Help with compression calculator!
09-20-2011, 06:45 PM
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Help with compression calculator! Ok guys, I'm sure I feel stupid but I've been trying diff compression calculators and all of them give me different answers.. anyone have links to accurate one or just the good ol formula. Heres what I got..
5.3L Not 0 decked standard deck is 9.240 0-deck at 9.236
-11cc Wiseco Pistons for 3.903 bore
stock crank 3.62"
Stock head gaskets .052 crushed
317 heads 70CC's
I think thats about it.. Thanks a million. Need to see how much to shave heads to try to get to my target.
5.3L Not 0 decked standard deck is 9.240 0-deck at 9.236
-11cc Wiseco Pistons for 3.903 bore
stock crank 3.62"
Stock head gaskets .052 crushed
317 heads 70CC's
I think thats about it.. Thanks a million. Need to see how much to shave heads to try to get to my target.
09-20-2011, 07:09 PM
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Stock stroke is 3.622" and I would recommend using thinner head gaskets to bring You closer to You're goal/target scr . Do You know how far the pistons come out of the cylinder at TDC ? I've seen compression calc's that did'nt ask this and some that do . I've seen comp calc's that ask how far down the piston the first comp ring is so You just have to look at a bunch of them to find the more accurate 1's . and make sure You're figures are accurate .
09-20-2011, 07:46 PM
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Care to share?? LOL. I know i'm overlooking something. zero deck they say is 9.236 with a 6.125 rod. i shouldn't have to zero deck the block so it should be 9.240. So it should be .004 in hole right??
09-20-2011, 09:12 PM
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Well its a street drivin boosted application. I'm trying to get 9.0-9.2. It shouldnt be outta hole any. If anything in hole right?? Based of the measurements the piston manufacture gave for 0-deck ?
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09-21-2011, 10:28 PM
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Man every damn calculator I use..different answer. What do you guys use?? As I understand from Weisco's website is the piston is sticking out .004. HELP! Need an answer or pointed in the right direction
09-22-2011, 12:26 AM
#13
^ Agreed. This isn't rocket science.
In / Out of the hole = (compression height + half of stroke + rod length) - deck height
Those values are variable with some basic algebra. I use this compression ratio calculator: http://www.csgnetwork.com/compcalc.html
In / Out of the hole = (compression height + half of stroke + rod length) - deck height
Those values are variable with some basic algebra. I use this compression ratio calculator: http://www.csgnetwork.com/compcalc.html
09-22-2011, 12:29 PM
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Whiteaw57- Hey thanks man for all your help. I was just curious why the compression calculators I was using were way off from each other. Heres the specs. School Me.
Wiseco -11cc
Compression Height 1.300
Rod-6.125
0 Deck- 9.236
Std Deck-9.240
Head Gasket-.052 compresed
Bore-3.903
Beaflag- Agreed its not rocket science. But when you have several compression calculators giving different numbers you want answers. I do not have the equation in front of me and was asking for assistance.
Wiseco -11cc
Compression Height 1.300
Rod-6.125
0 Deck- 9.236
Std Deck-9.240
Head Gasket-.052 compresed
Bore-3.903
Beaflag- Agreed its not rocket science. But when you have several compression calculators giving different numbers you want answers. I do not have the equation in front of me and was asking for assistance.
09-22-2011, 03:45 PM
#16
(1.300 + 6.125 + 1.811) - 9.240 = -.004 (in the hole).
You'll need to have the block surfaced if it is used as well as production variances on the rods / pistons. I would say a safe estimate is .010. Use .006 out of the hole.
I am getting 8.81:1 with the calculator I am using. All the number variances that are showing up in this thread are about .1-.2 of a point of comrpession. If you are getting varied numbers google the original formula and do the math yourself. Either way you are about .2-.4 low on your goal. Get the bottom end assembled, measure the distance the piston is in / out of the hole, and mill your heads as needed.
You'll need to have the block surfaced if it is used as well as production variances on the rods / pistons. I would say a safe estimate is .010. Use .006 out of the hole.
I am getting 8.81:1 with the calculator I am using. All the number variances that are showing up in this thread are about .1-.2 of a point of comrpession. If you are getting varied numbers google the original formula and do the math yourself. Either way you are about .2-.4 low on your goal. Get the bottom end assembled, measure the distance the piston is in / out of the hole, and mill your heads as needed.
09-22-2011, 09:38 PM
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From what I've seen with some of the different comp calc's is many of them are asking for different specs or #'s for You to plug in and that's why most are different from 1 another . Take a look at a few of them and see if they are asking for the exact same things n I'll bet You'll notice alot of them are asking for 1 or 2 different things than other 1's . The 1's that are gonna be most accurate are the 1's that are asking for the most #'s to plug in .
