Compression wrt Volume

[Bart001]

Has anyone done the math for compression.....
I was wondering for how much compression you pick up for lets say every 5cc you take out of each cylinder......
I'll try and skim through my physics book, but I thought while I was at work, maybe someone knew the answer.....

[RamAirGAGT]

Well, there is PV=nRT but I doubt that could be used. BTW just out of curiosity how would you take out 5cc? Too bad they don't make wilder cams for us to lower the compression if it does get raised.

[Blackrider]

http://www.jordierobb.com/GA%20Info/compression%20ratio%20calculator.xls

[Bart001]

There are many ways to pick up compression....
milling the heads or using thinner gaskets... etc...
Compression gives MOre power...

[TA^Guy]

Originally posted by Bart001
Has anyone done the math for compression.....
I was wondering for how much compression you pick up for lets say every 5cc you take out of each cylinder......
I'll try and skim through my physics book, but I thought while I was at work, maybe someone knew the answer.....
Hey I have a question for you...

If you have a 'buddy' that can built 1500hp motors in his shop, then why don't you ask him? I'm sure can provide the answers for you. I mean he did tell you to run 110 octane in your near stock 3100.

BTW, you won't need physics to figure out how much the compression will be incressed. It's mathamatical, go find your bore and stroke, combustion chamber volume and get cracking at some home work.

[RamAirGAGT]

Milling the heads to pick UP compression? Giving more volume in the heads decreases compression because there's more volume. I didn't know knowing the bore and stroke can be used to calculate compression-I thought that was used to calculate displacement. And, I do have the formula for that.

[Blackrider]

Originally posted by RamAirGAGT
Milling the heads to pick UP compression? Giving more volume in the heads decreases compression because there's more volume. I didn't know knowing the bore and stroke can be used to calculate compression-I thought that was used to calculate displacement. And, I do have the formula for that.
its all relative

[RamAirGAGT]

Do our cars have flat top pistons or dished? The only way I know of to increase compression is to buy smaller chambered heads or get taller pistons.

[92CamaroRS]

if you mill say. .020 off of the face of your head that makes the combustion chamber smaller and increases the compression. but what can cause problems here is it moves the valves closer to the pistons and also changes the angle and bolt holes of the intake manifold. IMO milling heads is a MAINTENCE ONLY operation, same with overboring.


simply put, start with the orignal volume of the chamber and the piston at the bottom of the cyl. then divide that by the volume when the piston is at the top of the bore.


other thigns that need to be considered is dishes, valve reliefs, domes, and also how far down from the deck the pistons are at TDC. and depending on what kind of compression ratio you are talking about, cam duration has a effect on this also.

[Colin]

^ :agree:

[TA^Guy]

Originally posted by Blackrider
its all relative
Originally posted by 92CamaroRS
if you mill say. .020 off of the face of your head that makes the combustion chamber smaller and increases the compression. but what can cause problems here is it moves the valves closer to the pistons and also changes the angle and bolt holes of the intake manifold. IMO milling heads is a MAINTENCE ONLY operation, same with overboring.


simply put, start with the orignal volume of the chamber and the piston at the bottom of the cyl. then divide that by the volume when the piston is at the top of the bore.


other thigns that need to be considered is dishes, valve reliefs, domes, and also how far down from the deck the pistons are at TDC. and depending on what kind of compression ratio you are talking about, cam duration has a effect on this also.
:agree: