Just think about 31psi.
It’s the pressure you run your tyres, from cold. If you would like to experience 31 per square inch, get the wetty on and dive 23m underwater. It’s also the pressure the turbocharged pumps into the 2.0-litre four-cylinder of the 2020 Mercedes-AMG A45 S.
The fact that Mercedes is making an engine off the factory floor that is being tortured with 31 pounds per square inch (more than 2bar) of boost, with a warranty, is outrageous.
To put it into perspective, remember the legendary Subaru RS Legacy, one of the pioneers of turbo four-cylinders. On its 1991 release, they were considered a rocketship; it made 197hp from its 2.0-litre turbo, from 12psi. All the hooligans and tuners got hold of these cars and ‘chipped’ (a generic term) to run 15psi/1 bar, which was considered madness. Even the Japanese heroes like the Evo VI Tommi Makinen ‘only’ made 276hp. How far we’ve come in 20 years.
Now AMG has doubled boost and the horsepower. It’s now the highest producing two-litre engine in production. It’s also the fastest hatchback you can buy. The numbers are staggering: 310kW (420hp) 500Nm, and performance in mind-bending. As a hatchback fan, this is the kind of car we dreamt of. Remember when we dreamed of having a car that could get to 100 under five seconds. This little German undercuts four: 3.9 if numbers excite you, and that’s as tested and proven on NZ road… er, drag strips.
Read more: Hot hatch warfare — Mercedes-AMG A45 vs VW Golf R vs Honda Civic Type R
Stomp on the gas and the car is smart enough to know it can’t give you the lot instantly: it’s not lag, just a setting that knows it’s smarter to dole out the drugs to a begging addict in metered doses. Then all hell breaks loose!
The boost gauge screams into the red on the configurable ‘performance’ dash display. The engine lets out the bark of an angry German Shepherd chasing a perp, second gear comes faster than you can flick a paddle, the purpose-built eight-speed DCT boofing like a supercar as it pops the next cog: the sounds are sublime, adding to realisation that you are in something special.
This is a car at the upper limit of mechanical physics. You feel like you are Tommi or Colin or Carlos or Richard or whoever your ’90s rally hero was; but the cool thing is, your Mercedes 2.0 is more powerful than theirs ever was, in a car designed to chug around town and drop the kids off at tennis. Or polo.
Now I’m not normally someone who dives into the technical stuff, mainly because I can’t be bothered reading the brochure, but in this one instance it’s a fascinating read.
So the engine is all new. The last generation A45 was a humble A-Class that AMG decided to shoehorn its performance engine into. This time it’s purpose-built. The last engine’s code was M133 and in 2020 they’ve moved to the M139. So what’s changed?
Merc-AMG has swung the engine around 180 degrees, so the turbo is at the back, and the intake is at the front to gulp in unbended cool air, which also means less piping and fewer pumping losses – like the the difference between blowing up a balloon, and a balloon which is attached to the end of 10m of garden hose.
The new twin scroll turbocharger is flash, and fueled not only by boost, but by science. It’s rolling on bearings not bushings for the first time, just like on the stunning 4.0 V8 engine we love in AMG’s big brothers. The turbo also is also fed via two separate passages, each from the two cylinders that fire closest together. The net result is faster throttle response and more torque, lower.
Now the cabin, for so long Audi has won this battle. I love the new Mercedes layout: everything works, even “Hey Mercedes” (ala Alexa or Siri). Within an hour it was how I operated the radio and the phone: it’s brilliant. Voice recognition never works: “Hey Mercedes” does.
The new flat panel ‘MBUX’ digital screen looks very modern without trying too hard to look modern; I think it will date well, and it makes buying a Mercedes before pre-digital dashes hard because they just look old fashioned. You can customise it, too. I predictably set it to the most racy looking one (wife’s eyes roll). Then dialed up the AMG performance page so I could see my engine stats. Don’t judge, you probably would, too.
The suede wheel gave me all the feels, fooling me once again into thinking I was a rally driver. It even has the yellow center stripe on it so you know when the wheel is straight for correcting those giant drifts you will never do, though it’s very possible. And on that, the colour. This one is yellow. I wouldn’t buy yellow. It’s a bit flamboyant for my taste. They always say if you buy a yellow car, it’s a car for life. Because the chance of ever selling it is slim. But I would buy this car… in fact, I want this car. Just in black or grey.
NZ exclusive: We test the Mercedes-AMG A45 S, the most powerful hot hatch ever made
But even if it wasn’t yellow, this car is flashy, its styling is loud - some would say ostentatious. The rear spoiler is gigantic, the aerodynamic splitters look like eyelash extensions - which as we know look good, but just not at the gym. Styling a hot hatch is fraught with danger: we criticise Audi’s RS3 for looking too bland. Are we also going to have a crack at Mercedes and say it’s too flashy? Probably, car enthusiasts are a hard bunch to please.
But they should be pleased, because this is a car that probably shouldn’t be built: 420hp from a 2.0-litre engine in a hot hatch is madness and everything we ever wanted in a bundle of energy, like a honey badger or a mongoose. It’s race-bred and built to function as a daily driver and it does both. At $118,990, it’s a chunk of change for a hatchback. But what’s the price of perfection? As long as it’s not yellow.
