BMW USED CARS

You've got to admire Aston Martin's balls. It
builds the DBS and only makes a manual gearbox available at the launch, yet all
the key players in this market offer at least an
automated manual. Imagine a Ferrari being launched without
the fabled F1 'box. Plus, Aston DB9 sales have been 90 per cent automatic.

But Aston thought the DBS was a sporty car and
deserved a manual only. To be fair, it seems like a refreshingly honest reason,
and is backed up by more than just marketing hyperbole. The USA, surely the
most pro-auto nation, buys most of its Astons as manuals.

Time for some science for piston heads. When this
Mazda 3s engine is stopped, the cars new i-stop system the companys first
crack at stop/start knows which piston is in the best position to restart
quickest. Its the one in the combustion stroke phase, where air and fuel are
in the cylinder and ready to be ignited. Sensors pinpoint which cylinder that
is, before the mixture is sparked and ignited, forcing that piston down first
and firing the engine into life faster. Its like placing bike pedals just past
noon, making it easier to push down and move off.

Another mental marker has popped into my head -
500Nm of torque. That's 369 lb ft, but 500 is easier to remember and it's a
number the high-end Germans seem to cluster their diesels around.

A quick glance at the stats in the
back of the book reveals that the 3.0-litre V6 TDI in the Audi A4 makes 500Nm
of torque. The BMW 330d makes 500Nm too - a 3.0-litre straight six diesel. And
so does this new diesel engine in the E-Class, the E250 CDI.

This is a remarkable engine. It's
only a four, that's the impressive bit - it's the same 2,143cc unit fitted to
the single-turbo C200 CDI and C220 CDI. But in this application, it has twin
sequential turbochargers running at full puff. Good.

I-Shift, they call the Jazz's automatic'
transmission. This is a misnomer. It doesn't. Shift, that is. Not very often,
anyhow. And not very well at all.

It is, in short, utter pants. You're at the
traffic lights. Light goes green. Pin the throttle. The little Jazz revs
sweetly, up and into the VTEC. I-Shift decides to change up, because that's
what automatic gearboxes do.

This A5's specification should be as good as convertibles get. After
all, the engine is the smooth, torquey 3.0 TDI (we love that in every Audi) and
it's attached to the twin-clutch S-Tronic box (which we like just as much in
every VAG product). Lazy gearbox to suit the wafting cabrio, economy of the
diesel to suit your wallet. And Audi really knows how to build great soft-tops
- the A4 Cabriolet was a constant best-seller.

But
things don't quite add up. The chief culprit is the gearbox, which is standard
fit on the 3.0 TDI. Positives first: it's a dual-clutch, so the changes up and
down the 'box in full auto are silky smooth and very slick. You hardly ever
notice them and the kickdown speed is much better than in a normal torque
convertor auto, too.

Four, wheel and drive. Those
three little words are what save the new Vauxhall Insignia VXR, for the simple
reason that they banish all thoughts of the torque-steering monstrosity that
was the Vectra VXR to the dark recesses of your mind.

Because despite producing 321bhp
and 321lb ft from a 2.8-litre V6 turbo, the Insignia VXR doesn't suffer from
any sort of torque steer at all. Those three words also sum up neatly the
attitude shift of VXR - gone is the chav factor, replaced here by something
more civilised. Less Burberry cap, more company rep with tie at a jaunty angle.

Useable performance' is the
buzz phrase now, even subtle' styling. Thank goodness for that, as VXR was in
danger of becoming an antiquated performance brand only four years after it
launched.

It's a sweet little car, the Mazda2. Not sweet in a cute way, but sweet in a crisp
and sharp way. Our only problem with it so far has been with the 1.4 diesel
engine, which is unrefined and doesn't suit the car's zingy nature.

So will this new 1.6-litre diesel solve the problem?
In short, yes. It might only be a few cubic centimetres bigger than the 1.4 -
which you can still buy - but it has a far more useful 88bhp and 158lb ft,
that's a third more than in the smaller engine, making it less thrashy and more
effortless. CO2 output is 112g/km, just 5g
more than the 1.4's figure.