explain to me what this means : piston dome cc vs. compression
07-26-2006, 09:22 PM
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explain to me what this means : piston dome cc vs. compression
ok, so maybe this is a dumb question, but i searched and cant find anything on it!
there is so many different dome sizes on pistons of all different CR's.
for example i have 85mm arias pistons, there 13.5:1 CRm, with a 7cc dome.
ive seen 12.5:1 with 8+cc domes...
how does the dome affect the compression on a motor, or the piston or whatever?
is it better to have a smaller or larger dome?
there is so many different dome sizes on pistons of all different CR's.
for example i have 85mm arias pistons, there 13.5:1 CRm, with a 7cc dome.
ive seen 12.5:1 with 8+cc domes...
how does the dome affect the compression on a motor, or the piston or whatever?
is it better to have a smaller or larger dome?
07-26-2006, 09:46 PM
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Re: explain to me what this means : piston dome cc vs. compression (B18 CYA)
Compression is affected by bore, stroke, combustion chamber volume, piston dome cc's, deck height, head gasket thickness etc. A 5cc dome on an 81.5mm piston on an 87.2mm crank will give you roughly 11:1 compression on an ITR motor. Change only the bore size to 85mm with all else being the same and compression goes up to roughly 11.7:1. The less dome the better as far as power production-a higher dome interferes with flame travel or some such technical postulate. If you can get more compression with a flat top piston, you are ahead of the game. DonF or some other technical wiz can explain it much better.
07-27-2006, 08:33 AM
#3
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Re: explain to me what this means : piston dome cc vs. compression (b19coupe)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe »</TD></TR><TR><TD CLASS="quote">Compression is affected by bore, stroke, combustion chamber volume, piston dome cc's, deck height, head gasket thickness etc. A 5cc dome on an 81.5mm piston on an 87.2mm crank will give you roughly 11:1 compression on an ITR motor. Change only the bore size to 85mm with all else being the same and compression goes up to roughly 11.7:1. The less dome the better as far as power production-a higher dome interferes with flame travel or some such technical postulate. If you can get more compression with a flat top piston, you are ahead of the game. DonF or some other technical wiz can explain it much better.</TD></TR></TABLE>
07-27-2006, 09:59 AM
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Re: explain to me what this means : piston dome cc vs. compression (jdm_ef9)
You should have not slept thru math class. A + 7cc dome 85mm bore , std deck height, B-16 head, will give approx 11.2 comp with a B-16 crank, 12.8 comp. with a LS crank, and 13.6 compression ratio with a 95mm crank.
cly disp. + top end volume divided by top end volume = comp. ratio
cly disp. + top end volume divided by top end volume = comp. ratio
07-27-2006, 01:26 PM
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Re: explain to me what this means : piston dome cc vs. compression (DonF)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF »</TD></TR><TR><TD CLASS="quote">You should have not slept thru math class. A + 7cc dome 85mm bore , std deck height, B-16 head, will give approx 11.2 comp with a B-16 crank, 12.8 comp. with a LS crank, and 13.6 compression ratio with a 95mm crank.
cly disp. + top end volume divided by top end volume = comp. ratio </TD></TR></TABLE>
what would mine be with:
7cc dome 13.5:1 piston
85mm bore
89mm stroke
.980" deckplate
and a gsr head (43cc chamber volume?)
cly disp. + top end volume divided by top end volume = comp. ratio </TD></TR></TABLE>
what would mine be with:
7cc dome 13.5:1 piston
85mm bore
89mm stroke
.980" deckplate
and a gsr head (43cc chamber volume?)
07-27-2006, 04:22 PM
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Re: explain to me what this means : piston dome cc vs. compression (B18 CYA)
??? i want to get my car running asap. and need to know this!
edit-- i tried this : cly disp. + top end volume divided by top end volume = comp. ratio , and got 13.1:1, is that correct?
edit-- i tried this : cly disp. + top end volume divided by top end volume = comp. ratio , and got 13.1:1, is that correct?
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07-27-2006, 09:53 PM
#8
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Re: explain to me what this means : piston dome cc vs. compression (DonF)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF »</TD></TR><TR><TD CLASS="quote">What is the piston to deck height? </TD></TR></TABLE>
also what is the piston to deck height that the manufacterer of said pistons to calculate dome volume...
You also need your compressed head gasket thickness.
also what is the piston to deck height that the manufacterer of said pistons to calculate dome volume...
You also need your compressed head gasket thickness.
07-28-2006, 01:40 AM
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Re: explain to me what this means : piston dome cc vs. compression (DonF)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF »</TD></TR><TR><TD CLASS="quote">What is the piston to deck height? </TD></TR></TABLE>
uhh piston to deck is a good question i dont know what it is ill look at my sheet tomorrow and see
gasket thickness is .030 its a cometic.
uhh piston to deck is a good question i dont know what it is ill look at my sheet tomorrow and see
gasket thickness is .030 its a cometic.
07-28-2006, 11:31 AM
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Re: explain to me what this means : piston dome cc vs. compression (B18 CYA)
07-28-2006, 06:22 PM
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Re: explain to me what this means : piston dome cc vs. compression (ranta18)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 »</TD></TR><TR><TD CLASS="quote">http://www.c-speedracing.com/h...c.php
Enter in your custom values and its easy.</TD></TR></TABLE>
no, no its not. ive done it and other people have done it for me and have got anywhere from 12:1 to 13.8:1.
edit-- not with cspeed, with the other 1 that asks more stuff i think its zealworks?
Enter in your custom values and its easy.</TD></TR></TABLE>
no, no its not. ive done it and other people have done it for me and have got anywhere from 12:1 to 13.8:1.
edit-- not with cspeed, with the other 1 that asks more stuff i think its zealworks?
07-28-2006, 06:24 PM
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Re: explain to me what this means : piston dome cc vs. compression (B18 CYA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18 CYA »</TD></TR><TR><TD CLASS="quote"> zealworks?</TD></TR></TABLE>
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