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High Octane Gas


69dejavue

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We can buy 93 octane gas in the midwest and much of the south but out west the gas is usually limited, regardless of brand, to 91. Is anyone aware of gas stations that sell higher octane in the Phoenix AZ area? Even the Shell, and Chevrons are only 91. The dividing line appears to be somewhere in mid Texas. East of that is 93, West of that is 91 all the way, and including, California.

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It must be a regional thing. About 15 years ago all we could get here in Tennessee was 91 but states to the North had as high as 94. Now the 93 is pretty much the standard unless you find E-85 fuel which is 105 octane but I don't think our cars can run it without modifications. Anyone know?

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We can buy 93 octane gas in the midwest and much of the south but out west the gas is usually limited, regardless of brand, to 91. Is anyone aware of gas stations that sell higher octane in the Phoenix AZ area? Even the Shell, and Chevrons are only 91. The dividing line appears to be somewhere in mid Texas. East of that is 93, West of that is 91 all the way, and including, California.

 

 

 

I live in Yuma, AZ and the highest Octane we can get here is 91, unless we go to the Loves Truck Stop where they sell 105 and 110 Octane Race Fuel. The 105 Octane was $5.83 a galllon last month, I haven't checked the price recently.

 

I ran half a tank of 91 and half tank of 105, didn't really notice a difference.

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I live in Yuma, AZ and the highest Octane we can get here is 91, unless we go to the Loves Truck Stop where they sell 105 and 110 Octane Race Fuel. The 105 Octane was $5.83 a galllon last month, I haven't checked the price recently.

 

I ran half a tank of 91 and half tank of 105, didn't really notice a difference.

 

I filled my Z71 with the 105 octane E-85 fuel a few weeks ago and didn't notice much difference on the first partial tank but the second full tank brought the truck to life. I didn't know a chebby could run so good.

I think you need at least one full tank to see any big difference. Just be careful what you buy. Most race fuels are leaded and will screw up catalytic converters. Also E-85 can only be run in vehicles designed or converted for it.

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You guys are all joking aren't you? Once the car is 'tuned' for a specific octane level that is it...put in higher octane and 'so what' -doesn't do a <bleep> thing. Your mind might tell you--I put in fancy high octane stuff - I have more power but that extra power you feel just exists in the fantasies of your mind. Higher octane fuel doesn't have more 'power'...the additives that get the higher octane are there to delay ignition--your actually getting less 'explosiveness' from the gas...this allows you you adjust your timing (aka a tune) etc...for a longer power burn and to avoid detonation (boom--very bad) in high compression engines...but unless you rebuild the internals to change compression etc...your limited to just changing timing and thus some power gains there...but with a factory tune set for 91...running 93/95 etc does NOTHING except in the reaches of your mind.... Exception--an old high mileage engine may have carbon build up on the cylinder tops and thus the compression ratio of that engine has 'grown' over time (like a wasit line) thus a higher octane gas might be needed to avoid premature detonation...

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There are advantages to the higher octane. Higher octane, contrary to your statement, is not less explosive. It merely means that the air fuel mixture will not detonate prematurely but rather only when the spark is fired, not before.

 

In addition, the vehicle calls for 91+, note the Plus sign.

 

In addition, gasoline, as most other quantities, has a plus or minus factor. You may be getting 90 or 92 octane due the potential for slightly higher or lower. The 93 octane adds that insurance factor.

 

A lower octane will detonate at a lower temperature. If you lived in AZ where it routinely hits 115+ in the summer time you would realize that the engines run hotter, especially with air condtiioning running constantly and the stop and go of rush hour traffic. Higher temperatures can cause a lower octane fuel to detonate prematurely. When an engine is very hot the air fuel mixture can Ping or even diesel due to the fuel air mixture being compressed and igniting due to heat and compression rather than spark.

 

Most engines will de-tune themselves with the computer if a knock or ping is detected so their is less chance of damage today. But the higher octane will allow the engine and the timing to be used to its full potential.

 

With this information I will ask again if anyone is aware of a Sunoco station with 94 octane or any other stations in the Pheonix area that sells 93 octane or higher (excluding E-85).

 

We don't need people to attack those that are merely asking for information re higher octane.

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You guys are all joking aren't you? Once the car is 'tuned' for a specific octane level that is it...put in higher octane and 'so what' -doesn't do a <bleep> thing.

Gently, Retro. ;) No, we are not joking. We are posing questions to each other because that is what we do here. When we want to know something outside our personal knowledge, we pose a question with the expectation that the responses will be helpful further the overall knowledge of Forum members. Usually it works out that way. Jim

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Gently, Retro. ;) No, we are not joking. We are posing questions to each other because that is what we do here. When we want to know something outside our personal knowledge, we pose a question with the expectation that the responses will be helpful further the overall knowledge of Forum members. Usually it works out that way. Jim

 

Jim, what are you going to do about the tune after the supercharger? One of the superchargers is tuned for 91 and the other 93. Which did you buy? If it is set for 93 what are you going to do?

 

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IMHO...

 

You guys are all joking aren't you? Once the car is 'tuned' for a specific octane level that is it...put in higher octane and 'so what' -doesn't do a <bleep> thing. Your mind might tell you--I put in fancy high octane stuff - I have more power but that extra power you feel just exists in the fantasies of your mind. Higher octane fuel doesn't have more 'power'...the additives that get the higher octane are there to delay ignition--your actually getting less 'explosiveness' from the gas...this allows you you adjust your timing (aka a tune) etc...for a longer power burn and to avoid detonation (boom--very bad) in high compression engines...but unless you rebuild the internals to change compression etc...your limited to just changing timing and thus some power gains there...but with a factory tune set for 91...running 93/95 etc does NOTHING except in the reaches of your mind.... Exception--an old high mileage engine may have carbon build up on the cylinder tops and thus the compression ratio of that engine has 'grown' over time (like a wasit line) thus a higher octane gas might be needed to avoid premature detonation...

 

Ummm...You're correct.

 

There are advantages to the higher octane. Higher octane, contrary to your statement, is not less explosive. It merely means that the air fuel mixture will not detonate prematurely but rather only when the spark is fired, not before.

 

In addition, the vehicle calls for 91+, note the Plus sign.

 

In addition, gasoline, as most other quantities, has a plus or minus factor. You may be getting 90 or 92 octane due the potential for slightly higher or lower. The 93 octane adds that insurance factor.

 

A lower octane will detonate at a lower temperature. If you lived in AZ where it routinely hits 115+ in the summer time you would realize that the engines run hotter, especially with air condtiioning running constantly and the stop and go of rush hour traffic. Higher temperatures can cause a lower octane fuel to detonate prematurely. When an engine is very hot the air fuel mixture can Ping or even diesel due to the fuel air mixture being compressed and igniting due to heat and compression rather than spark.

 

Most engines will de-tune themselves with the computer if a knock or ping is detected so their is less chance of damage today. But the higher octane will allow the engine and the timing to be used to its full potential.

 

With this information I will ask again if anyone is aware of a Sunoco station with 94 octane or any other stations in the Pheonix area that sells 93 octane or higher (excluding E-85).

 

We don't need people to attack those that are merely asking for information re higher octane.

 

And so are you. In fact, you're both saying the same thing, just in different terms.

 

First, OTC octane "boosters" are automotive snake-oil.

Second, just loading up on higher octane does not actually improve any performance, this is an illusion. However, higher octane can act as a safety measure in extreme and sudden changes in weather, altitude, ect.

If you're heading out on a long road trip where you expect to change climates, humidfity ect, i.e. a spring/fall drive from Chicago to Miami, buying higher octane along the way would be helpful, but not responsible for any significant improvements in performance.

And last, E-85/105 octane is likewise misleading. Yes, it is higher than average octanes, but your MPG sufffers. Try close monitoring of MPG performance over a minimum of four tank fills, and calculate your fuel expense. You'll find that you are spending more on the E-85, than you spend for your usual fill. If you got any immediate "change" from one or two tanks of E-85, it's prolly due to cleaning up the fuels system more than running higher octane. Thus, any comparasion must be done over a longer test period, not just one or two fill-ups.

 

Just my .02C, happy motoring gents.

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Ummm...You're correct.

And so are you.

 

In fact, you're both saying the same thing, just in different terms.

 

First, OTC octane "boosters" are automotive snake-oil. Second, just loading up on higher octane does not actually improve any performance, this is an illusion. However, it can act as a safety measure in extreme and sudden changes in weather, altitude, ect. If you're heading out on a long road trip where you expect to change climates, humidfity ect, i.e. a spring/fall drive from Chicago to Miami, buyin the higher octane along the way would be helpful, but not responsible for any significant improvements in performance. And last, the E-85 thingy is likewise misleading. Yes, it is high than average octane rated, but your MPG sufffers. Try close monitoring of MPG performance over a minimum of four tank fills, and calculate your fuel expense. You'll find that you are spending more on the E-85, than you spend for your usual fill.

 

 

LULu, correct me if I am wrong but E-85 has less BTUs than high octane gas. Is that correct?

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LULu, correct me if I am wrong but E-85 has less BTUs than high octane gas. Is that correct?

 

Don't have any BTU facts at my fingertips at the moment, but I believe so.

 

This is why I did my own study of E-85 when it became available here in Chicago. Sold by the liter here, the "price per" lured many supporters to the fuel, but most of them could not translate fuel cost per gallon/mile very well. I did the 4 tank study I suggested, and my MPG dropped by 3 MPG in the city, and my cost per gallon went up .35 cents. This didn't impress me enough to stick with the E-85, even at today's prices. Hope this helps.

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LuLu, to my knowledge E-85 is a gasohol, with about 85% alcohol, 15% gas. It has a higher octane but usually less BTUs (explosiveness) as expressed in British Thermal Units. It has a high octane due to the alcohol but less explosiveness so it develops less power and subsequently less mileage. You are correct that you receive less Miles Per Gallon. Then you have to weigh that against the usually cheaper cost per gallon. I would think that E-85 would be plentiful in the Illinois area.

 

Another problem is that unless a vehicle is set up for E-85 it can actually damage the seals, tubing, lines, and even cause rust of the gast tank as it can eat into ordinary metal. A vehicle that has been set up, or converted to, E-85 will not have problems.

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"Jim, what are you going to do about the tune after the supercharger? One of the superchargers is tuned for 91 and the other 93. Which did you buy? If it is set for 93 what are you going to do?"

 

I have not, technically, bought my S/C yet (can't give them money until my car goes in the doors). I was not aware that they are tuned for 91 or 93. Given my location, San Diego, I have to go with the 91. Jim

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LuLu, to my knowledge E-85 is a gasohol, with about 85% alcohol, 15% gas. It has a higher octane but usually less BTUs (explosiveness) as expressed in British Thermal Units. It has a high octane due to the alcohol but less explosiveness so it develops less power and subsequently less mileage. You are correct that you receive less Miles Per Gallon. Then you have to weigh that against the usually cheaper cost per gallon. I would think that E-85 would be plentiful in the Illinois area.

 

Another problem is that unless a vehicle is set up for E-85 it can actually damage the seals, tubing, lines, and even cause rust of the gast tank as it can eat into ordinary metal. A vehicle that has been set up, or converted to, E-85 will not have problems.

 

You are correct sir, and many new automobiles sold as "flex fuel" capable have these modifications in place, so, an owner can pick and choose his fuel as he drives.

 

The only reason I brought E085 into this discussion, was a post from another member who cited E-85's higher octane rating, but without citing its remant shortcomings, i.e. 25 percent more fuel consumption to achieve performance levels of typical pump gas. E-85 has better emmision numbers and less reliance on dino based gasoline, but this doesn't make it cheaper, or a more efficient fuel. Once you caluclate the cost per liter vs. cost per gallon, it's not cheaper fuel. BTW, everything in Illinois is 10 percent ethanol, can't get away from that mix without buying the 100+ octane race gas from the pump out back.

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IMHO...

Ummm...You're correct.

And so are you. In fact, you're both saying the same thing, just in different terms.

 

First, OTC octane "boosters" are automotive snake-oil.

Second, just loading up on higher octane does not actually improve any performance, this is an illusion. However, higher octane can act as a safety measure in extreme and sudden changes in weather, altitude, ect.

If you're heading out on a long road trip where you expect to change climates, humidfity ect, i.e. a spring/fall drive from Chicago to Miami, buying higher octane along the way would be helpful, but not responsible for any significant improvements in performance.

And last, E-85/105 octane is likewise misleading. Yes, it is higher than average octanes, but your MPG sufffers. Try close monitoring of MPG performance over a minimum of four tank fills, and calculate your fuel expense. You'll find that you are spending more on the E-85, than you spend for your usual fill. If you got any immediate "change" from one or two tanks of E-85, it's prolly due to cleaning up the fuels system more than running higher octane. Thus, any comparasion must be done over a longer test period, not just one or two fill-ups.

 

Just my .02C, happy motoring gents.

 

The E-85 is less efficient than standard gas but in my experience the trade off is worth it. I dropped maybe 1 mpg with the E-85 but saved almost $1.00 per gallon. Here premium is around $3.29 per gallon and E-85 is $2.39 per gallon.

As for the performance gain I did notice a difference. It might have been due to cleaning out the system but my truck ran better than it did when I drove it off the lot. On premium fuel it will not turn the rear tires over under full throttle but with the E-85 it would light them up. I have been back on premium for about a tank and a half now and my truck is back to its sluggish self.

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Call me stupid, but my SGT will tolerate 91 octane, and I buy 93.

 

Well, here in San Diego, all we have is 91 octane available and the car seems to run fine but I have not tested it in hot summer weather yet (have not had the car that long yet). Jim

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I sent a PM to Bud. Bud stated that in Las Vegas the highest octane is also 91 and the SGT runs fine. He also stated the SS is set up to run on 91. I would like to have that little bit of extra insurance with 93 but I guess we have to live with what we have. I would like to know why the Western portion of the US is stuck with 91 rather than 93. Another person has mentioned how the new Bullitt will run on anything from 87 to 93. There must be a differenece in programming. I don't know if that is something we could do or not. But the Bullitt is rated at 315 rather than our 319.

 

Thanks to all for the constructrive information.

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