Thread: 20V + 16VE pistons CR

Plus volume of spark plug hole between electrodes, just take it and measure it - it's about 0,5 cc!!!

To my knowledge this is the only way to do it properly.

It is the same accuracy as my way of CR check. I'll do this too as soon as my head will be prepared and motor will be assembled.

The thing with the 13.5:1 CR calculation is it was derived from factory compression ratios. Also, I remember they measured or took the SR20VE chamber volume to be 41.8cc.

How much more cc's does the piston clearance volume to the first ring add? anything significant?

What exactly would you use to fill the chamber? Oil?

Any kind of fluid that is temperature stable, low viscosity, and very visible. I would go with the green/yellow radiator fluid, nonmixed.

a type of plaster or gel would be good too, provided it can be done without ruining the cylinder, and you have a pinpoint accurate method of measuring an oddly shaped solid's volume.

That's why I ask, I dont wanna end up corroding or damaging something on a newly built motor.

Here's another measurement for the combustion chamber to add to the confusion:http://www.sr20-forum.com/turbo/24149-how-not-treat-genuine-sr20vet.html More-faster got 40.5 cc for the VET. The VET cylinder head is similar to the 20V, only missing VVL on the exhaust side.

I use a 50/50 mixture of anti freeze and distilled water with about 3 drops of Red Line Water Wetter per 1/2 gallon. It works good for me.

I am amazed by the different numbers for cylinder head volume that get shared. Especially since no one seems to be keen on milling the head to get higher compression ratio I would think that everyones answer should be about the same. I don't have a VE head yet or I could tell you my number, too and probably add to the confusion.

I tried to figure what the C:R would be using 16VE pistons with a SR20VE engine but with all of the varied reports of combustion chamber volume I gave up. I did figure that the 6.5cc on the 16VE piston seemed relatively real. I have a set of those in the garage waiting for my VE build so I guess that I will break them out and pour that to get an accurate number.