Unique Contrasts of Lexus RC F GT3 and Its Road Counterpart

My affection for grand touring and touring car racing has always been prevalent. The vehicles bear a striking resemblance to their daily-use counterparts, and I firmly believe that All Automobiles Appear More Attractive When Transformed into Race Cars. Who wouldn’t appreciate sleeker, more aggressive renditions of the Aston Martin Vantage, Porsche 911, BMW M4, or Hyundai Veloster N? The demarcation between purpose-built racing cars and civilian models becomes blurrier in higher-performance classes; however, the Lexus RC F GT3 manages to uphold an intriguing fusion of the two.

The Lexus RC F customized for GT Daytona (GTD) represents the International Motor Sports Association’s (IMSA) rendition of the globally acknowledged GT3 classification. In my view, the street automobile, with its flamboyant bodywork, low profile, and wide dimensions, exudes more of a racing aesthetic compared to many other high-powered sports cars. Conversely, the race-ready counterpart closely mirrors the street version, barring the enormous slick tires, center-lock wheels, added ventilation and aerodynamic elements, and a substantial rear wing.

These attributes establish a perfect foundation for examination. Join us as we scrutinize the distinctions between the standard RC F and the racing edition.

I must disclose that Lexus graciously extended an invitation for me to attend the 2021 Long Beach Grand Prix as one of its media invitees. The company covered my entrance fees and parking, granting me access to its race paddock and VIP suite.

In GT Daytona (GTD), the stipulations to emulate the street car are quite minimal. The RC F must retain its front-mounted engine and rear-wheel drive configuration, while the chassis’s core structure remains unaltered; however, other aspects appear to be open to interpretation. Nearly all of the GT3’s external coverings consist of carbon fiber, instantly altering the car’s appearance and texture. Measuring approximately 4.7 inches shorter and shedding around 1,000 pounds compared to its street weight of 3,958 pounds (depending on balance of performance, elaborated later), the GT3 is notably more compact and lighter. Despite this, it maintains the identical 107.5-inch wheelbase as its street counterpart. For enhanced safety and adept racing setup, it features an extensive roll cage, safety nets and harnesses, fire suppression setup, and racing-grade electronic systems.

The disparities extend further when inspecting the underpinnings within the GT3’s wheel arches, and I conversed with Greg Cates, Vasser Sullivan’s team manager, to gain a deeper insight into the technical modifications. “It boasts a dual wishbone suspension setup, both at the front and rear,” Cates remarked regarding its four-wheel independent suspension. In contrast, the street model is equipped with a dual wishbone suspension upfront and a multi-link system at the rear. He further highlighted that the race car is equipped with four-way adjustable Öhlins coilovers, a renowned Swedish company known for its top-tier racing and street-oriented suspension solutions.

The naturally aspirated V8 engine beneath the extensive carbon fiber bonnet also has its origins in the consumer model; nevertheless, the alterations produce a substantial impact. “It takes its foundations from the [factory] engine block, however, the traditional oil pan is substituted with a dry sump,” Cates elucidated regarding the RC F’s 5.0-liter 2UR-GSE V8 engine. “This modification is quite significant.”

A dry-sump system includes a small oil reservoir, typically positioned higher within the engine, and a pressurized setup that ensures continual oil circulation throughout the engine. It provides superior efficiency and performs better than a conventional oil-pan-based system in averting oil shortage during high-G-force racing circumstances. The race-spec 2UR-GSE engine has been expanded to 5.4 liters, generating over 500 horsepower, surpassing the street model’s 467 horsepower.

The engine and drivetrain also exhibit engaging discrepancies concerning their positioning within the chassis, aimed at enhancing.balance of mass and control. The power unit remains at the front, but that doesn’t preclude the possibility of relocating other components towards the rear.

“It features an X-Trac 6-speed sequential gearbox, and it’s positioned at the rear along with the clutch, bellhousing, and alternator, all residing towards the rear,” Cates articulated, highlighting the transaxle comprising the transmission and rear differential in unity. “Given the front-engine layout of the car, it’s desirable to transfer as much mass rearward as possible to attain a more favorable equilibrium.” This represents a stark departure from the conventional road car, where the 8-speed automatic gearbox is located at the front directly behind the engine, followed by a standard driveshaft sending power to the rear differential.

“As a team, your aspiration is always to enhance the equilibrium of performance for your car,” remarked Cates. “In my view, IMSA has executed this task rather effectively. Presently, we are slightly burdened. Every team encounters its unique challenges; in our case, we grapple with excessive tire wear at the rear. BOP not only affects our acceleration and deceleration but also amplifies stress on our rear tires. Consequently, it impacts us on multiple fronts rather than just one.”

In addition to shouldering a slightly heavier load than desired — this sentiment likely resonates with all teams — having the additional weight in the rear accelerates wear on the rear tires, significantly influencing a team’s strategic decisions during races. The scenario is particularly intriguing in the case of the RC F GT3, as its design philosophy from inception has been focused on relocating as much mass towards the rear to enhance the overall equilibrium.

“At the corporate level, discussions ensue regarding these matters, and you do have avenues to voice concerns about how BOP impacts your operations and fight for your stance,” Cates elaborated. “IMSA has handled this aspect fairly well. Those who follow racing, especially during tightly-packed moments under yellow flags among professional drivers, witness closely contested battles when racing resumes.”

After spending some time in the paddock, I moved to a section of the track that afforded me a close-up view and the opportunity to capture images of the intense on-track action, which was abundant at the Long Beach Grand Prix. It was truly fascinating to learn about the prowess of the RC F GT3 in IMSA GTD while being in close proximity to it, and subsequently witnessing its prowess through the challenging turns of this historic street circuit.

This article was originally published on Car Bibles.

Have a suggestion or query for the writer? Reach out directly at: peter.nelson@recurrent.io