What Octane
05-17-2002, 01:04 PM
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What Octane
I've always used 93 octane in my motors, but am wondering if I could get away with 89. Tthe fuel dock at the end of my creek only has 89, the nearest 93 is down the river a bit. Last time out one of the two places for 93 had broken pumps and I was REALLY low on fulel.
The motors are 454's with 9.8:1 static compression and the cams have 235/245 @.050 duration, Iron GM heads.
How much compression is anyone running against 89 octane?
-Greg
The motors are 454's with 9.8:1 static compression and the cams have 235/245 @.050 duration, Iron GM heads.
How much compression is anyone running against 89 octane?
-Greg
05-17-2002, 01:24 PM
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Hi Gary, glad your still around.
Forgot to mention that I do run a fair amount of advance, 35-36 degrees total all in by a little under 3000 RPM, and around 18-20 initial (I set the total and let the initial fall where it may). I've got the MSD's set to the shortest advance curve I could.
-Greg
Forgot to mention that I do run a fair amount of advance, 35-36 degrees total all in by a little under 3000 RPM, and around 18-20 initial (I set the total and let the initial fall where it may). I've got the MSD's set to the shortest advance curve I could.
-Greg
05-17-2002, 01:31 PM
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OK, 10:1 iron heads, and 36 degrees? Damn, I would stick with 93, cheap insurance.
I had to put 89 in my 525SCs once (late night fill up) and I was scared to push over 1lb boost. Bad thigs happen when you start to detonate.
Gary
I had to put 89 in my 525SCs once (late night fill up) and I was scared to push over 1lb boost. Bad thigs happen when you start to detonate.
Gary
05-17-2002, 10:57 PM
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Does anybody have a rule of thumb for degrees of retard for dropping from 92/3 to 89 or to 87 octane?
My MSD Digital boxes have a retard that can be wired to a switch. I was thinking of using it as a "cheap gas" retard but don't know where to start as far as degrees to retard.
Figured I would monitor it and see if it affected my cruise fuel economy. If not, I would intentionally use cheap gas on long (over a tankfull) cruising trips.
My MSD Digital boxes have a retard that can be wired to a switch. I was thinking of using it as a "cheap gas" retard but don't know where to start as far as degrees to retard.
Figured I would monitor it and see if it affected my cruise fuel economy. If not, I would intentionally use cheap gas on long (over a tankfull) cruising trips.
05-18-2002, 11:50 AM
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Guess I'll keep running the 93 (it really isn't much cost difference) and hope I don't need to use 89 to "get me home" anytime.
I'd hate to have to pump out 200+ gallons of fuel I can't use. It would take a LOOOONG time to burn that much waste fuel in the lawn mower
-Greg
I'd hate to have to pump out 200+ gallons of fuel I can't use. It would take a LOOOONG time to burn that much waste fuel in the lawn mower
-Greg
