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Toyota Camry, Sedan
#7 of 16 gas is gas
May 08, 2003 (10:57 am)
oil companies used to be vertical monopolies... from the wellhead to the cap on the full-service attendant's head, Amoco owned their business from one end to the other, Philips likewise, Humble/Enco the same. then they pretended to be verticals, but maybe all that they had in North Dakota was trucks painted with their logo, and a bunch of franchisees, with the pipeline company paid to be sure they pumped additives from the Spilco drum for each truckload.
now it's pretty segmented. your next tank of Citgo might be pumped and refined in Venezula, shipped to Houston, entering the Williams pipeline as a bunch of gasoline credits, and up in Minneapolis, whatever is in the tank when Liquid Transport pulls up to get a load of 87 octane for the LC road gas station goes in the tank, along with some "formula X" definition of additives from whatever chemical company was low bid last week that is specified for Citgo brand gas. and the ethanol for the 5 or 10 percent oxygenate can come from anyplace close. gas stations don't buy purple-tinted gas direct from the refinery, they buy credits at the delivery terminal.
individual operations can make a difference... if Joe changes his pump filters and Bill doesn't, Joe's gas will be cleaner. if Herm only sells 2000 gallons a week and Pete sells 150,000 from his 2500-gallon buried tank, then Pete is more likely to have the correct blend for the season on any particular day... and that is diddled from the raw stocks at the delivery terminal when it's time to make the change. if Spilco cleans their tankers and Drips doesn't, you could have dirty deliveries from Drips.
there are now government regulations on minimum amounts of detergent that all gas has to contain, so the infamous BMW run-clean engine tests are history.
it's a commodity like air, buy where you want.
#8 of 16 swschrad -Which gas contains the least amount of olefins?
May 11, 2003 (3:29 pm)
#9 of 16 Premium Fuel
May 11, 2003 (3:56 pm)
After a few years of miserable mpg, I decided to switch things up in my 99 yukon. I used premium unleaded and immediately noticed a difference in "responsiveness/accelleration". I haven't calculated it out but noticed a few more miles on my trip odometer between fill-ups. Am I just optimistic or can premium actually improve gas mileage, and improve it in a 4 yr old truck w/ 67K ticks? Any opinions?
#10 of 16 can't improve gas mileage
May 11, 2003 (5:24 pm)
using higher octane gas.
If the vehicle is designed to be able to take advantage of higher octane gas, you may notice an improvement in pep though.
May 11, 2003 (10:15 pm)
depends on where you are. I frankly haven't the slightest idea. google indicates that they are more modernly known as alkenes, which is a distillation product, I believe from reformulation (alkylation), and various alkenes run the gamut from ethylene gas to polyolefin fiber for carpets.
if you want to polymerize them, here's a treatise
most of the references refer to polymerized olefin as polypropylene, and in the context of fabrics. chevron's refinery page indicates alkylation is the head end for aviation fuel as a major product, so we're talking essentially kerosene with some heavier, waxier compounds mixed in. a drilling mud compound is also produced from this feedstock
I thought this link was long enough to break, but it tests OK on posting.
the critical question is whether the fuel in question, whatever its blend, and that is somewhat dependent on where the crude came from, meets technical standards to run in your engine. the raw, crude measurement is average octane. I have been to three of the top oil company sites at this point and nobody is publishing their formulas part of the reason is that I have read that with various EPA and state laws in the mix, there are well over two dozen "standard" formulas for good old lead-free 87 octane regular. wisconsin gas is not legal in Chicago, for instance, which complicates delivery and production.
in the end, it should burn the same. if you can't store brand X in your area and can store brand Y, try adding some stabil when you tank it, and be sure the tank is air tight... ethanol blends can separate and get funky over long storage.
#13 of 16 swschrad: Good sources and very interesting. Thank you.
May 12, 2003 (10:43 am)
After being "shafted" in Butte in '48 I knew that wasn't for me. A paper plant is what enabled me to earn money for college. I toured the Pontiac assembly plant in '60 and the Lincoln at Wixom in 96. Now, I want to tour a refinery after reading your sources. Thanks again for the post.
#14 of 16 kinley, they tore the top off the mountain after you left
May 12, 2003 (4:52 pm)
so maybe the rest of the mining crew wasn't as efficient?
go to www.chevron.com and click the refinery link, you can get a simplified tour of a refinery. you can also check www.howstuffworks.com for another look at the insides.
thanks to our buddy Osama, average Joes aren't going to get a chance to tour the nuclear power plants and refineries in the near future. I had a chance on may day a few years back to see a Westinghouse nuke with the reactor empty, and was able to stand on the catwalk and look into the belly of the beast. I thought that was kind of cool. won't happen now due to paranoia.
May 18, 2003 (7:49 pm)
I-Car-umba Care Care Encyclopedia. <http://www.icarumba.com/icarumba/resourcecenter/encyclopedia/icar_resourcecenter_encyclopedia_fuels1.asp#gasoline>
According to these guys, autotive gasoline varies measurably over the course of the year in terms not only of octane rating(s), but also in terms of volatility and density. Article says manufacturers intentionally vary the volatility of fuel to compensate for changes in ambient air temps/pressures as the seasons change. Now, if they can control that, then couldn't they more consistently deliver us controlled density and octane levels, too?
Could a denser fuel contribute towards higher power output for a car's engine? Assuming same octane rating, would a denser fuel have a greater tendency to knock?
#16 of 16 absolutely it does, T-beast
May 18, 2003 (10:09 pm)
you put summer gas in your car at 20 below, it's going to be real dense, all right... and isn't going to vaporize when it hits the cylinder, so it won't fire. winter gas at 80 degrees or higher will vapor lock.
the octane rating is going to stay relatively constant throughout this process. it's a comparative engine-based test to show that the fuel is balanced for the current conditions, and will deliver its promised octane. if you are blending winter fuel for 0 degrees, I believe they run the test at zero.
it's a double-check, because by now everybody in the fuel business knows that X parts of this feedstock and Y parts of that one blends down to 87 octane at 70 degrees, and they can modify the blend per their little chart to suit the weather. they test to be sure they will be competively accurate and the state commerce regulators won't catch them and fine them.
I'm not real sure about the "density" argument, but I have seen it used by folks against the oxygenated gasolines (MTBE, ethanol, etc.) because they typically provide a few percent less mileage. those fuels exist to meet EPA pollution requirements, and muttering or writing letters is not going to get the booze out of the tank.