LS1 stock SCR
06-04-2006, 04:40 AM
#1
TECH Senior Member
Thread Starter
LS1 stock SCR On the calcs that I use (with negative piston deck) I never get 10.1:1 SCR.
I know they do not take into account the gasket bore size.
But could that be the .018>.023 descripancy we get with calcs?
With -.005 piston to deck it is 10.28:1
and with -.007 it is 10.33:1
The only time I get close to the advertised numbers is if the piston to deck is 0, 10.17:1
Could someone shed some light on this?
I know they do not take into account the gasket bore size.
But could that be the .018>.023 descripancy we get with calcs?
With -.005 piston to deck it is 10.28:1
and with -.007 it is 10.33:1
The only time I get close to the advertised numbers is if the piston to deck is 0, 10.17:1
Could someone shed some light on this?
06-04-2006, 11:24 AM
#2
Assuming 3.903" cylinder bore and 3.940" gasket bore, the difference in combustion chamber size that is overlooked is on the order of ~0.055cc. (Insignificant?)
https://ls1tech.com/forums/generation-iii-internal-engine/519073-simple-math-question.html
...I have no clue how much that changes SCR. Maybe you can plug that into the calculator and see what it's worth.
https://ls1tech.com/forums/generation-iii-internal-engine/519073-simple-math-question.html
...I have no clue how much that changes SCR. Maybe you can plug that into the calculator and see what it's worth.
06-05-2006, 12:54 AM
#7
TECH Senior Member
Thread Starter
Originally Posted by oange ss
i got 10.21, using -.008 deck height, .060 gasket and 3.898 bore
and the stock gaskets .053 compressed.
3.898 bore
3.622 stroke
flatops = 0
Head chamber volume 66.67 ? (that is the only part I never measured)
Are the stock chambers larger than 66.67 ?
Chambers would be in excess of 68 cc for my original motor to be 10.1:1
There must something I'm missing?
I wanna knooooow
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06-05-2006, 02:49 AM
#9
TECH Senior Member
Thread Starter
I'm trying to figure out the stock LS1 static compression (at least the range)
A lot assume 10.1:1 but it seems more in the 10.2x:1
I just want to find out to adjust my DCR calculator.
A lot assume 10.1:1 but it seems more in the 10.2x:1
I just want to find out to adjust my DCR calculator.
06-05-2006, 08:54 AM
#10
i thought they were advertised at 10.2:1...and i used 66.67cc chamber also...still not sure on gasket thickness, my stock graphite miced out at .054 uncompressed, i think they would compress at least another .003-.004...the whole gasket thing is still a mystery i guess
06-05-2006, 09:50 AM
#11
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You need to take into account the ring land volume, which is the volume around the top of the piston right above the 1st ring. This will be:
Bore: 3.898"
Top Land Length: ~0.200"
Top Piston Diameter: 3.848"
Right above ring land: 3.854"
so, area=pi(r)^2
((3.854-3.848)/2)+3.848=3.851
3.851/2=1.9255
(1.9255)^2*pi()=11.648
(3.898/2)^2*pi()=11.934
(11.934-11.648)*.200=0.0572*(2.54)^3= 0.937cc's
So, you need to add 0.937cc's to your combustion chamber volume. I bet this will get you closer to your number!!!
Bore: 3.898"
Top Land Length: ~0.200"
Top Piston Diameter: 3.848"
Right above ring land: 3.854"
so, area=pi(r)^2
((3.854-3.848)/2)+3.848=3.851
3.851/2=1.9255
(1.9255)^2*pi()=11.648
(3.898/2)^2*pi()=11.934
(11.934-11.648)*.200=0.0572*(2.54)^3= 0.937cc's
So, you need to add 0.937cc's to your combustion chamber volume. I bet this will get you closer to your number!!!
06-05-2006, 12:18 PM
#12
Originally Posted by MSURacing
You need to take into account the ring land volume, which is the volume around the top of the piston right above the 1st ring. This will be:
Bore: 3.898"
Top Land Length: ~0.200"
Top Piston Diameter: 3.848"
Right above ring land: 3.854"
so, area=pi(r)^2
((3.854-3.848)/2)+3.848=3.851
3.851/2=1.9255
(1.9255)^2*pi()=11.648
(3.898/2)^2*pi()=11.934
(11.934-11.648)*.200=0.0572*(2.54)^3= 0.937cc's
So, you need to add 0.937cc's to your combustion chamber volume. I bet this will get you closer to your number!!!
Bore: 3.898"
Top Land Length: ~0.200"
Top Piston Diameter: 3.848"
Right above ring land: 3.854"
so, area=pi(r)^2
((3.854-3.848)/2)+3.848=3.851
3.851/2=1.9255
(1.9255)^2*pi()=11.648
(3.898/2)^2*pi()=11.934
(11.934-11.648)*.200=0.0572*(2.54)^3= 0.937cc's
So, you need to add 0.937cc's to your combustion chamber volume. I bet this will get you closer to your number!!!
It looks like you did this calculation and that is what was called for.
06-05-2006, 12:27 PM
#13
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RIght you are, I am going to keep that equation, sure is a lot shorter than the one I did!!!!
These are approximate numbers, I am not certain what the height or the slope of the angle on the stock piston is.
These are approximate numbers, I am not certain what the height or the slope of the angle on the stock piston is.
06-05-2006, 12:33 PM
#14
Originally Posted by MSURacing
RIght you are, I am going to keep that equation, sure is a lot shorter than the one I did!!!!
These are approximate numbers, I am not certain what the height or the slope of the angle on the stock piston is.
These are approximate numbers, I am not certain what the height or the slope of the angle on the stock piston is.
http://www.abe.msstate.edu/~fto/tools/vol/cylinder.html
