# Corvette ZR1X | Apex Predator

## Метаданные

- **Канал:** savagegeese
- **YouTube:** https://www.youtube.com/watch?v=cTAPiFxWk5k
- **Источник:** https://ekstraktznaniy.ru/video/44241

## Транскрипт

### Segment 1 (00:00 - 05:00) []

Heat. Heat. We're at the end of the line, Mark. the book end to the C8 generation when it comes to high performance variants of the Corvette. This was the ZR1X. We just got back from Soma to drive this 1,250 horsepower Corvette. I'm sorry. This car does 0 to 60 according to GM on a drag strip, so a prep service of 1. 68 seconds and will run the quarter mile in less than nine. And sadly for us at a circuit we don't know that well, we were rained out for two days straight. And you have a conspiracy theory as to why. Well, that's because they said, "Hey, bring out a competitor to try to beat us on the drag strip. " I'm like, "All right, we'll call it the Lucid guys. " So, John and Andrew came out with the Sapphire and right when we're ready to dominate the Corvette on the dragstrip, Mary Barra made the whole day rain. And the John Colton, their development driver, he's like, "I'm I'm going to run it anyway. " So, he did and almost stuffed the car. So, needless to say, the drag race didn't happen. But luckily for the viewers, there's going to be about 25 million different videos of people taking an 8-second/4er mile and turning it into a 20minute affair. So there's going to be plenty of content to see on the drag racing portion. But for us, I felt like given the scenario, we're going to have our own track stuff with this car. I thought all the engineers are there. These are the guys that worked on this car for so long that got to this point. And when you saw and you got to talk to them and how open they are with us, then probably they're tired of hearing us talk and our opinions, but they really it really did shift my perspective on what this car is and who's working on it. And these guys are incredible. Like they are one of the best that you're going to find in the United States in terms of working on a sports car. And having the money, the budget, and having a group of leadership that understands how to get a car like this done, it's it's everything came together. And I really do feel like this is the peak for this brand. It's absolutely peaked for this car and I pray that they can carry on some of the good things they did here and make it into a next generation that has all these good things and more. But I'm I was so grateful to have been able to talk to the engineers and that's largely what we're going to share with you is some of their story and how they got here. — I hope you like the reading rainbow because this is going to be the approach to this video. You're going to hear from uh the chief engineer, the executive chief engineer, some seauite leadership from General Motors. You're going to hear from Controls Christ. You're going to hear from the brake master. And of course, what did you call him? The electric motor connoisseur. — Yeah. Exactly. So, all these guys are in We couldn't get them in the room all together, but we put them separate. There's just too much testosterone. — Yeah. And my tea levels were just tanking because I couldn't handle all the horsepower. But anyway, we're going to take this for a drive at the end and sum all this up. I'm Ken Morris, senior vice president of product programs, safety, integration, and motorsports for General Motors. The Corvette has evolved over time, and it's evolved in some with big jumps and some with little jumps and the analysis tools have gotten so much better and our simulation better. you know, our driver in the loop. We installed that in 2017 in uh Milford. And so the things that we can do before we have hardware, especially as we're kind of integrating how's the software all going to work together on the systems, it's just every element has gotten more sophisticated, and along with that ability to work on the cars in advance so that you have, you know, we have a clear expectation of what we want. uh we can prove it out with analysis and then simulation and then we have it on track and that's where you know we really polish it off. We were learning, you know, how do you make a car that is fast and precise but without being edgy, you know, and so how can you be neutral

### Segment 2 (05:00 - 10:00) [5:00]

without worrying about over steer? And you know, the thing at least for me as a driver that brings confidence is knowing that I don't have to worry about the back end of the car. You know, especially any sort of snap behavior. And it's really important, but it's at the same time you don't want to numb it so much that it under steers all the time and isn't precise. And so when I started getting involved around 2006 and you know the C6 and the you know it was already in production but as we were evolving that what I always challenged the team to do was to make it approachable so that it wasn't the you know the 99. 9 percentile drivers can get the you know close to the best lap times. It's, you know, can someone that is an enthusiast but not a pro driver or not, you know, not a pro like a development driver get in and drive the car and feel comfortable and get times in it. And so I think that's evolved over time and I think C8's better than C7 is better than C6 is better than C5. And I think that's evolved over time. So I think that's part of it. I could describe ZR1X as the culmination of thoughtful planning and technical capability. It's the bandwidth of the eighth generation Corvette planned from the very beginning all the way to packaging the LT7 twin turbo. uh the width across those giant turbos from side to side, integrating the 1. 9 kilowatt hour battery pack and the central tunnel, the backbone tunnel that provides torsional rigidity to the chassis structure and all Corvettes and then nesting the bespoke very compact powerful front drive unit all planned from the beginning of the eighth generation architecture. Yeah, to expand on that, right, it's the intelligent use of electrification um in the car. It's not just a gimmick. Um it makes the car better. Um all the things you like about a mid-enine, rear wheel drive car. By having the two powertrains separated from each other and not having that mechanical link with the controls, we can do a lot of really cool things um that make the car feel natural. Um it's a different experience than a ZR1. Um, we like to say it's not necessarily good, better, best. It's different. Um, it's certainly more powerful in a straight line. It's obnoxious. You guys have seen the numbers. I mean, it's just truly amazing feeling. So, — take a,64 horsepower car at 186 horsepower to make it more approachable. — Yeah. Well, and we were talking the other day when I started at GM, I think the Corvette had 245 horsepower total, you know, back in the late 80s, early 90s, and we've almost added that much more on top of our 1000 horsepower car. So, yeah, there's so many crazy things about these cars that we work on these days. There's a reason that people started moving the engine to the back of the car in the what 60s. Um, so yeah, and the way the incredible team that laid this whole thing out, um, like you said, this you can't do this as an afterthought. You know, where do you The battery is pretty small when you consider what it does, but it's pretty big if you didn't think about where to put it long before you want to put it somewhere. So, — right, I think of it like it's revolutionary hypercar performance through evolutionary learning. Mhm. — So we planned the architecture to for this to be a book end of it, but all along the way developing cars like the Stingray, the Trackr Ready Z06, the Ultimate GT E-Ray, building on those components. So it's not continuous work on a ZR1X. It's knowing it's happening in the background. We have a lot of technical capability all working on their subsystems and components to get ready for the integration in the ZR1X when it's time to go build real cars, do real chassis tuning, real controls work and track development. — If you think about the people involved to your point, I mean, we've had such a great portfolio performance products in the last, you know, 15 or 20 years at GM. We talked a lot yesterday about Trailblazer SS's, Cobalt SS's, all the V series Cadillacs that we've done over the years. All of this stuff, if you — HR, — HHRSS, the panel, um, if you look at the folks that are even here at this show or the folks that work on Corvette, they they've cross-pollinated on a lot of those products. You know, Aaron worked on V series, Drew tuned the Celesteic. I mean, so there's so much of that goes on. And as you go through your career, any of us, you learn the things that you wish you could have done differently. And when you had a team that was sharpening a blade that just wasn't capable physically of doing you, we knew exactly what to do. And that's why we

### Segment 3 (10:00 - 15:00) [10:00]

were able to architect this incredible car. It's not an accident. Um the tools you mentioned, you know, we share a lot of the same people that help us with aerodynamics and cooling are working on doing our GT3 car or our um GTP car for Cadillac. Um or now some of them even off working on Formula 1. But a lot of these folks that really architected this car many moons ago, you know, like a decade ago, really kind of laid the bones down. They enabled this. This isn't an accident. So yeah. — Yeah. I guess you know we have if you ask any one of us we'd say we have our dream job. We're all car people. We're super enthusiastic. It's easy to work on a car like a Corvette. — It brings a lot of passion. Uh but people have experiences from all over the company they bring forward with them. And like most engineers, you never want to stop tuning. You can always make stuff better. In fact, Tony and I oftentimes have to say, you know, we're done here. We got to actually put this car in production and pay our bills. There's a lot of technical capability, technology advances, of course, that makes — our job easier to do, quicker to do in most cases. — But it's all built upon the people that have that experience from all over the company that are what make the car so special. — The crime, — well, the hardest part of our job, you just mentioned it, but I swear. And we were just in a situation in a conversation a couple days ago where we're arguing with somebody to like, okay, we have to stop, you know, and he said to me afterwards like, "I know you don't want him to stop. " I'm like, "No, I stop, but they have to stop. " So sometimes you got to literally put on your — Okay, all right. I got to be the adult here. You know, like you guys have to stop. Now that you've heard from some of the leadership responsible for the C8 ZR1, it's important to understand that none of this happened by accident and that the story really started all the way back in 2008. And what it took was careful planning, proper leadership, and of course buyin from upper management, so money to make this all happen. So, while the horsepower figures are impressive, yes, you have a 1,250 horsepower mid-enine, twin turbo V8 Corvette with an e- motor and huge tires and over a,000 lbs of downforce. What makes this car drive as remarkably as it does is all of the systems integration. So, first person you're going to hear from is Keith. So, we're back here with Keith. Keith had worked very heavily on the E-Rays electrification and now we're coming full circle again to the big boy and this car also has a very similar electrification strategy but it has been altered quite a bit to make this uh I I'll let you explain it. Tell me what the philosophy was and the change in your philosophy for the ZR1X. Well, yeah. So, we're very proud um of the electrification system we came up with on Ray and that this P4 system is through the road hybrid system where we have a front axle separated from the engine on the back. Uh this that's the same concept that we have here. And in fact, you know, um if it wasn't for having a,64 horsepower in the rear, we might have just carried the same system into the ZR1X. But what happens when you have 1,64 horsepower over 800 feet footpounds of torque? Uh there's just so much authority on the rear of the vehicle that as you yaw the vehicle, you need them to try to match that authority on the front. So we looked at what our max tractive capability was on the front tires. We looked at how much authority we would need to balance the rear. And we increased the front axle torque up to 145 ft-lbs. Um, we used some additional battery energy to increase the horsepower up to 186 horsepower. And then, um, we took our, uh, all of our software algorithms that do the balance between the front and the rear, the vehicle model that breaks that up. We had to become much more predictive. So, looking at the inputs that the customer is putting in, you know, how much they're getting into the throttle, steering, and start to feed forward some of that front axle torque. So, if you're coming into the curve and you're going to um you know start to steer in and you're you've got so much speed and you we're predicting how much traction you have, we'll start to pull through knowing that we don't want to let that car get into a bad situation. So, uh because it's so hard to recover when there's so much authority on the rear of the vehicle. So, uh all of that was done and improved on what we learned from the -ay — and the hardware changes to the physical electric motor. uh you've it's just more robust in terms of what you've done. Can you just detail those changes? — Well, so one of the big things um that maybe that I didn't mention just now was that we take the motor up to 17,000 RPM now. And we used to go to 16,000 RPM. The motor has a lot of centrial

### Segment 4 (15:00 - 20:00) [15:00]

forces trying to pull itself apart. And so we're, you know, going to control to that limit with a disconnect unit. And so we moved that disconnect up to 17,000. uh to make that safe for the motor, we had to increase uh and improve the bearings, the load on those bearings around the motor. We also had to in increase the um stiffness of the output shaft as well as the bearings around that to handle the additional torque that we were putting in. And then the structure of the unit was modified to it's a magnesium housing as you know but uh there's additional structure on there to just stiffen the housing and make sure that um you know again from the axial forces that we're getting with that additional torque that it was uh being managed properly. And so we did all of that through analysis and then proven out through all of our track testing and eventually 24 hours of track testing. — Okay. And so that extra RPM in the electric motor also gives you that higher top speed cap before that disconnect comes in place as well. — Yeah. And that was a really fun one. Um our leadership asked us, you know, what we thought that we would be able to achieve on a drag strip. And as we went through the analysis, we saw that we were uh well exceeding 150 mph on a drag strip. And it was very important to us to not disconnect the front axle on the drag strip because we were trying to get every hundth that we can. And actually really important here too, we reconnect even when you're in ABS. It's very important for us to be recapturing energy even when you're in ABS because going around a track you get in ABS a lot and so therefore we could miss a lot of opportunities to recapture energy. So there was a lot of work but done by the team to figure out how to reconnect and regenerate while in ABS with a lot of lessons learned there along the way very early in development that we were able to solve on how to sync up and do that very quickly and then reconnect and then at that higher speed you're going to recapture more energy. So, we were actually finding um as we went around um in Virginia International uh Raceway, we got 9% more capture per lap when we were doing this higher reconnect of energy capture. — In terms of your battery uh tech, I know it looks like you've raised the total output or is it was there chemistry changes to the batteries or more cells or was it just a software change to that? — Yeah, so it was a very intentional software change. Uh what we did, we had a lot of lessons learned again from Ray and how we were using the battery. And then we were started to see how we were going to use the battery with the ZR1X. And there's a couple points here. One, when you have all of this power, 1250 horsepower pushing a vehicle around a track, um you actually get to that disconnect point um much quicker than you did in an E-RA. So the amount of time sustained at max power is different. Uh we looked at all the models and our abuse tests and we saw where some assumptions about how we were using the front axle uh were um needed to be updated and corrected. And so we found through our analysis tools and then backed up through some testing but most important I guess I should say this battery testing takes a very long time. We have very um excellent capability of Warren but as you do the cycling it's a slow feedback loop on the damage and so you know we were working through but it was a slow feedback on exactly how much damage we were creating versus what our analysis would say for the life of the pack. Um so all of that we were able to go back and look at hey this battery is capable of much more usage without affecting its life and that's what we took advantage of with the additional software. So you kind of took the buffer off of it. There's a less of a buffer at the top end of the battery. — Yeah. It wasn't like it was a design in buffer because naturally we're going to keep margin in because we want this pack to live a full life which doesn't matter which vehicle it's in. But it was identifying in the way that we use it what that life really meant in using it. — Okay. Well, I'm going to have to put a stop to that conversation and we're going to start talking about the braking system. And this brand new braking system is in large part helping or fixing some of the biggest deficiencies that we have with the current generation Corvette. And I had an opportunity to talk with one of the lead engineers who had helped to develop this system and all the details that go into it. — I'm John Washington. I'm the lead brake system engineer for the J59 system on the ZR1X. — Okay. I I'm excited to talk to you because I think we talked off camera a lot and we talk a lot about brakes. brakes because when you're dealing with cars, modern cars that are now heavier or in this case making insane horsepower, you're getting up into the triple digit speeds basically without even trying. So, you got to bleed off that speed. And brake systems have come under a lot more stress. But in the modernization world of hybridization, you're going into brake bywire systems. uh you're doing regen brake blending. So, it's getting harder to make brakes feel natural along with giving you consistent stopping

### Segment 5 (20:00 - 25:00) [20:00]

power. So, when we're talking about the new brake system here, the Alcon collaboration you you've done, um John has worked on this brake system, and I can't believe when you said this. Tell them just tell them how long the development process has been on this caliper or the new updated brake system. Yeah, I want to say um I remember doing the first kind of even just spreadsheet math um initial calculations in late 2018 2019 time frame and then probably you know more core design uh work started um I would say in 2020 — and this caliper went into production in 25 — correct. So, you're talking about like a whole generation of development on a brake system, which I think it goes to show you that it, you know, you think of an entire car getting built and you're talking about it in 5 years, but we're talking about a brake system here. So, let's start with — why. Why did you go to this? Why was this so important? the brake system has to um basically supply the car with all the torque that it needs reliably over and over again, right? So, a as horsepower and you know increases, lap times decrease, even um in between braking zones, the amount of time you spend from turn one to turn two is less, right? Okay. So, brake power up, energy up, um, and cooling time decreases, right? And you're going faster in between, but that cooling time decreasing. So, we needed a basically a new system completely from scratch with, you know, new levels of caliper stiffness for the torque that we're seeing, uh, new levels of thermal capability um, for the heat and power that are going into the system, new levels of, uh, friction performance, right? And that's what kind of demanded, okay, you know, let's do this from a blank slate for the ZR1X. — So, you're taking a caliber design here, obviously, clean sheet, and then you're working with the guys at Elcon who are doing some of the major engineering and then also for motorsports. — So, this collaboration was there and a lot of this was designed and developed of the clearly in the digital domain and proven out there. — The caliber itself when we look at it, um, that there's clearly this is like a really good hybrid uh between a race caliper and like something that you could design for the street. — So this looks like it perfectly fits within the architecture or the wheel architecture of the Corvette. So how important was that in that design process? — It was very important. So, you know, like I said, we kind of start off in the simulation world where, you know, me, like you said, h half a decade ago, you know, we're doing lap time simulation of a ZR1X, right? Around we have different target tracks for brake temperatures and performance. And um when you're doing that, you're looking at, okay, you know, what pad sizing do we need? And then you know when we started working with Alcon we kind of lay out okay um here you know from a system level here's like the caliper stiffness and response time that we need to give the car the capability that we're after. I think it all starts virtually and you know we were working back and forth with them on kind of correlating our methods of you know okay this much fluid consumption this much travel at these temperatures at these torqus will give us the system response we need this amount of pistons to balance the pressure distribution at these high dels and also not introduce taper wear at too low a del so if you look at the caliper you have you know five pistons per pad it's a 10 piston caliper but they're not centered on the pad. They're offset. And that's how you compensate for the load transfer under really high amounts of torque. — And I think when you see this with a lot of brands now is it's just like everybody kind of uses the marketing of like we just put an off-the-shelf big Brembo brake that we pulled from a supplier, — you know, and that fits most cars, but this is really truly oneoff design for this car. Correct. specifically from, you know, pad material, pad sizing. You know, the concept of we hear constantly like, oh, you just keep adding more pistons. You add bigger, you add more pistons. But really, this is more about the efficiency part of utilizing this pad space. — Correct. — You know, with your piston design to make sure and you show very clearly like pad hot or pad hot spotting, you know, the distribution of pressure is very even to keep — longevity here. And this is something we talked about kind of off camerara is the idea of carbon ceramic, carbon ceramic matrix, you know, long strand carbon ceramic. Now, um the concern is when you get them outside of their heat range if they're not designed properly, they tend to really break down quickly. And this is one of your core tenants of this design is to make this system

### Segment 6 (25:00 - 30:00) [25:00]

almost like a lifetime part. Not the pad per se, but the cal the caliber of course without a rebuild. And then the rotor is far more resilient now because of the coating. Yeah. Long strand and the pad material. So kind of just — give me a crash course on that briefly. — Yeah, that's uh it's a great question because the performance car brake team at GM, we're all track rats. Um and you know, we care a lot about the customer at the track, right? And what they have to live with. We see it. We don't want to just engineer this to meet requirements. We want it to be, you know, a customer satisfier for street cars that go to cars and coffee and racetrack customers. And — so you opened up a financial division for home equity loans to give loans for breaks. — Exactly. So, you know, we put a lot of effort into what can we do to improve consumables, right? Like you said. So, we're very aware of the, you know, the carbon ceramics are great, but when customers have to live with them a long time, you know, we'll see them swap to like, you know, an iron kit or whatever it may be, like our true track rats that really put on a lot — like ours, our AP stuff. Yeah. — Yeah. So, you know, focusing on that, what we did here was if you look at the pad volume uh compared to the current system, um there's several millimeters more of pad thickness and on top of that um the the area of the pad is a significant I want to say it's like over 15% more or close to 15% more area. our, you know, our partners. We were getting into projects with them where we'll like run a wear schedule on the dyno and they will change friction manufacturing parameters with the same formulation to get us better wear rates, right? But not too much to where you worry about like the friction itself being jeopardized with too many heat cycles, right? So, you know, I want to say we experimented with well over 10 or 15 different formulations and then within those formulations, you know, changing the manufacturing parameters of those to really dial it in. And at the end of that, combined with the caliper that's wrapped around it, the front and rear optimized pressure distribution, um, all of these things, uh, lower temps, you know, large, uh, 16. 5 in rotors, 420 mm. What that resulted in is, you know, we're seeing over five times life, uh, pad life increase relative to the the, you know, what we've seen historically on core. Is that your like Brembo carbon ceramics compared to those or like what's the wear rate compared if you can even say? — Yeah. Um it like if you compare to say the Z06 carbon system, right? Uh we're at about 5x life, right? Pad life. — That's a massive difference. — It's So the last question for you before I let you go is obviously a lot of that just to follow piggyback on that a lot of that has to do with temperature management and heat management and keeping everything in its window of its heat range. But that's also the difficulty which goes into like NVH. Not only do you have to keep the system in the right heat range when it's really cold, really hot for optimization where you're not breaking and you're not getting the performance out of it. It's a counterintuitive nature of a high performance brake system of having to have this wide range of functionality, but you can't have any noise. Yeah. — And it has to be consistent in all these heat ranges. So, talk to me about all the work you had to do for NVH to get rid of the noise out of the pad. Yeah, it's really um clashing physics. The levels of friction we see on the racetrack can be upwards of 65. Your standard passenger car can be. 35. Early on, even virtually um you know with our wider engineering team, we had to design the caliper and you know collaborate with the suspension team. all the hard work they put into the knuckle itself on looking at analysis to make sure that we're in the right range of stiffness um to not light up certain you know frequencies for brake noise. And you know you have to even analytically look at pad design, caliper design, rotor design, you know, the cooling vents themselves um to not align in such a way where for example it creates like a really nasty 3 kHz brake squeal. You kind of do that analytically and then when you throw the pad in and into a you know dynamic system say on the brake dyno, you kind of have to start tuning friction. noise chamfers, things like that, right? So, like, um, through development, you know, it looks like such a little thing, this chamfer here, right? But we um we probably went through probably between the front and

### Segment 7 (30:00 - 35:00) [30:00]

rear well over a hundred noise tests between um corner d like an actual dynamometer in a lab and then we have a full car uh chassis dyno that goes through different levels of humidity, cold, heat, everything. We probably did 2 years of noise testing on this system because it it's not easy, but you know, it makes it a lot simpler to design a race car brake system if it's just loud, right? But, you know, we have a lot of customers who want to drive this car to dinner, who want to enjoy it out of cars and coffee and not, you know, be squealing like a school bus or a garbage truck every time they pull into the parking lot. This is the thing like when you you're spending 5 years of your life trying to develop a brake system and then you're like spending two years of the analytics of trying to get it to be quiet counterintuitive. This is a very long conversation about some of these subsystems that are the the detail work that really makes something like this the sweating these types of details is what makes these cars operate at a high level that most people don't have like a great appreciation for. So, I really thank you, you know, for your time to kind of go into the detail and uh we're going to obviously continue this on into the control side, which is the magic. So, obviously, we've talked about some of the formula responsible for the 01X, the enormous Alcon brakes, the LT7 with the E- motor in the front, but it's important to realize that a car is now just not a cobbled together series of components. Yes, you still have the C8 architecture with the double wishbone front and rear suspension. You have the crazy era, the thousand pounds of downforce, the MR dampers, but what matters now today is how you integrate everything together. Cars now are largely controlled by electromechanical systems. So, we're going to speak to Cody, who's one of the lead controls engineers on this car, who's going to walk us through some of the philosophy, but how he made all of these systems talk to one another with his team to make this car do everything. My name is Cody Buckley. I'm a chassis control integration engineer on the Corvette ZR1X. — This has some of the similar logic idea that the -ray has where you squat the rear by sending power to the front first. Walk through did that just directly carry over from the -ray. How are you doing it now with the 01X? Cuz to somebody's point who made this point, probably you a couple minutes ago, um the rear motor has a lot more power than the LT2 has. — Mhm. Yeah. So, when we started off, like we carried a lot of the same strategies and calibrations and software from the -ray, but as we were talking, when you get all that weight transfer from the ironically more front torque and more rear torque versus the E-Ray, it actually was popping a wheelie spinning the front wheels. So, we actually couldn't hit it as fast as you could on the front because it would cause this slower 0 to 60 in 1/4 mile because you're creating a physics problem with traction now on all four wheels. Super cool and fun, but you're spinning all four wheels. we needed to go faster with traction. So, we actually control that rate a little bit more to be more in line and more synchronous with the rear axle such that you get the traction on all four. And obviously, that was a combination of tuning on the e- motor as well as the suspension, the MR, getting that whole coordinated process to be absolutely perfect. Who gave you the idea cuz this is probably one of the few cars I've ever experienced to send power the front first to squat the vehicle. Obviously, it makes sense from a weight transfer perspective, but how did that come about? Yeah, honestly I think everyone understands the physics and how that happens, but like in practicality, I think we were just messing around one time and said like that's cool and then you kind of run with it, right? Like that's how we created a lot of our ideas and strategies. You just kind of go out and feel it out and see what happens. You know, your feel with the car and the motion and reaction. You can take that and do objective things with it, which I know you guys are all into feel and how everything responds with you. We take that and then we drive that to make metrics and objectives around our control systems. I think we were probably just messing around and noticed what it did and said, "Let's use that to our advantage and make some fun with this. " — Unlike a uh 849 Tessterosa or a Rouvalto or the new Tamario, sorry, I couldn't remember what it was called for a second. The Tamario, those cars, while they have an e- motor in front or even the old NSX, your e- motor is torque vectoring by brake. You don't have individual electronic torque vectoring through electric motors on the the two corners. How are you managing the brakes in the front to make sure that you can equally distribute the load that the front motors are doing? — Yeah. Is this like on a racetrack or — in a straight line when I'm just launching the car? Are you constantly uh shifting torque left and rear to try to manage the — slower? Actually, like what's makes our system beautiful when you think about the relationship to the driver to the car is when you have relatively simple hardware and I'm obviously overexaggerating. It's a really complicated drive unit, but the way it functions is simple. It's a 8 to 1. 5 differential single motor that splits the torque. And what makes it nice is you can have really intelligent controls, but we want it to feel natural. We don't really

### Segment 8 (35:00 - 40:00) [35:00]

digital and stepping around a lot because that gives you that computer feel. So, we spent a ton of time making it feel natural. But actually, when you're launching the car, specifically talking about straight line, we don't do any left to right vectoring via brakes. That's turned off. — Wow. So, we're letting it 100% be controlled by our all-wheel drive vehicle dynamics and then our motor controller. So, they're making that decision and really all they're doing is controlling the net torque. And then we can actually have an overflare control where if we end up doing a huge front wheel spin, we have like at the motor level called wheel flare control where it it's nearly before the wheel speed sensors are picking it up because it's at the detection of the motor and that has a handshake and a synchronization with the traction control that gets ahead of it. But that's all just torque control, no brake control. — Walk me through or walk the audience through how this car gets around a corner. — Yeah, sure. So, it actually gets pretty cool when you think about starting in the corner, like when you're coming in the brake zone. We had a lot of really neat strategy and software on the -ray, and we effectively dialed it to 11 on this car. Anything we could exploit for lap time, response, and feel, we went for. So, when you're going under braking, you've got friction and regen. When you start trailing off the brakes, you've now got you're going to trail into just regen, right? you're going to have no friction brakes. And if you did nothing, that would create an under steer moment in the car, right? You're driving a moment on the front, not doing anything on the rear. We created what's called regen brake torque vectoring or RBTV, which actually is a really intelligent algorithm that does calculations on what the impact to the desired path of the regen is. And if it's going off of path for a desired input, it will actually like the easiest way is to think of like a Hot Wheels, it starts pulling small relative brake pressure split on the rear where it increases the rear and offsets and creates like an over steer moment, but only enough to balance the regen. So this is all coordinated through the corner and as a driver, you don't actually know what's happening. You just feel the car drive into a corner like a rear wheel drive, but you're recapturing energy. And it's very specifically called regen brake torque vector because it's not traditional. It's only on the rear axle and only on the inside rear wheel. And the way this comes in is let's say you come in, you smack the brakes, you do a full ABS stop. Like think of like VIR turn one. — Okay. — And when you need to get down to the apex, you don't have to hold ABS all the way to the apex. You can start to trail in. But when you're trailing, you want the car to have a nice tuck balance. If you kept that regen, you'd struggle to get down to the apex. — You shift the weight forward. Yeah. — Exactly. And you've got that regen moment. Nothing happening on the rear. So in this condition, it's actually artificially adding inside rear brake bias to get the car to rotate like a drift moment, right? Like E brake feel, but only it's very dynamic, right? Algorithm, but it's enough to get the car perfectly or fine to get tucked down there. — So it almost feels like rear steer. — Yeah. It can kind of have those same effects, right? You could do the same thing with rear steer. But when we do this, it makes the car feel coordinated and consistent. And the thing is, we have to prioritize regen because we need the energy because you're going to use it all in the corner exit when you come out. But we can take learnings from the -ray and learning from the ZR1, put them together. So when you think of midc corner, our car really behaves almost identical to a rear wheel drive ZR1. There's a little bit of coast regen, but it's not enough to really have a significant difference to feel to the driver. But so midc corner all the systems are acting and you're using from a controls perspective the ELSD to on the rear axle to help drive the car to the desired balance in addition to the ride and handling chassis of the car. But once you get to that point where you're ready to put power down, of course, if you just mash the gas in like a 50/50 all-wheel drive, you're going to drive it with a Subaru, you're going to under steer over the corner, right? We have very intelligent algorithms that understand again the driver path, a friction circle of the tire grip at each corner, front to rear, and what the ELSD is doing as well to understand if we should or should not put power down. And what's really beautiful on the ZR1X is we have a really intelligent algorithm from the engine that explains the predictive or the amount of torque that's coming so that the all-wheel drive can get ahead of that. Right? So with turbos, you've got some more dynamics you have to deal with, right? If we did the same all-wheel drive split every time, you might get under steer, sometimes you might not. So, it's really important for us to understand what the engine's about to do because that can create a moment in the car as well. So, these predictive algorithms all work together to give you that feed forward split as you come out of the corner. And what that does though is like as you're tipping into the throttle, if it doesn't need all-wheel drive, we don't use it because we don't need to spend energy and waste it. You can use that for boost later in the straightaway on the front axle or hybrid boost. But when you get to the point where there's like a potential to have a moment in the car, which we get all the information from the sensors, available traction force, the differentials, performance, as well as what the engine's about to do, you can say, I'm going to start feeding in the front axle. And that's based on those algorithms, very dynamic. And when you get deeper into the throttle, you're going to start generating a rear to front wheel slip. And that condition triggers what we call our wheel control algorithm, which is a really true uh based on almost your feedback of what's going on. And that's what makes it so smooth and consistent where you're driving an all-wheel drive split. That's where it starts to feel like an all-wheel drive car. You've gotten past that initial potential for under steer

### Segment 9 (40:00 - 45:00) [40:00]

and now you're driving the car off the corner and you want that all-wheel drive dig cuz you know now you're trying to put down 1,64 horsepower behind you and that allows you to like feed into the initial split into this wheel control and then that's allows you to have that confidence as you tuck out of the corner. The last part of this, and this is a part that Mark talks about and we've talked a little bit with John Washington about — um the other controls is braking. — The contentious point that a lot of people have with the modern I know they're not break by wire. The pedal's physically connected to a booster, but the feedback loop is digital. — Um when you get onto brakes, traditionally, if you've come from older cars, the idea isn't just to stand on the brake pedal and have ABS sorted out, but that's how you program this car now, right? is smash the brake as hard as you can. Our ABS controls will figure it out and you will break quicker than if I threshold break into a in a big braking zone. Is that sort of the logic internally on how you're managing braking in this car? — Yeah. So, it comes two ways. Absolutely. Yes. We know the fastest way for our cars to achieve the best lap times is to do that. But to that point, we still do drive in those other drive styles. Like it's really important as a controls engineer that you drive to cover a different drive style and different bands of what people could do with the car. Like if I just drove it for me, it might be great for me, but it might be bad for you. So we got to cover those bands. So we do spend a lot of time in threshold and trail braking, making sure that front to rear bias is right. So like we've got our electronic brake proportioning. We have to make sure that's good as you come out of the brakes, etc. So we cover all those when we're doing our tuning and development. But yes, what's beautiful with these J59s, when you come into the corner with a 1000 horsepower in the rear axle and all that all-wheel drive help, you want to be able to ensure that you can stop consistently every time, every brake zone. So, for us, we needed to make sure our controls were up to the task, up to the par of making sure that every time you, you know, I got this when I come into this, I'm not going to miss the brake zone. roll deep. and we spent a significant amount of time making sure that regardless of what driver input you're doing at the ABS systems there to help you recover. So when we talked off camerara and this is a debate our team has had with you and not even right or wrong just I want to get through your logic is because you've st not you but because the technology that every manufacturer is using a variation of an electronic brake booster has stripped out the traditional feedback loop of hey idiot you're an ABS your braking zone is about to get longer than it would be if you weren't an ABS. uh how are you or what are you looking for now that when you're driving? What feel are you trying to work with to know that the braking zone's about to get longer? What do you look for as a driver, I guess? — Mhm. Yeah. So, obviously, like when you go back to Camaro or a seventh generation Corvette, you've got really good mechanical feel with where everything's going on. We all had to adopt to eBoost as well as we started driving these cars. One thing that I personally look into is like the del close loop. Like, if the Dell is not there, regardless what I'm pressing, I can tell something's wrong. I need to adjust. And then I get it like in the seat, but um obviously like that space is very different. Like when you talk like steering feel, everyone has an opinion. Everyone sees this differently. Braking's similar. So like that's what we use. Like we go off the diesel loop. Like if I'm pressing the brakes and I'm not getting the diesel I expect, that usually gives a good indication. But like when I'm tuning ABS, I can still tell what each wheel cycle is doing, like the actual control based off the feedback I'm getting from the seat. And that just comes with time. So I challenge like anyone that struggles with eBoost in general or our cars, give it a chance. Give it some time. Get try to get some more stops. And I think it comes with time and you get used to it. Just like you were saying like drifting on cars. It feels odd. It feels awkward at first and then you start to like it and then you love it because what you can do with it. I think eBoost brings some of those trends in as well. Like if you just jump straight into a car, it can be a little bit tough to get used to at first. But I think it comes with time. It's like with taste. But um it is different, right? So it is one of those things you got to get used to verse a mechanical system. — Understood. Thank you very much. Now a quick word from our sponsor, Open Track. Open Track is a track day insurance provider. You may not realize this, but if you drive on a track, your regular car insurance will not cover an incident. So that's where Open Track comes in. They sell individual event-based policies and annual policies like a regular insurance company. Now, as you're about to see in our track drive, we probably could have used some track day insurance because you never know what's going to happen. You can be caught out in a rainstorm like we were. You can have a blowout. mechanical issue. In some cases, you can't skill your way out of a problem you have on track. And hopefully, if you buy a track day insurance policy, it also allows you to enjoy your car with greater peace of mind. So, please use our affiliate link at the bottom of this video. Oh Lord, help me. Four Corvettes.

### Segment 10 (45:00 - 50:00) [45:00]

This is the fastest one. This is what they worked for since like 25 years ago. — 01X, Mark. — Yeah. You have future GM employees in the womb drawing this car up. So, what do we know? Uh, we know that we're in a car without ZTK on Pilot 4S's, not in track alignment. We're at Soma Raceway at a track with mixed weather conditions, which means it's wet in some sections and dry in others. So, uh, needless to say, there's high pucker factor. Uh, powertrain 1,250 horsepower in a Corvette with all-wheel drive. Mark, we know it's a lot more than that. It's more than that because cars are fast. Is it just fast or just do these systems work? That's the key component. — Well, uh, as we drive 140 mph to a braking zone, — I knew breaking zone. — Pardon? — I knew you weren't going to make that one. — I actually fault the ABS. — I did, Mark. as I screw that up. Um, what I will say is like the balance of these cars compared to the regular ZR1 is that car is a car that you drive around the rear the entire time. This isn't like we drove this in just truly horrifically wet conditions the other day with an -ray and then we drove this earlier today in lead follow where is also horrifically wet and yeah as you experience it's surprisingly stability forward I mean h what are your feelings? — Well the confidence part of having the front axle I think this is what's lost is you know people get phobic of like kind of hybridization or electrification of it. Yeah, it adds more power in the straight and dry, but really what it does is it stabilizes this car quite a bit. You know, when you start to feel the ascent moving around with over 1,00 horsepower and the speeds that this carries, there's a like you said, a pucker factor. I think I did leak stool earlier in the wet, but the front axle really does help to neutralize this car a lot. And all the controls that they've done, at least from our experience driving this so far, is everything feels really cohesive. You're not fighting it. It's not fighting you. It's not doing anything strange. I do feel safe in here to a certain extent. Um I mean, obviously, we're not in a dry, so I can't speak to the at the limit threshold of every system, but man, this feels like way more than anybody could possibly need. This is a manslaughter charge on the road waiting to happen. I think one of the things that I um like dynamically when you're as you're going through this, I don't know this track super well and again it's mixed conditions. I can be greedier on the throttle like can be in a CR1 and the torque bill you get sort of sub 160 which really is the only speed you'll ever be hitting in this track with these conditions does a really good job pulling you through the gears. I think the other thing I'm gonna notice is sort of the way the brake pedal now is connected to these alcons. Like other than back there where I got in the APS, I'm like, "Oh, I'm going to be Aaron Link. I'm just going to stand on the brakes and see what happens. " There's not a lot of brake feel, but the actual stopping power this car has. And I imagine on a Cup 2 R. I do notice that the brakes do feel a lot more potent. I mean, even in like this scenario, I feel like because they've provisioned the brakes properly for the power of this, it's far more consistent. And it it feels like you're it's communicating more to you than the previous system we drove. Clearly, we're not in the bone dry, so it's hard to predict, but I think all again, all these systems are they've learned everything they needed to learn and they maximized this car to the best of their potential. And that's what it's showing me. And then you look at the speeds, dude, I don't even want to load. I don't want to know how fast you're going. It's frightening how fast this car picks up. — Well, I am I am, let's call it, uh, driving easy knowing that part of the Shrek is wet and the speeds you see are so unbelievably effortless. I think comp and naturally I can't see as well because of all the cameras. Um, the speeds you're carrying in this car compared to like a Z06, which is always going to be my benchmark cuz that's the car I have so much seat time in, you're probably everywhere carrying between like 20 to 40 miles an hour more depending on the conditions of the track. It's like I look down, every time I look down, you're like over 100 miles an hour as soon as you pull out of a corner. I mean, it's just you can't drive this and not be at triple digit speeds. It It's just unbelievable what this car is. And I I'm just worried like the buyers of this. I hope they take some serious time to do some driver training before they go out and whip this thing around because it is it was down. Even for us, we drive a lot of cars. This is no joke. This is absolutely no joke. All right, Mark. So, with that, do you want to wrap this up, sir? — I do. I want to get out of here as soon as possible.

### Segment 11 (50:00 - 53:00) [50:00]

— No. Final thoughts on the Corvette ZR1X. First off, huge thanks to our title sponsor, Bridgestone. Without them, videos like this would not be possible. So, please take a look at their enormous tire catalog. Also, thanks to the sponsor to this video, Open Track. If you're heading to the track in the future, please consider one of their policies to keep you and your car safe. And of course, thanks to Falcon Northwest. Without their computer tools and workstations, Mark would not be able to edit any of these videos. And of course, I need to thank the Corvette engineers. Needless to say, Mark and I are annoying and we ask them a ton of questions. And what I will say is we are very privileged in getting to meet a lot of people responsible for some of the most incredible cars around the world. And I think the Corvette engineers specifically are some of the most remarkable engineers I've had the pleasure of speaking to. They are incredibly open and passionate about what they're doing and they are well aware their car is not perfect. And the fact that they're open to criticism and wanting to improve their product and not closed off to the outside world and what's happening is truly remarkable in this space. And the fact that it's the same group of people working on this project and they're truly passionate really does show when you spend time with them. So, we're deeply appreciative of being able to spend the amount of time we have with them. So, what about the car? Well, I'm going to say this because it was flatout downpour raining the entire time we had it. And the only amount of time we had with a car when it was even remotely dry was for about 10 minutes when we drove it on track with cameras rolling and trying to shoot a video. I can't tell you what it's like at its dynamic limit. But what I can tell you is it's incredibly quick. It very clearly can do 0 to 60 in sub 2 seconds. And the fact that you have a powered front axle in the case of an e- motor allows you to do things with this car that the regular ZR1 is just not capable of doing. The fact that we could drive a 1200 horsepower car on a damp track is a testament to how well the controls in this car are integrated. I think as someone who loves rear wheel drive, if I was in the position to buy either a 01 or 01X, I'd probably buy the car with the powered front axle. It lends a level of flexibility to this car that the rear wheel drive variants simply just don't have. In the future, I'm hoping to drive this car and track with Mark where we can experience the car at its limit. But in the meantime, what I will say is this is a truly remarkable piece of engineering and the fact that it costs less than say a regular GT3 is remarkable and a testament to the manufacturing power of the company. So that thanks for watching. Hope to see you again soon. Heat.