michael hurd
Stalker be gone.
- Joined
- Jul 30, 2012
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Anyone used one? From what I have read, ideal max dynamic compression ratio would be 8.0-8.25, 8.5 borderline for a street engine on pump gas. ( no computer controlled ignition, carb )
For the heck of it, I plugged in the numbers for an L30 5.0L
9.4-1 compression,
3.736 bore
3.48 stroke
5.7 rod
Entering the calculated intake closing ABDC point for the '395' or ramjet camshaft ( not sure if there is advance ground in or not )
This is the result I get:
Camshaft, Rod Length, Boost and Altitude Correction to Compression
Static compression ratio of 9.4:1.
Effective stroke is 2.50 inches.
Your dynamic compression ratio is 6.83:1 .
Your dynamic cranking pressure is 129.94 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 6.83 :1.
V/P (Volume to Pressure Index) is 85
With the stock cam ( specs from Sealed Power stock replacement listed at Rock Auto )
Camshaft, Rod Length, Boost and Altitude Correction to Compression
Static compression ratio of 9.4:1.
Effective stroke is 3.35 inches.
Your dynamic compression ratio is 8.89:1 .
Your dynamic cranking pressure is 183.23 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 8.89 :1.
V/P (Volume to Pressure Index) is 161
For the heck of it, I plugged in the numbers for an L30 5.0L
9.4-1 compression,
3.736 bore
3.48 stroke
5.7 rod
Entering the calculated intake closing ABDC point for the '395' or ramjet camshaft ( not sure if there is advance ground in or not )
This is the result I get:
Camshaft, Rod Length, Boost and Altitude Correction to Compression
Static compression ratio of 9.4:1.
Effective stroke is 2.50 inches.
Your dynamic compression ratio is 6.83:1 .
Your dynamic cranking pressure is 129.94 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 6.83 :1.
V/P (Volume to Pressure Index) is 85
With the stock cam ( specs from Sealed Power stock replacement listed at Rock Auto )
Camshaft, Rod Length, Boost and Altitude Correction to Compression
Static compression ratio of 9.4:1.
Effective stroke is 3.35 inches.
Your dynamic compression ratio is 8.89:1 .
Your dynamic cranking pressure is 183.23 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 8.89 :1.
V/P (Volume to Pressure Index) is 161