It’s not a question of how much the Focus can take, but how much you can handle

Mountune has long been a provider of sinister aftermarket programs for Ford and judging by its latest offering for the Ford Focus, it looks like that trend will continue. The tuner is offering two new programs for Ford’s resident hot hatch. One is obviously more powerful than the other, but the other one isn’t a slouch, either. I suppose picking one program over the other depends on how your stomach can handle all the extra juice both versions provide. Don’t worry, though. The third-generation Ford Focus will be far more enjoyable to drive in either state of tune. Just make sure to buckle up.

How Did Mountune Get the Focus RS to Deliver More than 500 Horsepower?

Understanding the machinations of Mountune’s m520 MRX power upgrade kit means that you have to get acquainted with its little brother, the m450 kit.

The two programs revolve around a factory-configured BorgWarner turbocharger.

In the m450 kit, Mountune installs a BorgWarner EFR-6758 turbocharger that helps make the Focus more responsive and less prone to that dreaded and far-too-annoying turbo lag. The rest of the kit includes a cart turbo adapter, a free-flowing catalytic converter and downpipes, and a compressor outlet/inlet elbow that’s made of five-ply silicone. With this setup, the Focus RS should be good for 444 horsepower and 428 pound-feet of torque. Those are muscle-flexing numbers, but still not on the level of what Mountune’s m520 MRX upgrade can provide.

So, why is the m450 kit important in understanding the m520 kit? Well, most of the equipment bits you’ll receive from the m450 program are also included in the m520 kit, including the aforementioned cast turbo adapter and the free flow catalytic converter. The difference — and it’s a big one — lies in the turbocharger. Instead of the BorgWarner EFR-6758 turbocharger, Mountune will drop a BorgWarner EFR-7163 unit into the Focus RS. You’ll know the difference because of the higher turbo code. That’s not all, though. Availing the m520 kit also means access to an upgraded fuel pump from Xtreme-DI and an uprated valvetrain that comes with revised camshafts.

Mountune Performance Can Make Your Mk. 3 Ford Focus RS Deliver Unbelievable Power
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The result of this tuning madness is a 2.3-liter turbocharged inline-four engine that produces a whopping 513 horsepower and an even crazier 516 pound-feet of torque.

You can watch a short video of the Mountune-tuned Focus RS during a dyno test and you only need to clean your ears of some wax to hear the four-cylinder engine roar like it’s about to eat someone’s lunch. Gods be good, indeed.

How Does the Mountune M520 Focus RS Compare to the Stock Focus RS?

Mountune Performance Can Make Your Mk. 3 Ford Focus RS Deliver Unbelievable Power
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For the record, Ford has yet to launch the RS version of the fourth-generation Ford Focus. The new Focus just arrived in 2018 so there’s a good chance that we won’t see the fourth-gen Focus RS for at least a few more years. We do know that it’s likely going to come with some form of a hybrid powertrain that could push its power and performance capabilities to new heights. There are rumors that the fourth-gen Focus RS will come with an output of 400 horsepower and 425 pound-feet of torque. It’s too early to say if that’s the case, but it does make for an interesting proposition.

For now, the third-generation Focus RS remains the focus (no pun intended) of Mountune’s aftermarket program.

This is an important distinction to make because, in stock form, the Focus RS’ 2.3-liter turbocharged four-cylinder engine only produces 350 horsepower and 350 pound-feet of torque.

There was a time when that output was enough to crown the hot hatch as the most powerful of its kind, but the recent arrivals of models like the 415-horsepower Mercedes-AMG A 45 have pushed the Focus RS to the middle of the pack.

Mountune Performance Can Make Your Mk. 3 Ford Focus RS Deliver Unbelievable Power
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Based on the raw numbers, the power increases provided by Mountune’s new tuning kits are staggering. With the m450 kit, you’re looking at an increase of 96 horsepower and 78 pound-feet of torque. Given that the stock Focus RS can sprint from 0 to 60 mph in 4.7 seconds, it’s reasonable to think that the bump in power would be enough to improve that time by at least 0.5 seconds. That would put it at 4.2 seconds, which happens to be the same 0-to-60-mph acceleration time posted by the aforementioned 415-horsepower AMG A 45.

Now, imagine what a 513-horsepower Ford Focus RS is capable of doing. D

o the math and the power increase generated by Mountune’s m520 kit adds up to 163 horsepower and 166 pound-feet of torque!

That’s a 50 percent increase in power coming from an engine with a beefier turbocharger in tow. Mountain didn’t release performance times, but are you going to doubt that a third-generation Ford Focus with an m520 kit in tow can’t pull off a sprint-to-60-mph-time of around 3.6 seconds? Let’s just say, in that case, I’m not betting against the Focus RS.

How Much Does the M450 and M520 Mountune Package For the Focus RS Cost?

Mountune Performance Can Make Your Mk. 3 Ford Focus RS Deliver Unbelievable Power
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Mountune’s m520 MRX Power program for the third-generation Ford Focus costs £5,974.99, inclusive of VAT. That converts to around $7,250 based on current exchange rates. It’s not a cheap tuning program by any means, but you can at least take comfort knowing that Mountune isn’t short-changing you on what’s included in the kit. Buy the m520 MRX kit and you receive, among other things, Mountune’s Ni-Resist turbocharger adapter, an installation kit that comes with all required oil lines and fittings, a preformed coolant hardline, an m520 software calibration, a turbocharger gasket set, a stainless steel hose clamp set, and, of course, the BorgWarner EFR-7163 turbocharger. Heck, Mountune’s even going to change the oil and filter in the Focus RS if you avail of its kit.

In the event that the m520 MRX kit is out of your price range, the m450 MRX program should suit you just fine.

It costs around half of the m520 MRX kit — £2,950 ($3,580) — and it comes with plenty of the same new tools, pieces, and equipment that you’ll see in the m520 kit.

The only difference is that if you get the m450 program, you’re not getting Xtreme-DI’s fuel pump and the uprated valve train that comes with the revised camshafts. The big difference, though, is the turbocharger. The BorgWarner EFR-7163 is not available in the m450 tuning kit. Instead, you’re going to receive the slightly less powerful but still potent BorgWarner EFR-6758 program. I suppose this kit should serve you well if you’re not up to the task of trying to corral a Focus RS that’s packing over 500 horses in its belly.

Is Mountune’s Upgrade for the Ford Focus RS Worth the Price?

Mountune Performance Can Make Your Mk. 3 Ford Focus RS Deliver Unbelievable Power
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Yes, it’s worth it, at least if you’re not willing to wait for the fourth-generation Ford Focus RS. If you already have a third-generation Focus RS and you want to take your relationship with it to the next level, Mountune’s engine upgrade programs are perfect for your steed. The power and performance upgrades alone are worth the price of admission. But beyond that, a Mountune program in a Ford comes with the latter’s full stamp of approval. You can’t go wrong with buying a kit, and the fact that you can even choose which level of upgrade you want makes it even better. If you can handle a 513-horsepower hot hatchback, then, by all means, ride that rocket. If you’re fine "settling" for a 450-horsepower version, that’s great, too. But you know what’s the best part? The kit isn’t expensive at all. Even the $7,250 price tag of the m520 MRX program is money well spent considering what you’re going to get out of it.

Further reading

2016 Ford Focus RS High Resolution Exterior Wallpaper quality
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Read our full review on the 2017 Ford Focus RS.

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