Product Information
Part #: 930285017. The Mahle Pistons PowerPak is a top - notch piston assembly kit for Subaru Impreza (2004 - 2007). It features a 99.5mm bore, 3.11 stroke, 5.137 rod, 23mm pin, 1.209 C/D, 8.5:1 compression ratio, - 22cc dome volume, and weighs 399 grams. This race - proven kit includes hand - deburred, forged pistons with a performance coating, high - quality steel pins, round wire locks, and low - drag performance rings. Our dragster uses Mahle forged pistons, and we highly recommend them for their strength and GRAFAL coating. Key features are forged aluminum pistons with CNC - machined crowns, hand - deburred finishing, forced pin oiling with machined drain backs, lightweight slipper skirt forgings, CNC - finished pin bores, reliable round wire locks, and pre - fitted German steel high - strength pins. Mahle's ultra - flat ring grooves and low - drag rings offer better sealing, and the improved coating reduces friction. The piston skirts are coated with GRAFAL, which cuts down friction, boosts scuffing resistance, enhances durability, and allows for a closer piston - to - wall clearance, reducing engine noise.
Using the Mahle Pistons PowerPak is straightforward. First, make sure your engine is clean and ready for installation. Carefully follow the included instructions to install the pistons, pins, locks, and rings into your Subaru WRX or STI EJ25 engine. When starting the engine for the first time after installation, let it run at a low speed for a while to allow the components to settle. For maintenance, regularly check the pistons for any signs of wear or damage. Keep the engine oil clean and change it according to the manufacturer's recommendations. Also, pay attention to the engine's performance. If you notice any unusual noises or a drop in power, it might be time to inspect the pistons. Avoid over - revving the engine, as this can put extra stress on the pistons and reduce their lifespan.
