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The pistons used from the factory in the Audi AAN are a nice piece that can withstand a severe punishment as long as your tune is right.  From the factory, the AAN was designed to offer good off idle response by way of a moderately high 9.3:1 (as advertised) compression ratio and a KKK K24 turbocharger that has a pretty restrictive turbine on the hotside.  While transient response on this setup was very good, it does have its limits when you try to push the envelope.  A turbo with a less restrictive turbine and hotside can help the situation, but to run a lot more manifold pressure safely, lowering the compression ratio is key to longevity.

If you are rebuilding your high-mileage AAN, it will become very apparent that the bores are likely out of round, or at a minimum there is cylinder bore wear at the zero over position from the ring set.  Honing the old bore and installing a new set of rings on the old pistons is, at best, a band-aid.  The proper method is to take the cylinders out to a larger size and restore the bores to a new condition along with a properly designed piston to allow a suitable compression ratio for the higher boost you plan to run.  You always must balance the relationship between ignition advance, compression ratio and fuel octane.

Our forged piston set has been designed specifically for the Audi AAN and has the desirable attributes of the factory piston set, including an offset dish to match the combustion chamber and a proper wristpin offset.  These pistons are made from forged 4032 alloy which means you get the best combination of strength and longevity in an aftermarket piston.  Consider that while a 2818 allow may be ultimately stronger, it will never match the 4032 alloy in terms of dimensional stability over the long haul, nor will it be able to run the same minimal piston to wall clearance as the 4032 alloy piece.  Our goal was a strong piston set that can be used and abused on a daily basis without fear of going soft or wearing out.  This piston set is setup to run on an 82mm bore, and sets the compression ratio at a conservative yet not too soft level of 8.5:1 while retaining a nice, thick upper ring land.  The combined dish and valve cut volume is 9.5 cubic centimeters thus properly lowering the compression.  Stacking or going with extra thick head gaskets to lower compression is the improper method and is a band-aid at best.  Thicker head gaskets provide a poor quench area in the combustion chamber and are an incredibly poor solution to lowering the compression on a turbocharged engine.  The design of our piston set allows for the charge to be centered on the spark plug, just like the factory piece.  It costs more to manufacture the piston set this way, but it is the proper way based on the design of the 20V's combustion chamber.

Our piston set offers a very nice balance between off boost response and high power production cabability.  Trying to run mega boost on the stock 9.3:1 compression engine means you will be stuck retarding ignition timing significantly to stay out of detonation.  Add to this a set of pistons with many thermal cycles and you can see how risky the situation becomes.  The piston set comes with wrist pins, retaining rings and NPR piston rings.  Piston rings are low tension and can be used on cast iron cylinders or on Nikasil plated cylinder bores.

This piston set is manufactured in Germany by Woessner and is exclusively available through Kuhn Performance Technologies.  Reasonably priced and built to our high standards for your enjoyment.  Couple these with the Carrillo Super A forged rod to acheive a very strong, light and very reasonably priced upgrade to your bottom end.  Custom piston sets are also available, please call for further information.