling, driver involvement, and the extensive team effort behind each session. He also compares high-end sims to popular platforms like iRacing and discusses the mental demands of sim driving. Plus, get a glimpse into his personal routine and thoughts on improving sim accessibility for teams.

Topics: sim testing indycar tire modeling driver in the loop simulation mental demands of sim driving team collaboration iRacing comparison race weekend preparation sim technology motorsport development

Rossi takes us through what a day of sim testing does for an IndyCar driver and team, what that looks like for him, and what he would change if he could.

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This is, is off track.

What's up? Hello, Timothy?

Here we are again. Uh, while James is <inaudible> in Japan.

We're just anchoring this whole show ourselves back home.

I like to think we're the, like we're the steady part of this show.

He's just that kind of errand thing that comes in and out, really the core.

Do I know it's annoying. Do I know it's annoying.

Is like, as much as I like to think that I am good at this, like James is pretty much the reason that you're successful . So,

I don't know.

I think it's, it's a good interplay between you two.

'cause I don't think it'd be good if it was just him.

I don't think it'd be good if it was just you.

I think it'd be great if it was just me.

Right, right. The internet definitely seemed

to agree with that last week.

Um, well, it's a, it's a Tuesday.

Um, James understandably is, is unavailable.

Uh, we're not gonna give him too hard of a time for it.

But I think you, you, you messaged me the other day and you asked a question and I thought it was a very good question and a valid question.

Um, what do, what do you do in the sim?

Like, what is, what does a sim day look like?

Um, and I think that's, that's very fair.

Uh, and the honest answer is it has evolved a lot.

So, you know, these scenario are, it's die racing all day.

Right, right, right.

Well, with Mario Kart, really , um, and maybe that's where I've gone wrong.

I've digressed too far away from the Mario Kart and tried to take this too seriously.

I mean, I'll, I'll be back in India in a couple weeks.

I can help you out there. All right.

We can, we can get back to it. . Um, so, um,

that just reminds me of the gift that you made me, which is just incredible and I can't wait to bring it home anyways.

Um, so Sims have, sims have, have been a thing in motor sports for, I mean, going on, I would say two plus decades now.

Um, you know, was, was really common in Formula One, uh, and has come to really all form of motorsports, whether that's IndyCar Cup, um, which is thought to be not very technologically advanced, but it obviously is.

Im a, I mean it's even Formula Two teams, formula Three teams, formula E.

Everyone is using simulation now.

And the reason for it is, as, as we're well aware, you know, the cost of of motor sports is pretty high.

Um, all championships including Formula One have restricted the amount of in-season and um, off season testing that a team can do.

So what's the next best thing?

Simulate the testing and the car being on the track.

And the problem with that is getting something that is close enough that you are confident in.

And I'm not saying close enough from a, from a motion standpoint, you know, we're all very aware of the fact that you're never gonna be able to replicate the GForce.

You're never gonna be able to replicate, you know, the vibrations and um, obviously the penalty of, of getting it wrong in the sim.

But what you can do hopefully is develop a tire model that is good enough to support on track changes.

And, and without getting too far into the weeds, if you think about a Indy car race weekend, you've got two essentially 45 minute practice sessions.

Um, it goes straight into qualifying, then you have a 30 minute warmup and then you have the race.

And so it's really not a huge amount of track time throughout the weekend.

Um, there's also not a abundance of tires and you know, as we've all talked about the tires this year in particular where pretty quickly, so it's very hard to get many changes in throughout the weekend.

Um, because, you know, you've got short sessions, you've got a lot of cars on track, you've got tires that are changing in grip every time you leave pit lane.

And so if you show up to a race weekend and think, okay, these are the 10 things that I want to try and accomplish, you know, to get the car in the window for qualifying, that's impossible.

Like there's no way you're gonna do it.

So where the SIM comes into play is you can take a test list of 30 things and very quickly, you know, eliminate stuff that's bad.

You know, you're not gonna, you're not gonna go to the simulator, spend a day there and develop a setup that you're gonna start the weekend with.

But what you will do is you'll take a baseline setup and you'll know that these 15 changes we know are gonna be <inaudible>.

So we're not even gonna waste our time trying to address whatever problem we have in reality with those changes because we already crossed 'em off the list in the sim on.

So wait, it's, hang on.

It's an incredibly useful tool for that. Yes.

So it, it's, it's basically testing.

Like if you're making changes to the car making changes to the tires, what's gonna not work?

I mean, I mean this with every bit of respect that's due, why are you there for that?

Right? Can't they just have a computer program run a

simulation of the car without you in the sim and see what works and doesn't work? So

That's, that's great question.

We have that as well. So that's, that's an offline sim.

Um, but the offline sim and, and really that's running at all times.

I mean, we use that as a tool on the race weekend.

You know, that's especially what you use it, you use it for overnight changes, right?

It's like, okay, alright, we've got these four problems.

We need to figure out a way to, you know, improve the car balance here, but not like ruin all of the good things that are happening.

The offline sim is a driver that is ultimately the perfect driver.

Um, but where the offline sim doesn't, there's not the human element to it, which is both a good thing and a bad thing.

It's a good thing because you're getting something to replicate a lap identically every single time.

It's a bad thing because for example, if the sim if the sim driver, the fake robot driver mm-hmm .

Crashes, then he dials back the performance.

Whereas a real driver, they might realize that in this corner there's parameters and reasons why they can't push as hard as they can in the other 16 corners.

So the real driver will still always be quicker because if a sim driver is going offline, if the SIM driver's locking up tires or whatever, they're gonna back it up really for the whole lap.

They don't have the ability necessarily, you can't program in the, the human computing part of, okay, well just because he had a lock up here.

I mean you can, but it hasn't made its way to indie car offline simulation.

Yeah. So, um, and then the other, the other thing is,

and this is talked about a lot in Formula One, especially around this whole tappin, you know, concept and dilemma, is that a car that is optimized in the wind tunnel, in the offline sim in the shaker rig might be a car that is so difficult to drive that the driver's not gonna have any confidence in it.

And so even though you might be giving up, let's call it two-tenths, three-tenths of ultimate lap time, by making something that has a bigger window, the driver's gonna far exceed that gain of two or three-tenths just because they have the confidence to rag <inaudible> and to push it harder.

So that's where the element of the driver being involved is very important in the, what's called driver in the loop still simulator.

Um, so at ECR we use it, we use it a, a huge amount.

Um, and the reason we use it so much is really because what we're trying to do is a lot of the work is not really going into a race weekend.

It's coming out of a race weekend.

So we flew to Charlotte straight from thermal and all that we did was correlate the data in reality to what the sim data is in trying to get that to match as close as possible because all of these small micro adjustments you're making to the tire is building a better tire for you to use down the road when we get to Road America to mid Ohio, to whatever else road courses are coming up on the calendar.

Um, so it's, it's a lot that goes into it.

Um, there, just to give you a scale, there are, for every sim session there is, um, three in-person engineers.

We have you well, I have my race engineer. Yeah.

Performance engineer. There's a tire engineer.

Then also on site is three engineers from gm.

Um, then there is also seven people dialed in to, uh, essentially a teams call, which is the other race engineer, the other performance engineer, the driver coach, the damper engineer, aerodynamics, everything.

So it's, it's essentially treated as a test session.

There's 13 odd people involved in making what is honestly just a exaggerated computer game go successfully for a day.

So it's, uh, it's, it's, it's a frustrating tool because there are still some things in simulation land where it's like, that would never happen in real life and it can get annoying as a driver 'cause you're driving the car as as accurately as as you can.

Um, and you're driving it as you would, you know, out on the track and then it'll speed off into the wall and, and that sort of thing.

And it can get annoying at times.

Uh, but ultimately the, the benefit outweighs the, the frustrating moments.

So it's a, it's a very useful thing and, and we're very thankful to, to GM for all the time and resource they put into it.

I mean, it's like a $30 million piece of equipment, so that's insane.

Yeah. Well, before we get into like what the specifics of

what a sim day looks like for you, you talk about giving you the best tire, right?

So obviously you're, you're giving what you're getting, what Firestone's gonna give you, but everybody can make adjustments.

So what kind of adjustments can a team make?

Is it just like what pressure goes into The tire?

Unfor? No. So what, what I'm talking about is like,

you're building a tire model.

So it has nothing to do with the settings of the tire, it's the vertical stiffness, it's the ya sensitivity, it's the, the amount of grip that it generates in certain phases of the corner.

Um, and unfortunately Firestone doesn't give any information, so we're having to create a tire model from scratch.

All right. So from your perspective, I know

after thermal we hung out and then you, you flew out the next morning straight to Charlotte.

What does a test day look like for you?

Yeah, I mean it's, it's a full day man.

So essentially, uh, when I'm coming from Indy, it's super convenient to have an airplane.

'cause I can fly myself straight in Concord, uh, regional airport, which is liter, I'm not kidding you.

Three minutes from the sim And you made like crazy good time the last time you was Me, right? Yeah. I mean like hour and it's

A good tail wind. Yeah.

Hour, 40 minutes, like door to door. Yeah.

It's pretty, pretty badass.

So, uh, it starts at 8:00 AM um, I'll walk you through the whole thing.

So I I, I like to fly down the night before 'cause I don't want to wake up at four 30 in the morning.

Um, no one does unless they're wanting to record a podcast. Less

Podcasting. Yeah.

Uh, exactly. Yeah.

Um, so I fly in the night before I go to, um, one of my favorite restaurants in Charlotte called, uh, Mac Daddy's or Big Daddy's.

Okay. I know Big Daddy's Burger bar.

Um, I do a Make your own salad, stay at the Courtyard Marriott across the street.

I'm in bed by like nine.

Wake up at seven 30, run to the Starbucks show up at the sim at eight, uh, get in the sim around eight 15 and then I'm in it until 1130 ish.

Christian flies down on the 9:00 AM flight, um, from India to Charlotte.

He lands around 10 45 Ubers to the sim and he drives the sim from like 1130 to three, let's call it.

Um, in the meantime, like I have lunch, I catch up on calls, emails, I help them, um, you know, with, you know, what changes, you know, we should, we should move up the order or whatever.

And then I get back in the sim from three to six and fly myself home.

So it's, it's essentially eight to six with a two and a half, three hour break, um, in the middle to get some food and to reset your mind a little bit.

And that's the way that we've, we've best found to do it.

'cause I will tell you there at previous teams, I've done full sim days.

That's just myself.

And even though there's no physicality involved, you are so mentally fried from staring at a screen trying to drive a race car on the limit that like by the time you get to hour five, six, you're so fatigued, it all goes to hell in a hand basket. Anyways. I was gonna

Ask About, it's more demanding to drive the sim than it almost is the real car.

I was gonna ask about that because yeah, obviously you, you're not dealing with like the same brake pressure, the ti the tire.

Yeah, you are, you are. Okay.

So it, there it is still some physical demanding, but like Yeah, I know anybody can relate.

If you had like a really hard day at work, even if it wasn't like a physically hard day, I can't relate 'cause I don't work.

Um, right. It's not like you, like when you get home

and you just wanna sit down and rest Well, no, when you, you know, when you have to go to like a school function for Hazel or anyone has to go to some cocktail hour and you're like, we're a trade show and you're on your feet for a long period of time and you're talking and you're trying to be engaging, like, I would never do this.

I don't try and be engaging or talk, but in theory, if I were to do that, uh, then you're exhausted.

You're, you're burnt out.

It's, it's taxing on your nervous system. Mm-hmm .

It's the exact same thing for driving a sim.

Like yes, the brake force is there.

Yes, the steering weight is there, but it's like an air conditioned room.

You're in your shorts and a t-shirt.

Like you're just kind of chilling I feel like. Does

Elio, does he get in full fire suit? I feel like?

Oh, oh, he's full fire suit every Yeah, he's Full fire suit.

I could a hundred percent see that. Yeah.

Yeah, , uh, Simon does that as well.

When or used to do that.

I think power gets into suit, but the rest of us it's shorts and t-shirt, dude. Yeah.

Why on earth would you be in your fire suit? ,

They're just trying to get in the zone, man.

They're trying to get in the zone.

I remember at one point Marco posted a picture on Twitter of like the speedometer, but it was in a sim and it showed like going two 30 and, and people were online like, I can't believe you would take a picture in the car while going that fast.

It was like, do you think really think he would like, So yeah, it's, uh, it's a lot of it is ultimately a lot of work for everyone involved.

Um, it's a big time consumer, but it's, especially for where we're at at at ECR and what we're trying to accomplish, it's been a huge benefit.

And um, yeah, we'll be back in the Sim strait after Long Beach.

So, uh, race Sunday, fly to Charlotte Monday, SIM Tuesday, um, and it's just part of, part of the job, man, but it's pretty hard to complain about.

Your, your most challenging task is to go play Video games, drive A video game. Yeah. Yeah.

I mean, I'm a little upset that that means we can't do an escape room Monday after Long Beach, but I'll get over it, I guess. .

All right, we've got a little more time left.

So if there was, let's say like you, you were in charge of either ECR tomorrow or Indy car tomorrow or Chevy or Firestone, what's like one thing, if you could just unilaterally make the change, what would you do to improve a sim day?

Uh, have our sim, whether that's ECR or Chevys in Indiana?

In Indiana. Well it sounds like

30 million for that, right?

Well, I took for granted, so like, I obviously drove for a Honda team for seven years. Yeah. And that's, I

Took for granted that's like 40 minute drive from Indy, right?

Well, no, it, no dude, it was like 25 minutes from my house. It was in Brownsburg.

Oh is it? Like, I thought it was further than that.

Yeah, it took, well it's now by the airport, but no Brownsburg.

So I took for granted how nice it was to wake up in my own bed, pop over to the sim and then be home in time for dinner.

But, uh, that is what it is.

Um, obviously it's a small advantage for Penske 'cause they're local, but, um, not a small advantage for Joseph 'cause he lives in Nashville.

But yeah, I would say to have a sim that's in-house, um, would be my number one improvement.

So if anyone has 30 mil lying around that they want to toss my way, I, I'll check out the, I'll, I'll check out the couch cushions.

I'll see what I got in there. Right, right, right.

, we'll start a GoFundMe for Alex Rossi, SIM .

And, and on that note, like I think a lot of people are probably curious about, you know, drivers also, like I'm not the only one that, that spends this amount of time in, in the Sims, but also there's quite a few guys, McLaughlin, Paolo, Jack, Harvey, Connor, there's, there's, I would say probably 10 David Lucas, um, that have at-Home Sims as well.

So, you know, iRacing in, in a lot of respects has, is come a really long way.

And in some ways it's a little bit better actually than the sim that we have.

I wouldn't say from a realism standpoint of like the, the motion, the platform, the graphics, the steering feedback, the break feedback.

But because iRacing is a, is a community, like there's a lot of budget that they have to continually improve the track models and to continually update the car and the tire model.

Like iRacing actually has a thermal tire model.

Thermal meaning temperature not racetrack. I was, whereas

I was curious.

Yeah. Whereas, whereas in the sim like in Charlotte, none

of the teams use a thermal tire model 'cause it's just too challenging to get to work.

Um, so iRacing can be a, a huge tool for guys, especially if they're new to the series, they don't know the tracks.

Um, that sort of thing.

I think from where I stand, like obviously all the tracks that we go to, I've now been racing at for a really long period of time, so I don't need to have the supplemental sim stuff to learn a track.

But, um, certainly, you know, at home rigs now that you can get for six, well, I mean, really three to $11,000 are in a lot of respects just as good as the $30 million sims.

And, and the guys that work on the GM one hate people when they say this.

But like, that's the reality. Like you can get very close to

what we're using, um, at home.

So, uh, if that interests you guys, go do it.

You can, I mean, like from, from the driver perspective, I, I get that like Hinge talks about learning tracks by using I racing on tracks.

He hasn't been to stuff like that.

But you couldn't do like a full sim day with those 13 people you said were involved on one of those. Could you, uh,

What do you mean by that?

Well, yeah, I'm saying like, if, if you had, say Canon set up in your basement and they said, Alex, we need to do a sim day, we're just gonna send a few people over to your house and call the rest of 'em in.

We're just gonna do the sim day from your place.

Like could you do that?

You you could do I would say 70% of it.

Okay. Um, you know, we're testing a lot

of like damper stuff out.

We're testing a lot of stuff out that's proprietary to a team, whereas that's not gonna be in a dropdown menu on iRacing.

But if you're like, you know, experimenting with diffs or roll centers or wheel bases or spring packages or whatever, all of options that are in a mechanical menu on iRacing, yeah, you could a hundred percent accomplish the same thing.

But kind of what we're doing is that next level.

Yeah, yeah, yeah. Um, which is ultimately

where the cost comes in.

'cause the vehicle model and the math and the computing power behind it is just that little bit more advanced That 0.5%.

That's the difference between, you know, 13th Place and Pole. It's

A little too close to home there, pal. But yeah, you're right. ,

You didn't start 13th, right? ?

No, but I mean, I think that's my average for the year so far.

20th and sixth divided by two is 13.

Damn. Wow. I wasn't even trying to make fun of you.

I was just pulling a number outta my ass. Sure. Yeah. .

It's all right. You your top 10 finishes, you know?