Mazda3 Diesel Sedan 2009 Review

Mazda3 Diesel sedan

Not so much
>> Driving position a bit finicky
>> Handling suffers slightly against lighter petrol variants
>> Could easily handle an automatic transmission

About our ratings

OVERVIEW
-- Competent diesel rounds out range
The diesel variant of the Mazda3 small car is late arriving in Australia. Petrol models were released earlier this year, but the diesel has been on hold until just last month.

Since the 2.2-litre turbodiesel is also fitted to the CX-7 and the Mazda6, presumably the production plant building the engine couldn't keep up with demand for the new engine in the different models and for the different markets. Whatever the case, the diesel '3' is here now and it has been well worth the wait. Mazda has squeezed the new variant into the range at a price under $30,000, while adding extra equipment.

PRICE AND EQUIPMENT

Based on the petrol-engined Mazda3 Maxx Sport, the diesel variant is fitted as standard with Bluetooth, satellite navigation, multi-function infotainment screen and a trip computer; features that weren't standard on the previous generation Mazda3 Diesel.

Other items fitted as standard include: 205/55 R16 91V tyres on 16x6.5 alloys, six-speaker MP3-compatible six-stack CD audio system, reach/rake steering column adjustment, air conditioning, remote central locking, cruise control, leather-trimmed gear knob/steering wheel rim, multi-function steering wheel and electric windows/mirrors.

MECHANICAL

At 5.7L/100km in combined-cycle testing, the new Mazda3 Diesel -- with its Euro IV-compliant 2.2-litre engine -- betters the 6.0L/100km of the previous 2.0-litre diesel model. CO2 emissions are also lower for the new, larger-displacement engine; recording a figure of 150g/km.

In addition to its larger capacity, the new diesel gains a lower compression ratio, improved fuel injectors with 10 small holes, rather than six large holes, ceramic glo-plugs, new pistons and longer, streamlined blades for the variable-geometry turbine.

As with other Mazda diesels, the new variant in the Mazda3 range only offers buyers a six-speed manual transmission. The new car, having been developed specifically with the European market, doesn't offer the option of an automatic transmission.

PACKAGING
-- Where the '3' misses the bullseye
Packaging for the Mazda3 Diesel was generally as described for the Mazda3 range from the local launch. There are a couple of issues we would reiterate from driving the diesel, which was a sedan. Firstly, the seats are bordering on the firm, but they are very supportive and hold the occupant in place properly -- particularly during harder cornering.

As mentioned in the petrol models' launch review, the driving position wasn't ideal for this reviewer. Finding a set-up that provided a clear view of the major instruments and reasonable reach of the steering wheel left the driver closer to the pedals, which was acceptable most of the time, but could leave you feeling cramped in the right ankle on a longer drive.

We've driven other small cars that provide a better range of driving position adjustment. Add to that also the handbrake lever located closer to the passenger's seat and there you have a couple of ergonomic niggles.

The high deck at the rear of the sedan compromises the rearward field of vision when reversing and parking, but it also contributes to an excellent luggage capacity of 430 litres -- although that still falls some way short of the 510 litre capacity of Ford's Focus sedan. The Mazda's boot is deep and relatively long, as well as being fully lined and easy to load.

For further information concerning SAFETY and COMPETITORS, see the above link to our earlier launch review of the Mazda3 petrol range.

ON THE ROAD

To put that figure in perspective, consider this: driving the Mazda3 during the week the car was with us was limited to some commuting, some fanging and some round-the-suburbs stop/start stuff. The only open-road driving was one section of freeway; perhaps three kilometres or so. Driving the Mazda in those circumstances and seeing a fuel consumption figure within 0.7L/100km of the official combined-cycle figure is impressive by any measure.
 
But it doesn't end with the car's fuel efficiency. As with other examples of the more modern diesels around, the Mazda powerplant is willing to rev beyond 4500rpm, and has a slightly sporty, 'petrol' character to the way it delivers power and torque from a standing start. It's not the sort of engine that just slogs away from standstill with zero revs up.

So the powerplant is far from typical of compression-ignition engines. There's very little turbo lag and you'll rarely experience qualms and sweaty palms when it comes to making a right turn across traffic. In another example, you can actually heel-toe readily because the engine's on the boil so fast.

It's very responsive exiting corners at speed and can launch with the best of them, as one startled owner of a warmed-over EA Falcon can testify. As icing on the cake, it's quiet at idle (whether you're standing alongside it or sitting in the cabin) but sounds fairly good when it's working.

The manual transmission shift is not as snappy as some transmissions around, but it's quite precise and you won't go wrong with it -- it's just a little stodgy when it comes to shifting.

Unlike other manual transmissions mated to the petrol engines in the Mazda3 range, the Diesel's six-speed box has wider spacing between the first three ratios than it does for the top three. From first to second and second to third, the revs drop by over a thousand RPM if you change up at 3000rpm. By contrast, spacing for the top three ratios (fourth to fifth and fifth to sixth) are much closer, almost as if Mazda has set up this gearbox to keep the engine on the boil at autobahn speeds.

The manufacturer has published two different final drive ratios, a lower ratio for the first four gears (3.42:1) and a higher ratio for fifth and sixth (2.95:1). In this regard, the Mazda3 diesel 'differs' from its petrol counterparts, which make do with just the one differential ratio. Plainly, the 'autobahn' ratio contributes to the different spacing between the higher ratios.

Mazda advises that the second final drive ratio is achieved through running the top two gears on a second output shaft with a different pinion gear where it meets the differential. According to the importer, this allows for a lighter, more compact transmission, improved fuel economy and better 'launch' acceleration.

As we reported from the local launch of the petrol-engined Mazda3 range, the steering is not quite a match for the best in the small-car segment (ie: Ford Focus and Volkswagen Golf, to provide two examples). But, also true of the other cars in the range, the diesel Mazda3 does turn in nimbly enough.

Driving the Mazda3 diesel in the wet didn't leave us feeling quite as confident as driving the petrol models in the dry -- and it wasn't just a matter of damp road surfaces. The Diesel certainly appeared further from the neutral ideal than the petrol models were.

Blame the added weight over the nose perhaps (160kg extra kerb mass for the diesel over the petrol Maxx Sport), but despite that, the diesel's roadholding was mostly surefooted in the wet. There was little torque steer through the wheel -- in spite of the car's prodigious potency -- and axle tramp required some serious provocation first.

As for the similarly-specified Mazda3 Maxx Sport, the diesel rides in a relatively firm manner, but remains composed over smaller bumps.

Composure is one of the stand-out points of the Mazda3 Diesel. This is a car that feels larger than it actually is, albeit in a good way. It's a competent tourer and a very good all-rounder in other ways. Drivers will enjoy the balance of diesel-like torque and petrol-like launch -- all the while seeing the fuel-efficiency benefit at the bowser.  

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