Here's What Makes Five-Cylinder Engines So Special (2024)

There are few sounds on Earth as peculiar as the off-beat thrum of an engine with an odd number of cylinders. It's like listening to music with weird time signatures; cramming five, seven, or nine beats into a four-beat bar. The result is an off-kilter noise that sounds better the more you listen to it.

Of all the odd-numbered engines, five cylinders seem to be the sweet spot for pure sound. If you've spent any time watching old rally footage, you'll doubtless have been caught off-guard by the howl of the Group B Audi's 2.1-liter turbo-5 as it attacked a stage.

Or maybe you were given an old Volvo as a hand-me-down, only to discover how fantastic the thing sounded without its airbox.

The distinctly characterful sound of a five-pot is a direct cause of its odd-numbered design. The exhaust pulses leaving the combustion chambers overlap each other due to the angles at which the pistons meet the crank, which creates the unique rasp-over-burble tone.

Having to counterbalance an engine with an uneven number of pistons also creates the need for a heavy balance shaft, meaning five-cylinder engines tend to rev up a little sluggishly, but produce more torque than four or six-cylinder engines of similar displacement. The added weight also makes these engines run and rev smoothly, with very little intrusion from annoying vibrations – only sweet intake and exhaust sound.

But despite its character and rather robust design, the five-cylinder engine is yet another creature in the automotive kingdom that we must add to the endangered species list. Neither Volvo, Volkswagen nor Fiat still produce their I5s anymore, and Audi's latest RS3 is likely to be the last generation to sing the song of the old Sport Quattros. Before we bid the five-cylinder engine farewell, let's find out what makes them so special.

They Make Normal Cars Sound Like Supercars

If you're an engine buff, the easiest way to explain a five-cylinder's noise is to describe it as a "baby V10." This is because the firing order and the crank angles are effectively the same when you double the piston count, thus a ten-cylinder engine will make a similar raspy roar as an inline-five, times two. Watch Mat Watson from Carwow drag race a V10 Audi R8 against an I5 Audi TT RS – notice how the engines sound. Turbocharging changes the character, but even moderately tuned ears should be able to pick up the commonalities between the two.

Crucially though, a five-cylinder engine is typically quite compact and can fit into engine bays designed for four-cylinders much more easily than trying to shoehorn a V6 or transverse inline-6 into an ordinary car – just ask Volvo. This means you can have the noise of a priceless supercar in your daily driver, and even though five cylinders will drink a little more gasoline than four, we'd argue whatever extra fuel costs it incurs are more than made up for in pure character alone.

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They're Typically Bulletproof

For some reason, history's more renowned five-cylinder engines, which is to say just about all of them, happen to be known for durability as much as they are celebrated for noise. Diesel-burning fives like the Mercedes OM617 found in most Mercs from the 1970s and 80s, and Land Rover's TD5 as seen in Defenders and Discoverys are known to pile on the mileage. In fact, a 1976 Mercedes 240D came second in our list of the top 15 Cars With The Highest Mileage Ever Recorded, racking up 2.85 million miles doing taxi duty in Greece.

Base Mk5 and Mk6 Volkswagen Golf and Jetta owners will also give you nothing but glowing reviews of the longevity of their 2.5 L inline-fives. The VW EA855 engine is one of the German giant's toughest. With minimal complexity, it can clock hundreds of thousands of miles with bare minimum servicing, something which can't be said of VW's 1.4 L, 1.8 L, and 2.0 L turbocharged fours. It also sounds phenomenal with some simple breather mods, particularly on the intake side. The stock routing of the air filter runs over the engine block, which "pre-heats" the air and hurts overall power output. A cold-air intake is a cheap fix for a lot more power, torque, and sound – more so than most other engine configurations.

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It Has Racing Pedigree

At the top of this article, we made reference to an Audi rally car and its famous five-cylinder engine. That car was Audi's Quattro S1, the dominant dirt-road monster which set the pace for the Group B championship and drove every other manufacturer mad trying to chase and beat Audi's mesmerizing off-road performance. The competition was fierce, including such incredible machines as the Ford RS200 and the Lancia Delta S4, but no vehicle will ever be an icon of the Group B era quite like the mighty Quattro.

Volvo also did some racing with its five-cylinders, famously entering an 850 R wagon in the British Touring Car Championship in the 1990s. That car would never win a race, but the sight of a big Swedish box bouncing around racetracks cemented that car in the memories of fans for years. That sight was accompanied by the unmistakable sound of a five-cylinder: Volvo's BTCC race-wagon ran a modified version of the 850 R road car's 2.3 L inline-five, producing around 230 horsepower.

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They're Found In Cool Cars

Just about any car, you'll find today with a five-cylinder is bound to be at least moderately interesting, if not searingly hot. Take the 1995 Audi RS2 pictured above. Believed by most to be the watershed moment for fast Audi road cars, the RS2 was a compact wagon with a 2.2 L turbo inline-5 and a chassis tuned by Porsche. Doug Demuro has one.

Then there's the Audi TT RS, which had a five-cylinder in at least two generations of the car, as well as the RS3 super-hatch (or sedan, for us) both past and present. You'll also find a five-cylinder in the Volvo 850 R, as well as just about all of their breathed-on cars until the late-2010s when Volvo moved to twin-charged four-cylinders and hybrid powertrains. Europeans were privy to a particularly spicy spec of Volvo's 2.5 L "T5" engine under the hood of the Mk2 Ford Focus RS, but North Americans were denied that car, as usual.

The Italians made a sweet five-cylinder too, appearing in the old Fiat 20V Coupes and some Alfa Romeos. American manufacturers largely ignored the odd cylinder arrangement, apart from the 3.5 L Isuzu-sourced unit in the Chevrolet Colorado and Hummer H3. The Japanese were similarly averse to five-pots, except for a few curiosities like the Acura Vigor, notable for having a chain drive between the engine and gearbox, something to do with packaging a longitudinal five-cylinder with front-wheel drive.

Though the 2022 Audi RS3 soldiers on with its five-pot for one more generation, they're just about the only manufacturer left giving the quirky engine a chance to shine. Apart from that one model, it's a colossal pain to find a new five-cylinder car these days. There are some gems out there on the used market though, and if you're as fascinated by the peculiarities of internal combustion as we are, we recommend the pursuit.

1-2-4-5-3 never sounded quite so good.