First drive - Mazda3 2.0 Sport i-Stop

Monday 12 October 2009

Opposites attract: the new Mazda3 gets a stop-start system and punchy 2.0-litre petrol engine – but it works

What is it? This is the first model from the Japanese carmaker to receive start-stop technology, coupled with a new 2.0-litre DISI (direct injection spark ignition) petrol engine. An engine of this size might sound like an odd choice to be combined with fuel-saving technology, but there’s method in Mazda’s madness.

So when you consider a 20% reduction in fuel consumption accompanied by an increase in power of the same magnitude, it all starts to make a bit more sense. And the numbers? 0-62mph in 10.4 seconds, 41mpg and 159g/km CO2. Not bad for a 150bhp petrol unit.

The i-Stop system – which is automatically activated when the car is started and can be deactivated via a switch on the dash – shuts down the engine when the car comes to a stop and the driver depresses the clutch to engage neutral. It restarts once the clutch is pressed again for first gear to be selected.

Mazda is keen to emphasise the importance of the direct injection engine, as it plays a key part in the efficiency of the start-stop system. It works like this: when the car stops, the engine control module switches off the engine once the pistons are equal and the cylinder air volume is in the optimal position for restart. A small electric motor then helps the engine to restart in just 0.35 seconds.

Is it any good? The i-Stop system functions efficiently and effortlessly, and is almost unnoticeable after driving the car for any length of time. There’s very little vibration when the engine shuts down, and start-up is also quiet and civilized, which makes for a smooth driving experience.

However, the i-Stop system has a number of programmed situations in which it won’t work. For example, if the driver or passenger removes their seatbelt or opens the door, the car can’t be restarted by pressing the clutch, and a key has to be used in the ignition.

The system also prioritises occupant comfort and won’t operate if the air conditioning or heater is on full, as it needs more power from the engine to cool or heat the cabin. And if the car detects a rise in cabin temperature above 2 degrees when start-stop is activated, it will automatically restart the car, regardless of whether the clutch is pressed, to enable it to reach the set temperature.

In terms of performance, the new 2.0-litre DISI engine benefits from decent levels of low-down torque for quick acceleration and overtaking. It’s also extremely quiet on tickover and, at motorway cruising speeds with little wind noise or road roar, makes for a relaxing long-distance cruiser. The 2.0-litre engine also feels eager, enhancing the car’s sportier character.

Like the standard 3 the Mazda3 i-Stop handles competently. It’s agile, there’s plenty of grip available, body roll is well controlled through tight bends and it feels well composed on twisty sections of road.

Should I give it garage space? The Mazda3 i-Stop is a good buy for many reasons, with economy one of the strongest.

Company car drivers in particular should see this as a viable alternative to a diesel model, as it combines a sportier driving experience with good economy and CO2 emissions that fall neatly under the company car tax threshold of 160g/km.

The start-stop system is also extremely efficient and we expect to see it being rolled out across other Mazda model ranges very soon.

And let’s not overlook the fact that the Mazda3 is simply a good car, one that firmly deserves its place among the hatchback class-leaders such as the VW Golf and Ford Focus.

Rating **

Specifications Model: Mazda3 2.0 Sport i-Stop

Price: £18,025

Engine: 1,999cc four cylinder direct injection petrol 


Power: 150bhp at 6,200rpm

Torque: 141lb-ft at 4,500rpm 


Performance:0-62mph in 10.4 seconds, 128 mph top speed

Fuel economy: 41.5mpg (combined)


CO2 emissions: 159g/km

On sale: Now