What the motor is is determined by the head. What head you run determines what fuel injection you use (kind of stating the obvious). To get 2 liters of displacement for cheap a complete 2.0TFSI short block with modified pistons is one option. Its been done a few times. The stock rods are an upgrade from the 1.8T rods and the pistons are pretty tough. The oil pump is an issue (the 2.0 has a built in counter balance system) and most covert to the 1.8T pump with a 1.8T filter adaptor. That's the lowest cost way to get there since you just need to mod the stock pistons and perhaps use a Cometic head gasket to get the CR right. Finding a decent 2.0TFSI to build can be an issue. I used a bare block, new crank and oil pump with Mahle 1.8T stroker pistons to build a one off 1.8T stroker with a balance shaft system. Not needed for performance but it is torquey and and really smooth. It's also gotten a lot more expensive since parts prices have gone up a lot.
The 2.0 block has more webbing, mostly to support the balance shaft unit and it also has beefy looking main caps. That's not needed for any 1.8T build, but it does look cool.
The next option is the 2.0 crank in the 1.8T block. That of course is the most common build. To save money you could modify a set of used 2.0T pistons to work with the 1.8T head. No matter what you need to have the block machined and would want a set of aftermarket rods. If I was to guess I would say $300 to mod the pistons and $400 for the block work. ITs been three years since I had any work done and I have not had pistons custom machined for a really long time so at best that's a WAG of $700 in labor to convert.
If your going that far getting a real set of 1.8T stroker pistons would be my recommendation. I really like the Mahle ones the IE carries. The alloy does not need super wide wall clearances and they have hard anodized ring grooves and coated skirts. Figure about $1000 for a set and of course you still need to get the block machined. That put you about $700 above the cost of reusing a set of 2.0T pistons, less once you figure in the cost of a set of rings to go along with the used pistons. As a WAG say $500 more for new pistons.
Basically, my recommendation is to find a set of dedicated 1.8T stroker pistons since the incremental cost is not that much. I dont know of a drop piston set that gets around having to machine the block. At this point any used block has enough time and miles that a fresh bore is a good call. I would recommend finding a shop that has a deck plate to pre stress the block when getting it machined.
A lot of this depends on what you want. You can have a lot of fun while spending less with a few shortcuts and still have a good motor. It's easier to get good results by spending more, but its not guaranteed. I have three years and 20,000+ miles on this build and the oil numbers still look great with low oil usage and blowby and its still nice and smooth. I plan on keeping the car at least three more years and its reasonable that the setup should hold up just fine. You can ask yourself how long does your build need to last. For sure, in five years I really don't see me using my A4 as a daily driver and I probably won't be driving it to work.
Mahle Pistons
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2.0TFSI block getting setup with IE rods used with a 1.8T head
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The somewhat crazy stroker that I put together:
https://www.audizine.com/forum/showt...oker-O6F-block
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Originally Posted by a.four
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