The performance car arena has changed almost beyond recognition over the last decade or so, primarily due to the ever-tightening emissions regulations that are forcing manufacturers to make drastic alterations. A market that was once awash with high-revving naturally aspirated engines with 10 and 12 cylinders is now predominantly made up of smaller six and eight-cylinder engines that use turbocharging or electrification to help cook up their power. Peak figures have been increasing considerably, but the level of drama and driver engagement has generally been negatively affected by the switch to this newer breed of power plant.
Porsche is no exception when it comes to this sea change, though one department of the German marque is working hard to keep the brand’s roots alive. It’s fighting a losing battle, but for now, its quest has proven a roaring success.
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Porsche Has Been Gradually Leaving The NA Engine Behind
Yellow 2017 Porsche 911 frontPorsche
Once upon a time, Porsche prided itself on relying on naturally aspirated versions of its legendary flat-six design to power its range of sports cars. The marque didn’t even offer turbocharging as an option until the 911 Turbo was released in 1982, and even then, the car remained its own entity aside from the rest of the 911 range. The marque followed the same pattern with the cheaper Boxster and Cayman models, which were primarily offered with NA flat sixes for most of their duration. Turbocharged four-cylinder engines were introduced later in their lives, but an NA 4.0-liter flat-six was also on the menu.
Over the last half-decade or so, things have changed drastically. Mainly led by ever stricter emissions regulations such as Euro 6, which came into effect in 2015, Porsche and its fellow auto manufacturers have needed to cut the amount of nasty stuff being thrown from the exhausts of their offerings. The NA flat six remained available in the Boxster and Cayman 718 until 2025, but both were discontinued partly due to the upcoming introduction of the even tougher Euro 7 emissions regulations. The same goes for the 911, which lost its standard NA engine at the introduction of the 991.2 generation way back in 2016.
The loss of the NA flat-six in these models was heartbreaking, seeing as the engine not only belted out an amazing noise, but also treated its driver to a crisp and responsive throttle response that made it a joy to thrash around.
Porsche’s GT Department Has Worked Hard To Keep The NA Flat-Six Alive
2026 Porsche 911 GT3 Manthey Kit at Road AtlantaPorsche
Happily, while the wider Porsche operation has moved away from the NA version of its historic engine, its track-focused GT department wasn’t so interested in waving goodbye. The GT department takes care of hardcore versions of Porsche’s models, such as the 911 GT2 and GT3, as well as the highly collectable Porsche Cayman GT4. It also works closely with Porsche’s Motorsport arm, with between 65–70% of the road car development being carried out alongside the pure racing versions of the car to ensure there’s a direct correlation between Porsche’s learning on the racetrack and its finished production vehicles.
The GT department has prided itself on keeping the Porsche 911 GT3 alive, which is the last sports car it offers with an NA flat-six tucked under its rear clamshell. The GT3 was traditionally the hardcore, track-ready variant of the standard 911 Carrera, though it effectively became its own entity when the base 911 switched to using a twin-turbocharged engine. As a result, the NA flat-six remains in production to this day, and it’s an absolute honey.
Porsche’s Last NA Flat-Six Is A Weapon
2025 Porsche 911 GT3Porsche
Given the 911’s roots of using an NA flat-six, it shouldn’t come as a surprise to learn that Porsche is working hard to keep the old girl going for as long as it can. Speaking in 2018, then Porsche GT and motorsport director Dr Frank-Steffen Walliser told Drive that “The uniqueness comes from the normally aspirated engine,” and that “As long as we can do it, we will do it.” Given that the emission regulation walls are swiftly closing in, the end may not be far away, but this shows the brand is determined to hold out until the bitter end.
Porsche 4.0 Flat Six
Layout
4.0L NA H6
Material
Aluminum
Bore x Stroke
4.02 x 3.21 inches
Power
503 hp
Torque
346 lb-ft
And we’re glad about that, seeing as the wailing 4.0-liter power plant kicks out an amazing 503 horsepower and 346 pound-feet of torque. When sent to the rear wheels via a six-speed manual gearbox – the GT3 being the only Porsche to still feature an example of the latter – and a lightweight frame, it’s a catalyst for the GT3 being one of the most fun and engaging sports cars on sale today. With a 0-60 mph sprint of 3.4 seconds being possible, the NA flat-six shows that it can still cut it against a sea of turbocharged engines. Aside from still being ultra-powerful though, it stands apart from a turbo unit due to its unrestricted engine note, which can almost burst your eardrums when you push it to its sky-high 9,000 rpm redline. By contrast, the turbocharged 911 GT2 can only hit 7,200 rpm at its peak.
Aside from providing a primeval scream when you push it to its limits, the lack of turbolag means you don’t have to worry about a sudden burst of wheelspin making your life difficult. The power delivery is beautifully linear, and amazingly refreshing versus a traditional turbo power plant.
The Porsche 911 GT3’s four-liter flat-six engine revs to 9,000 rpm.Porsche
Despite over 60 years of development carried out on the engine, the marque is still finding ways to extract more grunt and efficiency from the engine. Having been lifted directly from Porsche’s GT3 racing machine, which spends its time pounding round legendary tracks like the Nürburgring Nordschleife and the Le Mans Circuit de la Sarthe for a laugh, it’s full of advanced engineering tricks. The dry sump lubrication setup prevents oil starvation from wrecking the engine during heavy cornering, while titanium connecting rods and forged pistons are on hand to provide all the strength needed to keep the unit from detonating as you shift at 9,000 rpm.
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The cylinder walls are even coated with plasma to help reduce friction, which reduces heat within the power plant and allows it to rev more easily. The connecting rod bearings even get their own oil pump to help keep them lubricated, showing Porsche’s push to not only make the flat-six ultra-powerful and a joy to use, but also strong enough to deal with all the punishment handed to it.
Porsche’s Naturally Aspirated Flat-Six Is Nearing The End
The Porsche 911 GT3’s naturally aspirated flat-six engine revs to 9,000 rpm, all day long.Porsche
While Porsche is holding up its end of the bargain in keeping the NA flat-six alive in the GT3, the odds of it surviving past 2030 look slim. The Euro 7 regulations will make continuing with the power plant practically impossible, a sentiment that current Porsche GT boss Andreas Preuninger confirmed when speaking to Car and Driver in early 2026. When asked how long the engine could last, Preuninger stated that it could survive for “quite some time” in the US due to the nation’s less stringent emissions regulations; he wasn’t so positive about Europe.
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“In Europe, probably only a few years without any substantial changes,” said Preuninger. When quizzed about whether that means turbocharging could be on the cards for the GT3, he replied, “It might be”. Seeing as building two different engines for the car would be prohibitively expensive, this means that the next GT3 would likely need to be turbocharged in both territories.
There Are Already Signs The Next GT3 Could Be Turbocharged
Spy photos of a Porsche 911 GT3 RS test vehicle.CarBuzz / Valnet
This prophecy could already be well underway behind the walls of Porsche’s Stuttgart factory. Judging by spy shots secured by CarBuzz in 2025, which potentially show the test mule for the future variant due to its GT3-like bodykit, the car is running some extra camouflage above the rear license plate. This could well be hiding some extra venting, which would be needed if the car was running a hotter turbocharged power plant.
As of the time of writing in June 2026, there is no confirmation that the future GT3 will ditch the NA engine, but the words of Porsche’s GT boss don’t bring much hope that the awesome unit will survive into the next decade.
Porsche’s Racing Identity Will Also Have To Change
2026 Porsche 911 GT3 R side on trackManthey Racing
The potential end of the NA GT3 will also have to lead to drastic alterations to Porsche’s racing programs. Its most prominent interests lie with its customer GT racing exploits. These are primarily made up of the 911 GT3 R, which is built to the worldwide GT3 regulations and races in the likes of the IMSA Sports Car Championship and World Endurance Championship, and the 911 GT3 Cup, which competes in a range of regional and international series around the globe. Both cars still utilize the 4.0-liter NA engine, which thrills fans against a backdrop of rival vehicles having switched to quieter and less inspiring turbocharged power plants.
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The end of the NA power plant in Porsche’s production range will facilitate a change for its racers, too, since otherwise they’ll no longer represent the machines that enthusiasts can actually buy. This would be a crying shame, given that the 911-based racecars have used such an engine configuration since the model first arrived way back in 1964.
Whichever way Porsche’s GT department is forced to turn, it deserves huge respect for working as hard as it has to keep the NA flat-six alive and kicking in the GT3, even as the rest of the company fully embraces a turbocharged future. It’ll be a sad day when the power plant is put out to pasture, but at least Porsche ensured we got to enjoy it for as long as possible.
