Facts and figures
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Pole position for £25k
17.05.2006 |
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Every second counts here. That's because we only have 20 minutes to assess BMW's new 320si and, worse still, they'll all be spent on a race track. Moreover, this might be the one and only time we get to drive this car. A mere 2600 will be made available worldwide, in a homologation production run for BMW's world touring car. And only 500 will be coming to the UK.
My job is made easier, up to a point, by the fact that this model is largely based on the 320i M Sport, a car we're already familiar with. The suspension, gearbox, bodywork and interior are all carried overunchanged. The areas that have been tweaked include the wheels unique 18s inspired by the WTCC car, brake discs up to 300mm all round from 292 front and 296 rear, and most significantly the engine, hand-built Specifically for the 320si with more power and a very different character from the regular version. It may be stretching the point to call this a latter-day four-cylinder M3, but it's well on the way.
While it might still meet Euro IV emissions and be built at the Hams Hall engine plant in the Midlands, the 320si engine is no mildly tweaked version of BMW's regular 148bhp 1995cc unit. It has been engineered to rev higher; the dimensions are nearer square now that the bore is up by 1mm to 85mm and the stroke down by 2mm, to 88mm, while the induction and exhaust valves are all bigger, too. The compression ratio is up from 10.5:1 to 11.0:1, cylinder liners are aluminium alloy rather than cast iron, and there's no Valvetronic induction system; the higher rotational speeds of the race engine demand a conventional throttle. The cylinder head itself arrives from BMW's Landshut factory in Germany, where it's cast alongside BMW's F1 engines.
But it takes lifting the bonnet to unearth the most exquisite part of all: a carbonfibre cam cover. The fact that this saves 10kg and lowers the centre of gravity is valuable on the race car, and largely irrelevant on the road car. What matters here is that it looks as cool as hell.
The upshot of the changes are that the 320si's engine develops 171bhp at7000rpm (up from 148bhp at 6200) and the same 148lb ft as the 320i, but at 4250 rather than 3600rpm. The 0-62mph time falls from 9.8 to 8.1sec and the top speed is up by 6mph to 140mph.
At idle the engine sounds normal, gears engage with regular 320i precision and the clutch has the same weight and progression as usual. This might be a race-derived engine, but the package is pure 3-series. It's hard to assess the ride of these new 18-inchers with 225/40 front and 255/35 rear tyres on the smooth Brands Hatch surface, but on the nobblier concrete outside the pit garages it feels only a little harsher than usual.
Once on the circuit, it takes three corners before you hit a flat piece of track. Select a high gear, floor it and, hmm, there's reasonable grunt there. With little reference and without a 320i alongside, it's hard to tell exactly, but at low revs this car feels marginally less responsive than a 320i. Wait another lap for the same level piece of track, select a lower gear and do the same. That's better: a decent shove in the back, fullsome urge right round to 7300rpm, linear and responsive, although nothing like as urgent as the fastest hot hatches. It's best above 4000rpm, where it's surprisingly raucous, too - plenty of old-fashioned growl and volume, which is no bad thing.
Output and response tested, it's time to exploit the chassis, and here lies one of the reasons why we love the 3-series. This is a superbly balanced, benign and communicative car. Each bend is a blank page. Turn in too quickly and it'll understeer, or can be edged out to a nicely neutral cornering stance if you're smoother.
There's too much grip and too little go to provoke serious oversteer (though a lift will unsettle the rear controllably in faster corners), but the 320si can easily be pushed into straightening its line on power in slower bends. If anything, smaller rear tyres would make it more adjustable, but the decision on cornering stance is largely yours.
The fact that the 3-series is rear drive is a real help in this regard. Lift the bonnet and you'll notice another. The engine bay is long enough to swallow a six-cylinder diesel, so a 2.0-litre petrol motor sits so low and to the rear that the block's leading edge is in line with the front axle, aiding the BMW's balance.
And it is as the 320si pinks and tinkles while it cools in the pitlane that I realise that no other £25k car in this class would as gladly accept the punishment of 20 minutes' hard use on a track such as Brands. Will we get another go? Given that, at £25,000, this car costs £415 less than a regular 320i M Sport, we suspect not; they'll sell out in weeks. Shame there'll only be 2600 examples. A junior M3 could be something very special indeed.
Matt Prior
