Audi A4 TDIE : CLEAN MACHINE

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Audi has pulled out all the stops to boost the A4's economy. Steve Walker checks out the 2.0 TDIe model.

At the beginning of 2005, Audi's most fuel efficient A4 saloon just about managed to squeak over the 50mpg barrier for combined cycle economy. Today, the leading A4 manages over 61mpg. That's good progress from the German marque and the efficiency gains have not come at the expense of the car's ownership experience. Whereas the 2005 model had 114bhp, the modern day equivalent packs a much more satisfying 134bhp.

Audi's problem is that rival brands have made similar strides over the same period but it will be hoping that the A4 2.0 TDIe is good enough to get ahead rather than just keep pace with the fast moving market. There's no denying that car manufacturers have made huge strides in enhancing the efficiency of their vehicles over recent years. Their hands have been forced to an extent by legislation that has made efficient vehicles desirable for financial as well as ethical reasons and with most of the improvements achieved through relatively simple modifications, there's definitely scope to wonder why action wasn't taken earlier by the car industry. Whatever the motivations of the big brands, they did come up with the goods eventually and are continuing to do so with more advanced technologies arriving on the market seemingly by the month. The A4 TDIe certainly has advanced systems but its technology relies on getting the most from basic components that we're all familiar with.

"The car will even provide tips for owners on how to drive more economically"

It's Audi's 2.0-litre common-rail diesel engine that provides the power for the TDIe version of the A4. It has 134bhp in this guise which it generates at 4,200rpm. Between 1,750rpm and 2,500rpm, the engine gives its strongest torque of 320Nm, which should be enough to ensure that despite the attention that's been paid to efficiency, this A4 still has the muscle to entertain. The 0-60mph sprint is done and dusted in 9.5s, but trying to replicate that or the 143mph top speed is a sure-fire way to scupper your fuel economy. This efficiency version of the A4 actually features the sports suspension that's available elsewhere in the range. This will bring a firmer ride and sharper handling but the primary reason for its inclusion on this model is that it drops the ride height by 20mm, improving the aerodynamics. All TDIe models also come with a six-speed manual gearbox. Behind the A4 TDIe's headline capturing economy figures are a series of modifications that Audi has made to the car. Chief amongst them is the start-stop system which turns the engine off when the gear lever is in neutral and the clutch pedal is raised. Lower the clutch to move off and it takes just two tenths of a second for the engine to restart, so drivers shouldn't be left floundering, waiting for the system to kick in. Start-stop can be deactivated at the touch of a button but the energy recuperation system is always on. Here, kinetic energy that is usually lost when a vehicle brakes is recycled and used to recharge the battery, so there's less load on the engine when it's accelerating. Start-stop and energy recuperation feature on all the less powerful A4 models but there are also changes exclusive to the TDIe model. These include a longer top gear on the six-speed gearbox which allows the engine to work less hard when cruising at speed and a set of low rolling resistance tyres. There are also aerodynamic enhancements, including the lowered suspension and measures to flatten the underside of the car. There are a couple of trim levels available with the A4 TDIe - the standard spec and the plusher SE. All models get climate control, a CD stereo and electric windows, with the SE benefiting from 17" alloy wheels, while the standard models make do with 16" items. Only the A4 saloon bodystyle is available in 2.0 TDIe form, so buyers wanting an Avant estate will need to settle for one of the other TDI engines. There are actually four 2.0-litre TDI engines available on the A4 and the 134bhp unit in the TDIe model isn't the least powerful. Either side of this economy-focused model in the range hierarchy sit a 118bhp unit and a version with 141bhp but these lack the efficiency modifications made to the TDIe. With a 168bhp version of the same engine also available, the A4 range looks very well stuffed with 2.0-litre diesel engines and there isn't a huge difference in price or economy. The entry-level unit is only 4mpg thirstier but the TDIe is only £650 more expensive with its extra power and aerodynamic mods. There's a larger step up to the 141bhp engine, so the TDIe's lower running costs make it a nice compromise between price and performance. The fleet market is vital for almost every compact executive saloon and all the more so for affordable diesel models like the A4 TDIe. It will be aiming to lure company car users and fleet managers in with its 61.4mpg economy and 120g/km emissions, figures which were more readily associated with diminutive city cars just a few years ago. The car should prove highly cost effective for fleet and private buyers and it may even help owners to improve their own driving style with the DIS Driver's Information System. Integrated into the instrument cluster, the DIS prompts the driver at the optimum moment for shifting up and down the gears but it also provides further advice on how to improve economy. This advice is based on information gleaned from sensors around the car and has been shown to improve fuel efficiency by as much as 30%. It may be a bit of a culture shock being told what to do by your car but who wouldn't listen if there are big savings to be made? Audi's A4 2.0 TDIe is no petrol/electric hybrid. You don't have to plug it in overnight to charge it and it doesn't run on the juice from fermented cauliflowers. It's still a highly efficient vehicle for its size though and it gives a good representation of the current state of the art when it comes to extracting maximum economy from the good-old internal combustion engine. Brake energy regeneration, stop-start technology, aerodynamic tweaks - they all contribute to fuel economy for over 61mpg. The car will even provide tips for owners on how to drive more economically. It shows how far the drive for greater efficiency in our vehicles has taken us and combined with the high quality A4 package, the TDIe makes a well-rounded proposition.

Facts At A Glance
CAR: Audi A4 TDIe
PRICES: £23,340-£24,320 - on the road
INSURANCE GROUPS: 11
CO2 EMISSIONS: 120g/km
PERFORMANCE: 0-60mph 9.5s / Max Speed 143 mph
FUEL CONSUMPTION: (urban) 48.7mpg / (extra urban) 74.3mpg / (combined) 61.4mpg
STANDARD SAFETY FEATURES: Twin front, window and side airbags, ESP, ABS, traction control,
WILL IT FIT IN YOUR GARAGE?: Length/Width/Height, 4703/1826/1427mm