An unfortunate side-effect of the language barrier and the intensity of the technical-tsunami my friendly Audi engineer was attempting to render into plain English, was that I was giving a good impression of being a complete idiot, incapable of understanding even the most basic ideas behind the workings of a motor car. So, I was relieved and chuffed when, in the wettest interlude of the Bavarian rainstorm Audi had laid on to illustrate the efficacy of their new ‘quattro mit ultra-Technologie‘, I thought of a technical analogy our Audi guru had never heard of. I was trying to get my head around what the ‘ultra’ bit did in this new A4 allroad, when the light-bulb came on: ‘It’s like double de-clutching!’ I exclaimed triumphantly. Now it was his turn to look baffled. ‘It’s how you change down gear in vintage cars,’ I explained, trying hard not to look smug. ‘You have to spin up the gearbox to stop it grinding, so you let out the clutch as you go through neutral and give the throttle a blip.’
I was always going to like the new Audi A4 allroad, largely because I drive the older model every day and after four years of getting to know each other I’d say she’s second favourite only to my long-missed Peugeot 205 GTi in the list of every day cars I have owned and loved. Actually, there was this Elise I had an affair with. And a Subaru. Hmmm.
Anyway, this new version was like mine only more so: dynamic but not frenetic, refined but not boulevard, fast but not insane, frugal but not sanctimonious. Yes, there’s sharper steering in a BMW, more room in a Volkswagen, and yes the A4 version of the allroad is really just a macho A4 in heel-raisers: but if you want all-wheel drive because you live where the roads are often covered in turnips and you need to go down rough tracks as much as you need to drive to London, then the A4 allroad is a great car. You can take it as read, then, that in all these respects the new model is a better version of the already good old one.
Now back to the technical befuddlement. Because the really interesting thing about the new A4 allroad is under the floorpan and to see why we must quickly waltz through the pros and cons of four-wheel drive.
Most people who’ve ever put fuel in one will know a big drawback of a car with permanent all-wheel drive is how much they like their drink. It’s thirsty work running those two extra wheels and their drive-shafts, pinions and widgets. You might have traction when you need it, but you also have a bigger hole in your wallet each time you nip to the fuel pump.
That’s why ‘soft-roaders’ (like Volvo’s XC series, Range Rover’s Evoque) have a special clutch behind the gearbox which feeds power to the rear wheels only the times when the front wheels start to slip: this gives better fuel consumption, even if the reactive system is not exactly pure four-wheel drive. Plus the drive shafts and pinions of the rear wheels turn even when they are not engaged – and all that friction still impacts on fuel economy.
Audi’s attempt at the 4WD holy grail – instant, predictive 4WD traction, but closer to 2WD economy – lies in a system that is something like double de-clutching, where most of the time only two wheels are driven while everything between the gearbox and the rear wheels is at rest. When power is needed at the rear wheels a clutch spins up the drive-shaft and then a second snaps two castellated wheels together in the rear differential. It’s very clever and it all happens in 250 milliseconds. But – vitally – the system does not wait for the front wheels to slip before engaging. As my Audi engineer boasted, I would not be able to spin the wheels on his car, even if I stamped on the throttle in a puddle, because a veritable smorgasbord of computers monitors everything about the car and the way I’m driving it in order to ‘predict’ when AWD is needed.
Normally I’d reserve a dissection of differential internals for the midnight slot on Radio Grease-Monkey, but ‘mit ultra’ is worth the oily diversion. It appears to offer the best of both worlds: a four-wheel drive system that is effectively ‘permanent’, that is predictive, not reactive and which offers real savings on the drinks bill. Perfect. Make mine a double.
Model tested: Audi A4 allroad 2.0 TFSI quattro with ‘Ultra’ technology.
OTR: from £35,560
Fuel Consumption: 44.1 combined
Emissions: 154 g/km CO2
Tax Band: G
Power: 247 bhp @ 5 – 6000 rpm / 370Nm @ 1600 – 4500 rpm.
0 – 60: 6.0 secs.