Celebrating the naturally aspirated engine

Looking back on the greatest non-turbo engines ever made

In today’s age of automobiles, forced induction such as turbocharging has become the mainstay of the industry, providing more performance with greater efficiency.

Turbos have given car manufacturers the ability to ‘downsize’ their engines but improve upon performance and economy of the past.

In doing so, turbochargers have removed a lot of the character we have learnt to love – the high revving, responsive, natural feeling and that charismatic sound.

Here are our picks of the greatest naturally aspirated engines in automotive history as their time comes to an end.

 

Porsche flat-six engine

Porsche changed the rulebook when it decided to reinvent the six-cylinder engine, choosing to configure the cylinders in a flat layout rather than the more popular inline-six or V6 configurations. The result was one of the most unique sounding engines to date. Raspy at the bottom end but creating an unmistakable ‘howl’ at the top end, the flat-six has cemented itself in history as one of the all-time great engines. Found in every generation of the famous 911, the flat-six now features twin turbochargers (due to tightening emissions regulations), meaning the naturally aspirated versions are now reserved for GTS and RS variants only. Eventually, the ‘natural’ flat-six will be killed off entirely, but we have our fingers crossed that Porsche changes its mind.

Ferrari flat-plane crank V8

If you close your eyes and listen to a group of cars go by, chances are that you will easily be able to pick a Ferrari out of the lot. The flat-plane crank V8 from the famous prancing horse brand is one of the most recognisable engine notes of all time. Found in a majority of Ferraris, this V8 represents the exotic nature of the brand as other manufacturers rarely use this crankshaft configuration. From the F355 right through to the 458, Ferrari has stayed true to its roots by keeping that recognisable engine in most of its cars.

Honda VTEC four-cylinder

Honda is well-known for the development of the VTEC system, where the camshaft has two sets of lobes, one which operates at low rpm and another which operates at high rpm. When a certain engine speed is reached, oil travels into the camshaft and locks the higher lobe in place, lengthening the duration that the intake and exhaust valves are open, increasing performance. Notable examples of this engine include the 2.0-litre four-cylinder engine from the S2000 and the VTEC V6 found in the original NSX supercar. This technology has spawned multiple ‘knock off’ versions created by other manufacturers, such as Toyota’s VVTi, BMW’s VANOS and Mitsubishi’s MIVEC.

V10 engine

Another recognisable engine, the V10 is an exotic configuration rarely found in cars today. With its uneven firing order, this engine makes a unique exhaust sound at high engine speeds. Whilst notably found in Lamborghinis, Lexus used this format for its LFA sports car and Porsche for its Carrera GT supercar. Today, the only production cars to feature this engine are the Dodge Viper and the Lamborghini Huracan/Audi R8 (a shared platform).

Jaguar inline-six

Having been in production for almost 40 years, the Jaguar inline six is one of the most well-known six-cylinder engines in history. Having powered such cars as the E-Type and the Mark 2, the engine was distinctive for its double-overhead camshafts and perfect primary balance. BMW is also well-regarded for its straight-six engines which it still manufactures, although nowadays these engines are turbocharged.

Ford V8 engine

As a symbol of American muscle cars, the V8 engine is widely loved and respected all over the world. Ford has been making this engine configuration for decades and still does. It’s cross-plane crank gives the V8 a distinguishable off-beat tone – the signature V8 sound that people know and love. Some of its most notable engines include the 351 Cleveland, the 5.0-litre Coyote and the original flathead V8.