How Chevrolet is planning for IndyCar revenge against Honda

When IndyCar’s current 2.2-litre V6 engines were introduced in 2012, Chevrolet won six straight manufacturers’ titles. But now Honda has won the last four. While that’s never been an accolade that garners much attention, it’s important to the OEMs themselves and it provides a clear indication that the momentum has swung toward Honda.

Further evidence of this can be seen in the stats for series champions and Indianapolis 500 winners. Yes, over the last 10 seasons, the battles for these more prestigious honours have been more back and forth, but in 2020 and 2021 HPD drivers scooped both.

It must be particularly galling for the General Motors generals who remained stoical as Honda hurriedly added a second turbocharger to their original engine design back in 2012, and then smiled through gritted teeth in the manufacturer aerokit era as IndyCar granted Honda more areas to change its bodywork in order to try and catch up with Chevy’s superior Pratt & Miller design.

Even if Chevy was now looking for some kind of reparation in its time of need, it’s hard to see how IndyCar’s rule-makers could cut the Bowtie some slack. Whatever improvements are made, they need to come from a breakthrough by Chevy Performance and engine-builders Ilmor – and that’s difficult in a year when (a) IndyCar has heavily restricted the engine parts that can be changed and re-homologated, and (b) both OEMs are also neck-deep in developing the 2.4-litre-with-hybrid engines, which are due to begin testing in the first quarter of this year ahead of their introduction for the start of 2023.

Do Chevy and Honda focus on prepping for the next era, or on extracting the last bit of juice from their decade-old 2.2s? In Chevrolet’s case, it’s both.

“From a 2021 perspective, we didn’t have many clear strengths,” GM’s IndyCar programme manager Rob Buckner tells Autosport. “There are several areas we need to get better for 2022, so there’s no aspect of the 2.2-litre engine where we can slow down our development. We’ve got to improve pretty much any of the on-track performance tangibles, whether it’s power output, driveability or fuel economy.

Newgarden's Gateway win was one of just six in 2021 for Chevrolet engines as Honda swept the title and Indy 500

Photo by: Michael L. Levitt / Motorsport Images

“And then there are a lot of procedural things you need to do in terms of quality checks, the build process, going over all the hardware before the engines get shipped to the teams. So I would say our engine programme has everyone doing two full-time jobs at the moment with not wanting to give up anything on the 2.2-litre while also preparing the 2.4.

“We want to send the 2.2-litre out with a successful year and 2021 was one of our worst since we returned [six wins from 16 races]. At the same time, race engine formulas live on for a long time these days, and decisions we make early on can live with you for a decade, so we have to make sure we get the 2.4 right in every way we can, right from the start.

“Fortunately, between Chevrolet Performance and Ilmor, we have a very deep talent bench in the development group, people who have grown with the program. We have the right people to do what we need; it’s just that they have a lot of balls to keep in the air, particularly at this time.”

Given the minimal amount of fettling that the manufacturers can do to the current engine, how can Chevy improve this coming season? It could well be down to engine mapping, together with a revised approach to trackside data and feedback.

"Given our dissatisfaction with 2021, we’re reevaluating every part of our programme, including how we tackle a race weekend and how we operate with our teams. There are quite a few things, modified approaches, that we’re going to be trying in 2022" Robert Buckner

It’s long been known that while Honda offers its teams and drivers several variations of engine settings, attempting to tailor their units to individual taste, Chevrolet has traditionally been more restrictive. It’s not quite as bad as, “Here’s your torque curve for a dry track, here’s your torque curve for a wet track,” as one driver who has raced for both marques memorably complained to Autosport a couple of years ago. But still, those who have switched from a Honda team to a Chevy team have experienced a culture shock once they appreciated the rigidity of the rules imposed by their new engine supplier.

The payoff from Chevrolet not allowing flirtation with an engine’s danger zones was superior reliability, but once HPD improved its units’ durability, the greater ability to customise kept customers happy. Now Chevrolet’s approach appears to be evolving, something that will surely be welcomed by all of its teams.

Having myriad calibration options for a tweakable power delivery gives a driver and their race engineer another significant tool with which to chip away at lap time. It’s one of the quicker fixes – although by no means a fix-all – in a year when hardware changes are so minimal. Nonetheless, it’s clear that Chevrolet rather than its drivers, will still be defining the engine settings at any given track: it’s just that there will be more maps made available.

Buckner says Chevrolet is firing on both fronts to try and recoup success in 2022 and beyond against Honda

Photo by: Michael L. Levitt / Motorsport Images

“Given our dissatisfaction with 2021, we’re reevaluating every part of our programme, including how we tackle a race weekend and how we operate with our teams,” says Buckner. “There are quite a few things, modified approaches, that we’re going to be trying in 2022.

“We’ve raced this fundamental engine package for so long that, compared with near the start of the programme when we were learning about direct injection and twin-turbo lag, and when the ‘boxes’ we were allowed to work in were larger, now the potential gains are much smaller. With each passing season with the 2.2-litre, we’re having to get more refined and deeper into the details, and I think that will probably just carry on through 2022.

“Relying on driver feedback is probably not the right way of doing it because the details are so small that drivers won’t feel it, so we have to do a better job of summarising and making data-driven decisions on the way our engine operates at the track. That said, we use our drivers’ feedback to help define our goals, and our expectation for this year is to increase the levels of driveability refinement and consistency that the drivers are looking for.

“We get pretty constant feedback that our engines can be… pretty difficult to drive. We operate in a wide rev range so there’s some areas where our engine is very strong and some areas where we can use a bit more oomph.

“But some of the differences between the response of our engine and our competitor’s engine are inherent to the differences in architecture of the two units. It’s always interesting to get a driver’s reaction to getting out of one and into the other, to find out where our relative strengths and weaknesses are. Obviously we try and lift the performance of our engine to improve it everywhere, but the problem with engine design and calibration is that everything is a compromise, and what we always have to aim for is to make fewer compromises and bigger gains, which is a tall ask.”

One huge area where Chevrolet was perceived as inferior to its rival in the last couple of years was fuel mileage on road courses. This appears linked to the fact that when all engines were at their leanest fuel settings as drivers tried to extend a stint, the Hondas had greater low-rev torque punching them out of a turn.

On a medium-length straight they could arrive at the next turn traveling some six miles-per-hour faster, according to Autosport sources. Thus, all other things being equal in terms of driver and car handling, a Honda driver with that significantly higher terminal speed at their disposal could back off sooner on the straights, thereby saving more fuel, while turning the same lap time as a Chevy-powered rival.

Chevrolet runners like O'Ward have struggled to hit the same fuel numbers as their Honda counterparts on road courses

Photo by: Phillip Abbott / Motorsport Images

Loyalty and professionalism ensure Buckner will neither confirm nor deny that explanation, but he can at least describe how hitting fuel numbers is more than just down to the engine’s efficiency in a certain rev range.

“The gains you could find early on in the 2.2-litre formula were really massive,” he says, “so we could make calibration adjustments that were very impactful to fuel economy in terms of trading off fuel-burn for lap time. Now the gains are much harder to get because the engine package is pretty refined.

“But in working with the teams and drivers, we can still efficiently create a good fuel number with a minimal impact on lap time, and it comes down also to driver methodology, how comfortable the team can be running very deep in the collector [reserve], how comfortable the drivers are when really pushing hard on in-laps. All those little details start to matter.

"This year is as important as any other, so until we ship the fourth and final engines to the race teams, then the 2.2 engine is solidly alive and until we retire it on 11 September, it’s still a major focus" Robert Buckner

“This far into the 2.2-litre development cycle, the fuel economy gains we’re looking for are smaller, but they still can be found with engine calibration, mapping, and working with our teams and drivers. Our hardware’s 10 years old but we can change our calibrations.”

Certainly, at most tracks the improvements in fuel economy can’t come from teams adjusting the amount of drag on their cars. IndyCar is about to enter its fifth season with the current universal aerokit (add-on aeroscreen notwithstanding), so through various engineer and driver transfers, teams long ago converged on roughly the same ‘ideal’ wing settings for the majority of race circuits.

“There are certainly fewer variables than in years past when it comes to car efficiency,” says Buckner. “There’s only a couple of places – Indy road course and Road America – where teams would look at aerodynamically trimming the car and it having an impact on fuel economy. Pretty much everywhere else, you want to run max downforce, so making fuel mileage is all on driving style, team execution and engine mapping.”

Naturally, in any discussion regarding off-season progress, Buckner isn’t going to be as open as he could be. Asked what percentage of Chevrolet’s IndyCar program personnel are working on the 2.2-litre engine, what percentage are on the 2.4 and what percentage are on both, he says, “If you get Honda to tell you their numbers, I’ll tell you ours!”

With teams having converged on optimal wing settings, optimising fuel mileage is down to driver execution

Photo by: Jake Galstad / Motorsport Images

But he adds: “This year is as important as any other, so until we ship the fourth and final engines to the race teams, then the 2.2 engine is solidly alive and until we retire it on 11 September, it’s still a major focus.”

But of course the 2.4-litre programme is a long way down the road, and anything the OEMs discover at this stage with the 2.2s – as stated already, that’s extremely unlikely to be anything major in their 11th year – is unlikely to be applied to the 2023 engine.

“Because of the homologation tables, and what areas of development we’re working with, the two engines are pretty separate from each other,” explains Buckner. “The 2.4 engine at the moment is open for development right now, whereas in this offseason, the only areas available of the 2.2 were the exhaust system and pistons. The base engine homologation deadline was December 15th, although there are some areas that remain open that we can always be exploring – pistons, for example, can always evolve and you aren’t really tied down to a timeline.

“On the 2.4, right now we have free rein for the air inlet system, engine block, cylinder heads, ports, and so on, so there’s not a lot of potential crossover from the current engine. We can be developing anything we’d like for the 2.4, so this is the biggest possible window of opportunity to find performance.”

Buckner acknowledges the co-operation of Chevrolet’s fierce rival: “It would be rude of me not to thank and acknowledge Honda because we’ve been working closely with them and IndyCar on timelines for the 2.4, proposed testing schedules, and so on”. But make no mistake, fierce rivals they remain, and Chevrolet isn’t about to cede 2022 in order to succeed in 2023: the plan is for its engines to conquer with both the outgoing and next-gen engines.