How Real IMSA Race Car Technology Makes Its Way into Every Production Corvette

• Corvette engineers at GM say their race cars in the IMSA GTD Pro class have a closer connection between the track and street than any other road racing manufacturer.

• This year’s move out of the grandfathered IMSA GTLM into the IMSA-mandated GT3 category means GM is supplying privateer teams with the Z06 GT3.R

• The success of Corvette Racing, “didn’t happen by accident,” said Doug Fehan, the original program manager.

Win on Saturday and sell on Monday.

That’s the goal for the manufacturers competing in IMSA WeatherTech GTD Pro race on the Chevrolet Detroit Grand Prix circuit this weekend.

It’s an old bromide with an update.

The cars of the 10 manufacturers—Lexus, Porsche, Lamborghini, Aston Martin, Ford, Chevrolet, McLaren, Ferrari, BMW, Mercedes-AMG—competing in GTD Pro are light years ahead of the Detroit-derived stock cars of the 1960s that careened around NASCAR ovals in the name of Sunday wins and Monday sales. Thanks to the GT3 rules, these days a direct link now exists between GT race cars and the mega horsepower, ultrahigh performance vehicles popping up in showrooms.

The Corvette engineers at GM, whose headquarters in Warren, Mich. is not far from the revived Grand Prix circuit in downtown, say their cars have a closer connection between the track and street than any other road racing manufacturer. Engineers for other car builders might debate that claim, but there’s little doubt about the lust for tech transfer in Corvette aficionados that has been fostered by the racing team.

Saturday’s one hour, 40-minute race is the fifth round of the season for the GTP hybrids and the fourth for the GTD Pro entries. A victory by the Corvette Z06 GT3.R would be the first in IMSA by the team now called Corvette Racing by Pratt Miller. But it’s hardly “do or die.” Ever since Corvette Racing’s first major victory in the Rolex 24 at Daytona in 2001, the Pratt Miller team has been able to deliver success in racing and in design.

Bye Bye Pop-Up Headlights

What happened to the clunky pop-up headlights that GM’s Corvette engineers clung to out of stubborn pride? They went away thanks to the insistent request for better aerodynamics during the night at Le Mans. The 7.0-liter, 505-horsepower small block engine in the C6, the racing-inspired aerodynamics on the C7 and the C8’s mid-engine layout are other recognizable transfers between the track and the street that have helped drive sales.

An engine mounted behind the driver among other racing-inspired attributes of the C8 produced in Bowling Green, Ky. inspired the sale of a whopping 53,785 models in 2023, just short of the record set in 1979.

“You can just see visually how the tech transfers from race cars to the production cars and back to race cars from the C5R all the way up to the Z06 GT3,” said Josh Holder, the chief engineer at Corvette. “That’s just what you see, not to mention all the stuff that you don’t.”

Sometimes fans hear something in the Corvettes before it transfers to the street cars. The unmistakable high-revving pitch of the LT6 flat-crank V8 that was first heard at race tracks in the C8.R eventually made its way into the Z06.

“There was a lot of consternation about whether to put it in the race car first or not,” said Holder. “You cannot hide that sound. As soon as people heard the race car in public, they knew what was up. But it was the right thing to do, because it was the surest way to show that the tech transfer is real.”

The racing technology makes its way into the entire line of Corvettes. Factory driver Nicky Catsburg drives a Stingray, powered by an LT2 V8, when back home in the Netherlands. “Fortunately, I live close to the border with Germany,” he said with a wry smile during a Zoom interview. “I can confirm the Stingray can be driven at 300 kilometers per hour on the Autobahn.”

Catsburg, who won the Z06 GT3.R’s first IMSA pole at Laguna Seca in early May, will co-drive the No. 4 Corvette with Tommy Milner. Antonio Garcia and Alexander Sims will pilot the No. 3 entry. Both cars have been competitive in the first three races, but a garden variety of reliability issues, strategy decisions and racing luck have kept them out of Victory Lane in the highly competitive GTD Pro class.

IMSA Victories Equal Sales

A pause here, to confirm that the Corvette brand is hardly the only beneficiary of converting IMSA victories into sales. The Porsche 911 has a two-year waiting list. The German manufacturer, currently racing the 911 GT3 R, has been boosting its U.S. sales prospects for the 911 by choosing to build special cars for IMSA and sports car competition ever since the first RSRs arrived at Daytona’s 24-hour in 1973.

Ford, whose headquarters are in nearby Dearborn, has promoted street car sales with production-based GT engines and cars for decades, including the recent Ford GT1 and the new Mustang GT3. It will be run in the streets of Detroit by Ford Multimatic Sports. Joey Hand and Dirk Mueller (No. 65) and Harry Tincknell and Mike Rockenfeller (No. 64) will handle driving chores. While Multimatic is a longtime partner with Ford, thus far the high-profile partnership in GTD Pro has yet to bear much fruit.

Others in IMSA, such as Aston Martin, BMW and Ferrari have been racing their road cars since the dawn of the GTLM class. (The Italian car maker has long been known for high-revving flat crank engines to help reduce vibration.) It was the competition for U.S. sales versus imports that prompted the creation of Corvette Racing and the goal of beating European imports in their own backyard at Le Mans.

The Path from Factory to Factory Assisted

This year’s move out of the grandfathered GTLM into the IMSA-mandated GT3 category means GM is supplying privateer teams with the Z06 GT3.R, whose 5.4-liter V8 starts life on the assembly line before being modified for racing, which includes keeping IMSA’s Balance of Performance regulations in mind.

GM now describes the relationship with Pratt Miller as factory assisted. Previously, the focus has been on a two-car, full-blown factory Pratt Miller team that competed in IMSA and at Le Mans, where it has won nine times. The record includes 16 manufacturer and driver titles as well as four wins in the Rolex 24.

The success of Corvette Racing, “didn’t happen by accident,” said Doug Fehan, the original program manager who pitched a “symbiotic” structure to Dave Hill, the brand’s chief engineer. That soon led to that first major victory in Daytona in 2001 by the C5R. Fehan’s core idea was to generate a team of hand-picked Corvette engineers at GM who would interface with the racing engineers on the factory team directed by Gary Pratt and Jim Miller.

The shift to GT3 has resulted in what is now referred to as the “umbrella” program of Corvette Racing. It includes two privateer teams that race the new Z06 GT3.R in addition to the factory-supported entries of Pratt Miller Engineering. There are two privateer Z06 GT3.Rs in the World Endurance Championship (TF Sport) and two in the GT World Challenge America (DXDT Racing). AWA fields a brace of the ex-factory C8.Rs in IMSA’s GTD class.

There is no confirmation of how long the current contract between GM and the Pratt Miller team will continue. But the age-old bugaboo for privateers when it comes to competing against the factory does not currently exist, because there are not yet any customer teams in the GTD Pro ranks. For the near term, GM is selling GT race cars, engines, and parts across three series before the green flag ever drops.