Verstappen Racing's first test laps in Portimão immediately interrupted by yellow flags

Verstappen will share the #3 Mercedes-AMG GT3 EVO with Chris Lulham and Ben Barnicoat this weekend. The trio will compete in the Pro class and take part in Saturday’s three-hour Endurance Cup season finale. Organisers have announced a field of more than sixty cars representing ten manufacturers.

The extra track time on Thursday offers an opportunity to work on the setup and assess the car’s behaviour over longer runs. After all, a fast lap is not the only thing that matters in the race. The Mercedes must remain predictable on used tyres, and all three drivers need to be comfortable with the same basic setup.

Verstappen is about to complete some laps. The test session was interrupted during the first half-hour by a Full Course Yellow following a spin by Aliaksandr Malykhin in the #9 Porsche of Pure Rxcing. The fastest time so far is a lap of 1:43.295 by Lucas Auer. Chris Lulham has taken over the wheel from Verstappen, with his most recent lap a 1:44.231.

Portimao is known for its elevation changes and blind corners. As a result, drivers cannot always see the exit or turn-in point well in advance. The circuit features fifteen corners, combining slower sections with fast, sweeping turns. The long right-hander leading onto the straight puts particular strain on the tyres.

Pirelli has previously highlighted this strain in its circuit analysis. This combination makes setup a matter of compromise. The car needs enough support through fast corners while also maintaining grip as the track rises and falls. As the car crests a hill, the load on the tyres temporarily decreases. An unsettled rear end can cost the driver confidence and speed there.

A mistake in the final corner can also have a lasting effect. If a driver has to delay accelerating there, the loss of speed carries onto the straight. Conversely, a high top speed alone is not enough: without grip and confidence in the preceding corner, a driver cannot fully exploit that advantage.

Beneath the Mercedes’ long bonnet sits a naturally aspirated 6,208 cc V8, which AMG refers to as a 6.3-litre engine. It has no turbocharger. Thanks to its dry-sump lubrication system—which stores the engine oil in a separate tank and pumps it through the engine to ensure proper lubrication even in fast corners—the engine can be mounted low, helping to keep the centre of gravity down. The sequential six-speed gearbox is located at the rear axle. The GT3 also features adjustable traction control and ABS.

For Portimao, the way these technical features work together with the setup is particularly interesting. Verstappen can use the electronic aids to tailor braking and acceleration to the available grip. They do not take over the driver’s job, however: getting on the throttle too early or carrying too much speed will still cost time.

There is also scope to alter the balance aerodynamically. The front splitter helps generate downforce on the front axle, while the rear wing and diffuser support the rear. Adjustable dampers and anti-roll bars also give the team options for changing the car’s mechanical behaviour.

Based on these characteristics, the Mercedes has the technical tools to be competitive at Portimao. The test will show whether the team can find a balance that allows Verstappen to attack through the fast sections without asking too much of the tyres in the slower corners or over a full stint.

The competition brings a range of different concepts. Alongside Mercedes, Ferrari, Porsche, BMW, Aston Martin, McLaren, Lamborghini, Audi, Ford and Corvette are on the entry list. The field includes the Ferrari 296 GT3 EVO, Porsche 911 GT3 R EVO, BMW M4 GT3 EVO and Lamborghini Temerario GT3.

With its rear-mounted engine, Porsche opts for a different weight distribution. The manufacturer cites traction and braking performance as advantages of this concept. That can be useful when accelerating out of slower corners, although, here too, the setup determines how much a driver can make of it.

In developing the 296 GT3 EVO, Ferrari focused, among other things, on a more predictable and stable aerodynamic response. BMW, meanwhile, placed a strong emphasis on making the M4 GT3 EVO easier to handle and reducing tyre and brake wear. Over a longer stint, such characteristics can be more important than a small advantage over a single lap.

Mercedes has already shown this season that it has a competitive package. Maro Engel, Lucas Auer and Luca Stolz secured the Endurance Cup drivers’ title at the Nürburgring with Mercedes-AMG Team MANN-FILTER. Verstappen will therefore also have a strong benchmark within the same manufacturer.

However, predicting the outcome based solely on the car concept would be going too far. In the GT World Challenge, the different models are brought closer together through the Balance of Performance. As a result, engine displacement or engine placement alone says little about the final pecking order.

The starting point gives Verstappen reason to be optimistic, but execution will be decisive: confidence over the crests, enough speed through the long corners, and tyres that continue to perform throughout the stint. The paid test is the first opportunity to get that package in shape for this race weekend.