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MR420 (mTune only) [Mk2 Focus RS]

Calibration: MR375 > MR420 (in-field update) - electronic download

The mTune is a powerful handset that not only boasts the features listed below, it also facilitates easy mountune calibration updates, migration to higher power levels and new functionality.

This option is for customers who already have an MR420 upgrade installed on their Focus RS, or Focus RS500 and that want to benefit from the additional functionality of the mTune handset.

mTune features:

  • ECU performance calibration transfer
  • In-field calibration updates
  • 0-60 times
  • ¼ mile times
  • Monitor 5 OBD channels
  • Adjustable shift light
  • Full data logging
  • DTC reading / clearing
  • Soft touch rear case
  • LCD screen
  • Lanyard pin
  • Removable faceplates
  • Ambient light sensor

Each mTune is supplied complete with:

  • Holster with t-slot mounting
  • OBD and USB connection cables
  • Black faceplate
  • mTune zip-up case

Required hardware

  • mountune MP350/RS500 intercooler
  • mountune MP350/RS500 CAIS
  • mountune MP350/RS500 high capacity fuel delivery module
  • mountune X4 induction kit
  • Full 3" exhaust including sports cat
  • mountune cast I5 inlet plenum
  • mountune turbo recirculation valve
  • mountune MR420-spec hybrid turbo
  • mountune MR420-spec injectors

Please note: MR420 calibration should NOT be installed on vehicles not equipped with the correct mountune hardware. Power output, drivability and reliability may be affected and mountune are unable to support vehicles running alternative hardware. In any such instance no warranty is offered or implied by mountune.

Customer Reviews
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Filter Reviews:
    Adam P.

    MR420 + Forged Engine Internals

    Having owned my focus Rs for around a year with MR375, which is an awesome setup, I thought long and hard about upgrading to the flagship MR420. A couple of conversations with both Ryan and Fred, had me booked in for both MR420 and forging. After a warm welcome at HQ, I left my RS with them to work their magic. Just over a week later I collected the car in perfect condition, with all work completed and ready for me to begin the running in process. Immediately the car felt different, the engine felt smooth, tight and crisp. During the running in process I was very impressed, without thrashing, it still felt torquey and showed a willingness to rev. After 500 miles I returned to HQ and made use of the faultless hospitality (TV, Wifi, comfy sofas, drinks, snacks, plus the showroom to tempt you into more goodies) while my car was given a full diagnostic check and oil change. So here I am now, 1000 miles+ and fully run in. The result, INCREDIBLE. The power is linear but relentless. The hybrid turbo does a fantastic job of not feeling laggy and in my opinion the car dosent feel to dis-similar to the MR375 but pulls and pulls hard all the way to the Rev limiter. From a stand still the car rips through the gears at a ridiculous rate. All the fun characteristics of the Mk2 RS are still there, such as torque steer, pops and bangs from the exhaust but with the added feeling of being pinned in your seat throughout the rev range An incredible conversion and worth every penny.

    United Kingdom

    Mr green

    I haven't actually used the item as it was more a piece of a larger puzzle I was the first to be forged and within the first 5 to be converted at mountune using a new turbo rather than recon The item itself feels much smaller in the hand not an issue but still I mentioned it The case is a faux carbon which also nice the original concept was pushed as having a plain case included The hand set could benifit from holding more calibrations or even a hi torque version for those who have forged the engine (piston and rods) Also added security features would also be a big selling point Overall I am glad as always that I bought mountune

    David M.
    United Kingdom

    MR420 Transformation

    Initially I was disappointed with the waiting time to have this conversion carried out. But when I think about it now it was well worth the wait. It hasn't got the initial vicious punch in the back like the MR375 but the power is just relentless. Torque is more linear The car just doesn't run out of steam Fuel economy has improved Overall very very pleased with the work carried out. Bring on forging