Little Ticker With A Big Heart
Newcastle Herald
Saturday March 1, 2008
GREENPEACE probably won't like Volkswagen's latest Golf model, the GT Sport TSI, and nor will Friends of the Earth or any one of the other tribes of eco-warriors.
It is a car with a petrol-fuelled internal combustion engine providing its only source of motive power, which means it still drinks from a rapidly-depleting well and still has carbon dioxide and nitrogen oxide contained in the fairy kisses being blown from its exhaust pipe.But what the green army may not know is that, like most car makers, Volkswagen has put some serious thought into the engine powering this particular car in a bid to develop a small-capacity, petrol-fed power plant that delivers diesel-like levels of performance and economy, without some of the diesel engine complications, such as weight, noise and cost.The TSI stands for turbocharged, supercharged and fuel-injected.It si complicated, with a belt-driven supercharger and a gas-driven turbocharger connected in series, four valves per cylinder and direct fuel-injection, all dropped onto, into and around a relatively tiny 1.4-litre, four-cylinder engine.The supercharger provides all the bottom-end power and torque the engine needs from idle through to about 3500rpm, the point at which the exhaust-gas-driven turbocharger cuts in to maximise power and torque at the top end.By using a magnetic clutch arrangement on the supercharger and a control flap to ensure that the fresh air required for the operating point can get through to the exhaust turbocharger or the supercharger, the transmission from one form of forced induction to the other is seamless and the little engine is happy to spin quickly and happily to its red line.The engine's capacity is critical. Volkswagen says the 1.4's bore and stroke dimensions are about right and claim any significant increase or decrease in capacity will stymie the overall effectiveness of the engine.In terms of comparative performance between the 1.4-litre TSI (or, as it is more commonly known, the "Twin Charge" engine) and Volkswagen's 1.9-litre and 2.0-litre diesels used in the Golf range, the numbers tell an interesting story.The Twin Charge manages 125 kilowatts and 6000rpm and churns out an impressive 240 Newton metres of torque (that's 40 Newton metres more than the 2.0-litre petrol engine) from 1750rpm all the way through to 4500rpm. Pretty impressive.The 1.9-litre turbo-diesel makes 77-kilowatts at 4000rpm and 250 Newton metres at 1900rpm and the regular 2.0-litre turbo-diesel is good for 103-kilowatts at 4000rpm and 320 Newton metres from 1750rpm through to 2500rpm.It is the warmed-over 2.0-litre diesel used in the Golf GT variant (the same variant powered by the 1.4 TSI) that makes the most interesting reading. This particular oiler has the same power output as the 1.4-litre 125 kilowatts but at 4200rpm. With 350 Newton metres of torque available it has 110 Newton metres more but delivers across a narrower range, the maximum kicking in at 1750rpm and diminishing from 2500rpm.Which makes the on-road performance an interesting comparison as well. Both the 1.4 TSI and the 125-kilowatt diesel boast the same power and the same 220kmh top speed, but the 35-kilogram-heavier diesel is 0.3 seconds slower 0-100kmh (7.9 seconds for the TSI, 8.2 for the diesel).In terms of exhaust emissions, the manual TSI dumps 184 grams of carbon dioxide per kilometre, while the diesel makes 174.Fuel economy is an official 6.6 litres per 100 kilometres for the diesel (combined city and highway cycles) and an impressive 7.7 litres for the petrol.And for those to whom pricing will always provide the most critical point, the difference between the 1.4 TSI GT Sport and the 2.0-litre turbo-diesel GT Sport is just $2500 in the petrol car's favour.All that high tech, and cheaper than the turbo-diesel to boot.On the road the car is a bit anticlimactic. The 1.4 TSI behaves the same way as anything else from the Golf range, while serving as an interesting crossover between the petrol and diesel philosophies.Within a kilometre, even the most cynical will have either forgotten about or been impressed by the sparkling nature of the small capacity engine. About the only thing that will alert anyone to the fact that it is different is the low-speed, just-audible, turbine-like whine from the supercharger as the car gathers speed.That, and the reactive nature of the boost gauge on the lower edge of the instrument panel, which flicks backwards and forwards depending on throttle load and gear selection.It loves being worked, this little engine, and responds nicely to the throttle with only a little bit of turbo-lag noticeable and then only if the revs drop significantly at the downshift point.It's a step in the right direction, even if the doomsayers suggest otherwise.The only question mark concerns the maintenance of something that is so mechanically sophisticated.A small-capacity, petrol-fed power plant that delivers diesel-like levels of performance and economy.VOLKSWAGENGOLF GT SPORTTSIPRICE$34,990 (plus onroad costs)DIMENSIONSLength ................................4204 mmWidth ..................................1759 mmHeight ................................1479 mmWheelbase .........................2578 mmTracks (f/r) ........1540 mm/1518 mmTurning circle ........................ 10.9 mWeight .................................. 1340 kgMECHANICAL1.4-litre, inline four-cylinder with directfuel-injection, supercharger and turbocharger.125kW at 6000rpm, 240Nmat 1750rpm. Six-speed manual.CHASSISFront, transverse engine,front-wheel-drive, power-assistedelectro-mechanical rack and pinionsteering, four-wheel disc brakes withanti-lock, electronic brakeforcedistribution and brake assist, electronicstability control, traction control, 17x7alloy wheels, 225/45R17 tyres.SUSPENSIONIndependent MacPherson struts,lower A-arms, anti-roll bar front,independent four link, coil springs andanti-roll bar rear.FUELType/capacity: 98RON/55litresEconomy: l/100km (ADR81/01combined average)MAIN RIVALSCitroen C4, Ford Focus, Holden Astra,Mazda3, Peugeot 308, Renault Megane
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