GT4 In Project Motor Racing: The global Gateway To GT Racing

June 30, 2025

GT4 is a homologated category for production-based grand-tourer cars. Introduced in 2007, the class was conceived as an affordable, amateur-friendly counterpart to GT3, using road-car shells, stock powertrains and tightly limited aero. Today a new GT4 must pass the same safety audit as any GT3, but its technical freedom is intentionally narrower, and the homologation is frozen for several seasons to curb costs.

Performance Window & Technical Rules

Current regulations cap power at roughly 350–500 bhp and weight to 1,260–1,500 kg, enforced by Balance of Performance (BoP) issued before every event. (BoP can mandate ballast, restrictor size, ride-height or boost pressure so that, in theory, a lightweight four-cylinder coupé and a heavier V8 muscle-car—given the same driver—can post fairly identical lap times.)

Because the aero is minor—flat floors are banned and wings are a lot smaller than their GT3 cousins—drivers rely more on mechanical grip which has the effect of producing tight packs, plenty of slipstream racing, and a contest that places primacy on driver skills.

GT4 cars run spec tyres (Michelin in IMSA) and single‐make fuel and aside from mandatory roll cages, fire systems and race ABS, alterations are limited to springs, dampers and ECU calibration. This kind of limited options in setups also helps in creating tight-packed fields.

This stability is why an entire GT4 season—including purchase, spares and crash budget—can still land under €500,000, roughly one-fifth of a competitive GT3 programme.

Race Formats

GT4 series favour twin 60-minute sprints with one compulsory pitstop and driver swap; the European Series keeps both races on the same tyre set to contain costs. Britain and Germany mix in 120- to 180-minute enduros, while the U.S. calendar uses only the two-driver, one-hour template. All series share a rolling start.

Why Teams, Manufacturers & Drivers Love GT4 Action

• Budget certainty: With homologation locked and BoP, manufacturers can sell a “kit-car” that stays competitive for 5 to even 7 years. Privateers thus avoid the relentless update race that defines GT3.
• Marketing relevance: GT4 silhouettes are 70–80 % stock. When a street customer sees the same silhouette on Monday that claimed a podium on Sunday, showroom translation is immediate.
• Driver ladder: Amateur and upcoming driving talent get to learn how to race, how to negotiate traffic, and all about data systems that are identical to GT3 but at half the speed and stress—a perfect apprenticeship before moving up.
• Broadcast reach: Every GT4 race is freely available to watch on YouTube , helping the class deliver 113 million impressions in 2024 alone.

GT4 vs GT3 at a glance

GT4

• Typical power: 400–480 hp
• Aero load @200 km/h: ≈ 300 kg
• Base price (new): €230–300k
• Annual running cost: €450–600k

GT3

• Typical power: 550–625 hp
• Aero load @200 km/h: 700 kg +
• Base price (new): €500–650k
• Annual running cost: €2–3M

The Future

There are rumours of a global GT4 World Final after the success of the Manufacturer Ranking, and IMSA has floated the idea of adding a 3-hour standalone GT4 showcase during the Petit Le Mans week.

Bottom Line

GT4 succeeds because it strikes a three-way balance—fast enough to thrill, simple enough to learn, and cheap enough to fill the grid. This is the healthiest entry point into international GT racing, and it’s waiting for you in Project Motor Racing.

Close racing is guaranteed. But get your elbows out, because this is a stop for many stars on their way to LMDh and GT3 glory.

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