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Discussion Starter · #1 ·
Anyone know of a benefit in running Hi-test 93 octane in a stock 1987 305c.i. with headers? Was there a fuel octane requirement back in the late 80's? Any experience with recent fuel mix experimenting, pls. let me know. - Thanks, George :???:
 

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Discussion Starter · #3 ·
Carl, So,.. stop wasting my money and simply use regular ? Cause' it's a bargain rate of $3.75/gallon (so far,.::)! :yell:
 

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look i tune every motor i build to run regular.a stock 305 is 8.5 to 9.5 to 1 no need what so ever for premium. i live in idaho and they have the e 85 here and all of my cars run on it with the exception of my 94 caprice it needs at least 87. so yes stop useing 93.if your car is tuned correctly it needs no more than 87
 

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As others have stated, there's no advantage to running a higher octane fuel than is necessary. Of course you can always advance the initial timing and realize a slight performance increase if you're doing a regular diet of high octane.
On a related note, for those who put their Caminos in hibernation for the winter, do your final fill of the year with high-octane fuel. When developing the Volt electric car, Chevrolet engineers had to take into account that the backup gasoline generator might never get used, so their testing revealed that 91 octane fuel had a minimum shelf life of 12 months. That's the sole reason for the minimum 91 octane specification.

Bill
 

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As others have stated, there's no advantage to running a higher octane fuel than is necessary. Of course you can always advance the initial timing and realize a slight performance increase if you're doing a regular diet of high octane.
On a related note, for those who put their Caminos in hibernation for the winter, do your final fill of the year with high-octane fuel. When developing the Volt electric car, Chevrolet engineers had to take into account that the backup gasoline generator might never get used, so their testing revealed that 91 octane fuel had a minimum shelf life of 12 months. That's the sole reason for the minimum 91 octane specification.

Bill
How does octane rating affect shelf life?
 

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I only run prem. in my all stock 1987 305 Elky. Using prem, I get 22-24 mpg. Using reg, I get 17 mpg. Both are hiway driving. I fillup 3 times per week and only use prem. After 300,000 miles i've tried all combinations of fuels and straight prem works the best. When i [ill the plugs the are all clean and pruty. So, I will continue using prem. until something better comes along.
 

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How does octane rating affect shelf life?
Personally, I don't know.
At a recent GM training seminar, I asked why the same engine that usually runs 87 octane when used to propel a vehicle now requires 91 octane when used as a generator in the Volt. The reply was that with today's fuels, 91 octane was determined to have a longer storage life before deterioration. The Volt generator is programmed to fire up and burn off the existing fuel if no new fuel has been added in a 12 month period.
I don't claim to know anything about the chemistry of fuel. But GM is normally very consistent in their policy of designing all engines, except for a few high-performance versions, to be happy with 87 octane.
If the exception was made on the Volt purely because of long-term storage, that's enough evidence for me. Until I have any reliable evidence to the contrary, my baby's getting a load of high test before it's tucked away for the winter.

Bill
 

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I cant answer that but I do know my El Caminos 305 definitly likes 89 better than 87. It runs better and gets 2-3 better mpg. Definitly worth the extra 3-5 cents a gallon lol.

The only reason Id put premium in my El Camino is because we have a station around here that sells 92 octane without ethanol. Never tried it, but I have debated doin it
 

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Here in God's country, there are labels on the pumps stating that "This fuel is produced with less than 10% ethanol". The local lawn mower repair shop test the fuels from each gas station so he can recommend a place where his customers can get the best fuel. I have been using the same recommemded station for 15 yrs now. Their prem. is always 2 1/2% ethanol. And its the lowest price in town. This morning it was 3.59.. Of course i filled up.:texas:
 

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My elky was bought new by my father. I've been familiar with it since age 15. It's a 305/ 200c combo with 2.41 rear gears. Since new Dad complained to the dealer about how quickly the converter would lock and how hesitant it was to unlock--to the point that at 25-40 mph it would engage and the engine would lug and spark knock. Running 93 helps stop the knock but also seems to lessen the effect of the engagement. Been that way since new (dealer couldn't change it), is still that way 131,000 miles later. I know the compression doesn't justify premium, and people always 'feel' more power with it, but this vehicle has done this consistently for over 25 years and several dealer trips ( both for the issue and regular tune up) haven't changed it. Patrick.
 

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Mike, and this gas is?????????????
Sorry, Exxon.. the gas station in downtown Sealy is a SpeedyStop franchise. There are a number of them around this area. the one in Sealy is the only one I know for sure has good gas. They have their own fuel delivery trucks so I assume all the stations get the same gas from the same refinery.
 

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Absolutely no benefit at all. Save your money.
 

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If you do a search and read about gas you'll find that running a higher octane than the engine requires may have some bad side effects.

The higher the octane, the slower the gas burns. E85 burns VERY slowly compared to gas.

When you use too high an octane, since the gas burns slower, not all of the gas gets burned. Some goes out the tail pipe, and some causes carbon build up on the pistons and valves. Then you're not only wasting money, you're slowly hurting your engine.

If the engine doesn't ping on 87 octane, you don't need a higher grade. Same logic for 89, 91, etc.

Jack
 

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absolutely correct ,save your money,especially with todays prices.not like when i was a kid .27 cents a gallon for full service chevron prem.
 
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