With BMW’s last naturally-aspirated straight-six, the E90 330i is more special than its four-cylinder successors
The march of progress isn’t always welcome. Particularly in the corners of the Internet where hardcore car enthusiasts still lament the introduction of airbags and catalytic converters, for example.
I find myself straddling the fence on this topic. I cannot deny that, even just in the last decade, technical and technological advancements have made new cars safer, kinder to the environment, faster and more catering to the tech-savvy youth, continuing to keep cars relevant in the 2020s. But even the most ferocious optimist cannot deny that powertrain character has not advanced in that time.
This was first brought home to me when I got behind the wheel of the previous (F30) generation BMW 3-series in 330i form, some time in 2017. I was in the Black Forest in Germany, an area with some fantastic driving roads, in a high-end version of BMW’s celebrated
small saloon, and I couldn’t quite believe how underwhelmed I was. And it was all because of the engine.
You see, I’d completely forgotten that BMW had ditched its famous naturally-aspirated straight-six for the F30, replacing it with the now ubiquitous turbo four-pot. With slightly less power but a healthy chunk more forced-induction torque, the new motor was clearly faster, and (on paper at least) more efficient. Yet it was utterly, utterly soulless, as exciting as unseasoned noodles.
The noise and power delivery were what stood out, for all the wrong reasons. The turbo brought improved low-rev pull, but the flat torque curve removed any sense of ‘crescendo’ to revving it out, and no real performance reward for doing so. You end up short-shifting, in part to avoid the utterly anodyne, borderline irritating drone that accompanied engine revs.
It never used to be like this. In every 3-series generation prior to the F30, the four-cylinder engines were meant for middle-management types that largely wanted more prestige than a Ford Mondeo could offer (I’m deliberately glossing offer the revvier ‘iS’ and ‘Si’ models here), while the straight-sixes were aimed at enthusiasts. It meant that even though BMW’s M division wasn’t involved, and visually they were little different, high-end 3ers always felt special behind the wheel.
This was proven when I test drove a 2006 E90 330i a year later. At the time I’d assumed good ones were out of my budget but was intrigued by an ad for a clean one with 75,000 miles for under £3-000. Why so cheap? Well, it could’ve been because it was a less desirable SE model, but more likely it was because of the unusual Barrique Red (read purple/burgundy) exterior mated to woodette dash trim. Frankly, I couldn’t care less about the spec – in fact, its unusualness endeared me towards the car. And as soon as I’d driven it a few hundred yards, I knew I had to have it.
The E90 325i and 330i (or US-market 328i) used the last hurrah of BMW’s naturally aspirated inline-six, dubbed N52, or N53 in the higher-output later models. With double-VANOS, variable valve lift, a three-stage variable intake manifold and a block made of magnesium and aluminium, it was the firm’s most advanced version yet. Also seen in the lighter Z4 and 130i, its 254bhp (upgraded to 268bhp and 320Nm with the later N53) was enough to take the circa-1500kg E90 from 0-62mph in around six seconds.
In layman’s terms, that results in an engine that’s silky smooth, gutsy and surprisingly efficient at low RPMs – on a motorway cruise, I could see over 40mpg without too much effort. But wind it up at about 4,500rpm (when the VANOS kicks) and it changes character, unleashing an intoxicating snarl and firing eagerly to its 7000rpm redline. Whether it’s combined with a long-geared yet slick-shifting manual, or the smooth automatic, it offers character and engagement that greatly exceeds modern turbo fours.
It’s even pretty reliable. Indeed, many BMW enthusiast sites and forums cite the N52 as being one of the brand’s most bombproof engines, capable of being worked hard for hundreds of thousands of miles with only the typical VANOS failure being a weaker point. Problems such as worn piston rings that plagued its M54 predecessor haven’t reared their heads, while it lacks the complexity of its turbocharged successors. However, it’s worth noting that the later N53 switched to direct injection and used a high-pressure fuel pump, both of which increase the likelihood of problems.
As for the E90 itself? Well, it’s certainly not the most inspiring of the Bangle-era BMWs design-wise (rumours suggest the design was toned down in response to the controversy of cars such as the E60 5 Series and E63 6 Series). And it launched with run-flat tyres which killed ride refinement – though you’d be hard-pressed to find one running them nowadays.
But in all other respects, it’s an impressive car for the cash. The interior is well-designed and granite-hewn, general build quality is excellent, and it can take four six-footers and their luggage without complaints.
Unsurprisingly, being a BMW, it’s also superb at long distances and high speed. I took mine to Germany – first to the Nurburgring, and next to Munich to join some friends for Oktoberfest – and it both lapped up the slower miles and didn’t break a sweat nudging the 155mph limiter on the Autobahn. A few laps of the Nordschleife, too, allowed its balanced rear-drive chassis, excellent body control and meaty steering to shine.
I sold it late last year, mainly because I hankered after a V8 Jaguar (which you can also read about on Car Throttle) but also because it needed some cosmetic repairs and a new clutch. Of course, having seen the prices of used cars rise considerably during the pandemic, I regret letting it go for what I did. But I also regret jacking it in because little else for the money feels so utterly complete as an all-around daily driver. Oh, and that engine…