How IMSA's GTP revival proved worthy of its name

It’s easy to be wistful about defunct racing series of yore, be it CART-era Indycar, Formula 5000 or the sportscar leviathans of Can-Am, but bringing back a reimagined version of a well-loved category carries a risk of its own. What if you build it and nobody comes? What if it’s sacrilegious to the memory of what went before? What if it mirrors the past and drifts into oblivion again?

Back in the day, IMSA’s GTP class pre-dated FISA’s Group C rules and spawned some of the most fantastic and best remembered sportscars of the past 50 years. It ran between 1981 and 1993 and featured epic machinery including Porsche’s ubiquitous 962, Nissan’s fearsome ZX-Turbo and NPT90/91, Jaguar’s legendary XJR range, Ford’s undercooked Probe (and an earlier front-engined Mustang!), Toyota’s striking Eagles, BMW’s sensational but crash-happy March 86G, and the distinctive lines of the Lola-built, Hendrick-run Corvette.

GTP was in many ways an inspiration for Group C, the latter being altered to a fuel economy formula. That gas-saving ethos didn’t sit well in 1980s America, so for there to be an energy-frugal angle to GTP’s comeback is quite the irony. This year, IMSA became the first topline American motorsports series to run a common hybrid system at a time when electrification in the automotive sector is, if you pardon the pun, buzzing.

At IMSA’s helm is John Doonan, a sharp operator who turned from poacher (running the Mazda DPi programme) to gamekeeper (president). In the background, where he likes to be, is Jim France – the CEO, chairman and executive vice-president of NASCAR. Although his family is more famously associated with its stock car roots, Jim’s father Bill Sr founded IMSA in 1969 with John and Peggy Bishop, and he’s inherited an adoration of sportscar racing. In 2012, France bought what was the American Le Mans Series to join his Grand-Am Road Racing series, unifying the sportscar factions and leading to what we know today as the IMSA SportsCar Championship.

Under France’s studious watch, IMSA has been hungrily collecting automotive manufacturers: across all its many classes, it has a staggering 18 OEMs officially involved. Suddenly, the sportscar cycle that’s historically been boom and bust has a stable and highly invested platform. Strong ties with Le Mans organiser the Automobile Club de l’Ouest have emboldened IMSA to be arguably the US’s most progressive sanctioning body. Instead of creating a sports field and asking if anybody outside wants to play, potential contenders were already inside the stadium while it was being built, the rules crafted to suit their requirements.

Even though IMSA’s LMDh rulebook isn’t the same as the Le Mans Hypercar regulations (for multiple political reasons), IMSA’s GTP class was relaunched this year with a stout field of four high-end marques with proven racing pedigree: Acura, BMW, Cadillac and Porsche. Next year, Lamborghini joins the grid for the longer-distance races, while Porsche has already tested the customer car waters. Porsche motorsport boss Thomas Laudenbach is aware that the presence of factory teams won’t last forever, but he wants the 963 to become an ever-present in the vein of the 962 to ensure a sustainable future.

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IMSA made a statement when it elected to revive the GTP name for its new era, but it turned out to be a prudent call

But the hybrid element that set this project apart – especially after IndyCar postponed its plans until 2024 – was almost the straw that broke this camel’s back. During testing last year with Porsche, which became the guinea pig due to being furthest ahead with plans, it became apparent that the MGU wasn’t up to the demands required. It meant a hardware redesign amid a supply chain recently battered by a COVID-inspired crisis.

“We recovered quite well,” states Urs Kuratle, Porsche’s director of factory LMDh racing. “Reliability was our biggest problem at the start of the season. Everything was just so new.”

Daytona hosted the first test where all manufacturers were present, and it was a major eye-opener in terms of how many problems were being encountered. “It feels like rolling a rock up a hill,” groaned BMW’s Maurizio Leschiutta at the time. Cars were spending as much time ‘rebooting’ in the garage as they were running on the track and, with the Daytona 24 Hours just over a month away, the clock was ticking.

“I’m proud to say that I think we’ve entertained the fans this year. The racing was good; the cars look and sound great. From track to track, you didn’t know who was going to win" David Salters

“Technically it was very challenging,” reflects Leschiutta. “We were up against very competent competitors and we were the last to commit to the class. At Daytona we arrived with a car that was pretty much an unknown for us. We were simply learning through each practice, qualifying and the race.”

Fortunately, what threatened to be a circus turned into the amazing show that all involved had hoped for. With Daytona followed by the Sebring 12 Hours in March, the ‘36 Hours of Florida’ didn’t degenerate into a war of hybrid attrition; these were properly contested sportscar classics – Sebring could even afford a three-car, race-deciding shunt between the GTP frontrunners! It was the precursor to a season where all four manufacturers won races.

“When this whole programme was kicked off, the recipe to get everyone as tight as they have been was very effective,” says Mark Stielow, General Motors’ motorsport engineering director. “We can all complain about different things – a year ago we barely had a car running and we were all praying to finish the Daytona 24 Hours! To say we had some teething issues early on is an understatement, but we came a long way this year and it’s been a very successful season with a high degree of competition between us.”

Let’s go back to how this story started… The new era of GTP created some seriously cool cars, just like the old days. Using the next-gen LMP2 chassis as a ‘spine’, emphasis was placed on styling freedoms, as requested by the manufacturers, and this produced four noticeably different and striking machines.

Photo by: Michael L. Levitt / Motorsport Images

The new breed of cars have noticeably different style cues and bespoke soundtracks

The class had an audible calling card too, thanks to an array of engine capacities and set-ups. During testing, IndyCar star Colton Herta remarked: “I love how you can stand with your back to the track and be able to tell the cars apart.” And the transition from electric motor to combustion engine in the pitlane placed a really neat emphasis on the hybrid element.

Acura’s US motorsport chief David Salters summed it up best: “These cars look like the future and, when they switch from electric to ICE on the launch from the pitlane, it’s like Tron switching to the voice of God.”

They were difficult to drive, too. The previous prototype class, DPi, had become a pure aero battle between the engineers, as the cars were increasingly smothered in downforce. But IMSA’s new regulations put the LMDh machinery into a defined aero box, so manufacturers had to nominate which part of their cars to make adjustable. The dreaded Balance of Performance wasn’t a factor, since the cars’ natural strengths and weaknesses ebbed and flowed from track to track. Torque sensors were IMSA’s ‘spy in the cab’, so sandbagging was pointless too.

Due to the reduced downforce levels, coupled with increased weight and power, some teams turned to GT aces rather than proven prototype stars. It allowed exciting talents such as Matt Campbell, Nick Yelloly, Connor De Phillippi and Mathieu Jaminet to shine at the front of the field.

Another point to consider was Michelin’s reduction of tyre sets – on sustainability grounds – which led to a requirement to double-stint its rubber. No tyre warmers with these heavy yet powerful cars put a premium on out-lap driving skill, with new rubber meaning slower-than-GT3 pace and some truly lairy moments.

“We do this to challenge ourselves and we do it to entertain people,” says Salters. “I’m proud to say that I think we’ve entertained the fans this year. The racing was good; the cars look and sound great. From track to track, you didn’t know who was going to win. In racing, you tend not to look back – you’re always asking, ‘What can we do better tomorrow?’ – but I think we should reflect on how much the cars have developed, and our engineers have been finding stuff out about them all the time.”

Stielow adds: “I think this platform has really energised prototype racing for the fans. Our marketing colleagues are happy that there’s a lot more people engaged and watching it, I’ve never seen so many campers and people at Sebring glued to our race before. We’re lucky enough that we’re living through a renaissance of endurance racing and we’re writing part of the history.”

Rather than merely reanimating a dinosaur, GTP’s lost world has returned with further room for evolution due to an open software ethos.

Photo by: Richard Dole / Motorsport Images

Software development is expected to become a key performance differentiator as the ruleset matures

“I do believe that the biggest chunk of potential from now on is probably on the software side in various different areas,” points out Kuratle. “Hardware is the first area you can get solved, including the drivers and everybody. I’m not saying there’s no potential in the other areas, but the biggest part is going to be software from now on.”

If ‘old GTP’ was all about brawn, then ‘new GTP’ is about brains too. To keep the big-budget manufacturers involved it’s got to evolve, while keeping costs under control to allow high-performing customer teams to see it through inevitable leaner times ahead.

Budgets blown across the board – but with good reason

The litmus test of any new racing category is the cost to the participants when economic sustainability is king. All racing costs money, but what is the value proposition to the car manufacturers? There’s no doubt that IMSA’s hybrid age came at a higher-than-expected cost, mainly due to global supply chain problems and those early hardware issues. But most hurdles are behind LMDh now, and sources inside Lamborghini tell us that its initial hybrid running has gone smoothly.

"Overall, I can’t put an exact number to it, but it was quite a bit more money than we expected" Mark Stielow

“After COVID, every single thing has gone up in cost,” explains GM’s Stielow. “These cars are complicated. We had an initial budget and we kinda pushed through that. But that’s racing. We found new problems and we came up with solutions for ’em and that created more spend. Overall, I can’t put an exact number to it, but it was quite a bit more money than we expected.”

Like Cadillac, Porsche raced its LMDh car in WEC as well as IMSA, and had the added burden of customer teams to supply.

“All these extra costs are multiplied by the championships and the amount of customers we have,” says Kuratle. “However, I’m still sitting here, we’ve not been kicked out by our bosses! So that means our board members are OK with what we spent.”

For BMW, this was its first prototype campaign since its Le Mans and Sebring-winning V12 LMR days. For a company renowned for its ‘Ms’, Leschiutta’s watchword was “manageable”.

“It was a new product, a new business model,” he explains. “It was more expensive than we thought but it was still manageable.”

Photo by: Art Fleischmann

Porsche has sold customer cars to the JDC-Miller and Proton teams, which have mixed it with the works teams

To fulfil the value proposition, Acura’s Salters reckons that having “the right people in the room” made this added spend worthwhile.

“It’s entertaining to fight with our competitors,” he enthuses. “As we’re all top brands, it’s great to see. Yes, it is more expensive, but there’s good value for it. And I’d say there’s more potential still, with new manufacturers coming, but we need to be attentive that costs are controlled. Then there will be value, and that’s how you justify your existence to keep our leaders happy.”

New era, same old bitter rivalries

The first season of GTP Version 2.0 had everything: white-hot competition, elbows-out racing and even deception. But it came down to another Acura versus Cadillac title duel.

The championship was decided by a clash in the closing stages of the Petit Le Mans finale at Road Atlanta between Pipo Derani’s Action Express Cadillac and the Wayne Taylor Racing Acura of Filipe Albuquerque. In a winner-takes-all scenario, under the cover of darkness, race leader Derani took all of the track at Turn 1 as Albuquerque boldly tried to pass him around the outside. Contact was made and Albuquerque slammed hard into the tyrewall. The incident was reviewed by Race Control for an excruciatingly long time, but no action was taken, so Derani and season-long team-mate Alexander Sims were crowned champions.

Even that wasn’t the most controversial flashpoint of the season. This occurred four weeks after the season-opening Daytona 24 Hours.

Reigning series champion Meyer Shank Racing’s Acura had survived an overheating gearbox and fuel/oil contamination issues to win the showpiece race again. A month later, IMSA made the shocking announcement that its car had surreptitiously been running outside the rules.

Evidence of tyre pressure data manipulation was discovered by Honda Performance Development – whose ARX-06 car MSR operated – and it blew the whistle long after the official results had been rubber-stamped. Rather than disqualify the car, IMSA’s penalties were a deduction of 200 team and driver points, and its prize money. But MSR kept the win and the trophies – very much to the annoyance of those who sought to inherit them.

Dispute of a different kind decided the 12 Hours of Sebring, where a heated battle for victory between Porsche and the WTR Acura boiled over in a three-car crash in the closing minutes. That opened the door for AXR’s Derani, Sims and Jack Aitken to inherit a victory that would prove crucial in the title outcome.

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MSR's Daytona victory was tainted by the tyre pressure scandal that emerged afterwards

Shank’s Acura won two more races, legitimately this time, at Mosport and Petit Le Mans. And the fact that Tom Blomqvist and Colin Braun got to within 22 points of the title, after being stripped of 200, reflected the Acura’s outright speed. But Daytona disgrace came at the cost of losing its factory deal.

Porsche was in championship contention until the final round, where Nick Tandy was taken out by a collision between backmarkers. He and team-mate Mathieu Jaminet won at Long Beach – after a jaw-dropping run on one set of tyres – and on IMSA’s return to Indianapolis.

Amazingly, Wayne Taylor Racing’s Acura didn’t win a race all year, with Ricky Taylor coming agonisingly close at Long Beach but crashing out in his bid to grab the victory

They also took the chequered flag first at Watkins Glen, only to be stripped of victory in post-race inspection due to excessive rear skid-block wear. This handed BMW its only triumph of the season, for Nick Yelloly and Connor De Phillippi, who had led until the final six minutes of the six-hour event.

Amazingly, Wayne Taylor Racing’s Acura didn’t win a race all year, with Ricky Taylor coming agonisingly close at Long Beach but crashing out in his bid to grab the victory. He and Albuquerque could also look back in anger at those Daytona, Sebring and Petit Le Mans outcomes – they finished just 21 points shy of the title.

Photo by: Michael L. Levitt / Motorsport Images

A controversial clash with WTR's Albuquerque decided the championship in favour of Action Express Caddy duo Derani and Sims