Picking gas for High comp.
Picking gas for High comp. How do I pick a gas for a high compression motor? I have been to numerous gas websites and they each have a lot of information about octane and what type of compression they feel their gas should be used with but I don't know weather that is static or dynamic compression.
Is there a way to estimate dynamic compression without knowing ramp angles on the cam and degree the intake valve opens?
Is there a way to estimate dynamic compression without knowing ramp angles on the cam and degree the intake valve opens?
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
You need to know the intake valve closing, That's the only info you need about the cam to calculate DCR. I have 8.9 DCR, that needs at least 50% 100 octane race fuel and 25 degrees of timing max to keep it from knocking.
When in doubt, run better fuel then needed, and always start with a colder plug then you think you will end up needing. Better to start on the way safe side, then go to hot a plug or too little octane and hurt it right off the bat.
What does the setup consist of, might help get a reccommendation. Also, what kind of race fuel do you have available?
What does the setup consist of, might help get a reccommendation. Also, what kind of race fuel do you have available?
I have spoken with a bunch of people and I guess I'll take the advice given here and run on the high side of what I think I need. The engine builder said 110 and the tuner said VP C12 specifically. The SCR is between 14.6 and 14.8 depending on which calculator you use. My quench should be pretty tight as I am using a stock GM MLS gasket so bet I could get away with 110 but I can get C12 pretty easy so I guess I'll go ahead and use it.
Thanks
Thanks
