An original advert for the Italian-market BMW 320is
The thoroughbred S14 engine, as found in the E30 M3
The tax-busting BMW 320is is often called the ‘Italian M3’. Will Beaumont takes a look at what makes the S14-engined E30 such a special machine
As a fan of older, smaller and specifically four-cylinder BMWs, I couldn’t help but write about one that has recently been receiving considerable attention from enthusiasts: the E30 318is.
Living in the UK means that we’ve been denied some of the best limited-run BMWs, like the German-only homologation special Class II E36 318is, or left-hand drive only 2002 ti, but the 318is was only ever offered in Italy and Portugal. Not only does this make it exceptionally rare, but also largely understood.
There's a common misconception that the E30 320is is either a race homologation special or an M3 substitute, but in actual fact, it’s neither. This car existed for one rather less glamorous reason: to cleverly beat the taxman in Italy and Portugal, due to their huge tax on cars with engines greater than 2.0-litres!
The 2.5-litre, straight-six equipped 325i was a sales success for BMW during the 1980s, but fell flat in Italy and Portugal where it was exceptionally expensive. The M3 at the time was also subject to the tax, thanks to its 2.3 litre engine, but where the M3 was needed in the sales line up for homologation purposes, an affordable alternative to the 325i, was needed.
To do this, BMW motorsport's S14 ‘M3’ engine was given new con rods, crank and pistons to bring its capacity down to 1990cc. The bore remained the same as the 2.3, but because of the revised piston design the 320is's S14 actually ended up with a higher compression ratio. The M3's Getrag dog-leg gearbox was also borrowed for the new model. In the end, the 320is produced considerably more power than the 325i. However, it's the revs that both engines produce their peak power figures at that really highlights how much more serious the 320is's engine is, giving away its motor sport origins: 192bhp at 6900rpm compared very favourably to the 165bhp at 5800rpm of the 325i's 12 valve 6 cylinder M20 unit.
Watch the original Italian advert for the E30 320is here:
The S14 engine, like the rest of the M3, was designed to win races. It borrowed a block from BMW’s tried and tested four-cylinder M10 engine – used from 1962 to 1988 in a variety of BMWs, from ordinary 316 to thrilling 2002 Turbo. In race guise it powered many a BMW touring car and single seater. As is obligatory when talking about the M10 engine, we have to mention that the block was used to create the 1000+bhp turbocharged BMW F1 engines of the early ‘80s.
For the head design BMW motorsport used what they had learnt when creating the M1 and M5’s straight-6 M88 engine. With more finesse than they are often credited with, they removed two combustion cambers for it to suit the four-pot block. All that heritage and DNA combined makes the S14, on paper, a rather glorious engine.
Thankfully, it wasn't just on paper that the S14 excelled. Car Magazine said of the S14 in the M3's first review ‘So the sounds are marvellous: the power is intoxicating, but the true strength of this 2.3-litre four is the immediate, sensitive, subtle nature of its throttle responses’. Plus, if you needed any more persuading, the 2-litre version of the S14 was used right up until the mid ‘90s in the E36 Super Touring cars that won multiple championships.
So the 320is didn't lack pedigree, or at least its engine didn't. Despite sharing an engine, the 320is is certainly no M3, no matter what anyone tries to tell you. So it's not quite as powerful, but the E30 M3's stellar reputation wasn't due to outright power, rather the car’s handling and sublime balance. The 320is did without any of the M3’s trick chassis changes like the wider track, increased castor angle, strut mounted and thicker anti-roll bars, larger brakes or quicker steering rack.
Dropping a BMW Motorsport engine, designed to win races, into a humble boxy saloon just so that it doesn't get hit with a tax premium is such an overblown, and frankly aggressive solution to a mundane problem. What's more, I've always preferred the way the standard 3 series looks to the M3. It's more trim, looks lighter and more agile. The spoiler on the rear of the M3 seems quite literally that, spoiling that low, long rear boot of the standard E30 for the advantage of aerodynamic efficiency. However, my absolute favourite thing about the 320is is that it could be specced without the M-tech body kit, so to the untrained eye it looked as understated as a basic 316. There was even a four-door option.
Unfortunately, at least for anyone thinking of picking up one of these forgotten heroes, the 320is seems to be following the trend that the E30 M3 is setting, rapidly becoming more valuable. They're now too expensive for me to try and satisfy my own four-cylinder BMW addiction with one, ranging from about €8,000-€30,000 for the best.