JonGTR

The stock size of the 2.0 motor is 1975.

To get the measurement of the single bore:

V = 3.14 x Radius sq. x stroke

So to plug in for our stock 2.0 single volume bore you get:

V = 3.14 x 1.614" x 1.614" x 3.681" = 30.10943cu.in. = 493.405cc's

Take 493.405cc's times the 4 cylinders and you get ~1974cc's


Now I'm using a stock gasket, stroke, and Wiseco's 83mm dished pistons. They measure the dish to be -11.5cc's.

So using the same formula with Wiseco specs:

V = 3.14 x 1.634" x 1.634" x 3.681" = 30.86026cu.in. = 505.709cc's

Now add the 11.5cc dish to it and you get 517.209cc's

Take 517.209cc's multiplied by the 4 cylinders and I now have 2068.836cc's

So I gained .93 liters making my motor ~ a 2.1 liter.

01tibby

maybe you can straighten this up for me. how exactly is c/r changed in a piston. it doesnt make sense to me that a dish would change it, because the ratio of volume at bdc:tdc would still be the same, right?

KCVoRTeX

nope the ratio changes at both... you have more room for roughly the same amount of volume.

01tibby

ha, instead of always just thinking about it in my head i actually did it out on paper. i got it now. the change in piston displacement is a much higher percentage of volume at tdc than it is at bdc.

JonGTR

It changes because:

1. The bore went from 82mm to 83mm. So you get more volume by the cylinders width here.

2. The stock pistons have a flat top. The Wiseco pistons have a dished top. That's the 11.5cc per piston Wiseco calculated for us. It's about .77cu.in. of space in the dished area.

Casper

What about the quench area thats not calculated in... That has to increase those numbers at least a little.

JonGTR

When people take the measurement of the motor, it is really just the block only. I didn't change my head, but I guess if you did something to the quench area, then you could factor that difference in.

Dmitry

no really!

only bore and stroke influence on cylinder displacement. it doesn't matter what shape is pistons.

with 83 mm bore (on 2.0 engine with 93.5 stroke) you will get 2022.5 cc.

Changine head gasket thickness and/or pistons dish will influence ONLY in compression ratio.

faithofadragon

i guess you can calculate if you changed the quelch area by ccing the head

btw to cc a head ive seen guys get a sheet of plexiglass and mount it to the bottom of the head
then they drill a small holl in the middle of the quelch area and add water until the quelch cant hold any more
then you measure how much water was held in cc's

with this post ive realized that if i p&p my head and add a spacer im gonna have lower compression due to the more cc's in the quelch area i wanted near a 9.0:1 compression due to the low boost im gonna run hmmmm gonna have to rethink this all again...

Dmitry

when you do p&p, do you do any work to combustion chamber?

Faith, think to lower CR with porting combustion chamber you will need to machine 1-2 mm from combustion chamber.

and it will make your head weaker.