In the fuel fight between these identical BMW 3-series machines, we look at how dirty diesel tackles polished petrol
Picking a favourite among the BMW’s bestselling 3-series siblings is easier said than done. The BMW 320d and the 320i are closely matched on paper — they have the same shape, great interiors, are kitted out with identical equipment and have price tags that are just one small car apart. The 320i costs Rs 32.2 lakh, while the 320d costs Rs 36.4 lakh. All of these make choosing between the two a tough task.
We know 320d. It’s won all our comparisons and we think it’s the best, most usable 3-series on sale in India. It’s torquey, quick and well worth the Rs 36 lakh that BMW is asking for it. The 320i, however, might need more of an introduction. The so-called poor cousin of the Indian 3-series family doesn’t get BMW’s famed inline-six. Rather, it relies on the pedestrian 1995 cc four-cylinder petrol for power, and this makes all the difference. It may come at Rs 4 lakh less than the 320d, but for most purposes, the two cars are as similar as a 10-pound beef steak is to a cocktail sausage.
Revs up to the occasion
The case for the defendant, the 320i, is quite simple. Like any naturally aspirated BMW petrol motor, it loves to rev. Push the throttle into the carpet and watch the rev needle pick up momentum all the way to 6,500 rpm. Initial thoughts may linger on the word ‘slow’, but not for long. It’s a decent puller, with 20.4 kgm of torque at 3,600 rpm. It responds immediately to part-throttle inputs, but without much gusto. That said, the 2.0-litre four’s 156 bhp makes it worth stretching the engine to its redline. However, when you need that power quickly and want to overtake, the 320i makes you wait. The six-speed auto hesitates before downshifting and you need to be authoritative with the throttle if you want the two-gear downshift usually required for passing manoeuvres.
Diesel does it
In all aspects of performance, the 320d simply steals the limelight from its petrol cousin. It has so much more muscle (35 kgm, 177 bhp) that there’s a full three second difference between them from 0-100 kph. The ‘d’ makes its massive torque advantage immediately apparent by shooting away from the 320i. In the petrol, you need revs. In the diesel, you just need a light foot. In fact, if you shut your ears and avoid looking at the tachometer, you’ll find a diesel engine that thinks it’s a petrol — it makes power all the way to its 4,500 rpm redline and it’s free-revving. The full 35 kgm is a lot more accessible because it peaks at a low 1750 rpm, and the ‘d’ feels a lot more relaxed and effortless because of this. At higher speeds, the diesel becomes even more attractive. At 180 kph, when the ‘i’ starts running out of breath, the ‘d’ gets its second wind and tugs strongly till 220 kph.
The gearing is spot-on and gearshifts are quick and seamless . The obvious difference between them is in refinement, but there’s reason to be surprised here too. The thing is, you expect a BMW petrol to be silky, which this engine is not. It’s pretty crummy and there’s vibration that enters the cabin at idle. The other problem is that at higher speeds, the petrol revs quite a bit, causing some noise. The diesel, as expected, is audible, but it’s hushed when cruising, which only adds to its effortless nature.
Drive on to entertain
The spec sheets reveal that the petrol is lighter than the diesel by 55 kg. This matters because it is a big part of why the 320i is such a sweet handler. If you love feeling the balance and agility of cars, then we recommend this over the 320d. The steering is bang-on for accuracy and there’s enough grip from the narrower 205/550 R16 Bridgestone run-flats. It rides slightly better than the ‘d’ too, thanks to taller sidewalls.
That said, the 320d is a lot more entertaining to drive. Turn off the DSC system and hooliganism comes naturally to the driver — tail-out antics are easy. Peak torque comes in so quick and so strong that the rear 225/50 R16s can’t help let go. And in terms of purity of handling, it’s not that far behind the 320i. Sure, you feel the extra weight ahead of you, but the extra grip afforded by the wider tyres negates this a bit, and it’s almost as eager to turn-in. There’s a bit of a difference in steering feel, which is heavier than that of the petrol, but you won’t notice it unless you drive the two cars back-to-back. In fact, whichever car you end up buying, you’ll be more than happy with the way they drive.
Styling and interiors
If not for the badges, the style of alloy wheels, the tyres and the exhaust pipes, it’s difficult to tell the two cars apart. On the inside, you’ll find the same high-quality interiors, the fantastic driving position, the uncluttered dashboard and the slightly short-on-space rear seats. The 320i costs Rs 32.2 lakh on the road; the 320d Rs 36.4 lakh, but factor in the diesel’s longer range between the pumps (12.1 kpl versus 8.9 kpl for the petrol) and you’ll recover the extra money spent.
This may sound like blasphemy, but the diesel is the one to go for. Before you scream foul, listen to this. For some, the brief thrill of wringing the neck of a petrol engine combined with that smidge of added agility from having less mass over the front axle probably makes the 320i worth a look over the diesel. But this diesel doesn’t need to be wrung out. It’s as happy at low engine speeds as it is in max attack mode. It’s a lot quicker and a lot more effortless, and these are things we regard as essential in a sporting saloon. The ‘d’ can be huge fun when you’re in the mood and because its power is so much more accessible, it’s less of a hassle when you’re in town.