Originally Posted by 142 guy (Post 25890036)

If stock means the original early ring and piston design that may not be such a good idea. You need to do a little research to find out when VAG changed the ring design on the motor. If your 2014 uses the earlier design rings which have the oil consumption problem you probably don't want to repeat the problem by replacing with exactly the same OEM replacements. There is a design change to address the oil consumption problem; but, to use the later design OEM rings requires changing other stuff (pistons, rods) and ECS sells a kit with all the stuff necessary to use the later OEM design
Audi B8/B8.5 A4 Quattro 2.0T Engine Mechanical Pistons - 06H107065DM2KT - Oil Consumption Fix Kit (06H 107 065 DM 2KT) (ecstuning.com)

However, you don't want to order that kit until you confirm whether your engine is pre or post design change. No point in ordering the kit if you already have the late design. If you have the late design then one new OEM piston with rings might fix the problem. Of course, all of this depends on what you actually find after completing an engine tear down.

The IE piston package claims to use Mahle forged pistons with a low expansion alloy that sticks to OEM spec clearances. Forged pistons used to have a higher expansion rate that typically required high cold clearances and made for a noisy engine. So you might want to check those details. There is a reason most OEMs use cast pistons. I don't know whether you save any money compared to OEM because IE uses a 22mm wrist pins so you need to purchase the matching IE rods. The 2.0 engine being direct injection is sensitive to compression ratio and the shape of the piston crown. You might want to check to determine exactly how close the IE kit pistons are to matching the original pistons. Unless you really really really know what you are doing you probably do not want to fiddle with the compression ratio on the pistons. Go high and you may turn your engine into a ping monster. Sticking with OEM parts will be safe.

If you are changing turbos, presumably you are some how changing the ECU fuel and ignition maps to match. Once you are in to higher boost levels it might be appropriate to consider actually reducing the static compression ratio on the engine with a revised piston design. Dropping the compression ratio with higher boost levels may be required in order to manage detonation. That will sacrifice fuel efficiency in support of higher power levels and will require fuel and likely ignition re maps.

Originally Posted by silver_tt (Post 25891124)

Aside from the different oil control ring design, what are the differences in the KS vs Mahle piston?

Originally Posted by egebhardt (Post 25896892)

Just to be completely clear, it looks like a section of 1 valve is missing. It broke off?
I'd hate to know where it went flying.
I can't tell what cylinder it is but the tops of the pistons look fine.
I'm with Airbag. Fix it cheap and save for the next car.

Originally Posted by egebhardt (Post 25896892)

Just to be completely clear, it looks like a section of 1 valve is missing. It broke off?
I'd hate to know where it went flying.
I can't tell what cylinder it is but the tops of the pistons look fine.
I'm with Airbag. Fix it cheap and save for the next car.