I am finally converting to SD, but have a question. I am trying to determine the correct cylinder volume for use in an 8D bin.

My question is: When Calculating Cylinder Volume, do you calculate based just on the bore & stroke, or do you factor in: Head Gasket thickness, Head Gasket Bore, Piston Deck Height, Piston Ring Height and Piston dome/dish volume?

The difference is quite a bit. Just the cylinder volume is 833, but with the other amounts factored in it comes out to be around 927.

Thanks,

Mike

 

My best honest answer without having all the figures would be too:

Figure it out for GM's 305 and 350 and how they got those numbers and then do yours accordingly.

They were pretty smart in a lot of aspects and some things arent worth riocking the boat over.

later
Jeremy

 

Maybe this will help. You could use this program to calc C.I. and then divide by the number of cylinders. If nothing else it is a handy program to have.

http://members.***.net/azc4vette/vette/dcrvb6.zip

 

I would have thought the more accurate you are in calculating cylinder volume, the less you would have to make up for the inaccuracy in other areas. My .030 over 400 small block using just the base cylinder volume comes out to 6.667 L or 833cc per cylinder. I guess at a minimum, I should allow for the 20cc dished piston, bringing my total to 853cc.

Anyone have a definitive answer instead of speculation?

 

It is stroke times bore. Basically the CID divided by the number of cylinders.

RBob.

 

remember, there is a diff between DISPLACEMENT and total cyl volume.

 

If you are using Super 8d look at the comments section for the cyl vol.

 

This is true. However, for a GM SD ECM using the $8D code, Desert86Roc needs to use the displacement of 1 cylinder. Which for a 350 (5.7L) is 0.7125L.

For Desert86Roc's 406 the value he needs to use is 0.833L. Which is the volume of air that will be inhaled (@ 100% VE) when the piston moves from TDC to BDC.

RBob.

 

Again right from the description in Super 8D:

Cylinder volume is per cylinder. To calculate divide the total displacement by the number of cylinders. Example 350 in^3 =5.7 liters/8=.7125l/cyl X100 = 712.5