The mountune Forged Piston Set for mk2 Focus RS has been designed in-house by mountune Racing as a direct replacement for the standard part, and maintain many of the standard dimensions, including the 8.5:1 compression ratio.
The forged piston set is manufactured exclusively for mountune in the US by MAHLE Motorsport, utilising its 4032 grade alloy. This alloy was chosen by mountune's engine designers not only for it's strength and durability, but also because of it's high-silicone content, low-expansion properties. This means that a tighter piston to bore clearance can be used, which will result in a tighter seal and less noise when the engine is cold.
The forged pistons also feature a distinctive grey phosphate coating. This dry lubricant coating (not to be confused with a thermal film coating) provides a lubricant film in the pin bores and ring grooves until the oiling system of the engine reaches operating pressure; particularly useful during the initial start-up or break-in of engines to protect against galling and micro welding.
In addition to this, the piston skirts have also been treated with MAHLE's patented Grafal coating to reduce drag and friction in the cylinder bore, and also help to reduce some of the noise often associated with forged pistons.
Please note: Sold as a set of four pistons.
Had my MK2 RS forged by Mountune and again great product and great service from the whole team, very happy thanks Mountune
I paired these with the Carrillo rods offered by Mountune and a few other bits. Sent engine away to a renowned builder in Australia and was told that the balancing of these items was perfect. No noise and the added security of knowing I can push the boost levels somewhat are highly reassuring. As usual Mountune chooses it's externals suppliers wisely.
Will be fitting these Pistons with k1 rods , best set up for the st/rs if forgeing your ford.