► MAHLE’s quad-turbo engine named Mjølner
► Extreme V12 claims to be most powerful in a road car
► Fitted into Zenvo’s Aurora hypercar with hybrid tech
Think the V12 is dead? Engineering firm MAHLE Powertrain and Danish supercar maker Zenvo think otherwise. Say hello to Mjølner, the Norse nickname for what is being described as the most powerful V12 ever to be fitted to a road car – mainly due to the inclusion of four turbochargers.
Wondering how on earth that can possibly work in a road car? Well, keep reading for full details of both Aurora variants and extensive interview highlights from Zenvo’s key personnel.
Zenvo? MAHLE? Who?!
In case you don’t know, Zenvo Automotive is the supercar maker responsible for cars like the TSR-S – the track weapon that comes with an active wing that tilts and rotates for the best aero possible – among other brutish and hardcore cars. Its latest project, the Aurora, is designed to be more road friendly but still incredibly powerful. Jens Sverdrup, chairman of Zenvo, says ‘sound and visceral drama is what Aurora will be all about, and the engine is a vital element that we’ve turned up to 11.’
MAHLE Powertrain, meanwhile, has had a long history of automotive engineering, working with car makers to bring some iconic engines to life. It’s had several names over its operations, with its origins being traced back to Cosworth. ‘Our building was one side of the road and Cosworth’s was on the other,’ says John Hollingworth, sales and marketing director at MAHLE Powertrain.
‘We were split up in the early 90s, with the race division going one way and the road going the other,’ adds Hollingworth. ‘Eventually the race division went under Ford ownership, and we went under Audi ownership, branded Cosworth Technology, and that’s when we did the Nissan GT-R engine.’ Then-named Cosworth Technology also helped manufacture V12s for Aston Martin’s early 2000’s Vanquish.’
Tell us more about this mythical V12…
When it came to drawing up plans for the Mjølner, Hollingworth describes ‘very heated’ discussions with engineers as they debated how to get Zenvo’s request for a then-twin-turbo V12 off the ground. ‘I picked up the phone to Jens right away and said we could do it, but that there was the option on the table to do a quad turbo,’ he says. ‘As soon as he heard the phrase ‘quad turbo’, that was it.’
Named after Thor’s hammer in Norse mythology, this 9800rpm-redlining 6.6-litre V12 engine comes complete with four turbochargers, producing 1250bhp on its own. Zenvo and MAHLE have then incorporated it into a larger hybrid powertrain that develops 1850bhp all in.
‘The V12 is just the pinnacle of engineering, and most people aspire to get to one,’ says Hollingworth. ‘And for me, in a world where everyone is going electrified, to be able to leave a legacy of a V12… why not? It’s quite a joy.’
Why go four turbos? ‘Our engineering director said that twin turbos was too easy, but if you were to do it that way, you’d have quite a lot of lag,’ says Hollingworth. ‘You get a better transient response from the car if you put four turbos in.’
Something that also helps with lag is the additional electrification applied to the version used in the Zenvo Aurora. As well as increasing performance, engine response and adding an element of additional usability to the Aurora when the first production cars arrive in a year or so, the battery and electric motor setup is designed to make the engine globally compliant. ‘We’ve done emissions drive cycles with the engine already, but we’ve also done track simulations to give you that extra bit of performance coming out of corners,’ says Hollingworth.
The engine concept is modular – meaning V6 and V8 variants could be developed over time – but most importantly it has future-gazing legislation requirements firmly in mind. Using the MAHLE’s ‘Jet Ignition’ system, it will meet proposed Euro7 emission standards, for example.
Given the costs involved in creating its own powerplant from the ground up like this, Zenvo is expecting to get at least a couple of decades out of its investment. ‘We’re not designing engines for today, we’re designing one where we’ve got to consider emissions legislation and what that will be like in 10 years time – we have to have an engine that is still suitable and one that’ll meet market expectations in 2030 and beyond.’
What’s the Mahle Jet Ignition system?
Mahle Powertrain has been working on its Jet Ignition concept for over a decade. In very simple terms, it replaces the conventional sparkplug with a pre-chamber ignition assembly.
While this adds more complexity, it also allows for a faster and more precise ignition process inside the main combustion chamber – without resorting to a second igniter. This enables a significantly extended knock limit, higher compression ratios, increased performance and ‘ultra-lean’ running.
Once the mixture is initially ignited in the pre-chamber – which does use a conventional spark plug – the partially combusted result is then jetted into the main combustion chamber via a number of small ‘orifices’ to ignite the main charge.
The performance and efficiency improvements come from the way the jets of hot gas are able to penetrate deeper into the combustion chamber. And because there are between four and eight jets, depending on the application, main ignition takes place at multiple sites, ‘resulting in rapid and stable combustion’.
Conventional port and direct injection can be used, while Passive and Active variants enable the application exhaust gas recirculation (EGR) or a secondary low-flow direct injection system in the pre-chamber, respectively. The latter is again more complicated but also allows for ultra-lean burn with stability and even greater efficiency.
Mahle’s tech demonstrations so far have shown brake thermal efficiency (BTE – the ratio between the power output of the engine and the energy in the fuel consumed) of over 40 per cent, with a future target of over 45 per cent. A conventional petrol engine typically has a BTE of 20-30 per cent.
The result is the promise of ‘diesel-like’ efficiency and substantially reduced CO2 emissions. In the ultra-lean phase, NOx emissions have been shown to fall by 99 per cent.
I want to know more about the Aurora itself…
It’s currently undergoing its prototype testing as MAHLE Powertrain and Zenvo continue to work hand-in-hand. In fact, when I speak to Hollingworth, the Aurora makes its dynamic debut at the 2025 Goodwood of Speed.
The Aurora will be available in two flavours when it launches in late 2026 – the Agil for track use and the Tur for touring. And although both do without the preceding Zenvo TSR’s mad rear wing, both still have aero at their heart. The Agil in particular looks as if the wind tunnel development work was at the heart of the design process. Sverdrup told us that ‘we use aero going through the car rather than over it. It’s based on functionalism. Every part has a purpose and we’ve used the carbon fibre monocoque as part of the design.’
The Agil is a striking car in the flesh, with enough scoops and hollowed out sections to rival F1 cars at their most extreme. The Tur is more conventional, but by turning the quad-turbo, 6.6-litre V12 hybrid up to 11, it gets more power than the Agil at 1850bhp. This in a car with a claimed dry weight of less than 1450kg.
Zenvo has had to box clever with both in order to make the project feasible. Modularity is key, from the chassis to the engines. ‘They’re my babies. At the base of it was this idea of modularity, a modular platform so we can do many more models out of the platform, such as a junior hypercar, because it’s all carbon subframes.
‘Even the engines are [modular]. We are able to make V8s and V6s from the V12 because no matter how you spin it, it’s crazy crazy money to develop a V12 for a small company like ours. We have to make this last for another 20 years, at least.’
It’s a sensible strategy, as you might expect from the sensible Danes. Even the clients’ deposits go into an Escrow account so Zenvo can’t burn them on current R&D spend. Sverdrup admits it’s a tightrope at times, but he seems to have a clear-eyed vision as to how to ensure Zenvo doesn’t become another automotive vapourware project.
He has the experience and the right team around him – Sverdrup himself has worked at similar brands like Czinger, BAC and Koenigsegg while Jon Gunner, ex of Aston Martin Q, is now on board as CTO – to hopefully ensure it’s a success.