Mercedes-Benz’s CLA AMG is a remarkable car. Not only is it the most affordable AMG model on the market at under $50,000, but it’s also the performance marque’s first shot at a four-cylinder engine. Displacing just 2.0 liters across its quartet of cylinders, the CLA AMG generates an astonishing 355 horsepower, which allows the CLA to hit 60 in 4.4 seconds and can manage over 30 miles per gallon on the highway when drivers back off the pedal a bit. All in all, Mercedes has a bonafide performance-oriented four on its hands. Safety-first Volvo may have just blown Mercedes out of the water, as far as that segment is concerned.
Earlier this week, Volvo took the wraps off a new four cylinder engine that can reportedly deliver 450 horsepower — nearly as much as Chevrolet’s new Corvette Stingray offers from its 6.2 liter V8. Like the Benz, it displaces just 2.0 liters. Volvo’s secret lies in its turbochargers — all three of them.
Two of the turbos work directly with the exhaust produced by the engine, but a third turbo — that’s fed by an electric turbo-compressor — exists merely to spool up the other two in order to boost power and reduce lag. The turbos work in conjunction with a dual fuel pump setup, which is pressurized to 250 bar (that’s about 3,600 PSI).
This helps the new Drive-E engine achieve its enormous output potential, which outpaces the existing unit by 130 horsepower. The figure, although impressive, isn’t a huge surprise; Volvo alerted the autos sphere earlier that this year that the unit would have an output of “around 400 horsepower.” But few, if any, were expecting that number to be as high as 450.
For those who are not as mathematically inclined, this amounts to a monstrous 225 horsepower per liter, greatly outpacing the 177 horsepower offered by the CLA AMG. That’s not just exceptional by four-cylinder standards, that’s playing in the leagues of some serious automotive contenders. Volvo’s Swedish compatriot Koenigsegg, which makes some of the fastest cars in the world including the One:1, squeezes about 268 horsepower from each cylinder, and that car sells for well over $1 million.
It’s worth noting that in its press blast, Volvo deemed the engine a “powertrain concept,” though Autoblog noted that they would be “very surprised if this didn’t turn out to be the flagship engine we were promised for the XC90.” The new SUV, which is slated to be released next year, has not had a meaningful refresh since 2004 or so, and it has been redesigned from the ground up with a whole new menu of powertrains.
Building an engine such as this isn’t exactly a walk in the park, and there’s a reason we haven’t seen other automakers launching a multi-turbo strategy. More turbocharging means more heat generated, and the engine needs to be able to cope with the added stress of drawing out 450 horsepower from such a small source. This could lead to reliability and durability concerns later on, though Volvo has likely torture tested the unit comprehensively.
Volvo is not alone, however, in developing an engine based around an electric turbo as a means to spooling up before adequate exhaust gases are produces. Audi built a prototype RS5 with an electric turbo-equipped TDI engine, and the German marque said that the addition of the system helped boost efficiency by 15 to 20 percent. Like Volvo’s engine, however, the unit is still conceptual.