Land Rover Discovery Si4 review: 4-cyl petrol SUV tested Reviews 2023 | Top Gear
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Land Rover Discovery Si4 review: 4-cyl petrol SUV tested

£61,390 when new
Published: 09 Mar 2018


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Si4. What’s that mean?

Well, it means that under this very big, very heavy Discovery’s substantial bonnet lives a tiny engine that, only a few years ago, no self-respecting carmaker would have dreamt of fitting to anything bigger than a Mondeo. It’s a turbocharged 2.0-litre, four-cylinder petrol with 300bhp and 295lb ft, giving 0-62mph in 7.7 seconds and 124mph. Which, for a car that weighs almost as much as the bricks and mortar of the factory in which it’s built, isn’t half bad.

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The V6 diesel Disco we’ve been running for the last few months is about half a second slower to 62mph, but makes up for the increased weight (+137kg) with an extra 148lb ft of THRUST. The price difference is a whopping £600 in favour of the petrol – less than the cost of speccing a towbar.

Nice. That’ll go on petrol, surely…

Now, ‘our’ TD6 isn’t the most economical car in the world. On a long, motorway run you might see 30mpg (JLR claim 39.2). That’s at a steady 70mph – up the speed a bit (where legal, obvs) to 80-85mph, and it tanks down to mid-twenties. Even from a big, heavy diesel SUV with the aerodynamic properties of a Georgian mansion, that’s quite rubbish. And the trip computer is hopelessly optimistic, promising a few mpg over what proper math claims the Disco is actually delivering.

We haven’t had time to do any actual math for the Si4, but on a perfectly ordinary 76-mile commute out of London that involved a trafficy town bit, a long motorway slog and a quick B-road blat (can you blat in a Disco? Hmmm), its trip computer promised…23.7mpg. That makes it the least economical car I’ve driven this week. And so far this week I’ve driven an Audi R8 RWS, Porsche Boxster S and Honda Civic Type R. Tow or load it up with people and things, and you might dip down into the teens. LR claims 29.4mpg combined.

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Oh that’s not good.

It’s not, is it? Not surprising though. Small capacity, turbocharged petrol engines routinely claim massive mpg figures, but seldom deliver because they’re always on-boost. The Disco suffers from the same problem as, say a Ford Fiesta with the excellent little 1.0-litre triple. To make progress you have to work the motor, which means mpg suffers.

Ok. Let’s move on from all the eco stuff. What’s it like?

Even at moderate speeds it’s obvious there’s less weight over the nose. The Si4’s responses are sharper than the TD6’s, but that’s a bit like saying a half-mile long super-tanker is more manoeuvrable than one that’s two-thirds of a mile long. This is still a big car, and for the most part it drives like one. And that’s just fine – still rides really well, and for its size, remains an easy thing to roll around in. Quiet at a steady cruise (if a little vocal under hard acceleration), too.

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What’s really commendable though is that despite the Disco’s size, and this engine’s lack thereof, is that it doesn’t suffer from “big car, small engine” syndrome as much as we thought it might. As much as the 2.0-litre diesel, even. The gearbox is actually the most obstructive thing about the whole experience. It’s indecisive and far too keen to change down a gear (or two), when it should be using the (admittedly limited) torque on offer. And when it changes down you get the noise – the noise of a four-cylinder engine. And that just cheapens the whole experience. As we noted in our full review, the Disco is a car that “works best draped in money”. There’s nothing to be gained by skimping on kit and engine. Sure the 2.0-litre performs well enough given its size, but there’s no escaping the fact the big diesel is the engine that suits the Disco’s character best.

You could get away with the 2.0-litre petrol, but for the sake of £600 we’d still go for the big diesel. Sorry. We’re trying the six-cylinder petrol in the not too distant future. Maybe that’ll change our minds.


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