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Chevy: Initial hybrid test is about learning, not lap times

Chevrolet says that its initial test of the new IndyCar hybrid unit at Sebring is to establish that it is “fit for purpose” rather than to outpace the non-hybrid cars in it first outing. Chevy's IndyCar program manager Rob Buckner spoke to David Malsher-Lopez.

Will Power, Team Penske Chevrolet

Two-time and reigning IndyCar champion Will Power is at Sebring testing a Penske-Chevrolet equipped with the hybrid unit. But Chevrolet’s IndyCar program manager Rob Buckner says that the car’s lap times will not be representative of its potential since the unit is not yet “located in the correct place” and is instead being tested for durability.

“We’re running the hybrid variant on a 2.2-liter engine for the first time in our program,” Buckner told Motorsport.com. “Our competitor [Honda with Chip Ganassi Racing’s Marcus Ericsson] did the same thing at Sebring last December.

“Unfortunately we had a gearbox issue – not hybrid- or engine-related – that kept Will off track for most of Monday, but will continue testing with him today [Tuesday].

“The hybrid program is now at a point where we feel that the hardware is close enough to race intent where there’s actually value to run it on track. We didn’t feel that way in the second half of 2022, so although we’ve done a lot of dyno running with the hybrid unit, this is our first go-around on track. The pile of parts is getting much closer to what we expect to be racing at St. Pete in 2024.”

Buckner dismissed thoughts of making direct comparisons between Power’s best time on Tuesday – providing there are no more technical glitches – with that of cars testing in 2023-spec form with non-hybrid 2.2-liter engines.

“No, this hybrid test is not about performance development,” Buckner insisted. “It’s about hardware and software integration and learning. This not a fully correct pile of parts and the unit is not even located in the correct place [in the bellhousing] on the car. This #22 Penske-Chevrolet is very much a test vehicle and should be put it in the context of a prototype under development. It is heavier than all the cars without the hybrid system, and functionality is naturally limited as we learn the system.

“And then it’s very much a collaboration with IndyCar and Honda in applying anything we learn here across the entire hybrid program. I think we’ve already worked together very well – even though it can be hard to take off your competitor hat and work openly! I think the hybrid group has done what it intended to do, which is come up with a product that works for the entire paddock. Everyone has their specialties that they bring to the table and put the pieces of the hybrid where they best fit.

“Time is a limited commodity for all involved, so we’re all trying to learn as quickly as possible and share everything that is appropriate to share, and then after the Indy 500, we should be in a much better place to have a more representative test program. We will remain fierce competitors in terms of the ICE [internal combustion engine] side of things – we’re not showing them piston designs, fuel injectors or any of those other items! – but getting the hybrid piece ready and reliable in time is something for the common good.”

IndyCar had high power output targets for the 2.4-liter engine which was originally set for introduction this year, then was pushed back to 2024, and has now been put on hold indefinitely. Although no one in a position of authority is prepared to go on the record about it, this as yet mutable postponement, according to a number of Motorsport.com sources, was caused by the fact that Mahle’s proposed system, even once the company’s global supply chain issues were rectified, proved unsuitable for IndyCar application. Thus Chevrolet/Ilmor and Honda/HPD had to pull their engineers off the development and building of their 2.4s and instead work together on devising and developing a spec hybrid unit.

Neither Chevrolet nor Honda have ever been prepared to quote power outputs for their 2.2-liter twin-turbo V6s, first introduced to IndyCar back in 2012, but asked how much power the hybrid unit will add to the 2.2s in percentage terms, Buckner said it was too early to say with any degree of accuracy.

“I wouldn’t say we have a metric for the 2.2-with-hybrid if you’re talking percentage power gain,” he said. “We’re still working on the recipe of, How do you regenerate the energy? How do you deploy it? How much of it should be in the driver’s hands as opposed to the ECU’s hands? What is open to the manufacturers to calibrate and what is not?, etc. Those details are going to become clear throughout the course of this year. We should know more about power output mid-season in terms of direct comparisons to the 2.2 without hybrid.

“What I can tell you is that the 2.4 – just the ICE component of the powertrain – was going to see us up by 100 horsepower. We had seven development engines that ran over 150,000 miles on the dyno, and the very first one exceeded the specific output [horsepower per liter] of the current 2.2-liter race spec engine. So that program started as a high performer, and over two years the group did a wonderful job of finding more and more, and we were really excited about its debut…

“But things changed, we’ve had to shift our focus to making sure the hybrid is fit for purpose, and we have to get on with the new formula. At the end of the day we’ve all got to have a reliable package that the series wants on track, and while the content may change, we’ll keep putting in the detailed engineering effort required.”

On the subject of whether he foresees a day that IndyCar can reintroduce the 2.4 formula, Buckner replied, “Let’s get through the next six-to-nine months of finalizing a race-quality hybrid system mated to the 2.2. Then I’d imagine a year from now, once the 2.2 with hybrid has made a successful debut, IndyCar, Chevrolet and our competitor will discuss where we go next.”

However, he did say that pushing back the 2.4 to a later date would not make IndyCar more enticing for a long-sought potential third manufacturer.

“It would be very difficult for a third OEM because of the amount of time that we and our competitor spent on developing the 2.4s,” he said. “And to your earlier point, if you wanted to reinitiate the 2.4 formula a year or two down the road, with the analytical tools we have and the rate of development in motorsports engines, two years from now there would be things we’d want to do differently.

“What I’m saying is that the odds of us wanting to take the 2.4-liter engine that we’ve already developed out of mothballs and run it as is, but a couple of years down the road, are very low. The 2.4s that we’ve shelved will probably never take a green flag without a serious rework.”

For now, Chevrolet has to make the 2.2-liter with hybrid work, and this test at Sebring is for Chevrolet to understand “rates of regen, brake bias changes given that the regen comes from the rear axle, and how to deal with imbalances caused by that system – something that obviously doesn’t trouble us currently.”

Buckner continued: “The nice thing about electrification in powertrains is that once you have all of the pieces there, and the calibration tables, it’s almost infinitely adjustable in terms of regen rates, deploy rates. It’ll be great to get Will’s feedback, Penske’s feedback, and just remain open-minded – and then we’ll be open-book with IndyCar and with Honda about what we feel are race-suitable levels for regen and deploy. We’re all like-minded in that we don’t want to harm the racing product, because we all feel that IndyCar has great racing, and so whatever package and parameters we come up with for 2024 has to positively impact the series. There are a lot of things that we’re trying to amplify while not hurting the on-track product.”

In the mean time, several IndyCar teams are testing at Sebring this week and Buckner expressed high hopes that the progress that the Chevrolet and Ilmor engineers have made in the off-season with the 2.2-liter engine without hybrid can be as notable as that seen between 2021 and ’22. The improved drivability of the Bowtie’s 2.2-liter twin-turbo V6 was seen as making a large contribution to Chevrolet’s tally of 11 wins and 13 pole positions in last year’s 17 races, leading to its first IndyCar manufacturers’ championship since 2017.

That being the case, it might be natural to assume that Chevy’s work on the 2023-spec engines might have been geared instead toward trying to end Honda’s three-race winning streak at the Indy 500, Buckner said: “I’m very proud of our technical group in that they hit multiple areas and are always very driven, so I’d say they’re not resting on any areas of engine development. We’re expecting very strong engine competition. There are areas we’ll have polished to be a little better in some areas but our competition will have done the same – so for us it’s about looking at our performance across every discipline, be it road course, street course, short ovals and the big ovals.

“That of course includes Indy, which has been a problem for us for a couple of years, so there’s continued attention on that at all times. But like I said, we also don’t want to give up anything anywhere, so we’re trying to be quite ‘selfish’ in the development plans.

“Between improving the engine for 2023 and working on the hybrid integrations with various configurations, there’s no shortage of things to do. Luckily we’ve got a great group of people who stayed very motivated and just want to be successful, regardless of what the specifications of our product. Now we have a clear direction of where we’re going, it’s all hands on deck to not only perform strongly in 2023 but also make a solid debut with the hybrid package in 2024.”

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