First drive: Mazda's breath of fast, fresh air

MAZDA Australia has previewed the arrival of its go-faster baby, the MX-5 SP.

This turbocharged two-door convertible is due on sale in late January, having been enhanced by an in-house Mazda Australia project and assembled in Melbourne by Prodrive, the UK-based owners of Tickford.

The turbocharger kit, which includes an intercooler, revised engine management and a new free-flow stainless steel exhaust system, was devised by Mazda Motorsport's guru Allan Horsley, who previously served up the race-winning RX-7 SP (in 1995) and the Mazda 800 SP (in 1998).

The turbocharger adds "at least" 37kW and 99Nm to the standard 1.8-litre's output to give 150kW and 280Nm. We say "at least" because Mazda Australia is yet to finally tune the engine management system and dyno test the finished cars.

The SP is priced at $55,540 but air-conditioning, fitted in Australia on all MX-5s, is another $2500. The reason for this is that Mazda says some buyers may want to go racing with their cars and thus do not need the air-conditioning.

Other distinguishing SP features include a highly polished alloy fuel filler cap, SP decal on the rump as well as alloy highlights for the dash air vent surrounds, gearshift surround and a neat alloy gear knob. There's also a set of chromed scuff plates on the sills.

But it is under the bonnet that the hard work has been done, with three year's of sweat by the Horsley team resulting in a substantial rework of the ancillaries in the engine bay and a nifty carbon fibre airbox (embossed with MAZDA to make it look all the more authentic).

Work was thrown into disarray late last year when the up-dated MX-5 with the revised engine complete with sequential valve timing was released.

Mazda had reworked its under bonnet layout meaning Horsley's initial work was brought to nought and he had to return to square one.

With patience and care the re-routing of the plumbing has been achieved the exact length of the pipe for the inlet crucial to the smooth running of the engine.

Mazda's resources do not stretch far so the team decided to test the car on the Targa Tasmania in April. After two days bumbling along to make sure nothing would fall off, the Murray Coote-led expedition put the hammer down for the last five days and came home an impressive 20th outright.

The car was also durability tested at full throttle in second gear for sustained periods.

A new ceramic-based black high-temperature paint applied to the turbocharger body helped keep under-bonnet heat build-up under control, so much so that no expensive body modifications such as bonnet louvres were necessary.

Because the turbocharger and its associated plumbing weighs only about 30kg all up, Horsley did not need to mess with braking or suspension set-ups and the clutch and gearbox are said to be strong enough to cope with the 33 per cent increase in power and the 55 per cent increase in torque the turbo provides.

The turbo runs a conservative 7.5 to 8 pounds of boost, though in testing it has been run reliably up to 15 pounds.

The aim though has been lag-free response and increased mid-range pulling power, and this has been provided largely by clever mapping of a new engine management unit replacing the original chip.

The sequential valve timing system integrates easily with the bolt-on turbo and the engine itself does not need to be touched, aside from the application of different fuel injectors, spark plugs and a freer-flowing exhaust manifold.

The MX-5 SP comes with a full factory warranty and only 100 will be built initially.

The cars have already been allocated to dealers with most going to NSW (45) though Victorian dealers share 33 cars and handfuls are spread around the other states. With 130 Mazda dealers nationwide some (mainly rural) outlets will not have an initial allocation.

Mazda Australia is the first outpost of the empire to try a factory-approved turbocharger for the MX-5 and other markets are already studying its results.

The US and Europe have shown interest, though curiously Japan is still a little reticent.

But the big test will be fitting the system into a left-hand drive car.

For your $55,540 you get a 150kW rear-wheel drive two-seater sportscar with anti-lock brakes, six-speed manual gearbox, 16-inch alloy wheels, remote central locking, CD player, front fog lamps and dual airbags. The roof folds manually but has a glass rear window complete with demister.

Cars go on sale in January and if they prove to be a sell out a second run could be commissioned. But due to the homegrown nature of the kit and its 215 individual and unique components, the next batch would have to be of a similar size to make the project financially viable.

Just casting the turbo intakes requires a large number of units because the nickel and alloy mixture has to be specially prepared.

Mazda will take seriously demand for more cars but with only 35 RX-7 SPs and about 20 800 SPs, it does not need to make hundreds of MX-5 SPs to be content.

Driving impressions:

STANDARD MX-5 ownership adds up to a joyous driver-to-car interface.

The Roadster is designed to flatter drivers of all skill levels, while providing vice-free rear-drive characteristics, nimble suspension and plenty of direct steering and quick-slotting gear shifting.

With the arrival of the turbocharged SP, the MX-5 gains a hairy chest.

Stab the throttle and the row under the bonnet becomes dominated by a healthy induction roar. Once you are moving it becomes your permanent friend, a clear indication the cylinders are being crammed with plenty of mixture.

The result is firecracker acceleration but more importantly stunning mid-range response that pins you back into your seat. It's not jet-fighter acceleration, after all we are only playing with 1.8-litres and four-cylinders, but the ability to whisk past traffic at lightning speed means you spend less time on the wrong side of the road.

Added to the new induction roar is the beefy rumble from the exhaust. It is not so much a burble as a rasp, best appreciated from outside the car, and if you are sitting at the side of the road and one comes past on its way up a tortuously curving mountain pass, the exhaust note echoing off the valley walls will bring a smile to your face.

The happiest result of the mating of turbo with MX-5 as produced by Mazda is that the extra rush of grunt does not overwhelm the chassis.

It is a fairly well sorted chassis to begin with but the limits are set high and the turbo mixes well with the rear drive layout and the 16-inch rims and their Bridgestone rubber.

Make a right-hand turn from stand-still and bury the throttle and there will be the predictable (and amusing) wheelspin and smoke, but it is all extremely controllable and even haring into a series of bends real quick will not have your passengers reaching for the sick bag or clamouring loudly to get out.

With the arrival of the MX-5 SP, Mazda has a credible and far cheaper alternative to the Honda S2000, the 180kW $70,000 two-seater that best attempts to steal the Roadster crown.

While the SP might be a decent slice of cash more than the standard car, the extra performance, it's factory warranty and the inflated fun factor it brings, more than justify the extra money.

One test drive and you'll be hooked. Promise.