Introduced last season, NASCAR’s ‘Next Gen’ car for its headline Cup series was a complete break from previous machines, with the notable exception of the engine. As with the rest of the chassis, every aspect of the powertrain behind the flywheel was new for 2023, including a ‘spec’ five rather than four-speed gearbox, as described in RET 132 (June/July 2021).
Nevertheless, the prevailing engine technology was carried forward, albeit with revised intake air restrictor sizes and maximum permitted rpm. The latter was set at 9200 rpm, which was reduced to 9000 rpm this year and is enforced via the mandatory spec ECU supplied by McLaren Applied.
Start of the annual Daytona 500 in 2023 (Courtesy of NASCAR/Getty Images)
The 358 cu in (5.867 litre), 16-valve pushrod Cup V8s continue to be fed via a single four-barrel throttle body with a single injector for each cylinder situated downstream of it, one in each of the eight branches of the intake manifold that feed the individual cylinders.
hese days the air restriction is via a tapered spacer located within each of the four barrels and there are two maximum orifice sizes permitted – 1.050 in and 0.890 in. The former allows the engine to produce in the region of 670 bhp, the latter in the region of 510 bhp, with the lower power level enforced exclusively for superspeedway running.
Thus the engines were retuned accordingly for the introduction of the Next Gen car but in most other respects were carried forward. The engines in question all date from before 2010: the Chevrolet R07, Toyota Phase 11 and Ford FR9. To find out about the current state of NASCAR Cup engine technology, Anne Proffit quizzed four ‘expert witnesses’ as the 2023 season got underway.
John Probst
John Probst is senior vice-president, chief racing development officer, at NASCAR. He explained that a goal of the Next Gen car was to reduce engine running temperatures. The coolant radiator is located at the nose and previously, air passing through it was exhausted underneath the car. Probst noted, “You ended up with a balance of downforce versus horsepower.
“Typically, the more you closed off the air from coming in the front and going underneath, that was good for downforce. But it was bad for the engine, because you didn’t have the mass flow through the radiator. So a lot of development money went into running the engines at extreme temperatures and pressures.
“With the Next Gen car, we tried to address all of that by venting air from the radiator out of the hood; that’s why you see louvres in the hood. For the engine intake now, we take that through the radiator air inlet. So you’re discouraged from taping off the nose because there’s very little aerodynamic benefit from doing it, and it’s also the air inlet to the engine. Now, if you tape off the front, all you’ll do is run hotter and there'll be no performance enhancement.
John Probst is senior vice-president, chief racing development officer, at NASCAR (Photo: Anne Proffit)
“Even from last year to this, you’ll notice that the OEM set-ups have new noses and hoods. Last year we had what we called emergency cooling, where they could cut bigger louvres in the hood at particular events where we had very low airflow through the radiators. We didn’t want to do that as a normal course of business, because the hood is a prime spot for sponsor decals. So for this year all three OEMs submitted new hood louvres. That means now that we shouldn’t have emergency cooling needed anywhere.”
Of the fact that there are now just two NASCAR-imposed tapered spacer dictates, Probst remarked, “We used to have more packages than that, and I think the current simplicity is a good idea. It creates efficiencies. Whenever you can do more with less, that’s better.”
In respect of the 510 bhp superspeedway package, Probst said, “We adjust the power level at superspeedways in so far as we need to, to keep the speeds generally under 200 mph. But as we get into the high 180s we see better and better racing. So it is a mix of safety and quality of racing that determines what power levels we run on superspeedways.”
Both the ‘510’ and ‘670’ packages currently have the same rpm limit. “NASCAR has a hard rev limiter, this year at 9000 rpm,” explained Probst. “If you hit that, it’s where you'll hear the [cylinder] cuts going on. The builders have the ability to put a soft limiter leading into that, which they all do, and usually it's about 200-250 rpm below.”
In respect of engine control Probst noted, “Software in our sport is largely locked down. It is an area that we have elected not to compete in as far the type of software goes. But at the same time, each engine manufacturer has enough leeway in the values they put in for the different parameters. So while the software is all the same, they do have a pretty good range of parameters they can use to program the ECU.”
When it comes to how each engine manufacturer approaches each engine package, Probst said, “Any differences will usually be with top-end stuff. Or maybe even the crankshaft, because the superspeedway power level is lower and they probably all take a bit of a different approach there. But certainly, from the top-end stuff I would expect to see some pretty big differences in the geometry of all of that.”
Nevertheless, there is now equality of engine performance across the manufacturers, as Probst explained. “One of the ways we ensure we have parity is that three or four times a year we will test engines from the racetrack,” he said. “When we take the car, we take the engine out in the r&d centre and use the electronics that were on the car when we took its engine. Then we’ll run it on our dyno.
“The whole purpose of that is to make sure we continue to have parity across the garage. And I will say that we don’t have any kind of balance of performance adjustment we can do. So our way is by letting people know if they have work to do and, if so, where they have to do it. We just let them know where they’re at [relative to the other engines].
“Since we launched the Next Gen car, where you’d maybe expect there was potential for the engines not to have parity – because it was a big step change in how the engines are mounted – it’s nevertheless probably been the best parity we’ve had since we’ve been measuring the engines. When we plot horsepower versus rpm, they’re all equally as strong.”
Probst said he anticipates that in the future the Cup engine regulations “will evolve tremendously. We aspire to fully sustainable fuel in the very near future. The other thing we are entertaining with our OEMs now is whether there is a way we can use technology – torque sensors perhaps, or fuel flow metering – to allow multiple engine architectures to work their way into our sport.
“That is an aspirational, aggressive goal for us within the next 5 years.”
Asked if he envisions any downsizing, turbocharging or hybridisation, he replied, “One of the main tenets of Next Gen was to become more product-relevant to our OEM partners. That’s something we take seriously, not just from the car but from the powertrain as well. So we lean on them to guide us in the direction to go. So anything from sustainable fuel, hybrid electric, hydrogen combustion, you name it, we’re looking at all of it.”
So do you think turbocharging has any place in NASCAR? “I would never say never. I think our main goal would be to be able to find a way to use technology to allow engines of different cylinder counts or induction systems to mix and match. Obviously, it’s important that we keep parity in our sport, so it will be within that context.”
Do you anticipate a move towards an IMSA GTP scenario, whereby a manufacturer has a lot of freedom of engine type, albeit within the context of a homologated power curve?
“That is something we are [considering]. We do not currently have any sort of active ongoing Balance of Performance in our sport; it’s all done on the front end. So I would say our goal is to find a way to allow different engine architectures to compete against each other. And to bring in additional OEMs into our sport is a goal we've had for a while, so we’re actively looking for ways to accommodate that.”
Wes Adams
Wes Adams is lead trackside supervisor for ECR Engines’ NASCAR engine group. These days ECR works on NASCAR engines in conjunction with Hendrick Motorsport. Adams explained, “We formed an alliance with Hendrick, called HCD – Hendrick Childress Development – whereby we share information on the engine side. And of course, all that information is relayed directly back to Chevrolet.
“That means there are more minds on it. It’s a bigger group developing the same parts, so instead of two groups doing their own development, we share it, which should get us to the end goal quicker.”
In respect of the impact of the introduction of the Next Gen car, Adams highlighted the exhaust system. “The exhaust no longer has a crossover, each bank’s exhaust is completely separate. For decades we ran a crossover between the banks, so this change gave us some calibration challenges.
Wes Adams is lead trackside supervisor for ECR Engines, NASCAR engine group (Photo: Anne Proffit)
“Then the fitment for the new car was mainly about our front [timing] drive and our accessory drives, to make them fit within the chassis, which has the steering rack located right in front of the engine. One of the biggest reasons RCR got the deal with NASCAR to develop the Next Gen car was that our engine was the closest to fitting into the car, it took the least amount of changes to fit it, compared to our competitors’ engines. That was due to the location of the front drive accessories, including the oil pump and alternator.”
Adams admitted that HCD faced some engine issues in 2022. “Those seemed to be isolated to the speedway tracks. In redesigning the front drives we had made some changes to our cam timing drive. And we found that there was a lot of heat there, which was causing our belts to fail. So during the off season we had to completely redesign it, hopefully to make it a more durable package.”
When it comes to changes in the regulations for 2023 that have had an impact on the engine, Adams said, “They did lower the maximum rev limit from 9200 to 9000 rpm. And they’ve outlawed the use of engine cool-down units during practice and qualifying, so we have had to manage that too.”
Considering the 670 and 510 bhp packages, Adams noted that the latter is mandated at Atlanta as well as Daytona and Talladega. “Atlanta became pretty much a superspeedway track last year after they repaved it,” he said.
Considering hardware differences between packages, Adams remarked, “There are of course induction differences, with the greater restriction of the 0.890 in tapered spacers making the engine want a different camshaft and different exhaust system; it’s fine-tuning around that more restricted airflow. It’s all top-end stuff; the bottom-end stuff is pretty much straight across the board. We’ve squeezed that juice about all we can.”
Quizzed on the role of engine sim in Cup these days, Adams said, “Our sim work is very important. Our engine models go into driver-in-the-loop simulators so we’re constantly updating those models. Also, the same models go into our AVL dynos, where we do race simulation and so on.”
As for the routine engine mileage this year, Adams said, “We will try to run at least two races on each engine, so 1100-1200 miles is not abnormal to see on a single build.”
Is that different from past years? “Not since they started the engine seal rules, although we have inched up a bit. We used to try to run a 400-mile race and a 500-mile race to keep the mileage under 1000, but now we feel our durability is at a place where we can take in two 500-mile races and not worry about it.”
What is the loss of performance with mileage? “None – our engines actually perform better on the second hit. I don’t know if that's common across the other competitors’ engines, but we feel good that our engines go and race 500 miles and come back and actually run better than they did before they left.”
The Chevrolet R07 Cup engine (Courtesy of Chevrolet)
What, if any, are the ongoing areas for engine performance development? “There are very few places that NASCAR allows us to work on any more, the rules are pretty nailed down. The biggest places we can work are the induction system on the manifold and on the exhaust system, with different size and shape of headers.”
Asked how he anticipates Cup engine regulations evolving over the next few years he noted, “The big discussion is hybridisation, and I don't know if that's coming sooner or later. I don’t think anybody in this garage area knows.”
Do you envision downsizing and/or turbocharging? “That could become a part of it. Definitely downsizing. NASCAR is going to be really reluctant to go to turbocharging, because there are things around it that are harder to police. But they’re still trying to have some relevance to what is being sold for street cars – and that’s definitely the trend on the street.”
Do you anticipate a move towards an IMSA GTP scenario in which a manufacturer has a lot of freedom, albeit within the context of a homologated power curve? “Any big change like that is such a huge investment for the teams. I’m not sure there’s enough money in it right now to force that kind of change on the teams.”
David Currier
David Currier is senior engineering manager of engine engineering at Toyota Racing Development (TRD). Regarding the introduction of the Next Gen car he said, “Probably the biggest impact for us was the fit of the engine in the car, there’s a lot less room. With the old car, everything was open underneath but now everything has to be accessed from the top, and there’s more stuff in there.
“Because the undertray on this car is an aerodynamic device, the teams would rather not take it off. They get it positioned just right so that it’s able to pass the inspection scans. So, ‘Please don’t make me take this off, because I have to make sure I'm okay on inspection.’ So it was a different challenge, for how we had to design the engine [package].
“Another thing was the exhaust. With the Gen Six car the left-hand and right-hand bank exhausts merged before exiting out of one side of the car. With Next Gen there’s an exit on both sides and the exhausts from each bank never connect. So that made the exhaust development and the engine tuning quite a bit different. But it was a typical development path of working through that to optimise the engine.
“Also, this car has a five rather than four-speed transmission, and there’s a lot more shifting now. That then plays into how we develop the engine and how we set up the way the engine runs. So overall, things are very much the same with the Next Gen car, but you kind of play in a different area and emphasise different things.”
Back in the days of flat tappets and over 10,000 rpm it was standard practice for Cup engine builders to exploit the concept of lofting. In these days of roller tappets and a 9000 rpm hard cut, is lofting still exploited?
David Currier is senior engineering manager of engine engineering at TRD (Photo: Anne Proffit)
Currier replied, “Back in the day it was a very specific flat tappet. We’re still limited on what we can do with the roller tappet due to some constraints from NASCAR. We have to run wire [coil valve return] springs and we probably all have some loft in there.
“Basically it’s about what you can do with the [cam] lobe, it’s that geometry and what’s going on. We are stressing the spring with very high valve accelerations to try and get as much power as possible.
“When you’re doing that, especially over many revs, you’re going to have regions where the valve’s going to be lofting. It isn’t going to be in contact with the cam at all times in order to balance all that and get the most out of it.
“Of course, on the flip side it makes things less durable because you’re beating things up when things are flying around and not totally controlled. So we have to balance both of those considerations. But generally, people are going to have loft with these cams in this format of engine.”
In respect of reliability in 2022, Currier said, “We did have an issue. We got into an environment where there was something we weren’t expecting. And that was an area you don’t normally get into it that much. We had something unique happen with our engine that caused something to occur, and we just had to figure out what that was, and then we got it all fixed.”
In respect of engine mileage Currier reported, “This year we have to run an engine two weekends more times than last year, so we have to be a bit more careful on the durability. It’s not so dissimilar, but it is different.”
On the other hand, Currier noted that the Next Gen car’s aero has pushed engine temperatures down. “Before ,crew chiefs always wanted to put more tape on the car, almost taping it off completely for qualifying. They were always pushing our maximum temperature allowances for more downforce, but there is no longer a gain there.
“So, because an engine runs better cold than hot, the trade-off now is to run it cold and get out more horsepower. So it’s actually made things a lot easier for us, in that we don’t have to push the lubricants and some of the engine components as much. So that has taken that extreme temperature part of it out – provided there are no hot dog wrappers [blocking the radiator] and similar situations that we have to deal with from time to time.”
In respect of the 670 engine package, Currier said, “We will tailor it [differently] for road courses and short tracks, because you tend to get bogged down more there and need more low-end torque. Then, at a big track, you need more high end power, so you tailor the torque curve accordingly. But that isn’t a NASCAR-mandated thing, it’s internal thing that all the engine builders will do, whether it's for driver preference or an individual track basis.
The Toyota Phase 11 Cup engine (Courtesy of Toyota)
“But with the changes that we make between tracks, the power level doesn’t change a lot: you’re talking maybe 5 hp. They’re very similar as far as peak power goes, it's just a question of how much you drive the bottom up and then whether you trim a bit off at the top.”
Asked about the key differences between the two NASCAR specs, Currier said, “Certainly, manifolds and exhausts are changing, and cams are another one. Then there are a lot of subtle things with the superspeedway [engine], because you’re running almost one speed, because it’s so restricted, then friction is a big thing. So you’re doing all kinds of things to get as much friction out of it as possible.”
When it comes to the 9000 rpm limit, Currier observed, “Part of NASCAR’s motivation was to make the engines run longer; the lower the RPM, the less hard it is on the hardware. The other part though is that if you’re in a single gear, with lower maximum rpm you tend to get bogged down more. And the drivers tend to complain more, because it doesn’t feel like the engine is as strong.”
For development work, Currier noted that TRD does transient dyno testing. “We can do simulated shifts and run duplicated laps just like the drivers run. We use it quite extensively because, of course, over the years track testing has been very much curtailed to save costs.
“So all durability testing and a lot of the driveability testing is now all done on the dynos, whereas years ago we would have done a lot of that work at the racetrack. Now we have to do more through simulation and dyno work.
“These days we are using sim more, especially for things like gear selection when Goodyear or NASCAR changes the tyre and we then have to forecast what that’s going to do to speeds. What gearing do we need to get the RPM in the appropriate place? And just so we know, are we covered durability-wise? We’ll work through all that using simulation.”
In terms of routine mileage, Currier reported, “Usually we try and target two race weekends, which of course varies a lot. But generally we’re a little over 1000 miles.”
Is there any loss of performance with mileage? “You always lose some. In the specs we do the engines each have their character. Some of them break in, whereby you’ll actually gain performance during the first race; it might be going up and then it might be going down during the second. In the end, we’re usually down a bit, but not very much – fractions of a percent.”
Asked about the strengths and weaknesses of the Toyota against its rivals, Currier said, “I think [in the past] we had maybe a bit more emphasis up top, meaning higher power at the higher revs. Some of our competitors had a bit more down low, which meant on some tracks we were a bit better off and on some tracks they were.
“But these days, from the NASCAR dyno the engines are very close on performance, so then it comes down to fuel mileage. I don’t know if we’re at the top of the heap but I think we’re pretty good on fuel mileage. However it depends so much on driver technique – that can be a bigger factor than us by far.”
Asked how he anticipates the engine regs evolving over the next few years, Currier said, “I think most of it is going to head towards trying to reduce cost in some way, trying to entertain other OEMs as well as keep all the current OEMs in the series.”
Does he envision downsizing, turbocharging or hybridisation? “That one's a pretty big nut to crack. There’s talk like that, because obviously many other OEMs [not currently involved] are more interested in that since they don’t have pushrod V8s.
“When we got into NASCAR we didn't have a pushrod V8 so we had to do a custom engine, which cost a lot. We bit that off but I think a lot of other OEMs wouldn’t, so there’s certainly a lot of talk about what can be done to bring in other options, whether it’s I4 turbos, V6 turbos or just a V6. Whatever it might be, you have to entertain those thoughts to try and make the pool a bit bigger.”
Does he anticipate an IMSA GTP type of scenario where a manufacturer has a lot of freedom of engine type, but within a homologated power curve?
“I think that has to be discussed, because it is one way of doing it, especially if you’re taking production-type engines. One of the less expensive ways of getting into a series is to take an engine that already exists and be able to use that.
“We have experience from way back of the NASCAR Goody’s Dash [stock car series] in which we used a small engine that was high-revving and so had high power at high revs and not much low-end torque. The Chevy that countered us had very good low-end torque but not a lot of higher-rpm performance. So one would dominate at one type of racetrack, the other at another.
“It was very awkward for both manufacturers and for NASCAR, and it isn’t something I think any of us would want to get into again. There has to be a way of making it more equal.
“On the flip side, none of us like Balance of Performance. Certainly, from an engineering point of view, I don’t like my hands being tied. So it’s kind of a balance that is needed but it has to be discussed, just to be able to allow other players into the game.”
Doug Yates
The 2022 NASCAR Cup series was won by Penske driver Joey Logano powered by a Roush Yates Engines Ford. Current president and CEO of Roush Yates Engines, Doug Yates notes that the Cup-focused engine company formed when he and his father Robert joined forces with Jack Roush is now in its 20th season. Throughout that time it has flown the Ford flag, and these days it is the exclusive supplier of the marque’s Cup engines.
The current Ford FR9 came along in 2009, and since 2012 has been fuel injected. As Yates noted, even with the introduction of the Next Gen car last season, “On the surface, the engine remains the same.”
However, he added that for 2022, the engine rules were changed. “The Speedway package for Daytona, Talladega and now Atlanta remain the same power, at 510 bhp. But for everywhere else there is a change from 750 to 670 bhp. At the same time, NASCAR has reduced the maximum rpm from a 9500 rpm hard cut to a 9200 rpm hard cut.
“In addition, the mounting of the engine in the car itself has completely changed. Also, the bellhousing is an all-new design, and where the transmission had bolted directly onto it, now there is a transaxle mounted in the rear of the car. And the biggest change of all is the introduction of a five-speed sequential rather than a traditional four-speed gearbox.
“With that we went from where we shifted almost only on road courses to where we shifted on almost every track. So that has really changed the engine operating range and the duty cycle. There has been a lot of work to do there on the development side.”
Doug Yates is the president and CEO of Roush Yates Engines (Courtesy of Ford)
Yates further reflected, “A big thing was working closely with Ford Performance and the simulators they have at the Ford Tech Center to understand the proper torque curve for each track using the Next Gen car. Ford, like the other OEMs, has multiple driver-in-the-loop simulators. And what we do there is plug in our power curves.
“So we work hand in hand with the teams as to what our power curve is; they plug that into their model. And from there we can change that curve to try to find performance. Then we go to work on how to reshape to that [optimised] curve with our hardware and software.
“With the Next Gen car the engine air inlet system has changed quite a bit as well. We went from a traditional cowl in front of the windshield to air induction through the nose. So it is an entirely new airbox that [Ford Performance engineer] Christian [Hertrich] and his team have worked on.
“Then it was learning how to operate a car with this type of induction system. NASCAR now allows a blocker plate behind the radiator to control the airflow out through the hood louvres. So that balance between how much air goes into the engine and how much goes out of the louvres was another challenge.”
When it comes to reducing the engine running temperature inherent with the Next Gen car Yates reported, “We used to run up to 300 ºF [149 ºC] water inlet temps, and that’s been reduced by 50 to 100 degrees. So with that, we had to basically go back and reconfigure the entire engine. It had to be optimised for cooler temps, which included clearances. All the components affected by operating temps were revisited.”
Yates admitted, “When we started out with the Next Gen car we did have some valvetrain issues. The valve spring is still the most highly stressed component in the engine. We started 2021 with an 8500 rpm target for each track, and there was a lot of work at the beginning of the year just to understand [the implications of that].
“Ford Performance and the teams would come back with their suggestions on final drive [ratios] and gear sets. But at several tracks, we missed that peak rpm target; we were overspeeding on shifting. So at the start of 2022 we had a couple of valvetrain concerns. There was a learning curve, I would say for the first five to 10 races last year, and then we had it sorted for the rest of season.”
Yates explained that 8500 rpm is a target for maximum speed with the chosen final drive and in fifth gear, “but in fourth gear you could be well above that at a lot of tracks. NASCAR had the 9200 rpm hard cut and they brought that down to 9000 rpm for this year to close that gap between it and the 8500 rpm target, hopefully to save some cost.”
Comparing the 510 bhp Superspeedway engine and the 670 bhp engine used everywhere else, Yates remarked, “Both are now capped at 9000 rpm, but the difference is that the Speedway engine runs in a very narrow rpm speed band, whereas the 670 engine needs a broader torque curve. The biggest difference is really the tuning for a narrow versus broader range of rpm.”
In terms of hardware, aside from the obvious differences of camshaft profiles and so on, Yates observed “There are subtle differences in the form of clearances, piston cooling provision and things such as that, things you’re always chasing for frictional gains to optimise the package.”
Asked about the role of dyno testing in Cup these days Yates said, “The biggest change from when I started 30-plus years ago is our testing ability. We have two transient dynos at Roush Yates where we can do whole race simulation. But ahead of that there’s all the gathering of the information for engine simulation, to plug into our models.
“Then comes the performance development, followed by durability testing. Good testing is key to building good engines. You really have to understand the changes you make [especially] at the level we’re looking to for improvement. One horsepower makes a difference at Daytona. So we are always searching and we are always improving our test cell capabilities, to be able to find those performance gains.”
The Ford FR9 Cup engine (Courtesy of Ford)
Quizzed about routine engine mileage, Yates noted that this year a 670 bhp engine needs to be able to run three races. “You are then looking for 1500-mile durability, and that’s been a change for us. You need a 150- mile engine but you are still looking for the performance of a 500-mile engine. So that’s always the balance for the engine builder: to try to figure out how to achieve both [aims]”.
Is there a loss of performance with mileage? “Quite the opposite. Over time, an engine gains a bit of performance from the frictional side of things. So we usually see a little pick-up [when dyno testing an engine] between race one and race two. There’s usually a bit of a frictional gain after the first race.”
But at the end of the second race, would it still be as good as it started out? “It's pretty stable.”
What are the ongoing areas for engine performance development? “It's always to increase airflow and reduce friction. The valvetrain is still an area that we spend a lot of time on. Cylinder heads, intake manifolds and exhaust systems have a lot of focus too. And then anything we can do to reduce the frictional losses within the engine. So it’s quite broad.”
We put it to Yates that, back in the day, Cup engines ran to over 10,000 rpm and had to use a flat tappet. In those days, lofting was used a lot. Is there still the use of lofting, given 9000 rpm and the use of roller tappets?
“It is not like it was back in the day for sure”, he replied. “The rpm chase in those days was very interesting; Jack Roush was a leader in that. He ran his engines harder, whereas the engines my dad and I developed didn’t turn as high rpm but did produce more power. When we put Roush Yates together the combination came out pretty well!
“With the flat tappet we were chasing DLC on DLC. There was performance there but that was a really difficult solution. So the roller tappet has made life a lot better; it is something we don’t have to worry about as much.”
But is lofting still exploited in this current scenario? “We’re still as aggressive as possible on that side of things, but it’s a bit different with roller lifters now.”
We asked Yates what he considered the strengths and weaknesses of the Ford Cup engine. “We had a fantastic weekend in Atlanta this year – we qualified first to eighth, which hadn’t happened for many years. And we had a really strong Daytona [500]. So I’m really proud of our 510 package.
“Our 670 package is very strong, especially on the faster tracks. We won Michigan last year for the eighth year in a row. And we continue to work hard on our short-track package to make sure we’re prepared well enough to compete for the championship every year.”
How does Yates anticipate the engine regulations for Cup evolving over the next few years? “That's a great question but I don't have all the answers. There’s been a search for relevance. In the past few years the questions have come up: should we be hybrid; should the sport take a look at EVs?
“But I think it's coming back around to the fact that the current engine works really well for what it’s intended to do. The fans love the noise and the excitement of a V8, and NASCAR is pretty happy with that side of it. So I think going forward, we’ll be looking at sustainable fuels. We’ll look at different ideas to limit development [costs] a bit.
“We ran mufflers this year for The Clash [at The Coliseum] and we’re going to run a muffler system for the road race in Chicago. So I think toning down a bit for certain tracks and cities is something the sport is looking at as well. But to answer your question, I think the V8 pushrod engine is going to be around for a little while yet.”
Quizzed about IMSA GTP-type hybridisation Yates replied, “I think Jim France has done an incredible job with IMSA. It’s a great place to introduce new technology. And from there, I think it's a case of whether that technology make sense for the Cup series. Can you police it, and is it safe? If so, perhaps it could be introduced.
“So I think IMSA's a good testbed for the future of the sport. And I think the Next Gen car was driven somewhat from the IMSA type model that Jim is so familiar with. We’ve talked for ever about making the Cup car more production-relevant, and the Next Gen car does that in many ways.”
IMSA GTP has imposed a homologated power curve, and each manufacturer has a lot of freedom to use whatever type of engine they want to attain that from. Could Yates see that approach working in NASCAR, as a means to bring in more manufacturers?
“I believe the current manufacturers would entertain racing against other platforms. But I think we are some way from understanding how that [concept] would work [in Cup] to ensure everyone is on a level playing ground. And then the billion dollar question is, would the fans accept it? Is it something that’s good for everybody and brings more excitement, more entertainment?
“If it checks those boxes, I think people would be open to it. End of the day, NASCAR has to be great for everybody. It’s got to be great for the Ford Motor Company, and then Roush Yates is going to be part of that. If [this is the solution] we’ll accept it and adapt. I generally try to be open-minded about these things. I want what is good for the sport.”
The Cup engine
NASCAR downscaled from Big Block V8s in the 1970s, after which production-based, sired-in-the-1950s Small Block V8s from Chevrolet and Ford became the mainstay of the Cup series. Then along came Dodge and Toyota with quasi-Small Block engines, superficially similar but purpose-designed to be in keeping with the existing iron block, aluminium head pushrod engines rather than derivatives of actual production V8s. As the last to the party, Toyota could cherry-pick what it considered the best characteristics of the others.
That led to NASCAR defining in detail what it considered acceptable, and ultimately to it approving purpose-designed replacements for the Chevrolet and Ford Small Blocks. The Chevrolet R07 arrived in 2007 (RET 27, December/January 2008), the Ford FR9 in 2009 (RET 37 March/April 2009).
Compared to the superseded production block V8s, these purpose-made, still 12:1 compression ratio, wedge head productions had for example a compacted graphite iron block from a specialist foundry. They exploited more fully the potential of the criteria to which the newer engine designs had conformed.
Today’s R07, FR9 and Toyota Phase 11 are fundamentally unchanged over the intervening years, aside from the introduction of EFI and E15 (still 98 RON+MON/2 but now with 15% ethanol) fuel as of 2012, and a switch from flat to roller tappets for 2015.
Cup started using tapered spacers in 2015, and come 2019 that year’s Daytona 500 season opener was the last race to still use a restrictor plate. Thereafter, that year a 1.170 in tapered spacer (one per throttle body barrel) was used at all tracks of less than 1.33 miles with a 0.922 in spacer used elsewhere. Horsepower was about 725 bhp with the former and about 550 bhp with the latter.
A ‘Gear Rule’ was used from 2010 as a means of controlling engine speed prior to the current ignition-cut approach. Where before its introduction rpm had approached 11,500 rpm, its dictates for 2015 saw the target rpm drop from 9500 to 9000. One other change in recent years is that engine life has been increased by means of seals and a cap on the number of sealed engines that can be used within a season.