je 12.5.1 compression pistons too high?
04-01-2007, 09:05 PM
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je 12.5.1 compression pistons too high?
got a gsr block with je 12.5.1 compression pistons with b16a head and planning to run blox b cams (toda valve springs or crower). Motor is out of the car, but i'm planning to get it cleaned before installing. I wanted to know if this compression would be too much for DD. Drive about 40 miles a day. Goal is to have a reliable DD, but can still make over 200whp.
04-02-2007, 06:31 AM
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Re: je 12.5.1 compression pistons too high? (slo blue)
I wouldn't run that high compression on a daily driver. Yes, a "good tuner" could probably have you run 93 or 94 octane on the street, but for what?
You don't need sky high compression to make 200whp......
You don't need sky high compression to make 200whp......
04-02-2007, 08:14 AM
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Re: je 12.5.1 compression pistons too high? (alterdcreations)
the motor i got came with those je 12.5 pistons. I know they are high. I just wanted to know if there are too high for the 93 oct and DD. A lot of DD. Should i use a cometic head gasket to lower the compression a bit to about 12.1 or so?
04-02-2007, 08:24 AM
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Re: je 12.5.1 compression pistons too high? (realis9)
should i get a cometic thicker HG to lower compression a bit or change the pistons ( really don't want to do it) or stay with them?
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04-02-2007, 08:30 AM
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First of all before you get excited about finding out if your compression ratio is safe, I suggest you find out what it actually is.
12.5-1 pistons rarley equal exactly that compression ratio. Do you know if they were listed at that comp ratio for a gsr head or b16, 89mm stroke or 87.2, **** maybe even an ls head ? You just never know what you actually have.
You need to know the specs of your pistons. comp height and dome. Measure ptd height and cc your combustion chamber before you go any further in finding out if your comp ratio is safe.
You may be very suprised as to what compression ratio you will actually end up with.
If your compression ratio does come out to 12-1+ I'd use a slightly thicker headgasket to get down to around 11.8ish-1.
12.5-1 pistons rarley equal exactly that compression ratio. Do you know if they were listed at that comp ratio for a gsr head or b16, 89mm stroke or 87.2, **** maybe even an ls head ? You just never know what you actually have.
You need to know the specs of your pistons. comp height and dome. Measure ptd height and cc your combustion chamber before you go any further in finding out if your comp ratio is safe.
You may be very suprised as to what compression ratio you will actually end up with.
If your compression ratio does come out to 12-1+ I'd use a slightly thicker headgasket to get down to around 11.8ish-1.
04-02-2007, 08:39 AM
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Re: (LG_R32)
i would find out what your compression ratio is.... but i run 12.5:1+ compression daily and have had no problems with detonation with 93 oct... its all in the tuning
04-02-2007, 10:34 AM
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Use the compression ratio calculator on the KB silvolite website feeding it all your info from cam specs to rod length and stroke. Actually CC your heads and go from there.
I personally run a 13.3:1 compression ratio on the street with 93 and no problems because I have enough cam to bleed off the compression dropping dynamic down to low 11's. It doesn't have a lot of timing below 4500 rpm's but pulls like a raped ape up top and I have no problems driving around lugging the motor at 1500 rpms in 5th.
I personally run a 13.3:1 compression ratio on the street with 93 and no problems because I have enough cam to bleed off the compression dropping dynamic down to low 11's. It doesn't have a lot of timing below 4500 rpm's but pulls like a raped ape up top and I have no problems driving around lugging the motor at 1500 rpms in 5th.
04-02-2007, 10:56 AM
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Re: je 12.5.1 compression pistons too high? (realis9)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realis9 »</TD></TR><TR><TD CLASS="quote">anyone ever ran this high compression on a DD?</TD></TR></TABLE>
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04-02-2007, 11:00 AM
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Re: (Jay_Sensing)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jay_Sensing »</TD></TR><TR><TD CLASS="quote">
I personally run a 13.3:1 compression ratio on the street with 93 and no problems </TD></TR></TABLE>
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.
I personally run a 13.3:1 compression ratio on the street with 93 and no problems </TD></TR></TABLE>
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.
04-02-2007, 12:13 PM
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Re: (realis9)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by goforbroke »</TD></TR><TR><TD CLASS="quote">
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>
because we choose to
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>
because we choose to
04-02-2007, 12:15 PM
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Re: (alterdcreations)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by alterdcreations »</TD></TR><TR><TD CLASS="quote">
because we choose to</TD></TR></TABLE>
great answer.....
because we choose to</TD></TR></TABLE>
great answer.....
04-02-2007, 12:44 PM
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Re: (realis9)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realis9 »</TD></TR><TR><TD CLASS="quote">would pics of the pistons in the block help anything?</TD></TR></TABLE>
No. If you can'y meausure and check the things I had mentioned you should take it to a shop and have it done.
The dome specs will be available from je but your head needs to be cc'ed and piston to deck height measured IMO.
No. If you can'y meausure and check the things I had mentioned you should take it to a shop and have it done.
The dome specs will be available from je but your head needs to be cc'ed and piston to deck height measured IMO.
04-02-2007, 01:50 PM
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Re: (LG_R32)
STATIC compression is NOT some magical # that will tell u if ur car will run good on pump gas, its just a ratio of volume at TDC vs. BDC. Its only helpful to look at static compression with cam choice, cause that is what makes dynamic compression
04-02-2007, 02:00 PM
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Re: (goforbroke)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by goforbroke »</TD></TR><TR><TD CLASS="quote">
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>
well u cant run 13.1 compression with stock B16 cams and expect it to run ok without pullin a tard-load of timing(pump gas). only with bigger cams comes the higher CR pistons
think about a bigger cam with more overlap. That means loss of pressure in the cylinder (common sense) so u can run more STATIC compression to get u back to the same dynamic compression.
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>well u cant run 13.1 compression with stock B16 cams and expect it to run ok without pullin a tard-load of timing(pump gas). only with bigger cams comes the higher CR pistons
think about a bigger cam with more overlap. That means loss of pressure in the cylinder (common sense) so u can run more STATIC compression to get u back to the same dynamic compression.
04-02-2007, 02:06 PM
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Re: (goforbroke)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by goforbroke »</TD></TR><TR><TD CLASS="quote">
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>
well im running pct's in a c5 block with a b16 head, neither head nor block has been cut or decked and my car is great on 93, i mean if you have to run 93 with a gsr motor why not up the compression
granted 12:1 would be ideal for the street but i got a deal on the block i couldnt refuse
just wait till everyone has e85 and runs 14:1 compression on a daily driven motor lol 
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>well im running pct's in a c5 block with a b16 head, neither head nor block has been cut or decked and my car is great on 93, i mean if you have to run 93 with a gsr motor why not up the compression
granted 12:1 would be ideal for the street but i got a deal on the block i couldnt refuse
just wait till everyone has e85 and runs 14:1 compression on a daily driven motor lol
04-02-2007, 02:11 PM
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Re: (goforbroke)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by goforbroke »</TD></TR><TR><TD CLASS="quote">
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>
For the 10 reasons listed below. You guys are gettign rediculously wrapped around the axle over static compression. The more compression you run, the more cam you can run meaning the more power you can make. You can't put a healthy set of cams in a 10:1 motor because it's going to bleed off so much of that dynamically it's going to kill the motor and it would have made more power on stock cams.
I do it because I don't chose to follow the path of the ever cynical "I know more than you because I learned everything there is to know on Honda-Tech" guys.
I never claim to know everything but I have been building hot rods a long time and have gotten away with higher on a well built V8 and pump gas using a lot of cam and nothing more than a Digital 6 to control timing. Car made good power and was a blast to drive.
That a good enough answer for you?
In short, becuase if you know what your doing and have access to a badass tuner, it works and works well.
For what? I'm still trying to figure why people run super high compression on their dailyl driver. Someone please explain this to me............ANYONE.</TD></TR></TABLE>For the 10 reasons listed below. You guys are gettign rediculously wrapped around the axle over static compression. The more compression you run, the more cam you can run meaning the more power you can make. You can't put a healthy set of cams in a 10:1 motor because it's going to bleed off so much of that dynamically it's going to kill the motor and it would have made more power on stock cams.
I do it because I don't chose to follow the path of the ever cynical "I know more than you because I learned everything there is to know on Honda-Tech" guys.
I never claim to know everything but I have been building hot rods a long time and have gotten away with higher on a well built V8 and pump gas using a lot of cam and nothing more than a Digital 6 to control timing. Car made good power and was a blast to drive.
That a good enough answer for you?
In short, becuase if you know what your doing and have access to a badass tuner, it works and works well.
04-02-2007, 03:32 PM
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Re: (goforbroke)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realis9 »</TD></TR><TR><TD CLASS="quote">So thicker HG and high duration cams and good tune and i'll be safe on 93 pump gas? </TD></TR></TABLE>
with the box cams you should be good with the stock head gasket but lowering the compression will not hurt you too much in power and make it safer for you if you get a bad tank of gas.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jay_Sensing »</TD></TR><TR><TD CLASS="quote">For the 10 reasons listed below. You guys are gettign rediculously wrapped around the axle over static compression. The more compression you run, the more cam you can run meaning the more power you can make. </TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jay_Sensing »</TD></TR><TR><TD CLASS="quote">In short, becuase if you know what your doing and have access to a badass tuner, it works and works well. </TD></TR></TABLE>
with the box cams you should be good with the stock head gasket but lowering the compression will not hurt you too much in power and make it safer for you if you get a bad tank of gas.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jay_Sensing »</TD></TR><TR><TD CLASS="quote">For the 10 reasons listed below. You guys are gettign rediculously wrapped around the axle over static compression. The more compression you run, the more cam you can run meaning the more power you can make. </TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jay_Sensing »</TD></TR><TR><TD CLASS="quote">In short, becuase if you know what your doing and have access to a badass tuner, it works and works well. </TD></TR></TABLE>