We take the mountune m460D Focus ST diesel out for a spin.

We get behind the wheel of mountune’s Focus ST diesel, complete with their latest m460D power upgrade of course…

The diesel variant of the Mk3 Focus ST has to be one of the most underrated fast Fords of modern times. And if it hadn’t been for the VW scandal and diesel all of a sudden becoming the fuel of Satan overnight, I’m pretty sure the fast, frugal, and really quite fun 2.0-litre Duratorq ST would have been much more popular.

Unlike previous ‘sporty’ diesel models – which were standard run-of-the-mill bases underneath some funky-looking bodykits – the Mk3 Focus ST is the first derv-powered fast Ford to actually share the same platform as the full-fat ST model. It was built for performance but then toned down for economy, rather than the other way around.

And this means the diesel ST is actually a very rewarding car to drive. However, if there is one criticism you could throw at it, that diesel engine does feel a little lethargic – especially compared to the punchy EcoBoost petrol-powered ST. But that’s where mountune come in, and why I’m here sat in their latest demo car for their new m460D upgrade.

The m460D is a fantastic little upgrade that really does make the ST diesel more fun to drive. You can have the upgrade fitted at mountune HQ or one of their Pro Dealers for £350, or it makes a great little DIY install which re-flashes the ECU with the revised calibration using the supplied OBDII cable and dongle that come in the kit (priced at £429). There’s no need for any further hardware upgrades, yet power jumps to 200PS and torque rises to a whopping 460Nm – the latter putting it on par with the petrol version’s MR300 kit.

Mountune say that all of this grunt chops the 0-60 time from 8.1s in the standard car to a much sprightlier 7.4s, while in-gear acceleration from 31-62mph (which is a much more useful and realistic ‘everyday’ figure) has also been slashed by 0.5sec too. So, let’s get it out on the road to find out shall we…?

Immediately the first thing you notice is how refined everything is. It’s all very ‘OE’. That is until you plant the throttle and pull away. Instantly there’s a strong surge from almost idle, it’s much stronger than in the OE car. And, it keeps pulling for longer too. Fair enough, as a diesel it’s not going to win any rev-off competitions, but it does hold on to the power for a good 500rpm longer than the standard car. The optimal shift point is still around 4000rpm, but it starts pulling strongly from as low as around 1500rpm, so you still get a really useable, and, for a diesel, quite a wide spread of power.

Obviously, if you keep revving it, power does fall off – it will do, it’s a diesel. But you drive it differently to a petrol engine car. Nail the shift points correctly and it’s huge amounts of fun; you can ride that wave of torque through the first 4 gears with utter ease. And on narrow country lanes like the ones we were testing on, that sheer grunt and huge kick up the backside is awesome fun. I can imagine, if you wanted to, you could destroy a set of front tyres over a weekend in this thing.

Yet it does all this without feeling like it’s even been touched. There’s no clouds of black smoke every time you step on the throttle as we’ve come to associate with tuned diesels, and the m460D kit even keeps the factory DPF re-generation strategy too.

Around town and on the country lane sprints, the m460D can be a real a hoot to drive – easily as much fun as a standard or even mildy-tuned petrol ST. However, when we headed out onto the motorway the diesel’s ultimate lack of power does begin to show. The EcoBoost engines are renowned for their mid-range grunt, and stepping on the throttle even at motorway speeds will still give that surging sensation as you instantly start to build speed. In comparison, the lower-powered diesel doesn’t have quite the same effect – which just shows how times have changed as that used to a be a trait reserved purely for diesels.

But this is more a criticism of the diesel version over the petrol model, and we can’t really expect a first stage ECU upgrade to cure everything. What the m460D does do, though, is give the stock ST diesel a good poke up the backside and makes the drive much more entertaining when you want it to be. And that is mountune’s forte. They have a talented knack for hitting that sweet spot that doesn’t affect the everyday usability and road manners of the standard car, yet still manages to turn the fun factor up a notch or two. The m460D encourages the inner maniac in you to come out to play when the conditions allow, but when 9-5 life kicks in there are no prices to pay or compromises to make. It almost feels like it was intended to be a factory-approved upgrade… but with diesels being the enemy and global pressure on car manufacturers to produce eco-friendly hybrid models, Ford were never going to approve a diesel upgrade… were they?

All I know is, for £350 you can add a serious amount of fun-factor to the ST without fear of it upsetting any of the dayto-day practicality that probably persuaded you to buy the car in the first place. Diesel owners rejoice!