C8.R changes for IMSA GTD Pro this year

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IMSA has revealed the Daytona-specific Balance of Performance table that will be utilized for the kickoff of the WeatherTech SportsCar Championship season, confirming identical BoPs for the new GTD Pro class and GTD category.

Released on Wednesday, (see attached PDF) the table has also set the starting technical configuration for the nationally homologized Chevrolet Corvette C8.R GTD.
The former GTE-spec car, adapted to the GT3-based platform, will run the Roar Before the Rolex 24 with a reduced 41.3 mm air restrictor and at an increased minimum weight of 1320 kg.

It compares to a 44.5 mm air restrictor and 1270 kg weight the car ran in GTLM trim at Daytona last year.
In addition, the Corvette will also be configured with ABS and modified aero, including the addition of a 15 mm rear wicker.
IMSA has also made a number of BoP changes to cars compared to last year’s Roar and Rolex 24 configurations.

The Aston Martin Vantage GT3 has been given a 30 kg increase in minimum weight, with the Mercedes-AMG GT3 Evo getting a 10 kg addition and the Porsche 911 GT3 R a considerable 45 kg more weight, although offset with a 3 mm increase in its air restrictor that will equate to increased power.
Both the Acura’s NSX GT3 Evo22 and Ferrari 488 GT3 Evo 2020, meanwhile, have received turboboost reductions compared to 2021 levels.

The sanctioning body has also established the BoP for the McLaren 720S GT3 and new BMW M4 GT3, both of which did not take part in last year’s race.
Per the regulations, IMSA reserves the right to make class-specific BoP adjustments to GTD Pro and GTD if deemed necessary but is understood to be in favor of retaining the same performance levels across both GT3 categories.

The DPi class, which has been reduced to a two-manufacturer battle between Acura and Cadillac for this year, sees no major performance-related changes compared to last year’s BoP for the Roar and Rolex 24.
The biggest changes to the Chevrolet Corvette C8.R in GTD Pro specification have been the addition of ABS and a move to the class-wide Michelin customer tire, according to drivers Jordan Taylor and Antonio Garcia.

The Pratt & Miller-run squad will compete in the new-for-2022 class utilizing a modified form of its GT Le Mans class-winning entry, permitted by IMSA for the next two seasons in the WeatherTech SportsCar Championship, prior to launch of an all-new Z06 GT3.R in 2024.

After having initially tested the ABS system in last year’s GTLM non-points race in Detroit and conducting post-season testing at Virginia International Raceway in the modified specification, Taylor and Garcia believe that there will still be “a lot of learning” heading into the season.
“There are a lot of little details that IMSA is making us do to get the C8.R closer,” Taylor explained.
The car wasn’t designed for the class, so they’re trying to make it as even as possible.

The biggest aspect is understanding the way the tire works.
The team has spent so many years with Michelin to develop the confidential tire to work properly for our car.
Now we’re moving to a tire that will work for a front-engine, mid-engine and rear-engine car.
Understanding how the way that works and maximizing it for not just one lap, but for over a stint will be a huge thing to learn.
ABS is another thing to understand the brake wear with that system.

It’s good to have someone like Nicky [Catsburg] who has so much GT3 experience who can lend a hand for Antonio and me who don’t have as much experience as he does in this type of car to understand what it’s supposed to feel like and how we make the most of that.
There will be a lot of learning. Antonio and I spent two days in the car at VIR after Petit Le Mans last year to get a feel for things.
I’m sure the Corvette Racing guys went back, studied all the data and made their developments.

“There have been other drivers in the sim developing those items that we were working on since then. I think we’ll have a good package for Daytona.”
Garcia added: “Adding ABS is the biggest change for us. IMSA and Corvette Racing are doing a good job of adjusting a GTLM car into a GTD car.
There has been a lot of work together to put together all the data and get our Corvette to the GT3 spec.
The biggest difference is the tire for this year. We will have to adapt to that.

“A lot of the speed differences in previous years were due to the confidential tire to the customer tire, basically.”
Despite other changes, which also include a significant power reduction and mandated 15 mm gurney on the rear wing, Taylor said the car still ‘feels like a Corvette’.

“The C8.R has been really successful since it came out with the mid-engine layout,” he said.
The biggest thing was understanding how the way the tire worked, the window that it works in, how you use it, how much you can slide it, the temperature window that it works in. Those little details are good to understand.

The tire degradation is going to be a different aspect for us.
The ABS was different, just maximizing it in how much pressure to use, how consistent you can be if you’re pushing the brake pedal too hard.
“Little details like that were good to get a feel for last year before we go to the Roar, where most of the work is for the Rolex and not really for car development or driver development.”

Garcia: GTD Pro/GTD Interaction An Unknown

The Spaniard said the possibility of GTD class cars mixing within GTD Pro entries is one of the biggest unknowns going into the season.
While the GTD Pro class features 13 entries for the Rolex 24 at Daytona, an additional 22 GT3-spec cars are set to do battle in GTD, which remains unchanged compared to last year.

“It will be interesting, for sure,” Garcia said. I’m not used to that, and knowing we aren’t racing for the same result will be different.
There could be a point where a GTD car is leading the GT field and end up winning the race.

It will be strange for most of us. I don’t know if they are planning to split the classes in the pit stops or something.
For sure, there will be a lot of play out.
If you are leading, you’re going to want to have a ton of GTDs between you and the next Pro car.
It’s going to be difficult to play out, especially on strategy.
“If you decide to stop at the same time, and you end up all the way at the back of the GTD field, it will make things even tougher.
We don’t know how it will play out.”
 

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