1999Firehawkls7

iTrader: (3)

Using the Wallace Racing Dynamic Comp Ratio Cal. (http://www.wallaceracing.com/dynamic-cr.php) this is what I came up with,
(Trying to get the Max DCR for my Stock Bottom End Ls2)

How I entered the Info:
Number of Cyc.................8
Bore in In.......................4.0
Stroke...........................3.622
Rod Length.....................6.098
Static CR.......................10.75:1
Inlet Valve Closes ABDC....48 (Comp Cam Card says)
Boost Pressure in PSI........0 (N/A Motor)
Target Altitude................0 (I live in Ohio)

Results:
Static compression ratio of 10.75:1.
Effective stroke is 3.17 inches.
Your dynamic compression ratio is 9.53:1 .
Your dynamic cranking pressure is 199.09 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 9.53 :1.
V/P (Volume to Pressure Index) is 190

Did I enter this in right?
Is this the Max Dynamic Compression Ratio I can run?

First time ever using a Dynamic Compression Cal.

Thx!

redtan

iTrader: (5)

I made the same error in this thread:

https://ls1tech.com/forums/generatio...ynamic-cr.html

You're supposed to use the IVC at 0.006 not 0.050. Should be on your cam card, if not look up the lobes on the comp cam lobes list and it will give you the duration at 0.006.

1999Firehawkls7

iTrader: (3)

Heres my Cam Card, looks like im going to have to call Comp...

whats the rule of thumb for the highest DCR w 93 Pump Gas?

1989GTA

. I know 8.5 DCR is good for 91 octane as long as you have a good quench etc. So maybe a little higher for 93 octane. By the way there are other factors involved such as a good cold air intake to help control detonaton.

Update. read cam card wrong.

SNLPerformance

iTrader: (15)

It closes at 72.5* @.006 as that from my calculations that cam has 3* advance. Have run 9:1 DCR on 93 octane in really good set ups. That particular cam checks in at 8.0:1, why is your static only 10.75:1?

1999Firehawkls7

iTrader: (3)

W the Static at 11.5 in the Org. Figures the DCR was around 10.5 which seemed high so I kept knocking it down until I hit the 9.5:1 DCR area....

1999Firehawkls7

iTrader: (3)

New Figures..

Static compression ratio of 12.2:1.
Effective stroke is 2.61 inches.
Your dynamic compression ratio is 9.07:1 .
Your dynamic cranking pressure is 186.89 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 9.07 :1.
V/P (Volume to Pressure Index) is 147