Check My Compression Ratio Calculations .
#182945
01/03/09 08:49 PM
01/03/09 08:49 PM
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Joined: Feb 2004
Posts: 3,076 Renton, Wa.
Classof70Chally
OP
super gas
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OP
super gas
Joined: Feb 2004
Posts: 3,076
Renton, Wa.
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I'm ready to take my 440 block in to be decked, (already bored, honed and aligned honed). I am installing Diamond forged pistons and was using their C.R. calculator to figure my static comp ratio. Their number seems a bit high and I was hoping someone smarter than me (not hard to do ) could double check my figures. My numbers are as follows: Bore 4.350, Stroke 3.750, Rod Length 6.760, Gasket Bore 4.500, Gasket Thickness .039, Top Ring Down .240, Valve Relief -4cc, Chamber Volume 84cc, Proposed Piston to Deck Height .005. Diamonds calculator shows that combo adding up to a static CR of 10.89 to 1 . The heads are aluminum (440Source). Thanks.
Last edited by Classof70Chally; 01/03/09 09:05 PM.
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Re: Check My Compression Ratio Calculations .
[Re: mopowered]
#182950
01/03/09 09:16 PM
01/03/09 09:16 PM
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Joined: Jan 2003
Posts: 17,918 Akron, Ohio
ProSport
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,918
Akron, Ohio
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I got 10.25 on the Wallace calculator.
1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
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Re: Check My Compression Ratio Calculations .
[Re: ProSport]
#182951
01/03/09 09:30 PM
01/03/09 09:30 PM
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Joined: Jul 2006
Posts: 4,319 Puyallup, WA
StealthWedge67
master
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master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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Just a question, but why run the ragged edge of detonation with 10.25:1 compression in a street only motor?
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Check My Compression Ratio Calculations .
[Re: Classof70Chally]
#182956
01/04/09 01:09 AM
01/04/09 01:09 AM
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Joined: May 2004
Posts: 854 Brisbane Australia
572B1
super stock
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super stock
Joined: May 2004
Posts: 854
Brisbane Australia
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Quote:
I'm ready to take my 440 block in to be decked, (already bored, honed and aligned honed). I am installing Diamond forged pistons and was using their C.R. calculator to figure my static comp ratio. Their number seems a bit high and I was hoping someone smarter than me (not hard to do ) could double check my figures. My numbers are as follows: Bore 4.350, Stroke 3.750, Rod Length 6.760, Gasket Bore 4.500, Gasket Thickness .039, Top Ring Down .240, Valve Relief -4cc, Chamber Volume 84cc, Proposed Piston to Deck Height .005. Diamonds calculator shows that combo adding up to a static CR of 10.89 to 1 . The heads are aluminum (440Source). Thanks.
The diamond calculator rates your motor at 10.1 not 10.89.you put in the wrong info.-4 for dome + 4 for dish. valve reliefs would be a dish not a dome.Try +4 instead of -4 and you will see your compression ratio is around 10.1 to 1 cheers Rob.
Last edited by 572B1; 01/04/09 01:15 AM.
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Re: Check My Compression Ratio Calculations .
[Re: 572B1]
#182958
01/04/09 10:45 AM
01/04/09 10:45 AM
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Joined: Jan 2003
Posts: 16,925 NC
440Jim
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,925
NC
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Quote:
The diamond calculator rates your motor at 10.1 not 10.89.you put in the wrong info.-4 for dome + 4 for dish. valve reliefs would be a dish not a dome.Try +4 instead of -4 and you will see your compression ratio is around 10.1 to 1 cheers Rob.
Bingo! Ding, ding, ding
With aluminum heads, flat tops, etc. even 11.+ would be fine, IMO. Sleep easy on this one.
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