Skip advert
Advertisement

Posaidon boosts the Mercedes-AMG GT S to 690bhp

New hardware and software gives GT S Huracan-trumping performance

You could say that the Mercedes-AMG GT S’s standout feature is its deep bellowing V8. That’s not to say the chassis is lacking, but the twin-turbo unit was certainly a key ingredient in securing victory against the Porsche 911 Carrera GTS in the car's first head-to-head test (evo 204). And now, thanks to German tuning house Posaidon, that V8 is available with substantially more firepower.

Advertisement - Article continues below

Swapping the standard inboard turbos for uprated items, increasing the size of the intercooler and fitting a freer-flowing exhaust system has enabled Posaidon to fine-tune the ECU’s mapping so the engine now produces 690bhp and 553lb ft of torque.

This represents a substantial increase of 187bhp and 74lb ft of torque over the standard car, and ensures the Posaidon GT S shaves six tenths from the factory model’s claimed 3.8sec 0-62mph time. Top speed also grows to 216mph, 24mph more than standard, ensuring the car now has enough grunt to out-drag a Lamborghini Huracan. 

Posaidon says that it could have upped torque even further, but it chose to cap the number at Mercedes’s recommended torque limit in order to ensure the mechanically unmodified seven-speed dual clutch gearbox remains reliable – though admittedly, Posaidon does offer a ‘box remap and will, if provided with a written request to do so, up torque beyond the recommended limit.

The German tuner also offers uprated brake components, but no new parts for the car’s chassis setup are currently available. But with all-round double wishbones, adaptive dampers and an electronically controlled limited-slip differential part of its standard armoury, the AMG GT S is arguably already well placed to handle more power. 

Interestingly, owners of the non-S AMG GT can also be catered for, because Posaidon’s engine performance upgrades are also available on its less potent V8 – in this case the car’s final output would represent a 234bhp and 111lb ft of torque over standard. It’s worth noting that the GT doesn’t receive the S’s electronic LSD however, instead making do with a mechanical system – so Posaidon tuned GT owners might find that this output increase requires gentler throttle applications…

So what’s the price of all of this engine work? Posaidon says that it’ll supply and fit all of the parts for €25,000 (this price includes Germany’s 19 per cent sales tax). While that might initially sound like a lot, let us not forget that a Posaidon AMG GT S’s output would rank it alongside the likes of the Lamborghini Huracan – and that car starts at £186,760.

Skip advert
Advertisement

Recommended

Mercedes-AMG GT review – better than the original, but a match for the Porsche 911?
Mercedes AMG GT 55
In-depth reviews

Mercedes-AMG GT review – better than the original, but a match for the Porsche 911?

A sophisticated new chassis, up to 805bhp and a more practical cabin provide the Mercedes-AMG GT with everything it needs to take on the best in the b…
13 Apr 2026
Skip advert
Advertisement

Most Popular

MST Mk1 Evo is an extreme Ford Escort road rally recreation
MST Mk1 Evo front
News

MST Mk1 Evo is an extreme Ford Escort road rally recreation

MST’s Mk1 Evo is a tarmac rally weapon that only vaguely resembles a Ford Escort
7 Jul 2026
One-off Ferrari 599 shooting brake is the dream supercar estate
Niels van Roij Daytona Shooting Brake Hommage front
News

One-off Ferrari 599 shooting brake is the dream supercar estate

If a Ferrari FF isn’t quite to your taste, or a bit too common, why not commission a coachbuilder for a one-off 599 shooting brake?
8 Jul 2026
The Red Bull RB17 is alive: F1 stars to drive 15,000rpm V10 special at Goodwood
Red Bull RB17
News

The Red Bull RB17 is alive: F1 stars to drive 15,000rpm V10 special at Goodwood

Red Bull’s rival to the Aston Martin Valkyrie AMR Pro and GMA T.50s Niki Lauda goes to the ultimate extreme, and we'll see it in action for the first …
8 Jul 2026