what is the highest compression a b-series can run on 93 octane gasoline without detonation/knock? Is 12.1:1c/r and 93 octane acceptable(daily driver)? Everything I read about this compression ratio (B16a/w.PCT's) is missleading to me. Opinions vary from 10.8:1 all through 12:1. Im confused about a precise c/r.

Thanks

 

The B16A2 with PCTs , OEM head gasket and mild head = aprox 11.8:1 CR

A friend of mine is running that setup over a year now on 93, no problems at all.
I will be running 12.1-3:1 on my daily driven HB on 93 as well

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xtrada ver1.6 &raquo;</TD></TR><TR><TD CLASS="quote">what is the highest compression a b-series can run on 93 octane gasoline without detonation/knock? Is 12.1:1c/r and 93 octane acceptable(daily driver)? Everything I read about this compression ratio (B16a/w.PCT's) is missleading to me. Opinions vary from 10.8:1 all through 12:1. Im confused about a precise c/r.

Thanks</TD></TR></TABLE>

You should be fine on 12:1 with a good tune and some cams

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jolly &raquo;</TD></TR><TR><TD CLASS="quote">The B16A2 with PCTs , OEM head gasket and mild head = aprox 11.8:1 CR</TD></TR></TABLE>

11.91:1

 

i think people get confused with high compression and making power. whats the point of having super high compression and not being able to get the full amount of power out of it, when someone running lower compression has more power with a good tune a more reliabilty. you just have to find that line where too much compression starts to hurt you on the street

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crawlin &raquo;</TD></TR><TR><TD CLASS="quote">i think people get confused with high compression and making power. whats the point of having super high compression and not being able to get the full amount of power out of it, when someone running lower compression has more power with a good tune a more reliabilty. you just have to find that line where too much compression starts to hurt you on the street</TD></TR></TABLE>Exactly--I have a bunch of domestic mags where they see if they can run 12:1 to 12.5:1 builds with large cams on 91 octane. They CAN run them on the street--for street type driving if its not too hot out--but for any kind of performance if they want to push the car they always use 100 to 105. Alot of times you can get away with pump gas with alot of compression, but that doesn't mean its better than a bit less compression--where you are able to run full timing and good AFRs. Its pointless to have over 12:1 using 91 to 93 octane. You can get away with it by retarding the timing, but at that point you would have been better off staying 11-11.3:1.

 

i have a mild built b20vtec runnin 12.5:1 c/r daily drivin 93 octane shes runnin fine

 

its not that the car wont run fine its the point are you getting the most power out of your setup

 

yeah i have to agree in saying its better to have 11 ish CR and run full timing...

 

http://www.sportcompactcarweb....e_car/
CTR cams,CTR pistons.what octane,im curious(wondering)?

Thanks


Modified by xtrada ver1.6 at 11:08 PM 12/3/2006

 

thats a race car, porbably running real aggressive timing and 100 octane...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xtrada ver1.6 &raquo;</TD></TR><TR><TD CLASS="quote">what is the highest compression a b-series can run on 93 octane gasoline without detonation/knock? Is 12.1:1c/r and 93 octane acceptable(daily driver)? Everything I read about this compression ratio (B16a/w.PCT's) is missleading to me. Opinions vary from 10.8:1 all through 12:1. Im confused about a precise c/r.

Thanks</TD></TR></TABLE>

In all honesty it all depends on your dynamic compression ratio, rather than merely the static "magic" number everyone keeps asking about.

With different camshafts that allow for different amounts of overlap you'll will have the capacity for bleeding off static compression bringing your dynamic compression to a much more streetable level. Also, something to remember is that every motor is machined to an acceptable tolerance. So within that range motors will vary minorly.

So to answer your question I suppose we need more details. For example what cams you plan to use, head mods, deck height, etc.

An excellent example would be a 13:1 setup with a Buddyclub stage V that runs on pump gas. BC5's bleed off up to 45psi.

There is no one-size-fits-all when it comes to piston selection.

 

True.
Cams:s2s1,
stock ports,
stock deck height,
along with mentioned.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xtrada ver1.6 &raquo;</TD></TR><TR><TD CLASS="quote">what is the highest compression a b-series can run on 93 octane gasoline without detonation/knock? Is 12.1:1c/r and 93 octane acceptable(daily driver)? Everything I read about this compression ratio (B16a/w.PCT's) is missleading to me. Opinions vary from 10.8:1 all through 12:1. Im confused about a precise c/r.

Thanks</TD></TR></TABLE>

i have a ls/v with pct's on ls rods....head milled(dont know how much but combustion chamber is now 42.00cc on a b16 head), block milled and cometic 3 layer headgasket...12.4:1 on 93 octane wth hondata S200

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by groundzerocivic &raquo;</TD></TR><TR><TD CLASS="quote">i have a ls/v with pct's on ls rods....head milled(dont know how much but combustion chamber is now 42.00cc on a b16 head), block milled and cometic 3 layer headgasket...12.4:1 on 93 octane wth hondata S200</TD></TR></TABLE>

what do your timing maps look like?

 

not to thread jack but i have a b16a with probe high dome pistons that are 7.1 which is a bit bigger than pcts, and a stock gsr head (which should raise compression?)with a comedic head gasket and ive used the compression calculator but not so sure its very accurate so would any one know an aprox. number for my CR(static)?

Again: b16a+probe high dome pistons(81mm)+stock gsr head & cams= ?CR?

thanks for any input

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allnaturalb16 &raquo;</TD></TR><TR><TD CLASS="quote">1. not to thread jack but i have a b16a with probe high dome pistons that are 7.1 which is a bit bigger than pcts, and a stock gsr head (which should raise compression?)with a 2. comedic head gasket and ive used the compression calculator but not so sure its very accurate so would any one know an aprox. number for my CR(static)?

Again: b16a+probe high dome pistons(81mm)+stock gsr head & cams= ?CR?

thanks for any input</TD></TR></TABLE>

1. yea, you did.

2. how funny is your headgasket?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xDEFTONESx &raquo;</TD></TR><TR><TD CLASS="quote">

1. yea, you did.

2. how funny is your headgasket?</TD></TR></TABLE>

1. ok so what just a quick question......

2. and my cometic head gasket is hilarious....

3. thanks for the knowledge homie

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by that one doood &raquo;</TD></TR><TR><TD CLASS="quote">

what do your timing maps look like?</TD></TR></TABLE>


dont really know...wasnt able to be there when the car was tuned...i was at werk