Question regarding fuel
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H
HHGT
Guest
Stay away from Shell. Had two separate incidents in both GTs where the car just died at the light. RVKing who also owns a GT here on the forum had the same thing happen after refueling at a Shell station. I now only use Chevron. I suspect seasonal additives may cause anomalies.
BlackICE
GT Owner
Gentlemen,
The base formula for gasoline in most areas is mandated by law. So Shell or Mobile (or any brand) gasoline will vary from area to area. There are still over 100 boutique blends used throughout the USA and the winter formulas are different from the summer formulas. The difference is in the additives and detergents that are blended into that base fuel. The best additive BY FAR is Techron and it is only found in Chevron and Texaco (now owned by Chevron) gasoline's. Mobil, Shell, and the other majors use nitrogen blends that are much less effective. The worst gasoline by far is the raw base gasoline with no additives that is sold by Costco, Sam's Club, and grocery stores. In less than 10,000 miles a ton of carbon will build up on intake and exhaust valves which reduces both power and mileage without quality additives. I am currently a dealer for both Shell and Chevron but I only use Chevron gas in my cars. Cheers.
Chip
The base formula for gasoline in most areas is mandated by law. So Shell or Mobile (or any brand) gasoline will vary from area to area. There are still over 100 boutique blends used throughout the USA and the winter formulas are different from the summer formulas. The difference is in the additives and detergents that are blended into that base fuel. The best additive BY FAR is Techron and it is only found in Chevron and Texaco (now owned by Chevron) gasoline's. Mobil, Shell, and the other majors use nitrogen blends that are much less effective. The worst gasoline by far is the raw base gasoline with no additives that is sold by Costco, Sam's Club, and grocery stores. In less than 10,000 miles a ton of carbon will build up on intake and exhaust valves which reduces both power and mileage without quality additives. I am currently a dealer for both Shell and Chevron but I only use Chevron gas in my cars. Cheers.
Chip
BlackICE
GT Owner
Indy GT
Yea, I got one...too
Chip's answer is always welcome when discussing the topic of gasoline and he is certainly qualified by years of experience to wade into this topic (reference his classic treatise on boutique gasoline blends many new owners may never have read). Thanks Chip.
But the initial question really lacks foundation. When you ask about the "quality" of something (especially gasoline which has a multitude of measurable attributes) WHAT are you really asking for?
I'll pose just a few attributes off the top of my head so you might see what I mean- "quality of" Color, octane variance, alcohol, alcohol type, alcohol variance, moisture content, sediment content, Reid vapor pressure, viscosity, density, oxygenation additives, cleansing additive package (including Techron), etc., etc.
Luke Warmwater
Permanent Vacation
Isn't the age and condition of the station's storage tanks more of a concern? I have plugged a couple fuel filters shortly after fueling at a couple stations that had old tanks. I will always avoid filling at a station as well when I see the delivery truck refilling their tanks thinking that this is just stirring up all the crud in the bottom. There is one station here in Denver that sells "clean" non ethanol fuel during the summer months that is all I run. The last tank before I park it for winter is 111 race fuel with a stabilizer.
how bad is ethanol?
Because the boaters and 2 cycle guys despise 10% ethanol gas, I can still get ethanol-free 93 octane. The station owner knows the jobber that supplies him, but I didn't ask what national supplier the jobber buys from. I've always gone with the assumption that ethanol-free trumps any other consideration (except, of course, an older station with contaminents peculiar to old tanks, water in tanks, etc).
So do Chip or others feel this is NOT correct and Chevron with it's additives is a superior choice to ethanol-free?
Thanks
Because the boaters and 2 cycle guys despise 10% ethanol gas, I can still get ethanol-free 93 octane. The station owner knows the jobber that supplies him, but I didn't ask what national supplier the jobber buys from. I've always gone with the assumption that ethanol-free trumps any other consideration (except, of course, an older station with contaminents peculiar to old tanks, water in tanks, etc).
So do Chip or others feel this is NOT correct and Chevron with it's additives is a superior choice to ethanol-free?
Thanks
Indy GT
Yea, I got one...too
Uh, you should also "despise" the 10% ethanol gas as well! Don't leave this loathing to just us boaters. (and the alcohol lobby continues to push for higher levels of ethanol 15-20%, so they can sell more product and force yet more engine problems)
As I stated above, Chip knows his gasoline and I look forward to his comments.
Let me, in the interim, make a few comments based on my experience and book knowledge.
You are absolutely correct to purchase if you can gasoline which has not been blended by any alcohol (methyl or ethyl). Cleansing additive packages are something different and vary by blender. These are as they say "cleaning" packages to help clean fuel injectors, intake valves, carbon build up in the combustion chamber, etc. They in and of themselves will not hurt the engine whether they are added (national brands which usually cost more) or not added (cut-price no-name gas stations).
What does matter to the engine as far as damaging or not is the fuel's octane rating, which has nothing to do with power from the engine. Typically you always want to run as high an octane fuel as the engine NEEDS independent of "how" the oil company blends the fuel to achieve this octane.
The only caveat is gasoline fuels blended with alcohols need further attention. Blending gasoline with alcohol makes it “greener” as the alcohol brings to the combustion process chemical oxygen (from the chemical makeup of the alcohol, C2H6O for Ethanol) which is used in the combustion process. But you need MORE of this blended fuel to supply the energy to the engine to be converted into work. This is so called oxygenated fuel. The resulting blend DOES have or display a higher octane rating but the amount of “energy” (or BTU content) is quite a bit less in the alcohol blended fuel relative to pure gasoline. Ethanol only has 62.2% of the energy content per pound mass than does gasoline (for those wanting the actual numbers, higher, constant pressure heating value at 77F, Ethanol 12,780 BTU/lbm vs 20,556 BTU/lbm for Isooctane). Research octane of Ethanol is around 107. Again, typically octane does not have anything to do with engine power.
This is true for the FGT engine, but as technology marches on is not true for the Boss 302 engine which incorporates imbedded knock sensors in the engine block. These sensors provide feedback to the ECU spark advance logic which advances engine timing (which produces more engine power) until the knock sensors detect and annuniate to the ECU which then stops advancing the timing. But this is a completely different topic.
My recommendation is to always purchase unblended (alcohol free) gasoline if you can. It has a much higher energy density relative to an alcohol blended fuel.
(da*m, I built another watch.....sorry guys)
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twobjshelbys
GT Owner
The "if you can" is getting harder and harder. Most of Colorado (Front Range and mountain areas, for sure, not sure about eastern plains) now have 10% alcohol "oxygenated" year round. It used to be winter only but the air quality police and corn lobby got it year round now.
The Grey Ghost
GT Owner
A good site for finding the pure gas (with no alcohol) in your area is:
http://pure-gas.org/
Another note is I don't think all Shell, Texaco, Mobil, etc. buy from the same supplier by brand.
I have 2 Shell stations in town about 1.5 miles a part.
One runs pure gas and the other does not. I believe they buy from different suppliers as well.
Unfortunately not all states require the alcohol content to be posted, so you don't always know.
Jeff
2112
Blue/white 06'
Of course we blend our fuel up here too, Ethanol in gas and Biodiesel in Diesel. Both junk.
My local Chevron dealer sells Techron in bottles too FWIW.
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My local Chevron dealer sells Techron in bottles too FWIW.
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ethanol
Thought it obvious from my post that i also despised ethanol. I drive a fair distance to purchase ethanol-free. Aware of the higher BTU per volume or 'density' issue, as this has been described many times. Waiting to hear what Chip says re: no ethanol vs. Techron if one must choose.
Thought it obvious from my post that i also despised ethanol. I drive a fair distance to purchase ethanol-free. Aware of the higher BTU per volume or 'density' issue, as this has been described many times. Waiting to hear what Chip says re: no ethanol vs. Techron if one must choose.
AJB
GT
I stick with BP Premium 93 octane here in Michigan. It has 10% ethanol (ALL gas here in Michigan does as far as I know)
We do NOT have Chevron here in Michigan...
Chip - maybe you want to locate to the 'great white North" and sell some.
By the way , thanks for the clarification re: Costco and Sams etc... I never use but now I know 'why'...
andy (AJB)
We do NOT have Chevron here in Michigan...
Chip - maybe you want to locate to the 'great white North" and sell some.
By the way , thanks for the clarification re: Costco and Sams etc... I never use but now I know 'why'...
andy (AJB)
H
HHGT
Guest
Indy -
While I agree with both Chip and yourself regarding the nuances of fuels during vehicle operation, I'd like your opinion on one particular aspect of ethanol or methanol blended fuels. When storing a vehicle over the winter months, wouldn't one of these blended fuels work nicely to "dissolve" any condensation that might develop in the fuel tank. Since water molecules are miscible in alcohol, any water molecules would likely not separate from the fuel mixture. Of course, it's also best to fill the tank as full as possible when storing, to limit the surface area exposed to the atmosphere.
Give me your opinion....
Ralphie
While I agree with both Chip and yourself regarding the nuances of fuels during vehicle operation, I'd like your opinion on one particular aspect of ethanol or methanol blended fuels. When storing a vehicle over the winter months, wouldn't one of these blended fuels work nicely to "dissolve" any condensation that might develop in the fuel tank. Since water molecules are miscible in alcohol, any water molecules would likely not separate from the fuel mixture. Of course, it's also best to fill the tank as full as possible when storing, to limit the surface area exposed to the atmosphere.
Give me your opinion....
Ralphie
Joe Dozzo
Well-known member
Best tip in a whie, thanks! Found a station about 8 blocks from my office with current comments; one of very few in CO.
Indy GT
Yea, I got one...too
I do not think there is a choice here (if I understand the question). You can purchase Chevron branded fuel and get the Techron cleansing package blended into the fuel at the tank farm, or you can purchase unbranded fuel and purchase a bottle of Techron at a local auto supply store and add it to your fuel load yourself. The ethanol issue is different. We as consumers have little choices as to pulling into a gasoline station and purchasing alcohol-free fuel. Some states require pump labels to be displayed showing the amount of alcohol content, others do not. So sometimes you know and other times you have to research to find a station which sells alcohol free gasoline. The EPA, CARB and the corn lobby want all motorists to “enjoy” the oxygenated fuels for their marketing reasons.
Sure it does! If you ran a load of 90% gasoline and 10% water through you engine do you think it’s “performance” (and again I do not know what performance metric you have in mind) is compromised. Absolutely.
Ralphie, I always enjoy your technical opinions as well. This is a good question and one that I had to ponder a bit. Let me first state you REALLY do not want any gasoline blended with methanol. When alcohol blending first started to become popular with gas stations who could “cut” their fuel with an extender and make more money on the blended product, there were terrible phase separation issues between the methanol, moisture and gasoline. Also fuel system material compatibility issues wherein the methanol deteriorated delivery lines, fittings, floats, needles, seats, floats, etc. Oh and another big negative is again the energy content. As I previously stated ethanol only has 62.2% the energy of gasoline, well methanol only has 47.5% the energy density of gasoline. Not real good. Avoid methanol blended fuels.
But most of the oxygenated fuels now use ethanol (if not exclusively) and you are absolutely correct the alcohol in the fuel does attract moisture, assimilate the water into its chemical structure and allows the bound water to be burned in the engine. For storage periods (winter months of nonuse) I can see the value of possibly filling the tank to capacity (to reduce surface area as you state) with alcohol blended fuel. This might provide a slight benefit, but remember during the winter months with low ambient temperatures the relative humidity is low as well so the air in the storage facility has a lower moisture content as well. Those in Fla, Texas, California, etc which have higher winter temperatures and higher ambient temperatures are probably enjoying driving their car year round and so this would not really apply to those in more temperate climates. But if you do store, for a length of time, it might be better to have a load of alcohol blended fuel in the tank. Upon reintroduction to service, burn that down as low as possible and refuel with alcohol free fuel if you can.