LT1-LT4 Modifications 1993-97 Gen II Small Block V8

help me understand dynamic cranking pressure

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Old Oct 7, 2010 | 01:01 PM
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Default help me understand dynamic cranking pressure

I used this calculator to calculate DCR:

http://www.wallaceracing.com/dynamic-cr.php

for my 227 crane with 53cc/355 (4.03/3.48/5.7)altitude 660, with a 1074 gasket I'm at 11.4 static and right at 230.xx on dynamic cranking pressure and a DCR of 10.7.

I then input my new cam settings and get 216 dynamic cranking pressure.

However, if I up the compression to 12.0 it comes back to 230.xx dynamic cranking pressure. and a 10.7 DCR. an impala head gasket would put me at 11.75 which would bump up the cranking pressure to 225.

So my question
How should I interpret the dynamic cranking pressure info?
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Old Oct 7, 2010 | 02:54 PM
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try a diff calculator such as the one on kbsilvolite
your DCR numbers are to high for pump gas which should be no higher than 9.0
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Old Oct 7, 2010 | 03:12 PM
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with this calculator http://www.kb-silvolite.com/calc.php?action=comp

i get 9.46 and my baby crane was at 10.2.
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Old Oct 7, 2010 | 08:05 PM
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DCR is really a misnomer... There's nothing "dynamic" about using the IVC to determine the theoretical compression the motor sees, which isn't very accurate. I guarantee I could spec two cams that would give you the same "dynamic" (fixed) compression ratio, or cranking psi, and yet one would ping like there's no tomorrow, and the other woudn't be anywhere close to detonation.
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Old Oct 7, 2010 | 09:28 PM
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Originally Posted by Wicked94Z
DCR is really a misnomer... There's nothing "dynamic" about using the IVC to determine the theoretical compression the motor sees, which isn't very accurate. I guarantee I could spec two cams that would give you the same "dynamic" (fixed) compression ratio, or cranking psi, and yet one would ping like there's no tomorrow, and the other woudn't be anywhere close to detonation.
But then how would all the internet experts sell cams?
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Old Oct 7, 2010 | 10:22 PM
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i'm just trying to learn in the process, thought I'd ask and see what other people thought since I never saw that # being calculated before or being discussed.
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