The firm’s new m235 kit, which costs £575 including VAT, offers an extra 10bhp from the previous M225 upgrade and gives the 1.5-litre turbocharged three-cylinder engine an extra 35bhp from unmodified versions. It also boosts the Fiesta’s peak torque to 258lb ft, compared with the official 214lb ft of the standard version.
Alec Pell-Johnson, Mountune’s performance chief, claimed the kit “delivers both significant performance and driver enjoyment”.
As well as upgrading the output of the Fiesta ST engine, the modifications include developments to boost usability and performance, while ensuring the car retains the feel of an official manufacturer model. No-limit shift optimisation is included as part of the kit calibration, which combines with the firm’s established enhanced exhaust overrun function.
The m235 kit includes an extended durability cycle that monitors cylinder pressures when additional ignition is used, providing a "significant and usable" increase in power and torque throughout the rev range. The upgrade has been subjected to what Mountune calls a “rigorous testing and development process”.
Customers will be able to use Mountune’s Smartflash app to install and control the calibration, allowing them to make changes to the performance of their vehicle as required. The m235 upgrade includes three calibrations, including a Performance setting with more aggressive launch control and enhances exhaust noise, and an Anti-Theft setting that fully immobilises the car.