Did anyone ever document or dyno how much of a difference it makes switching from 2.0 to 1.8 pistons? I know the 1.8's have the same bore but a different design on top. I think I remember reading that they bump compression to 11.5:1

 

I don't think anyone ever dynoed before and after. I've read they raise the compression to 11.0:1. Not sure if there was math involved or just a estimate.



I just (like 15 minutes ago) put my new 1.8 pistons on my rods and installed rings. Hopefully I can get the engine back together next week.



I got a decent deal on the 1.8 pistons. Brand new OEM for $13 a piece. They do have a noticeably taller bulge on top of the piston.

 

I did the dyno, I got 12 more HP 10 tq with 1.8 pistons and cams. I did have a the cam gear, cold air intake, an Apex Neo and other supporting mods.