BMWBLOG Test Drive: The N20 Engine

In the early days of Bavarian Motor Works, the four-cylinder engine was the basis for many of the cars. The combination of the small, two-door BMW sedans was successful in a big way. By the early 1970’s the diminutive New Klasse was able to step out from the shadow of the bigger E3 and E9 sedans and coupes powered by 3.0 liter inline-6’s. Namely, the 2002tii and 2002 turbo placed BMW’s turbocharged four cylinder engines on the map as both reliable and powerful during an energy crisis. Yes, the M10 engine was a force to be reckoned with.

Fast forward a decade and Formula One’s Turbo Era is in full swing. A modified version of the BMW M12 (a slightly revised version of the original M10), turbocharged, put out 1,500 horsepower in qualifying trim and brought Nelson Piquet another world championship. The four cylinder concept found further success in the naturally-aspirated iteration called the S14 in a little known car named the E30 M3.

Three decades on and the four cylinder engine has all but left the North American market. Due in large part to the mentality of Americans that a four cylinder simply isn’t a premium engine and therefore doesn’t belong in the likes of a BMW – despite Audi having successfully applied this formula to the A4 for over a decade. Apparently the adage a gentleman never drives anywhere with less than six cylinders in front of him?

Well, for 2012, BMW have brought back its newest four cylinder, the N20, a single turbo four-cylinder engine producing 240 horsepower with a tasty 260 lb-ft of torque. Many of the hardcore fan base have criticized BMW for substituting the smaller 2.0 liter N20 for the outgoing naturally-aspirated 3.0 liter inline-six. While I will miss the N52, an intelligent, lightweight big 6, the N20 represents the new direction many car manufacturers must go with the impending CAFÉ regulations. The N20 will reportedly return 20% better economy over the N52 – going a long way towards BMW hitting the required fleet average with the forthcoming regulatory changes. Whether enthusiasts like it or not, this is the way forward – that or would you rather BMW stop selling cars in North America?

Exactly, moving on.

While the N52 was a great engine – the best of the naturally-aspirated sixes with magnesium block – it will disappear in 2012 and in its place, something down a liter of displacement and short two cylinders. The good news is the N20 is actually a solid follow-up to the N52 as BMW’s base engine in the 1,3,5, X3 and Z ranges.

I was able to test the N20 recently in the first two guises in which it will appear in North America: the 2012 528i and 2012 Z4 sDrive28i. Interestingly, the N20 initially finds itself in two cars directed toward radically opposing buyers. Ironically, with the outgoing N52, the engine felt the same no matter the chassis in which it sat – an E90 328i or an X3 xDrive28i, the character of the big six was always there. This is where the N20 deviates and shows a much more Jekyll & Hyde personality.

My first experience with the N20 came with the F10 528i. After a quick shot up the always lovely Interstate 95 from Jacksonville to gorgeous Hilton Head Island, I caught up with BMW of North America at the 10th annual Hilton Head Island Concours d’Elegance. Upon arriving at the concours, where BMW was the featured marque, I hopped into a 2012 Alpine White BMW 528i powered by the TwinScroll 2.0 liter turbo.

Upon starting the 528i, there was no perceivable difference from the old six cylinder and new turbo four. Mated to the 8-speed ZF gearbox, the N20 is a buttery smooth proposition and the two seem well-paired when executing gear changes. Surprisingly, for being a single turbo engine, there is never a sensation of turbo lag – the engine felt spritely when letting the gearbox shift for you. While cruising, and with the Adaptive Drive system in either Comfort or ECO modes, you’re left with a feeling that you sometimes get from a Rolls Royce Phantom – a nearly silent engine in a massive car as you’re wafted along down country back roads.

In all honesty, the average 528i buyer will likely never tell a difference from the 2011 528i to the 2012 528i – and that’s not a bad thing. The consumers interested in a 528i will never feel as though they’ve somehow been robbed of the BMWness by having a turbocharged fou- cylinder in place of the iconic big six in the engine bay.

The Z4 with the N20 is a wholly different car all together – and not just because the car looks about 500 lbs, two doors and its roof. This is where enthusiasts will want to check back in to this article.

The N20 as the power plant for the 2012 Z4 convertible is where the engine truly shines as an enthusiast’s engine and comes into its own. On the second day of the Hilton Head Island Concours, I was able to hop into our Z4 equipped with the M Sport/Citrus Yellow Package and the always-eye-catching Atacama Yellow – certainly a color that will catch the attention of your local smokeys on the back roads leading to Hilton Head.

Mercifully and juxtaposed to the 5 Series, the Z4 came with the wonderful , short-throw six speed manual. This was the drive I’d been waiting for all weekend, a transmission that would give me more direct access to the 260 lb-ft of torque the N20 touts, a full 60 lb-ft more than the N52 – and a good 1,500 RPM’s sooner too!

Thumbing the Start/Stop button, the little N20 burbled to life with a bit of a growl from the exhaust. With heavy traffic surrounding the Concours, I engaged in a bit of around town driving to warm up the engine.


Disclaimer: BMW hosted and dined us at Hilton Head Island Concourse, as well as putting us up in a beautiful hotel. No apple strudel or bratwurst were included.


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