Just got home from the All Chrysler in Carlisle. Drove the 68 Barracuda. 250 miles each way. My 340 10.5:1 compression has never knocked but I have always run 93 Octane in it. On the way home I stopped for a fill up and selected the highest octane. Just as I was squeezing the handle I noticed it was 92 Octane. I thought, what can 1 octane matter. I put 11 gals in a 18 gal tank. I drive about 2 miles and hit the on ramp. I stick my foot about 1/2 way into it and the ole 340 really rattles. The rest of the way home, everytime I try to give her a good load, I detect a ping. Had to lay off her the rest of the way. I don't think 1 octane could make that much difference. My guess is somebody selling 87 for the price of 92. Any opinions here???
can 1 octane make this much difference?
- Thread starter freshayr
- Start date
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7demon2
Registered User #1824
maybe....a gas station attendent once told me that the octane ratings are an average. he told me that they can be a point or 2 off sometimes. you might just be able to chaulk it up to cheap gas this time. maybe the 92 was not really 92 but 91 or 90? hard to say......
GoodysGotaCuda
Mr. Goody
I agree with the mentioned above. Sounds like you need to back off the timing or something a hair to accomidate for a little variation station to station. Out here are summer mix of regular gas (we only get up to 91 normally) seems to get pretty watered down, and mixed with 105* temps...it for some reason pings in my (9.7:1) and my buddys (10:1) 318's. Well instead of a detune we run 91/100 octane mixes and the issue goes away.
moper
Well-Known Member
Octane is a true rating, but the effects of storage and mixing can change it. If you are moving thru a certain area of the country, the fuel blend will change. Fuel in New York city is different blends from what I have in CT. We have the 10% ethanol fuel here, and that changes things too. You will be lean if your car was tuned on non ethanol mixed fuel, and then you run it. Add to that the possibility of the tanker filling the wrong octane tanks and mixing up octanes, and the extra water the ethanol fuels attract and hold..and it's no wonder you get some ping with unknown fuel.
GoodysGotaCuda
Mr. Goody
just remember, your probably on the edge with 10.5:1 anyway with 93, unless you are running aluminum heads. So you should, i guess, atleast stay with a similar brand of gas wherever you are to maybe keep this to a minimum...
cavemanmoron
Well-Known Member
I bet the gas got put in the wrong tank.
A local station near me has started selling Only 87 octane. ehh.
A local station near me has started selling Only 87 octane. ehh.
dusterdon
Well-Known Member
I remember a few years back that my 68 gtx would run better on Mobil 91.5 octane than Amoco 93. Go figure. Around here we can still get 94 octane Sunoco, or leaded 104 race gas at some stations if you can stand the price.
don
don
A360
Benton
Here in Australia we have 3 grades
I run 98 octane (10.5 360) as the normal fuel but we have 95 and 91 as alternatives.
87 octane what could run on that .
I have come down to the 95 octane at times depending what town I am in and it certainly affected the engine big time.
cheers
Benton
I run 98 octane (10.5 360) as the normal fuel but we have 95 and 91 as alternatives.
87 octane what could run on that .
I have come down to the 95 octane at times depending what town I am in and it certainly affected the engine big time.
cheers
Benton
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