The first-ever water-cooled, 8-cylinder, 90-degree V-engine that Porsche ever built was built so right that it’s still used today, in the 2022 Porsche Panamera. Going on its fourth generation and 45 years of use, the Porsche V-8 is still a force to be reckoned with on and off the track. Let’s see how this engine was produced and where it will go into a future of electric vehicles.
The V-8 That Made The 928
Porsche’s V-8 engine development actually began about 46 years ago. Before 1976, Porsche had 8-cylinder engines, but—as was the design and engineering language of the Stuttgart brand at the time—they were air-cooled and laid out in a flat H-pattern, rather than the 90-degree, water-cooled V-engine we’re familiar with today. Those early engines were also limited to racing around tracks rather than for public use, like parking near a Lüchow’s.
Porsche decided it wanted to change that with a completely new car for 1977. A car that not only would have its first water-cooled, 90-degree, eight cylinder, V-engine, but also one with a front-engine, rear-wheel drive layout. This completely new car was the 1978 Porsche 928, and we were impressed with Stuttgart’s first try at this type of layout and engine in our magazine issue at the time: “It is the new concept, that of a front engine and rear transaxle, that will eventually rule. The 911 has been a magnificent car, one of the greatest in all auto history. But in the 928 it has met its match.”
The First Generation
At the time of its introduction, the 4.5 liter V-8 also had the largest cylinder displacement from Porsche. Despite using the same 95mm bore as the 3.0 liter Turbo flat-six, the 78.9mm stroke gave each cylinder a 559cc displacement, though the largest up to that point was 499cc. Even more amazing for the time was the lack of iron cylinder liners in the aluminum block. Despite using steel-plated pistons, the bores of the Porsche V-8 were cast into the Reynolds 390 aluminum alloy block.
Topping the bank of each block were wedge-type combustion chambers with single intake and exhaust valves slanted 20-degrees outward from the cylinder centerline. These first engines were also single overhead cam (SOHC) with a rubber timing belt that also drove the water pump. With an 8.5:1 compression ratio and 91 octane fuel, this engine was capable of 240 hp at 5500 rpm. This would increase to 300 hp in 1979 with a bump in displacement to 4.7 liters, with 97mm cylinder bores.
In 1986, the V-8 would go from two valves per cylinder and SOHC to four valves per cylinder and dual overhead cam (DOHC). While Porsche’s Engineers were tinkering, they increased the cylinder bore to 100mm to bump displacement up to 5.0 liters. The resulting 288 hp may seem like a step backwards, but it was new emissions standards and the lack of octane higher than 91 that limited the power output.
That is until 1987, when higher octane fuel was finally available and power rose initially to 320 hp until reaching an ultimate output of 330 hp in 1989. That’s where it remained until production of the 928 ended in 1995, which also brought an end to Porsche’s first generation V-8 and any consumer V-8-equipped Porsche models on sale until 2002.
Second Generation
The introduction of the second-gen Porsche V-8 a few years after the first left production also introduced another new type of vehicle for Stuttgart: the SUV. The debut of the Cayenne convinced Porsche it need a V-8 as a powerplant again. This time the engine was completely new. Displacement dropped from the 5.0 liters of the 1995 engine to just 4.5 liters, but power output from this new unit improved to 340 naturally-aspirated horsepower.
However, that number wouldn’t be enough for everybody, and a pair of turbos were added for the Cayenne Turbo to bump output up to 450 hp. Three years later, the Cayenne Turbo S debuted with 521 hp, making it the second most powerful engine from Porsche at the time. Yep, that meant an SUV was less than 100 horses behind the Carrera GT supercar in power, which had five more cylinders and 1.0 liter more displacement to make its 603 hp.
Direct Injection Era
While the architecture of the second generation Porsche V-8 didn’t change much, Porsche did take advantage of increasing the displacement with the switch to direct injection (DI) in 2007, which was required to meet the New European Driving Cycle (NEDC) for fuel consumption. SUVs with this engine and are known as 957 Cayennes. The second gen’s displacement was also bumped up by 3mm for a new 4.8 liter displacement in 2007.
The Cayenne S and its naturally aspirated V-8 made 385 hp—a 45 hp increase—the Turbo now made 500 hp—a 50 hp increase—and the Turbo S made 550 hp—a 29 hp increase, with the 2007 upgrades. Along with the bump of the S, a new Cayenne GTS debuted with the same naturally aspirated, 4.8 liter V-8, but it came with 400 hp.
The Panamera was introduced in 2009, but unlike the Cayenne before, it did not shepherd in a new era of the V-8. Instead, the second-gen naturally aspirated 4.8 liter V-8 was tuned to 400 hp thanks to some new exhaust work and engine tuning, and these new changes would also find their way into the Cayenne less than a year later.
Then came the ultimate versions of the naturally aspirated V-8s in the GTS models. The Cayenne GTS pumped out 420 hp and the Panamera GTS sent 430 hp to its wheels. As if that wasn’t enough, the ultimate versions of the second-gen turbo V-8s would see 520 hp in the Cayenne Turbo, 550 hp in the Panamera Turbo S, and up to 570 hp in the Cayenne Turbo S. Porsche’s engineer’s just kept finding more power in the V-8 they’ve got, so why build a new engine?
Third Gen And Hybrid Power
Well, you may need a new engine if you plan to go hybrid, which is exactly what Porsche did. The third generation V-8 and a new hybrid system debuted in 2013, the latest and greatest generation to date. This new engine and electric power marriage made its presence known in the 918 Spyder, billed as the first-ever supercar with a hybrid powertrain.
This V-8 didn’t start out as a pedestrian engine, either, as it actually came from Porsche’s MR6 racing efforts. It was detuned for the street and emissions legal use. Even detuned, the ICE and dual electric motor setup put down 875 hp to the wheels in the production 918.
At only 4.6 liters of displacement, the street-legal hybrid MR6 turns around 132 hp/liter and propelled the 3,791 lb 918 Spyder from stop to 60 mph in just 2.2 seconds. Only the 2022 Tesla Model S Plaid beats that metric with our own officially recorded time of 2.0 seconds, though Tesla likes to say it was 1.98 seconds under very specific conditions. That said, the 918 Spyder does beat it in top speed, maxing out at 218 mph while the Model S Plaid caps out at 200 mph (after a software update bumped up its top speed).
Another important part of the 918 Spyder was the sound its ICE engine made. While the cylinder bank was still 90 degrees, the MR6 motor used a flat-plane crankshaft, which makes for a very different dynamic sound when you put power down. While there probably wasn’t much of a performance gain, going to a 180 degree crankshaft did necessitate a new firing order, and the sound was nothing like the second generation V-8s making it truly exotic.
Trickle Down From The Spyder
With the hybrid power of the 918, more pedestrian versions of the Porsche V-8 and electric motor combination made their way to the Panamera and the Cayenne. These new hybrids have a unique sound from their earlier non-hybrid counterparts, thanks to 4.0 liter displacement with twin turbos, rather than the 4.6 or even 4.8 liter naturally aspirated or turbocharged displacements seen previously.
These engines also now use a “Hot Vee” or, as Porsche calls it, a “Hot-Side Intake” in which the turbochargers are located in the valley of the engine rather than hanging off the heads. Despite the 0.5-liter drop, the 2022 Panamera GTS still puts out 473 hp while the Turbo S spins the rollers to 621 hp.
The Panamera Turbo S E-Hybrid version output is increased to 690 hp thanks to its 134 hp electric motor located between the engine and the PDK clutch pack. The Cayenne Turbo S E-Hybrid is the same story, and powers its way to a 0-62 mph time of 3.5 seconds. Only the 2022 Cayenne Turbo GT is faster with a 3.3 second time, despite the lack of the hybrid system. This is thanks to its extensive weight savings—the Turbo GT weights 5,000 lbs versus the 5,673-lbs Turbo S E-Hybrid—and of course the 631 hp, 4.0 liter twin turbo V-8.
New LMDh Program, New V-8 Hybrid Tech
Come 2023, Porsche will have a new race car with tech that should trickle down to the street, once again. The new LMDh prototype program in IMSA will feature a Porsche V-8 with an electric motor to boost its power. Just how much new tech from the LMDh race car will make it to street-driven Porsches will be a waiting game. As other luxury brands promise to kill off their bigger gas engines, it’s just great to see that the V-8 won’t die off from the iconic brand that brought us an amazing 45 years with the 928, Cayenne, Panamera and 918 Spyder. All models that were brought to life thanks to Porsche’s unique V-8 engine.
Keyword: The Great V-8: Celebrating the Power Behind 45 Years of Porsche Dominance