BANSH-alena-jol-EE Posted February 20, 2009 Report Share Posted February 20, 2009 hello, i have been running my shee on 87 octane for a while, just switched to 91 octane gas, is this ok for a stock engine? Quote Link to comment Share on other sites More sharing options...
drap660 Posted February 20, 2009 Report Share Posted February 20, 2009 Yes that is fine. You should run between 89-93 octane. 87 is a bit low, 91 is fine Quote Link to comment Share on other sites More sharing options...
TwistedSheeRida Posted February 20, 2009 Report Share Posted February 20, 2009 i wouldn't run anything lower than 91 especially with the shitty fuel nowadays. the store by me still sells 93 Quote Link to comment Share on other sites More sharing options...
deckheight Posted February 21, 2009 Report Share Posted February 21, 2009 Depends on what year it is... You can run 84 octane in a stock 87. Most other years, as you already know, run just fine on 87 octane in stock form. 91 octane is good for all years and puts you way off the detonation zone. Rule of thumb is don't run higher octane fuel than is needed though. Quote Link to comment Share on other sites More sharing options...
spurdy Posted February 21, 2009 Report Share Posted February 21, 2009 Depends on what year it is... You can run 84 octane in a stock 87. Most other years, as you already know, run just fine on 87 octane in stock form. 91 octane is good for all years and puts you way off the detonation zone. Rule of thumb is don't run higher octane fuel than is needed though. What is the difference in the 87 model that allows you to run such a lower octane level that is not acceptable for most other years? Or did I misunderstand your post? As I understand all the motors are the same with some slightly different tranny gear ratios throughout the years. SP Quote Link to comment Share on other sites More sharing options...
deckheight Posted February 22, 2009 Report Share Posted February 22, 2009 Cylinder deck heights and piston dome volumes are all the same, but very early shees came stock with larger combustion chamber trapped volumes. All of the 87 shees that I am aware of came with 24.2cc OEM head domes. Add another .8cc for head gasket volume = 25cc total (84 octane). Most everything else came with apx. 22.4cc head domes plus gasket volume for 23.2cc total (87 octane). The above octane estimates assume relatively fresh fuel... What is the difference in the 87 model that allows you to run such a lower octane level that is not acceptable for most other years? Or did I misunderstand your post? As I understand all the motors are the same with some slightly different tranny gear ratios throughout the years. SP Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.