You don't often think of Alfa Romeo as being at the technical forefront of the car world. More the Versace to everyone else's Brunel. But not with the MiTo - it's the least attractive Alfa and with new MultiAir engines, it's now one of the most technically advanced.
As with all brilliant engineering solutions, the MiTo MultiAir offers an obvious answer and comes from the same guys who pioneered common rail fuel injection on the 156. Most engines have a cam which is the mechanical link between the crank shaft and the valves - you can make this connection complicated with variable valve timing, but up until now you couldn't time the valves independently of the cam. If you wanted a performance cam, you needed to leave the valves open for longer - fine for flat out driving, but you'd be wasting fuel in normal use.
What Alfa Romeo has done is to introduce an electronically controlled hydraulic link between the cam and the valves so that you get infinitely variable valve timing, because the electronics have replaced the cam as the brain of the valves. In the MultiAir, all the cam does is work the exhaust valves and provide the pressure for the hydraulics. So now when you press the throttle you don't work a butterfly in the throttle body, you control the valves via the ECU. MultiAir has ditched the pressure losses that butterfly valves create and made everything flexible and efficient.
The MiTo has a 1.4-litre turbo that gives decent outputs (133bhp and 133lb ft) but is also capable of scaling itself right back so that CO2 and mpg are better. It works brilliantly. Official figures put it at 50.7mpg and 129g/km and bothare impressive for a petrol, albeit a small capacity one, and are about 10 per cent better than the ‘normal' engines. NOx emissions fall by a whopping 60 per cent. Incidentally, even though the MiTo has been out for under a year, all bar the low-powered petrols will be replaced by MultiAir units - 104bhp, this one and a 167bhp.
You can't feel any difference, apart from the turbo. Because pressure losses have been eliminated, this doesn't have to boost pressure as much, which means lag is almost non-existent. Alfa has patented the tech this time around - it didn't with common-rail and look how ubiquitous that became. If the reaction of an engineering pal of mine is anything to go by, MultiAir is heading the same way.