The big question concerning IMSA's new LMDh cars on their debut

After an almost intolerable wait, the LMDh era is upon us. A full three years after the momentous day when a category billed as the saviour of top-flight sportscar racing was announced, the cars are finally going racing.

Tens of thousands of kilometres have been completed by the four manufacturers that will go head to head in this weekend’s Daytona 24 Hours, but many questions remained unanswered in the lead-up to the opening round of the IMSA SportsCar Championship. Not least whether the machinery racing in the GTP class is ready to go twice around the clock at the self-styled World Center of Racing. 

What we shouldn’t forget is that when LMDh was unveiled back on the eve of Daytona in 2020, the category was due to come on stream in 2022, in both IMSA and the World Endurance Championship. The world changed in the months that followed the so-called convergence announcement as COVID took hold and, by September and the delayed running of that year’s Le Mans 24 Hours, it had become clear that the introduction of the new breed of hybrid prototype developed around the spine of a next-generation LMP2 car would be delayed until this year.

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Announcements from major manufacturers that they would be taking the new cost-effective route of developing a top-class contender that could race in the world’s two premier sportscar series quickly followed. There are six confirmed so far: Porsche, Cadillac, Acura and BMW, who will do battle this weekend, will be joined by Lamborghini and Alpine in 2024. 

Porsche, the second to announce after the project from Volkswagen group sister marque Audi that never came to fruition, was first to get up and running with a car delectably dubbed the 963 in homage to the 962 Group C and GTP car. It hit the track just over a year ago, the German make getting a six-month head start on its rivals. None of the other LMDhs started running until the summer.

That would suggest that Porsche is much better prepared than Cadillac, Acura and BMW, but the reality is much more complex than that. Porsche spent much of those six months debugging the 30kW off-the-shelf hybrid drivetrain manufactured by Bosch, Williams Advanced Engineering and Xtrac. Had the 963 not been up and running back at the start of last year, the prospects for Daytona might well be looking pretty bleak. It was only as the end of the summer approached that an update of the hybrid system dubbed internally by Porsche as “version 2.2” meant the corner was turned. 

Porsche was up and running early last year, but this involved a lot of debugging the new hybrid system rather than performance testing

Photo by: Juergen Tap / Porsche

The Porsche Penske Motorsport squad, the new organisation that will run a pair of 963s in both IMSA and WEC, has covered the most kilometres of the LMDh operations. Of that we can be sure. It had twin test programmes in Europe and North America from the summer and has completed an endurance simulation. The total distance completed going into last weekend’s Roar test and qualifying days at Daytona has been put at “more than 30,000km” by Porsche director of factory motorsport Urs Kuratle, which he adds was the goal set by the marque earlier in the programme. 

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Porsche undertook what was a 36-hour test at Sebring in October, while Cadillac is the other LMDh manufacturer to have successfully gone through an endurance simulation. It ran 24 hours, also at Sebring, at the start of November with the Chip Ganassi Racing squad that will mount single-car campaigns in IMSA and WEC this year with the Caddy V-LMDh.

It has been more forthcoming about the results of its long-distance running than Porsche. It suggested it was an encouraging test at the time, but a couple of months on it appears that it was near-faultless, or something approaching that. 

"We are happy with the milestones we’ve hit, but we’re not sitting here saying that we’re 100% confident the cars are going to run flawlessly through the race" Jonathan Diuguid

“Just tyres and fuel the whole way,” is the description of the test by Earl Bamber, who drives the additional Cadillac Racing entry fielded at Daytona by Ganassi before it moves over to the WEC. “We had one or two things at the beginning, but that was just about learning how to handle the car. After that it was faultless. It was an impressive test.”

BMW, the last of the LMDh manufacturers to get its contender out on track right at the end of July, was at Sebring with its new M Hybrid V8 at the same time as Cadillac, but its attempt to run a continuous 24 hours was thwarted early on by gearbox problems. There wasn’t time to reschedule another long-distance test.

BMW had two cars present at Daytona in early December for the second of the so-called sanction tests organised for the LMDh manufacturers and appeared to have the most problems of the four. But Bobby Rahal, whose operation runs the two cars under the BMW M Team RLL banner, insists that his squad subsequently had “a very good test at CoTA [Austin]” later in December. 

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Acura opted against running an endurance simulation, preferring instead for its Wayne Taylor Racing and Meyer Shank Racing teams, the former now partnered with Andretti Autosport, to rack up distance on components during regular testing of their new ARX-06s. The two teams had a car each from early in a programme that began in Europe with a shakedown and then one full test in mid-July. 

Cadillac has also completed a 24-hour test with its new V-LMDh at Sebring

Photo by: Cadillac Communications

“We were just trying to prioritise given where we were in the programme and with parts supply,” says David Salters, president of the California-based Honda Performance Development operation that masterminds Acura’s motorsport activities. “It is what it is, and we believe that we have done the preparation we need.”

However much testing has been done, none of the four manufacturers is saying that they have unburstable cars. 

“We are happy with the milestones we’ve hit,” says Jonathan Diuguid, who is managing director of the Porsche Penske set-up. “But we’re not sitting here saying that we’re 100% confident the cars are going to run flawlessly through the race. We’re going in as prepared as possible for every scenario we can plan for. But testing is not racing.”

Every team in the nine-car GTP field will be competing with a hybrid racing machine for the first time. That brings many challenges. 

“Twenty-four-hour races are always harder when you don’t have a logbook or set-up book or all the other things ready to go when you get to the track,” says Gary Nelson, team manager of the Action Express Racing squad that is running a solo Caddy V-LMDh in IMSA this year. “We’re going to create pretty much from a blank sheet of paper a programme to try to win the 24 Hours. We don’t have that muscle memory we’ve had in the past, because everything is all-new.”

Nelson suggests that electronic glitches will be the most likely hiccups faced by the GTP field through the race. He points out that so many systems on the car are now controlled by computer.

“We have a lot more things that go by wire now,” he explains. “Where we used to have manual shift, we went to shift by wire and paddleshift and then we went to throttle by wire. And multiply that by four or five other different components on the car that are now going through a computer. So, probably electronics will be the focus on trying to make sure all of those computers do what they’re supposed to do.”

AXR team manager Nelson anticipates electrical gremlins will be the main cause of issues at Daytona

Photo by: Jake Galstad / Motorsport Images

These concerns over reliability beg the question whether this, the 61st running of the early-season Daytona enduro – not the 61st edition of the 24 Hours as IMSA proclaims – will turn into an old-style long-distance race with teams running to a reduced pace to try to get to the finish cleanly. Diuguid is insistent that isn’t going to be the case.

“I think we all know racing drivers: even if we told them we want them to go out there and protect the car, they don’t listen very well all the time,” he says. “If you don’t go out and push, you are going to end up third. It should be a GTP podium,” he adds, meaning an all-GTP podium.

Neither Diuguid nor any of his opposite numbers at the other teams seem concerned that an LMP2 might be able to claim an upset victory. The LMP2s have been slowed for Daytona this year in the name of what IMSA calls “class stratification”. A smaller-diameter air-restrictor has been imposed on the secondary prototype class, though not as small as mandated in either the WEC or the European Le Mans Series, and the same rev-limits from those series introduced. Weight has also been increased by 10kg and six seconds added to the minimum refuelling time. 

"I don’t even know how many LMDhs there are, but you would have to think that at least one would run through the race reliably. And if they do hit problems, they will have the pace to catch back up" Ryan Dalziel

Ryan Dalziel, LMP2 winner with the Era Motorsport team in 2021 and an overall winner in an Action Express Riley-Porsche DP in 2010, insists that neither he nor the Era team are going into this year’s race with thoughts of overall victory.

“I’m definitely not approaching the race thinking about anything else other than class honours, even though we know there are doubts about the reliability of the cars in GTP,” says the expat Briton. “I don’t even know how many LMDhs there are, but you would have to think that at least one would run through the race reliably. And if they do hit problems, they will have the pace to catch back up.”

The LMP2 pole mark at the Roar last Sunday was a 1m40.5s, which compares to the best qualifying time last year of 1m37.2s. The LMDhs are pretty much on a par with the Daytona Prototype internationals of old: Tom Blomqvist claimed pole on Sunday with a 1m34.034s, which compares with Tristan Vautier’s qualifying mark for the JDC/Miller Motorsports Caddy squad last year of 1m34.031s. What the LMDhs gain in having more power than their predecessors, they lose in the extra weight they carry. 

That will take its toll on race pace. It is easy to overlook another big change at Daytona this year in the light of the arrival of the new cars. The tyre allocation has been drastically reduced, and that is going to make double stinting de rigueur.

LMP2 cars have been slowed, and crews don't anticipate being able to fight for outright honours

Photo by: Michael L. Levitt / Motorsport Images

Last year, each DPi car had 38 sets of Michelin slicks for race week and 10 sets for the Roar, which included a 100-minute qualifying race. Typically in the past a team might go into the 24 Hours with 30 fresh sets available. This time only 33 sets are available, of which just 21 can be used in qualifying and the race. The other difference in 2023 is that there are now two specifications of slick available rather than the one of old. 

“In the past you had so many tyres that you pretty much threw on a new set every time you put fuel in the car,” says Bamber. “Tyre degradation is definitely going to play a bigger role in the race this time, especially because of how heavy the cars are. There’s going to be significant disparity in times between someone out there on new tyres and someone on old tyres.”

On one-lap pace all nine GTP entries were within a shade over eight tenths in qualifying at the weekend. Whether or not IMSA planned to react to that and tweak the Balance of Performance wasn’t known at the time of publication. But Daytona this weekend isn’t going to be about what the cars can do over one lap. 

“You need an easy-handling car, one that feels good on full tanks or with a light fuel load and that still works at the optimum level at the end of the race,” says Porsche Motorsport boss Thomas Laudenbach. “Time over a single lap will be balanced anyway, so having a peaky, fast car I don’t think will be the key to success.”

Pace over a single lap is unlikely to be the determining factor at Daytona

Photo by: Jake Galstad / Motorsport Images