Let's Talk About Gasoline....

tumprgt · Jan 21, 2008

While test driving a BMW X5, which has the same "requirements" of 91 octane, I flat out asked the sales guy and a tech if it would run on 87. After much hemming an hawwing they admited that it would but there would definitely be a drop in performance and that they could not void the warranty. The problem with requiring 91 octane is that gas stations are not required to sell it. So what do you do if you are out of gas and at one of these stations?

Car companies like to make threats, but if you push back enough, they will cave and admit to some of their little quirks.

BTW Randoo, thanks for putting this post on topic. Let's all admit that what ever gas station we go to we will be buying the oil of someone(s) we may have issues with.

firemothjoe · Jan 21, 2008

RHill said:
A third possibility is more Patriots and fewer Suburbans, Excursions, Tahoes, Expeditions, Hummers, F250s, Ram 2500s, etc. If everyone moved down one or two sizes, demand would probably drop enough to make a big difference. And if the politicians . . . . oops. I'll stop right here.

I wish I could say I agree with ya, but I don't. Its called the Tata Nano. Its gets 50mpg and only costs $3,000. When its released on the open market, gas prices will go up ten fold. Why? Because countless thousands more people will be on the road. Especially in India and China. So, yeah, our only hope is an H2 and Tahoe that runs on love and not gasoline. Otherwise, its a massive global human dieoff.

silvermike · Jan 21, 2008

firemothjoe said:
I wish I could say I agree with ya, but I don't. Its called the Tata Nano. Its gets 50mpg and only costs $3,000. When its released on the open market, gas prices will go up ten fold. Why? Because countless thousands more people will be on the road. Especially in India and China. So, yeah, our only hope is an H2 and Tahoe that runs on love and not gasoline. Otherwise, its a massive global human dieoff.

I agree firemothjoe. We can conserve all we want but the two nations with the largest population are industrializing. If they are willing to pay $100+ USD per barrel then we either find our own sources or pay up. ....Or change the game using technology or lifestyle changes.

homac · Jan 21, 2008

RHill said:
A third possibility is more Patriots and fewer Suburbans, Excursions, Tahoes, Expeditions, Hummers, F250s, Ram 2500s, etc. If everyone moved down one or two sizes, demand would probably drop enough to make a big difference. And if the politicians . . . . oops. I'll stop right here.

I agree wholeheartedly.

The noose is tightening around those who use a gas guzzler for the daily commute. Europe and most of Asia have had much higher gas prices for a while. In a sick way I do not mind higher gas prices as it will force some to conserve a bit more....

To use a Suburban as your daily commuter vehicle is ignant !

mexborder · Jan 21, 2008

Friends I have that work @various petro test companies say chevron best and shell worst--IMFHO I use chevron since back in days geb+pups

Terasec · Jan 21, 2008

if thats the case

RHill said:
A third possibility is more Patriots and fewer Suburbans, Excursions, Tahoes, Expeditions, Hummers, F250s, Ram 2500s, etc. If everyone moved down one or two sizes, demand would probably drop enough to make a big difference. And if the politicians . . . . oops. I'll stop right here.

we would all be driving 50hp, 2 door econoboxes,
why drive a 20mpg FDII Pat when they want you to drive a 25 mpg FDI pat,
being Italian what i love about the US, is the freedom to buy and drive what you please,
if you can afford it, its your choice, not someone else telling you what to drive,
Europeans drive small cars not by choice but out of need.
large cars are so taxed,
only the wealthy drive 6 cylinder cars.

Akula · Jan 21, 2008

Terasec said:
we would all be driving 50hp, 2 door econoboxes,
why drive a 20mpg FDII Pat when they want you to drive a 25 mpg FDI pat,
being Italian what i love about the US, is the freedom to buy and drive what you please,
if you can afford it, its your choice, not someone else telling you what to drive,
Europeans drive small cars not by choice but out of need.
large cars are so taxed,
only the wealthy drive 6 cylinder cars.

Very true. I have often heard people driving tiny econoboxes or hybrids trying to hammer somebody else's driving habits and vehicle needs into something that would work with what they chose. For example, they'd tell me that "if you didn't get out when it was snowing and waited for the snow to clear, just rented the truck from Home Depot when you needed to haul large things, and used your wife's 4 door car when you needed to move more than 2 adults, you'd be able to drive a Smart car!" Well yeah, and if my aunt had male genitalia, she'd be my uncle.

I drive what I drive because this is what I chose to drive, and I know what uses I have for a vehicle. I like cargo room, nimble handling, and all weather capability. I don't want to rent a truck when I have lumber to haul or wait out bad weather (if my wife doesn't make it to the pharmacy, it doesn't open, and that can be a public health issue). I don't need somebody else trying to redefine my life "for my own good." If I don't want to pay the fuel costs, I'll get something else; I have already economized my vehicle choice due to those costs- I wasn't interested in paying the feeding costs for a Commander or Grand Cherokee, so I bought a Patriot.

The moment we start legislating "for your own good," we won't quit until we've micromanaged every area of everybody's lives. It's always easy to say "just one more thing, and everybody will be happier/healthier/better looking/whatever else." I like my God, my guns, my Jeep, and my house in the 'burbs, and I am not interested in giving those up because some self-appointed nanny thinks he has better ideas for my life.

/rant off...

:blah:

luwana · Jan 21, 2008

I got a $200 gift card from Chevron and used it exclusively for a month and watched my mpgs go down from 25.5 to 21.8 - on a long trip I was only able to get it up to 24.8. I realized what was going on and put in a tank of the cheapest stuff I could find and the mpgs went up almost immediately. I burned through that tank and finished off my gift card and the mpgs went straight down again. I got Chevron gas in Nevada & California - no difference. I've been using the cheap Rebel gas and back up to 25.5. IMHO additives are empty calories especially when you've got a lifetime warrenty.

Since it's voting season - here's a helpful site to follow the money - OpenSecrets.org

MrSensible · Jan 21, 2008

Octane Sensor?!?!?!?!

Now I've heard everything. There is no "octane sensor" in any vehicle. In injection systems the mix is primarily controlled by two sensors. The first is the TPS (throttle position sensor) and the second is the O2 sensor. There are others that effect the mix as well, but those are secondary.

The O2 sensor constantly "sniffs" the exhaust for O2 content. If there is too much, it riches the mix. Too little and it leans it. The TPS measures your demand for power.

Gas is pretty much gas and no, age has nothing to do with the quality. The octane rating is supposed to be measured after "blending". That includes ethenol. There are very few other additives that the EPA allows and all of those are strictly for air quality purposes that vary region by region.

If you encounter a station or series of stations that seem to have "bad gas", don't use them. Odds are that either the station or it's supplier is cutting the gas with something. I have heard horror stories about stations and distributers using things like Isopropyl alcohol, anti-freeze, filtered waste oil, diesel fuel and even plain old water.

Also consider how you measure your mileage. If you are calculating it manually from fill-up to fill-up keep in mind that the more common problem is that the pumps are doctored. local studies have found that pump accuracy can vary by as much as 20%.

Akula · Jan 22, 2008

MrSensible said:
Now I've heard everything. There is no "octane sensor" in any vehicle. In injection systems the mix is primarily controlled by two sensors. The first is the TPS (throttle position sensor) and the second is the O2 sensor. There are others that effect the mix as well, but those are secondary.

The O2 sensor constantly "sniffs" the exhaust for O2 content. If there is too much, it riches the mix. Too little and it leans it. The TPS measures your demand for power.

Gas is pretty much gas and no, age has nothing to do with the quality. The octane rating is supposed to be measured after "blending". That includes ethenol. There are very few other additives that the EPA allows and all of those are strictly for air quality purposes that vary region by region.

If you encounter a station or series of stations that seem to have "bad gas", don't use them. Odds are that either the station or it's supplier is cutting the gas with something. I have heard horror stories about stations and distributers using things like Isopropyl alcohol, anti-freeze, filtered waste oil, diesel fuel and even plain old water.

Also consider how you measure your mileage. If you are calculating it manually from fill-up to fill-up keep in mind that the more common problem is that the pumps are doctored. local studies have found that pump accuracy can vary by as much as 20%.

There is also very often a knock sensor that can detect preignition and will dial back the timing a shade to compensate. That is the source of cars requiring premium fuel being able to run on regular gas. My wife's Acura demands premium for full power, but if it gets fed regular, the computer will self-adjust the timing to prevent knock (which can potentially blow holes in the tops of the pistons), reducing available power. It will then take it at least a couple of tanks of premium to get things adjusted back to normal.

Octane requirements are there for a reason; the manufacturer usually has designed the run the engine at compression levels where preignition can be a real problem on lower octane blends. That is so they can get more power out of a given size of engine. Personally, I don't understand why people would spend the money for an expensive car that required premium, and then cheap out on the fuel (thereby getting the same amount of performance they'd have gotten with a cheaper car).

tumprgt · Jan 22, 2008

I am not to proud to admit when I haved errored and this is one of those times.
1. Octane sensor. I assumed that since my old POS '85 Ford Bronco II had one (the service manual specified one on the back of the carb) that the new vehicles would have. In a sense they do but only to determine if there is not enough. Sensible is partially correct in the sensors used but most (if not all) cars these days also have a knock sensor. By monitoring a multitude of sensors (the listed ones included plus the Mass air, fuel pressure, temp, ...) the engine control unit will try to find the optimal timing and fuel/air mixture for the requested demand/RPM within its programmed specs

2.All cars can run on 87 octane. I miswrote. The ocatane level represents the gasoline's ability to resist preignition under compression. If the ECU can not get the compression below a certain ratio and can not adjust the air/fuel mix, there will be knocking. Most new cars on the road today can make enough adjustments to compensate for lower octane.

So now that I have admitted faults, we get get to the topic. Will higher octane in the Pat improve performance/gas mileage? No. When the the ECU was programmed, it was done with 87 octane, since there is no sensor that can read a higher octane, it can not advance the timing to give you more power. If the ECU was programmed to 93 octane then you would gain performance if you used it since it would run in "detuned" mode on 87.

As for gas mileage for station to station. He in SE WI where it is required that we have blended gas, we definitely have a drop in mileage. Where my folks live one county over, they still use 100% gas so I get much better mileage. The difference can be significant. On a trip a few years back, my Saturn SL1 got about 30 mpg on a trip to Madison. On the return trip, I filled the tank (I ran it dry visiting friends in Madison) and got upwards of 50. I couldn't believe it myself but I confirmed by only putting in 2 gallons on the 100 mile trip. I would look at the gas you are pumping to see the ethanol content as I have found that to be major difference in my mileage.

At one time the reason to use Premium grade was because of the added amount of detergents added to the fuel. Now with Top Tier gas having roughly the same amount across all grades, save money by buying 87 (higher if you are going off roading) from a reputable station.

indianrefining · Jan 23, 2008

tumprgt said:
The truth about gasoline is really ugly.

First, all factory new cars are required to run on the lowest ocatane, 87. I wont say it will run at it's best performance, but it will run. Some dealers wont tell you this, but then then again they are getting paid to sell you a car that goes really fast, not how you can be a miser. All new cars have an octane sensor so they can adjust their timing to the needs of the gas. As for the Patriot, it has variable valve timing and of course spark timing so it can definitely handle any octane thrown at it.

As for the brands that is where it gets really ugly. Let's say a Mobil fuel depot in Iowa (I chose a city far from a refinery for a reason) requests 89 octane gas. The supplier in Louisiana sends the fuel. The supplier may get this fuel from Mobil or Shell or Citgo refineries. It does not matter, at this point the raw fuel has been refined to the same Federal Govt specs. so it is all the same. When the fuel gets to the depot in Iowa is when the propietary additives are added. Usually these additives are the cleaners or in my case 10% ethonal and the other additives to give me a "boutique" blend here in South East Wisconsin

All in all gas is generally the same from station to station and brand to brand. Are some cleaners better? yes. I guess it all depends on how much you want to believe the advertising. In all the cars I have had, I usually choose the lowest priced name brand station. But then again, gone are the days of Bob's gas station

BTW, Mobil is actually ExxonMobil the world's largest company by revenue, at $377.6 billion for the fiscal year of 2006.

As an IT person I should not be pushing Wikipedia (but as someone who has done a ton of research in his life it is a good place to start) but they have some articles on gas brands and more interestingly, what we now think of as "Major" oil companies were actually part of Rockefeller's Standard Oil

Largely in agreement. As you said, gasoline is a fungible commodity and has to meet certain minimum specs. The differences between brands comes in when the various additive packages are blended in. As long as one sticks with a "major" (Chevron, Texaco, Shell, etc.) he should be okay. But I, too, would steer clear of un-branded "rack" gasolines. As to all of the "majors" being descended from the original Standard Oil Company (i.e., the Standard Oil "Trust"), you mis-spoke. Only Standard of New York (Mobil) and Standard of New Jersey (Exxon)(now ExxonMobil), Standard of Ohio (SOHIO, which was bought by BP), Standard of Indiana (AMOCO, merged with BP), Standard of California (Chevron), The Continental Oil Company (CONOCO, now ConocoPhillips), and The Ohio Oil Company (Marathon) are the surviving parts of the Trust. (The Texas Company - TEXACO - for one, was never part of the Trust. However, TEXACO Inc "merged" with Chevron in 2001, and TEXACO is now a Chevron brand.)

RichJet5353 · Jan 23, 2008

I usually buy Sunoco (which uses mostly US produced oil) , but also Lukoil, and have no political problem with Citgo. Chavez is no angel but he's not as bad as the middle east oil shieks, plus he does give discount fuel oil to poor households. Besides, there are some Americans who consider Mr. Bush the Devil.

quasimodem51 · Jan 23, 2008

I so don't understand.

If the patriot never knows it's getting higher octane fuel, then why is it recommended for off-road use. I don't think the Patriot *knows* it is off-road if there is no foretelling indication like wheel slip or putting the Patriot into L for the CVT2L crowd. Even if it does somehow, is the Patriot tuned to expect higher octane fuel has been added and it computes for its use?

Just trying to understand what happens if a vehicle where 87 octane is recommended gets a tank of fuel that has a higher octane component. Better gas mileage? Worse mileage? No change? More oomph? Less oomph? What?????

indianrefining · Jan 23, 2008

quasimodem51 said:
I so don't understand.

If the patriot never knows it's getting higher octane fuel, then why is it recommended for off-road use. I don't think the Patriot *knows* it is off-road if there is no foretelling indication like wheel slip or putting the Patriot into L for the CVT2L crowd. Even if it does somehow, is the Patriot tuned to expect higher octane fuel has been added and it computes for its use?

Just trying to understand what happens if a vehicle where 87 octane is recommended gets a tank of fuel that has a higher octane component. Better gas mileage? Worse mileage? No change? More oomph? Less oomph? What?????

The engine is tuned for optimum performance with 87 octane gasoline. On-road or off-road use isn't a factor, one way or another. If you were doing some really heavy towing, you might get marginally better performance with 89 octane, although that's doubtful. The only real difference you would see would be more vacant space in your wallet.

tumprgt · Jan 23, 2008

When you are off roading or towing, you tend to put the engine under a greater load. This is where the higher octane would help. You can run at the same timing and not get knocking.

Remember back in the day when you timed the cars yourself and you set it to a spot let's say 12 BTC. It ran fine under normal conditions but under heavy acceleration it would knock once in awhile. You then had to bring it back to 9 or 10 BTC to make it go away completely but the pickup was never the same. If you were running a higher octane gas, you probably would not have had the knock as the higher octane fuel resists preignition. The same holds true when off roading, your tend to put the engine under "abnormal" stress, so the ECU would adjust the timing to compensate if it sense the knocking. Thus reducing the torque/power then engine can deliver. The higher octane would reduce the chance of knocking thus allow the engine to give you its max.

Also with the possiblity of more detergents in the costlier grades, it doesn't hurt when you engine goes from hard pounding getting up the trail, to idling at the top, to running on a dirt track, to fording a stream, to...

DaveJKJ · Jan 24, 2008

indianrefining said:
Largely in agreement. As you said, gasoline is a fungible commodity and has to meet certain minimum specs. The differences between brands comes in when the various additive packages are blended in. As long as one sticks with a "major" (Chevron, Texaco, Shell, etc.) he should be okay. But I, too, would steer clear of un-branded "rack" gasolines. As to all of the "majors" being descended from the original Standard Oil Company (i.e., the Standard Oil "Trust"), you mis-spoke. Only Standard of New York (Mobil) and Standard of New Jersey (Exxon)(now ExxonMobil), Standard of Ohio (SOHIO, which was bought by BP), Standard of Indiana (AMOCO, merged with BP), Standard of California (Chevron), The Continental Oil Company (CONOCO, now ConocoPhillips), and The Ohio Oil Company (Marathon) are the surviving parts of the Trust. (The Texas Company - TEXACO - for one, was never part of the Trust. However, TEXACO Inc "merged" with Chevron in 2001, and TEXACO is now a Chevron brand.)

Interesting stuff. Down the street we had a Mobil station that suddenly changed it's signs to Exxon. And right down the street from that station there was an unbranded place that suddenly had new pumps and signs that said Mobil.

I do agree with other's comments that all major brands are better to use than the unbranded ones. I try to use major brands as much as possible.

RHill · Jan 24, 2008

tumprgt said:
When you are off roading or towing, you tend to put the engine under a greater load. This is where the higher octane would help. You can run at the same timing and not get knocking.

Remember back in the day when you timed the cars yourself and you set it to a spot let's say 12 BTC. It ran fine under normal conditions but under heavy acceleration it would knock once in awhile. You then had to bring it back to 9 or 10 BTC to make it go away completely but the pickup was never the same. If you were running a higher octane gas, you probably would not have had the knock as the higher octane fuel resists preignition. The same holds true when off roading, your tend to put the engine under "abnormal" stress, so the ECU would adjust the timing to compensate if it sense the knocking. Thus reducing the torque/power then engine can deliver. The higher octane would reduce the chance of knocking thus allow the engine to give you its max.

Also with the possiblity of more detergents in the costlier grades, it doesn't hurt when you engine goes from hard pounding getting up the trail, to idling at the top, to running on a dirt track, to fording a stream, to...

I agree with what tumpgrt said.

quasimodem51 said:
I so don't understand.

If the patriot never knows it's getting higher octane fuel, then why is it recommended for off-road use. I don't think the Patriot *knows* it is off-road if there is no foretelling indication like wheel slip or putting the Patriot into L for the CVT2L crowd. Even if it does somehow, is the Patriot tuned to expect higher octane fuel has been added and it computes for its use?

The 2008 Owner's Manual says, for the FDII,

When the system has the 4WD lock lever engaged and is in the Low Off-Road mode or reverse, the engine calibration changes to run higher spark advance with premium fuel for optimum off-road performance.

If someone got into the Engine Control Unit (computer), it would probably be possible to redo the ignition advance program and advance tables to run higher spark advance all the time, getting some more performance and fuel mileage with premium fuel. But the change probably wouldn't save enough fuel to make up for the increased price of 91 octane over 87.

FWIW and YMMV.

quasimodem51 · Jan 24, 2008

Thanks so much, indianrefining, tumprgt and RHill.

Mitigating the "vacant space" in my wallet overrides the perceived performance gains from using 89 octane. For some reason I just felt better; but I guess it is like washing your Patriot. For some reason it just feels like it runs better when it knows you babied and cared for it a bit. [wry smile]

tumprgt · Jan 24, 2008

Quasi,
At one of our local car washes, the exit door has a quote: "A cleaner car run better". Your statement just reminded me of that and I agree, the perception of it it is more expensive it has to be better sometimes overrides reality. Sometimes it is true ($50 used Yugo vs a new Pat) sometimes not ($500 pair of designer jean vs good o'l Levis)

Let's Talk About Gasoline....

tumprgt

firemothjoe

silvermike

homac

mexborder

Terasec

Akula

luwana

MrSensible

Akula

tumprgt

indianrefining

RichJet5353

quasimodem51

indianrefining

tumprgt

DaveJKJ

RHill

quasimodem51

tumprgt

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