Input Parameters Are the Following:
Cylinder head Volume (CC) = 76.00
Piston Top Volume (CC) = -12.00
Cylinder Bore (Inches) = 4.0
Cylinder Stroke (Inches) = 3.48
Deck Height (Inches) = 0.000
Head Gasket Thickness (Inches) = 0.040
Computation Results:
Computed Compression Ratio is 10.9 to 1

does this seem right it seem kinda high to me.
the pistons i have are stl=H345np60 and they are even with the deck

I bet on the "Dome CC" section you put in "12" instead of "-12".

i put in -12

8.4 using two different calculators (That assumes a 4.166" dia. gasket and a -12cc piston)

10.8 with a 12cc DOME piston.

Ed

what if i went to 64 cc heads

Approximately 9.44 - 1. Ed

Edit: This site (www.smokemup.com) has some of the best calculators I have come across. I think you need to join as a member, but again, some of the best you will find on the net. Ed

i for got it is 60 over

Correct me if I am wrong, but if he went from 76cc to 64cc, his CR will be in the 11-ish range.

yea i got close to what edge got using my own home made excel file.

76cc heads
12cc of piston volume
10 cc for the gasket
4.00 bore and 3.48 stroke

I got 8.312:1

You went the wrong way with the piston cc's.... most calculators need a minus number for dome pistons and a regular number for flat tops. Meaning that you are losing -12cc of volume instead of gaining 12 cc's like you would with a flat top below the deck....

Keith

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K-Star Automotive
Performance Engines
It's better to have a gun and not need it, then need a gun and not have it.

76 cc = Approx. 8.6 - 1


64 cc = Approx. 9.7 - 1


Ed

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that with a 4.00 bore i have 60 over

Thats how he calculated it. Looks at the bore measurement he entered. 4.06.

__________________
1997 BMW M3 - 3.2litre Inline 6 cylinder

what if i went with 49cc? the new dart heads have 49 an some have 54

11.55:1 with the 49cc heads

keith

__________________
K-Star Automotive
Performance Engines
It's better to have a gun and not need it, then need a gun and not have it.