Thread: 20V + 16VE pistons CR

Can you show me a diagam of some sort because this whole notchng pistons is new and different for me. I JUST PUT THINGS TOGETHER. Sorry:o

jonwepa,

Will post some photos as my pistons will be ready.

Thanks man. i really need visuals, but once i see it I got it!
Cant wait.

More compression for my B11 - SR20 Forum

Do u mind pming your phone number i am a question guy and i have alot for about your whole set-up.

SR16VE piston notched 1mm (valve reliefs are deeper for 1mm.
This is done by machine.



Some polishing by hands. Also sharp edges are cut and softened.






I think with this handwork compression falls down a bit too. I will measure these pistons volume in a days.

good stuff src it always good to get rid of sharp edges sharp edges get hot

AWESOME! Definitely let us know what the compression comes out too!
I have a set that will be heading to the machine shop if this works on 93 pump gas.

Ok, just measured them. I came to 3,3cc piston dash volume (in bore) with these modified notches.

They are +0,5mm in diameter and +1mm deep, cut sharp edges.

So, summarized:

if we take into consideration 40,5 сс volume (more_fasterer's data) for stock 20V head, we will get 12,3:1 CR using 16VE notched pistons like mine.

if we take into consideration 41,8 сс volume (Andreas' data) for stock 20VE head, we will get 11,97:1 CR using 16VE notched pistons like mine.

My modified 43,15cc combustion chamber will bring me 11,65:1 CR using mine 16VE notched pistons. Safe enough I think!

The one thing which must be corrected is gasket volume. I will measure my compressed gasket as soon as my engine will be assembled.

bugger me 1mm off each one takes the comp down that much! what if you take them down .5 of a mm will that keep it closer to 12.5:1 in a 20VE

on a side note.. are the pistons coated on the top from factory? i know they have a coating on the skirts but are they coated on the top? will they need re coating if they are?