Compression rate M20

["Apfelthaler, Horst" <Horst.Apfelthaler@xxxxxxxxxx>]

Hi all,

I've a question to the engine builders:

Last year I did an e to i upgrade on my eta engine (eta block/pistons, i
head) and i'm wondering what
CR this engine has.

before: compression measured 12.5 to 13.5 bar after 4 strokes with WOT
after: the i head takes about 1 bar because of larger combustion camber -
measured 11.5 to 12.5 bar.

question: 
do the 13.5 bar compression refer to a CR of 11:1 (euro eta non cat) or I'm
completly wrong in this theory?
My doubts came up as I got an information of 3 different eta piston styles
(3.5mm dish, 0.9mm dish, and 0.65mm
elevation on top of the pistons) referring to 9:1 or 11:1 CR.

Image of my pistons - the go up to be even with the block, I did not measure
the dish...
http://silverstone.fortunecity.com/chicane/541/images/history/m27-block1.jpg

What CR does my engine have?


Regards

Horst
http://silverstone.fortunecity.com/chicane/541/

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