I need help im totally ignorant to the subject of compresion ratios.....someone told me i should run 11:1 to hit mid 14s in my SOHC VTEC ( ofcourse with other work but anyways how do i change compression ratios what does it do how does it work infrom me please!!!!!!!!!!

 

well I know if compression in one cylinder is lower than all the rest something is wrong.

-Captain Obvious.

 

higher comp pistons....thinner head gasket...go to the search button and type in compression

 

simply put it's the ratio of difference between the volume of the cylinder with the piston at tdc and bdc.

 

11:1 ratio

think like this....take 11 gallons of air...and stuff it into a 1 gallon bottle

thats what compression does....makes more potential energy

 

for some n00b friendly explanations

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dan GSR &raquo;</TD></TR><TR><TD CLASS="quote">11:1 ratio

think like this....take 11 gallons of air...and stuff it into a 1 gallon bottle

thats what compression does....makes more potential energy</TD></TR></TABLE>

right. if you have 11 "gallons" of air and fuel inside your combustion chamber, it will obviously produce more horsepower than only 9 gallons.

 

Thanks guys . now how do i make it 11 instead of what it is stock.do i need to do any internal work like pistons and rods valve springs when i turn up the ratio!!!!!again thanks!!

 

you would need pistons to go up to 11.

 

https://honda-tech.com/zerothread?id=386525

This is what you have been asking for. I had this question several moths ago, I went and found it for you. It breaks it down completely and lets you know how comression works.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dan GSR &raquo;</TD></TR><TR><TD CLASS="quote">11:1 ratio

think like this....take 11 gallons of air...and stuff it into a 1 gallon bottle

thats what compression does....makes more potential energy</TD></TR></TABLE>

- I like how you put that. Good topic by the way.

 

since we are asking questions, how do you know what octane to run at what ratio?

EDIT: and what would you use to test the ratios?

 

i would run premium on anything over 10:1, and race gas on anything over 13:1

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris y0! &raquo;</TD></TR><TR><TD CLASS="quote">i would run premium on anything over 10:1, and race gas on anything over 13:1</TD></TR></TABLE>
yeah. i run 12:1 and im ok on 91. just be sure to tune it