CP Piston & Ring Set for Audi/VW 1,8L 20 Valve - Bore (81.0mm) - Size (STD) - CR (9.5) - Set of 4

If you're rebuilding the engine in your Audi or Volkswagen with the 1.8L 20-valve engine, this set of four forged pistons and rings from CP Pistons is a solid choice. These pistons are designed for an 81.0mm bore and come in standard size, meaning they're meant for engines where the cylinders are still within their original specifications. The compression ratio is set at 9.5:1, which is a common target for builds that balance street drivability with improved performance, especially when paired with modifications like turbo upgrades or performance camshafts.

CP Pistons are well-known in the performance engine building community for their strong construction. These are forged pistons, meaning they start as a solid block of aluminum that's heated and forced into shape under extreme pressure. This process creates a much denser and stronger grain structure compared to cast pistons, making them far more resistant to the high pressures and temperatures found in performance applications. This strength is crucial for reliability, especially if you plan on increasing boost pressure or pushing the engine harder than stock. The included rings are also a key part of the package, ensuring a proper seal between the piston and cylinder wall for optimal compression and oil control.

This set includes all four pistons and their corresponding ring sets, so you'll have everything needed to outfit your entire engine. Keep in mind that these pistons are not CARB approved and cannot be shipped to California. For any engine rebuild, it's always best practice to consult the manufacturer's detailed installation instructions to ensure proper fitment and assembly, especially regarding ring gap and piston-to-wall clearance.