Mercedes-AMG A45 S – long-term review

Time to give the A45 some context. A couple of things happened in the last month that helped that along nicely. First of all the question of its compactness. Now, by and large the A45 is a small car – it’s under 4.5 metres long, and exactly 1.85 metres wide. Compared to the Audi RS6 I ran before this means it can be threaded down tight roads pretty successfully. Less wincing when you meet hard-charging delivery vans and worrying about where the extremities are. You fill less of the road’s width, so have got more space to play with. And that’s important: you can choose and alter your line through corners with more scope and being in a small car, a hot hatch at that, feels cheekier.

Sort of. It’s hardly like this is an Up GTI. The A45 still presents an aggressive face to those coming the other way and a riotous wing to those it’s just swept past. And it’s not that small. Look at it next to the Alfaholics GTA-R – another half a metre shorter and only just over 1.5 wide. Now there’s a car that makes your average B-road feel like a dual carriageway. And it’s so light, too, half the weight of the AMG, basically. Half! 830kg gives it a power to weight ratio – as the name suggests – of 290bhp/tonne. The A45 musters only 262bhp/tonne.

But that’s not important. What matters is what they’re like to drive, and in that regard, the A45 is definitely a modern product: complex, tech-laden, rapid, capable, charisma engineered in, rather than being inherently part of the car. It is amusing as the engine’s fizzy and the whole car eager, but there are a few dynamic rough edges. I’ll get on to those in the coming reports. The Alfaholics is simply a complete tearaway. Mainly because it’s not trying to do more than one job. It’s job is to have fun, end of.

Moving on. Having mentioned power to weight figures, here’s why sometimes they can’t be trusted. I know the lengths Mercedes went to liberate 409bhp (415PS) from the latest A45. It span the engine through 180 degrees, the brand new block (used nowhere else) is able to withstand 160 bar combustion pressures, the single twin scroll turbo (twin turbo and superchargers had to be dismissed for packaging reasons) runs on roller bearings and is water, oil and air-cooled. It boosts at up to 2.1bar. There are three water pumps. It delivers 409bhp and 369lb ft, plus meets all emissions and efficiency legislation. It’s a ridiculously clever thing.

But HP Tuners offer a £900 kit for the old 380bhp A45, that boosts it to 515bhp. Which is a lot. The 1,555kg old car weighs a bit more (progress going in the right direction there), but still has a power-to-weight ratio of 331bhp/tonne. So it’s faster, right?

Wrong. The engine mapping required to preserve the gearbox means you only get the full hit once you’re in the meat of fourth gear. There, it’s impressively rapid. The rest of the time? No quicker against the stopwatch than the current car. Both do 30-70 in 3.1secs, and the latest A45 S does 30-100mph in 7.0secs, three tenths ahead. 0-60mph? New blows old away: proper launch control means 3.8secs plays 4.3secs.

But more than that, the new engine is viceless. The compromises HP Tuners made to extract 515bhp go further than restricting torque in low gears. It also baulks then surges when pulling away, and you can sometimes see black smoke in your wake. Some of this is likely down to the mapping (which they’re looking at), but the point with their car is that while it’s unsophisticated, it’s amusing and delivers new A45 pace for less than half the price. Used first gen A45s are now under £20,000 and if they get the mapping sorted out, it could be much more impressive.

And yes, I’m still uncomfortable that the A45 costs more than the BMW M3 did a couple of years ago and remain unconvinced of the quality. There’s a few creaks and groans inside. On the massive plus side, I have discovered the Super Sport screen layout: central rev counter, large gear indicator and speed reading. Combine that with the Intelligent individually configurable drive mode and I can now pretty much get the car how I like it with one twist of the steering wheel dial. Plus I now know what to do should the lumbar support intrude again. That, as far as I’m concerned, is rapid progress.

Miles: 4448
MPG: 28.2