Gasoline differences?

[Charon]

As culero said, they can carry multiple products in multiple compartments. Technically, if you're branded you have a branded supply contract and cannot shop around. You are guaranteed supply from the major oil company, but you have to take whatever price is offered (usually 6 cents or so higher than the spot market).
If you are an unbranded marketer, you can look for the lowest wholesale price at the rack and order as needed for the stations in your operation (but in a crunch you may find yourself unable to get supply or paying higher than branded for that supply). You can also have a “branded like” supply arrangement with a wholesaler for unbranded product at a certain price point above the market. You can even, though not typically, buy branded surplus even with branded additives. And, the same truck could fill up at the same terminal with branded gasoline (with the appropriate additive package) and unbranded gasoline in different compartments. The big no no is buying unbranded supply when you are a branded dealer or marketer. But the oil companies track that pretty closely to make sure it doesn't happen.

Typical margin on a gallon of retail gasoline for the retailer is under 10 cents. In some markets it approaches zero, especially when you add in the credit card processing fees and hypermarket competitors that don’t really aim to make money on the gasoline product and use it as a loss leader or loyalty reward for store purchases. The focus of the “traditional” retailers/marketers today is to use gasoline as a volume generator and make money in the store, the deli, the ATM and the car wash. If it’s a good month for gasoline then all the better. If it's a bad month (where you can end up losing a few cents pre gallon for a period of time) then you better have all your other profit center ducks in a row.

Charon

[mora]

Originally posted by culero
Actually, most modern cars will benefit in terms of power and mileage from using the higher octane fuels, especially when ambient temperatures are relatively high.

The engine management systems we have now use what manufacturers refer to as "adaptive strategy" to optimize performance in real time. In particular, much of the time ignition timing can be stretched out a tad farther without causing detonation when using higher octane fuel, and this allows the management system to take advantage of that to achieve better efficiency.

..........(ASE certified Master Technician with 25+ years experience, hung up the wrenches in 2001)

That's true but the adaption doesn't necessarily happen automatically. Many makes reguire an adaptive drive to be made by a tech by a standard procedure. Others adapt automatically, but that happens over time, and the driver will not notice an instant change if they fill up with a higher octane fuel.

EDIT: Now that I gave it a second thought, most makes reguire an adaptive drive to be made to ensure that the car runs smoothly when it's returned to the customer. I believe most makes will actually adapt automatically over time when driven normally.

Just out of curiosity. What kind of schooling is reguired to be a certified technician there?

[beet1e]

Culero - very interesting post at 2:11.

Originally posted by culero
Deposit buildup on the backs of the intake valves in particular is a huge factor.  

Back in the 1970s, I had a car with a 2.3 litre engine with a blown head gasket. The oil had a milky appearance - I understood this to be because of antifreeze having leaked into the oil.

So a friend helped me to dismantle the engine. We took off the cylinder head and removed all the valves. The exhaust valves had burned reasonable clean, but the inlet valves - wow! The deposits were so bad that the valves looked more like bells than valves. My good friend volunteered to clean them up while I went to buy some new valve springs. When I got back, he had finished. He'd had to use a knife to break off the deposits, which were rock hard. I swept all the debris into a shovel and put it in a dustbin. I was amazed how much there was. And the old valve springs were so worn that they had compressed to about half the length of the new ones!

That was a carburated engine. I do believe that carburettors were set to deliver the correct stoichemical combustion mixture at normal running speed, but this led to the engine running richer than optimum at low speeds - hence soot deposits in the exhaust pipe if the car had been bumbling around town for a few weeks. I take it that with modern computerised engine management systems, the ideal combustion mixture can be maintained under any conditions.

Lazuerus, the other guys beat me to it - a tanker can have about seven compartments. I found that out when working for Phillips Petroleum in the 1980s, designing a sales order system. The other thing I found out is that various fuel retailers will uplift product from other companies when it suits them! Eg., a tanker from company ABC has run low on a product, but needs to make a delivery in an area far from home base. Rather than drive all the way back to home base, he will uplift fuel from company XYZ in the area where delivery is to be made and then make the delivery. ABC and XYZ will have a reciprocal arrangement for doing this.

[lazs2]

mtbe is just more EPA junk science.. we should put a stake through the heart of the EPA while we still can..  in just a few more years the EPA will permeate every facet of our daily lives.   For the worse...

If you thought the IRS and the DMV were evil.... you haven't seen anything yet.

lazs

[culero]

Originally posted by mora
That's true but the adaption doesn't necessarily happen automatically. Many makes reguire an adaptive drive to be made by a tech by a standard procedure. Others adapt automatically, but that happens over time, and the driver will not notice an instant change if they fill up with a higher octane fuel.

EDIT: Now that I gave it a second thought, most makes reguire an adaptive drive to be made to ensure that the car runs smoothly when it's returned to the customer. I believe most makes will actually adapt automatically over time when driven normally.

Just out of curiosity. What kind of schooling is reguired to be a certified technician there?

No schooling is required, although many schools here exist that target ASE certification as their baseline for curriculum. Demonstration of knowledge by testing and accumulation of on the job experience (minimum 2 years) are how you become certified.

Various areas of specialty are tested for certification - engine repair, engine performance (management systems), transmission, drive train and suspension, electrical systems, heating/air conditioning, and brakes are the eight seperate certifications you need to be rated Master.

Recertification every 4 years is required to maintain status. ASE contracts with local universities nationwide to conduct their testing, and pays their faculties to set up controlled test environments and proctor the tests. The cost to the technician is about $70 per test.

ASE also certifies medium and heavy duty truck technicians, in similar areas, and also paint/body repair technicians. ASE is a non-profit industry-based organization that's been around since the late 70s.

I've always participated and supported them enthusiastically, because they test rigorously (you need to know or you won't pass their tests) and have worked hard to maintain an independent status - no government association. They've become so well respected they are our national standard for technician certification. Its IMO a model for how other trades can keep the government out of the business of regulating them.

As to adaptive strategy - I realize what I wrote was very general. It is pretty much specifically correct for the Big 3 US manufacturers. And what I specifically referred to (timing changes in high ambient temperature in reaction to fuel grade) will actually happen pretty quickly. In closed loop operation, the ECU will creep the time out until feedback from the knock sensor tells it to stop and/or cut back. That obviously will happen a little bit later with more octane, resulting in just a tad hotter timing and thus a tad better performance.

Yes, it does take a little longer for this to be fully integrated with adjustments to the fuel delivery curve, because the ECU checks overall performance for fixed periods of time before changing "blocks" (imagine a checkerboard, witrh each square representing a slightly different table for management parameters) in order to make more extensive adjustments such as overall curve, etc.

Of course, some of the smaller and cheaper cars' systems aren't as complex, but in general the above is pretty much accurate.

culero

[culero]

Originally posted by Charon
snip
The results on the before and after valve stems were fairly significant. I was told one treatment would generate the "after" but I still find that somewhat hard to believe.

I've done enough engine surgery in my time to be able to tell you its absolutely true.

Ask Capt. Virgil Hilts, he's more expert than I am in this particular area (engine repair).

culero (more of a "GP", likes heating/AC/electrical best)

[culero]

Originally posted by beet1e
snip

That was a carburated engine. I do believe that carburettors were set to deliver the correct stoichemical combustion mixture at normal running speed, but this led to the engine running richer than optimum at low speeds - hence soot deposits in the exhaust pipe if the car had been bumbling around town for a few weeks. I take it that with modern computerised engine management systems, the ideal combustion mixture can be maintained under any conditions.

Yes. Its actually been demonstrated in urban areas that a modern management system can produce exhaust with less pollutants in it that the ambient atmosphere its breathing. (Ironic, eh? )

The fact that many carburetted engines produced more soot at low/idle speeds wasn't that the calibrations for normal speed required that low speeds be too rich. Actually, you're talking about seperate control circuits within the carburetor.

The low speed circuits have a tougher job inherently because they have less air to work with due to the throttle being closed. The calibration of the low speed circuits is much more sensitive, and thus often gets out of whack. Plus, other conditions which tend to exaggerate mixture problems (such as float level problems, leaky fuel inlet valves, manifold vacuum leaks, etc) can have a more profound effect at low engine speeds.

Actually, properly maintained modern carburetors on healthy engines became pretty good before fuel "injection" (its actually not injection, but that's another discussion ) took over. What made them dinosaurs is the basic fact they were tricky mechanical beasts to keep in proper tune, while injection systems were MUCH less complicated mechanically and relied on electronics to maintain calibration (MUCH MUCH more reliable).

culero

edit PS - thats "stoichometric", BTW

[rabbidrabbit]

Culero and folks, great thread!  It would be great to see some non partisan test results on which additives are how effective.

Culero, I agree completely with your point on higher octane yeilding slightly better results.  In higher compression cars like my Prelude (10:1) I can see even as much as 4 MPG increase when using 93 Octane vs 87 Octane fuels.  However, for the 4-5% better milage you pay 20-30% more in fuel costs.  Hence, a net increase in operating costs.  For that reason I said it serves no benefit for those with low compression engines and marginal benefit even for those with high compression engines like mine which "require" 92 Octane.

[beet1e]

Originally posted by culero
edit PS - thats "stoichometric", BTW

Yes, stoichiometric, even. I don't know where I got stoichemical from.

OK, Culero, here's a question for you: Would you recommend the use of 3rd party fuel additives for my diesel car? The temperature here rarely drops below -5°C, and the maker (VW) doesn't make any recommendations for additives. Another question - what is your opinion of those "premium" fuels, which claim to clean the parts of your engine that other fuels cannot reach, but which cost MUCH more? On fuel and oil, I have taken the view that if such products were needed, VW would have told me.

[culero]

Originally posted by rabbidrabbit
Culero and folks, great thread!  It would be great to see some non partisan test results on which additives are how effective.

Culero, I agree completely with your point on higher octane yeilding slightly better results.  In higher compression cars like my Prelude (10:1) I can see even as much as 4 MPG increase when using 93 Octane vs 87 Octane fuels.  However, for the 4-5% better milage you pay 20-30% more in fuel costs.  Hence, a net increase in operating costs.  For that reason I said it serves no benefit for those with low compression engines and marginal benefit even for those with high compression engines like mine which "require" 92 Octane.

Depends on what you mean by "benefit". You are right in terms of short-to-medium-term cost/benefit.

Personally, I like visting the pumps less (thus using less ragh....err, Arab petroleum) enough to be willing to pay a slight premium.

Side note: that's a BIG reason why I am still driving my POS 1985 Ford Tempo diesel - it gives me 30+mpg in-city, about 40 highway. Plus, I appreciate the ease of maintenance and superior low speed performance attributes a diesel provides, but that's another discussion.

Also, while I cannot positively confirm it, anecdotal experience makes me tend to believe that the premium fuels run cleaner. I surmise they may get extra additives, but that's just a guess. That contributes to long-term cost/benefit, if you tend to drive vehicles long enough to realize that.

Hell, I even run my boat and lawnmower on premium (and they are carburetted) because of this belief.

culero  (believes his beliefs in this area are "informed" )

[culero]

Originally posted by beet1e
Yes, stoichiometric, even. I don't know where I got stoichemical from.

OK, Culero, here's a question for you: Would you recommend the use of 3rd party fuel additives for my diesel car? The temperature here rarely drops below -5°C, and the maker (VW) doesn't make any recommendations for additives. Another question - what is your opinion of those "premium" fuels, which claim to clean the parts of your engine that other fuels cannot reach, but which cost MUCH more? On fuel and oil, I have taken the view that if such products were needed, VW would have told me.

As I mentioned upthread, keep in mind VW advertises as part its products attributes "cost per mile". Think about what that implies. They aren't talking about cost over the long run. Go deeper than what the corporate line is, ask someone who has personal contact with a factory service engineer and you may hear differently

My experience in the trucking side of things was only about 4-5 years, the bulk (and most recent) was in automotive (gasoline) so I'm less informed as to diesel (we have very few diesel cars here).

That said, my experience is that anecdotal information is all over the map regarding 3rd party diesel additives, and what I've heard specifcally from OEM factory reps is that all you need is to buy top-quality major brand fuel (that's what I do in my car). ]

If you do wish to use additives, some knowledgable folks I know who DO recommend them recommend POWER SERVICE and LUCAS  products.

FWIW, I am a BIG fan of the Lucas oil treatments, they are excellent.

culero

[rabbidrabbit]

If you are running higher test fuel solely for the benefit of a cleaner engine would it not be signiificantly more wise to run on the  cheaper fuel and toss in a cleaning additive every 15k miles or so?  This would give you the benefits at a fraction of the costs..  The other benefit you mention, 1-5% better mileage over the range given by a small fuel tank should be rather insignificant.  You are talking maybe a quart over the capacity of 15 gallons.  I don't know about you but that amount makes no difference to me when deciding when to refuel.

[culero]

Originally posted by rabbidrabbit
If you are running higher test fuel solely for the benefit of a cleaner engine would it not be signiificantly more wise to run on the  cheaper fuel and toss in a cleaning additive every 15k miles or so?  This would give you the benefits at a fraction of the costs..  

If in fact the additives are the ONLY factor involved in greater cleanliness, yes. Points to consider:

1) How effective is it to use what you know will dirty things up more, then clean occasionally, compared to running the cleanest possibility all the time?

2) Further, how often and how much is enough if you choose to add cleaners intermittently?

3) If better power performance is the result of higher octane fuel, doesn't it follow that for the same level of power produced, less throttle input (therefore less burn) is required? Wouldn't that automatically result in less deposits from the combustion process?

Those are necessary question to answer if you wish to compare costs accurately.

Originally posted by rabbidrabbit
The other benefit you mention, 1-5% better mileage over the range given by a small fuel tank should be rather insignificant.  You are talking maybe a quart over the capacity of 15 gallons.  I don't know about you but that amount makes no difference to me when deciding when to refuel.

Don't get me wrong, I agree you are making very valid points here that represent very good advice for many (arguably most) people.

What I am challenging and discussing with is your original assertion that there are NO benefits

culero

[rabbidrabbit]

You challanged them properly.  I was generalizing my position since I'm yet to believe that the costs outweigh the benefits in most if not all circumstances.  You make valid points but I'm yet to be convinced that my simplified response is inaccurate in whole.  So far I don't see how the costs outweigh the benefits.


I'd love to see some sort of unbiased study of say Techron and other additives that would help explain their real benefits if any.  I'd have no problem with dumping something in my tank if I had  reason to believe it was superior to what I'm doing now.

[culero]

Originally posted by rabbidrabbit
snip
You challanged them properly.  I was generalizing my position since I'm yet to believe that the costs outweigh the benefits in most if not all circumstances.  You make valid points but I'm yet to be convinced that my simplified response is inaccurate in whole.  So far I don't see how the costs outweigh the benefits.

We have no argument here, I agree you're right regarding cost/benefit in general for many/most people.

I'm simply arguing that there usually is some notable immediate performance advantage, that there may be long-term cost benefit for those who use a car all the way up due to less engine wear, and also the intangible benefit that better mileage is worth paying a tad more for (in my case anyway, as always YMMV )

I think we're basically on the same page, we're just developing different preferences due to personal taste.

culero