compression ratio
You are not currently logged in. Login to myAccount   Forgot Your Login?   SignUp For a Free Account
 
Buy TShirts & DVDs!-Sell Your StreetRod FAST!-Help-Contact Us
Quick Search:
compression ratio
Posted: September 17 2005 12:09 AM
 
Jan Schneider (aka storm) [ View ] [ Email ] [ Car Ads ] [ Blogs ]
Lafayette, New Jersey
 
I need some help on determining compression ratio. I have a 454 passenger high performance big block bored 60 over with trw L2377 flat top pistons. Heads are open chamber #336871 which according to Mortec are 118cc chambers. I need to determine an approximate compression ratio so I know what gas to use. I think with this combination it should be about 9:1 but I am not sure. Any help would be appreciated.
 
 
Comments
 
Posted by FastCo44  -  09/16/2005 12:16 PM

To determine the compression ratio you use the following formula:



Vcc+C/C = CR



C = Chamber Volume in cubic centimeters (cc)



Vcc = Swept Volume (Area of the Bore X Stroke). Convert the bore diameter and the stroke length into millimeters (mm) and use the following formula:



Vcc = pi D2 x L / 4 then divide that answer by 1,000. pi = 3.142, D = bore diameter in mm (this number is squared), and L = the lenght of the stroke th mm.



To the Vcc answer add 6 mm for the head gasket.



If you post the bore diameter and stroke (measurements in inches is OK), I will do the math and post the result.
FastCo44 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Sunnyvale, California
 
Posted by orphans2  -  09/17/2005 12:09 AM
Mine loves the premium flavor, the higher octane the better. Sometimes I think I might be a little nuts, but mine seems to perform better on 94 octane then it does on 93. Doesn't make a lot of sense but it does seem to. Wish they'd bring back Amoco's 104.
orphans2 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Stewartstown, Pennsylvannia Charter Member since November 2001
 
Posted by storm  -  09/16/2005 08:17 PM
Thanks for all the responses. The ratio works out to 8.9:1. Should be good to go on regular gas.
storm [ View ] [ Email ] [ Blogs ] [ Car Ads ] Lafayette, New Jersey
 
Posted by Crazyhorse Rod Shop  -  09/16/2005 10:07 AM
as long as your under 10:1 you will be ok with 87 octane. theres a formula but my old brain aint trustworthy enough to remember. i'll see if i can find it.
dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003
 
Posted by Rods & Customs by Leon  -  09/16/2005 11:14 PM
premium will still burn better.........Less octane only helps when it come to the computer tuned engines, In my vett, it runs better with the higher octane, but then the check engine light comes on, On the mid-grade it runs fine and the light don`t come on, I would say on a 8:9.1 that you can run what you want but it will dictate the performance, run the premium when you have the extra change to spare but for just crusin, don`t waste the money
Rods & Customs by Leon [ View ] [ Email ] [ Blogs ] [ Car Ads ] Highlands, Texas Charter Member since May 2004
 
Posted by JAWS  -  09/16/2005 06:22 PM

Here's a link to a compression calculator



http://www.classictruckshop.com/garage/shopmathengine1.asp
An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004
 
Posted by orphans2  -  09/16/2005 11:35 AM

Just buy premium, it works every time. And you will be helping out our economy and the long suffering petroleum industry. Or you can use the old method of just filling up with regular and wait to hear the pinging. If no pings,stay with the regular, otherwise see the first sentence of this little diatribe.



I kind of envy you people who can run regular.
orphans2 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Stewartstown, Pennsylvannia Charter Member since November 2001
 
Back To Top
Please Login or Register to Comment
Existing Member? Sign In.
New Visitor? Click Here to Get Started!
 
Existing Member but forgot your Login Information? Click Here.