info on effects of compression ratio

[grumpyvette]

http://www.popularhotrodding.com/tech/0311_phr_power_squeeze/

 

http://www.empirenet.com/pkelley2/DynamicCR.html

 

http://victorylibrary.com/mopar/cam-tech.htm

 

http://victorylibrary.com/mopar/otto.htm

 

http://victorylibrary.com/mopar/deck-height.htm

 

http://www.csgnetwork.com/compcalc.html

 

http://naca.larc.nasa.gov/reports/1925/naca-report-205/

 

http://www.e30m3performance.com/myths/more_myths1/comp_ratio/comp_ratio.htm

 

http://www.ecen.com/content/eee7/motoref.htm

 

http://www.hotrod.com/tipstricks/34219/index5.html

 

http://naca.larc.nasa.gov/reports/1926/naca-report-232/

[Kevin Shasteen]

good links grumpy.

 

FYI: For all who are reading these links you need to realize that many a time, as in the case of the next to last link that Grumpy posted: the next to last "Hot Rod" link, an author will confuse the term "Dynamic Compression" with the term "Dynamic Compression Ratio". The two terms are mutually exclusive: they are related but they are not identifying the same fundamentals.

 

Compression can be synonymous with Cylinder Pressure therefore Dynamic Compression is a reference to the usable Cylinder Pressure after the Intake Valve Closing (IVC) and is measured with a pressure gauage; whereas, the term Dynamic Compression Ratio is not a psi...it is a ratio. You can measure the psi output on a Pressure Gauge but you can not measure a Ratio on a guage.

 

The Dynamic or Static Compression Ratio is indicative of a mathematical relationship between one measurement of volume to the second measurement of volume: in the case of a Compression Ratio this measured relationship is between the "Cylinder Volume + Total Combustion Chamber" and the "Total Combustion Chamber". This relationship is expressed in the compression ratio formula:

 

(Cyl. Volume + Total Chamber Vol) / Total Chamber Vol = SCR

 

while the formula for calculating the DCR is:

 

(Cyl. Vol after IVC + Total Chamb Vol) / Total Chamb Vol = DCR

 

I see the magazines confusing this vernacular all the time: there is a difference...a pressure is not a ratio and a ratio is not a pressure. Combine the two in the correct equation and you can calculate Cylinder Pressures but the two terms are not one in the same.

 

Kevin,

(Yea,Still an Inliner)