OK Tom, Let's Talk GAS!!

[ROCKET62]

Tom,

As the local expert, and "Fuels & Lubes Geek of the Realm", I was thinking of you as I filled up with some gas this weekend at Shell. They have 93 octane, but it is an ethanol blend and has the new "Nitrogen" blah, blah, blah. BP in town only has 91 octane, but I think it is pure gas? Can't seem to find any pure 93 in Iowa - and still looking.

So what's the word on what's best?

Thanks!

ROCKET!

 

[plumcrazy]

noticed the same last week

 

[Tom F&L GoR]

Marketing 101 means being first is a lot better than being better. But first...

Chemistry lesson: Ammonia is a good cleaning material. Ammonia is NH3. The additives that are put into gasoline are "cleaning" agents and also have Nitrogen. They are (to greatly simplify) derivatives of nitrogen compounds. So Shell says they put nitrogen in their gasoline? Every other gasoline marketer does also, and has been for years. Shell was just first to say so.

Another example: STP contains "jet fuel" or was it "rocket fuel"? A common diluent for the additives that you pour into the gas tank is kerosene. Kerosene is like #1 diesel fuel is like fuel for jet engines on airplanes. So STP got the "quality" cough cough of jet fuel as the diluent and said so on the bottle. (Surprise, only about 5%-15% of the bottle contents are "additives" and the rest is something to make it runny so you can pour it into your gas tank.)

and now a Marketing lesson: AIDA

Attention
Interest
Desire
Action

You have to get the customer's attention (promotions, colors, noise), then say something to keep their interest (use Danica Patrick, a racing theme, something enthusiastic.) Talk to them to make what you sell something they desire (more horsepower, more hair, last longer!!!), then give them a reason for action (20% off coupon, enter free sweepstakes, buy one get one free!)

So Shell got your attention with the signage, said something different about their fuel to be interesting, you might want it because it makes the gasoline better (cough, cough) and they only say it about the premium grade (geez, that premium is gonna make my car fast!!)

It's amazing what an engineer can learn.

 

[Tom F&L GoR]

Part II

Gasoline is fungible; it is a commodity sent through pipelines. It is only different when the tank trunk picks up a load at the terminal and the additives are injected. That's right, only the 0.02% (or less) of additive is what makes Shell different than Valero than Chevron.

There were a few brands that kept their fuel proprietary, but it's so much more expensive to do that I believe the economy has probably gotten them all to stop doing it. Sunoco was one.

So all of the local stations get the same base fuel, just different cleaning additives. The octane will be the same. The perceived difference might only be due to station underground tank cleanliness.

Sorry. The perceived difference is in the advertising... like how much NITROGEN they added.

 

[Tagoo]

The only thing I might add is that difference you see between the 91 and 93 in your town is probably just the addition of ethanol. My dad (retired-Chevron distribution guy) told me that 10% ethanol gives you an increase of 2 octane points. For example 89 octane (pure) gas plus 10% ethanol equals 91 octane. 91 octane (pure) gas plus 10% ethanol equals 93 octane. Of course, I'm waiting for Tom to check my facts and my math

 

[Tom F&L GoR]

The only thing I might add is that difference you see between the 91 and 93 in your town is probably just the addition of ethanol. My dad (retired-Chevron distribution guy) told me that 10% ethanol gives you an increase of 2 octane points. For example 89 octane (pure) gas plus 10% ethanol equals 91 octane. 91 octane (pure) gas plus 10% ethanol equals 93 octane. Of course, I'm waiting for Tom to check my facts and my math

I didn't check the math, but that is what was done in the "good old days." EPA now regulates emissions more strictly so the base gasoline that the ethanol is added to is a special recipe. This pre-ethanol gasoline is called RBOB (Reformulated Blendstock for Oxygen Blending) and will be low octane until the ethanol is added. Oil companies do not like to "give away" octane for free!! The yellow sticker on the fuel dispensing pump will always show the final octane rating.

 

[Mopar Boy]

OK Tom, Let's Talk GAS!!

Too many beans you guys?

Robert

 

[CitySnake]

That's right, only the 0.02% (or less) of additive is what makes Shell different than Valero than Chevron.

Remarkable, though not surprising. So the quick math suggests that in a typical 20 gallon tank, the additive difference amounts to one half a fluid ounce.

 

[Newport Viper]

So then is "top tier" gas worth it? Top Tier Gasoline

Or is it back to the "AIDA" marketing?

 

[Tom F&L GoR]

"worth"

well, Top Tier has more detergent and there are tests to prove it cleans up parts and keeps them as clean as the OEMs want. It is unambiguous as to what it should do.

The additive cost to the gasoline marketer is on the order of 200-300 points, or $0.002 to $0.003 per gallon. Often higher treat rates are only available in the premium grades (and so people get used to thinking premium is better, where in reality it is simply that the marketer only added the extra detergent to the premium. They could add it to all three grades.) so you pay $0.10/gallon more.

A bottle of a quality "complete fuel system cleaner" once an oil change will provide the same benefit. The only difference is getting it at small amounts every fill-up or getting multivitamins once in a while. I have no technical preference either way. Do the math and see which way is cheaper.

It would be nice to get Top Tier in all three grades from somewhere. (Texaco used to always put same amount in all three; Texaco=Chevron now and Chevron always put more in premium than regular and midgrade.)

 

[Newport Viper]

Thanks Tom! I use Chevron.

 

[Abe Froman]

Well done and informative… Thank you

 

[dave6666]

AIDA?

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[Madduc]

I need to start watching INDY racing more!!

 

[Tom F&L GoR]

Wow, she has the biggest...

watch on her wrist!

(See Dave, AIDA works!)

 

[jdeft1]

Perhaps I'm wrong but didn't the government decide that all on-road gasoline will be 10% ethanol now??? ... and they don't have to advertise the fact??

Just wondering........

 

[Tom F&L GoR]

I think it's moving in that direction, but it that it's still an air quality issue. If your region has more than 2-3 days of an excursion over the limits, the region has to implement some remediation. And that stations still label the fuel as containing ethanol makes me think we aren't there yet.

Economically, when ethanol producers go out of business with a requirement to use ethanol, it again makes me think it's not 100% ethanol blended... yet.

 

[jdeft1]

I'm not sure where I got that from... Around here, emissions are an issue so I guess it could be a local thing. (Wash. DC metro area)

 

[GR8_ASP]

The federal government has initiated investigation into increasing the 10% ethanol level to 15%. The problem is really with those vehicles previously made to the 10% requirement which will not perfom acceptably but will use the fuel unknowingly.

 

[okloneranger]

On the simple side: What is your opinion concerning 10%eth. vrs. 100% gasoline (is it truely all gasoline) when it comes to both mileage and possible corrosive effect on engine metals and sealing or gasket materials used in and on the engine? In this state you can still find "no ethanol gasoline" and I only buy that for not only the Viper but also the daily drivers. A relative works for one of the oil companies and told me the Govt. was paying the oil companies to re-do pipelines due to corrosive effect of ethanol on welds and pipes. Plus, he said the ethanol-gasoline was actually more expensive than 100% gasoline. Anything federally mandated makes me suspecious.

 

[Tom F&L GoR]

On the simple side: What is your opinion concerning 10%eth. vrs. 100% gasoline (is it truely all gasoline) when it comes to both mileage and possible corrosive effect on engine metals and sealing or gasket materials used in and on the engine? In this state you can still find "no ethanol gasoline" and I only buy that for not only the Viper but also the daily drivers. A relative works for one of the oil companies and told me the Govt. was paying the oil companies to re-do pipelines due to corrosive effect of ethanol on welds and pipes. Plus, he said the ethanol-gasoline was actually more expensive than 100% gasoline. Anything federally mandated makes me suspecious.

Mileage should worse by not more than ~3% (the oxygen content of EtOH.) There are a few intermediate levels of O2 use, but marketers go to 10% EtOH to maximize tax subsidies.
Corrosive effects should be non-existent.
EtOH blends cost more, but tax subsidies make it competitive. Varies by state.

After so many years, it is highly likely every gas station, gas tank, fuel line, vehicle, etc has seen ethanol a number of times, so the "cleaning" that will happen as it loosens rust or other gunk anywhere (and plugs filters) has happened.

In my opinion, a fuel injected vehicle is immune to 10% EtOH fuel, and likely can learn to deal with 15%. The PCM isn't bumping on the edge of driveability at 10%, so a little more can't be a drop off the cliff (I think.) The economics of 10% EtOH are not good; can't see 15% is going to be better... Less driving for now and when the economy picks up, a shift to more fuel efficient cars will keep oil imports low. Why else use ethanol? If the US wants to make it a viable economic choice, eliminate subsidies and tariffs, pay less and import it from Brazil.

Carbureted vehicles are likely to notice and will hestitate, stumble, and warm up poorer.

 

[Canyon707]

Tom what makes up the summer blend. In Calif it raises the preice about a dime. Interesting enough diesel also goes up. Is this a market ploy or a real fuel change that costs more?

 

[triplexotica]

I have something interesting to add.

While my Snake was getting serviced this summer prior to VOI-X the dealer gave me a Caliber to drive.

I pulled up to a gas station selling E85 and filled up with the E85.

The car ran ok a little high on the RPM's though.

I did notice that the tank did not last nearly as long as with "regular gas".

That was the first and last time I used E85.

 

[Tom F&L GoR]

Tom what makes up the summer blend. In Calif it raises the preice about a dime. Interesting enough diesel also goes up. Is this a market ploy or a real fuel change that costs more?

Refinery production has to be scheduled 3-6 months ahead, so some of the cost is guessing the forward demand. Therefore temperature, causing a greater demand for heating oil, pushes diesel cost up or down; then there is a zero-sum game of diesel vs. gasoline.

That said, gasoline is technically more expensive in summer because of the volatilty requirements. It used to average about 15 times per year that gasoline sold at the pump was adjusted for volatility. ( I believe it is less times now because the range of volatility allowed is smaller.) Components like butane are inexpensive and high octane, so oil companies would like to add it to gasoline. But the lower volatility in the summer disallows this.

California also has limits on how high a boiling point component is allowed (gasoline boils beginning at ~150F and up through ~300F as the various size molecules evaporate.) So with restrictions on the volatile end and the non-volatile end, plus the confusing issue of ethanol and tax credits, and I'm surprised the cost stays within 10 cents.

 

[Tom F&L GoR]

I have something interesting to add.

While my Snake was getting serviced this summer prior to VOI-X the dealer gave me a Caliber to drive.

I pulled up to a gas station selling E85 and filled up with the E85.

The car ran ok a little high on the RPM's though.

I did notice that the tank did not last nearly as long as with "regular gas".

That was the first and last time I used E85.

Pump gas (even with 10% ethanol) is the standard 87-89-92 octane. E85 is 105 octane. The Caliber is able to adjust and take advantage of the higher octane, so the performance should be better (although the RPMs are controlled by your foot, not the fuel!) However, ethanol is only 2/3 the energy content of gasoline, so fuel economy will be 2/3 the miles per gallon. It all makes sense.

How much did the E85 cost?

 

[dave6666]

Blend #PBQ80

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[Tom F&L GoR]

Dave, is this how Texas survives the "gas" crisis? Or produces one...

 

[Canyon707]

Is there a bottom line difference with 91 0r 93 octane?

 

[Viktimize]

Is there a bottom line difference with 91 0r 93 octane?

Yes, more resistance to preignition with 93 octane. Chances are you won't feel any difference with 93. But you can hook up a computer and watch how much timing your knock sensors are pulling. If 91 octane doesn't pull any timing, then 93 will be no added benefit.

I refine the crude that makes gasoline, and I still don't understand the "Nitrogen enriched fuel" marketing. Nitrogen is something we remove from oil when we treat it. Essentially the best oil would have 0ppm N2 in the product. We treat it higher than that, because they don't want to waste money over treating, when industry only demands a minimum of say 5ppm for example. So "Nitrogen Enriched", just tells me that the refinery relaxed their minimum targets, and you're now getting worse gasoline.

Nitrogen is an inert element. So in theory any nitrogen you add to your gas, would only serve to take up volume space that could be filled with gasoline, causing you to burn more gas to create the same power.

And wow, this is an old thread................

 

[plumcrazy]

if the car runs good on 91 and no detonation...use it