gasoline questions (nothing to do with current prices)

I’ve got several q’s concerning gasoline.

• First, I’ve heard of a group in SoCal that wants to fight the current price hikes by temporarily getting rid of high octane gas at the pump and replacing it with an additional med octane pump. Now that sounds stupid to me, but here’s the question: I have a sports car which, according to the owners manual, requires high octane fuel.

Is this hype? Or will cutting back hurt my engine and/or performance?

• Question two: I had a mechanic tell me to use Chevron fuel, claiming that their additive (Techron) actually worked and keeps engines cleaner. Is this a legitimate claim? Or should I assume his brother owns some Chevron stations around town?

• Lastly, what’s up with every gas station in the U.S. charging $X.XX 9/10. That 9/10 of a cent seems like… an insult. Are they really pretending to save us cash by dropping the price from $2.01/gallon to $2.00 9/10/gallon? How much does the average station earn a year for those extra 9/10 cents?

And pay close attention to the price marquees… the numbers are all changeable. Except for those damned 9/10 cents which are usually permant parts of the price!

Follow the owner’s manual. Car manufacturers have no incentive to sell high-octane gasoline; they do have an incentive to make you satisfied with their car. Yes, running a high-performance/high compression engine on low cotane gasoline can cause knocking.

Techron is a detergent. All major gasoline brands contain detergent. In fact, I think that ALL gasoline sold in the U.S. contains detergent.

The $0.009/gal is an ancient marketing gimmick that turned into a tradition so powerful that nothing can kill it.

You see that extra insanity of fractions of a cent in gasoline prices as filmyak said, becasue of marketing. Look at it this way, no one actaully includes it when they speak. People say 2.43 rather than 2.43 9/10, or more logically 2.34. So, when I see two filling stations across the street from one another and one appears to be a cent cheaper, I go to the cheap one. We don’t notice there is almost no difference, and people seem to be motivated by very small differences when purchasing gasoline, more than anything else.

First, sorry, I meant to say Nametag, not Filmyak in my last post. Second, you wanted to know how much they make off of that 9/10ths of a cent. Acording to this, we go through 360 million gallons of gasoline a year. That means that by adding on the 9/10ths they are making an extra 3.24 million dollars a year.

Sorry, you asked per gas station. Using the info here (dated 1998), we see that you average gas station pulls in an extra $6,053 a year off of that additional 9/10ths.

What Octane ratings mean

Or, alternatively, sacrifices $605 dollars a year by shaving 1/10th of a cent off the price. Isn’t that a more realistic view of what is happening?

no, because an extra 1/10th of a cent would bump it up to where the customer may (as marketing seems to believe) think it’s an entire cent more expensive. 1.99 9/10 seems like a whole cent below 2.00.

Whoops, I see what you’re saying now. I guess it all comes down to how the gas station looks at it. Are they sneaking in an extra 9/10 of a cent? Or are they shaving off 1/10 of a cent to make it seem cheaper?

It’s an illusion. Nobody is fooled anymore.

The answer is it may, or it may not depends on the actual requirements of your car, and how you drive. Best to follow the recomondations in your owner’s manual.

Chevron has advertised that for years that the big three car makers in Detroit use Chevron for their EPA certification tests. The kicker is that they have to have Chevron trucked in from another state special to use, since Chevron is not sold in Michigan. Also back in the eighties as cleaning additives were the rage, Chevron packaged Techron into bottles for addition to fuel tanks over and above what was in their gas. This is the only time I have ever recalled a carmaker recommending an additive for either fuel or oil. Several carmakers published technical bulletins recommending the use of Techron. Lastly also back from the late 80’s I have personally seen cars that had stalling problems cured by the use of Chevron gas.
so is it good gas? Yes. Is it better than everything else out there? I don’t know, but it is about the same price as the other fuels, and I do know it works.
Your mileage, of course, may vary.

They do know that the refineries don’t actually make any mid-grade gas, do they? The mid-grade at the pump is just a mix of the regular and premium ‘made’ in the pump.

I subscribe to Car And Driver and they had something about this in their technical questions section. This guy said that he had a supercharged car (which for our purposes is pretty much the same as turbocharging since both force more air into the combustion chambers) and that he would run 87 octane in it, and does this hurt the car?

The response, predictably, is that you can in fact run lower octane-rated fuels in your car, but due to the large volumes of air created by the supercharger it is an absolute necessity to stay out of the boost because the detonation would be very destructive. The car has some safeguards against that, such as advancing or retarding timing, but nonetheless lower octane fuels shuld be used only in situations where the higher rated stuff is unavailable and the lower octane fuel should not be used on a regular basis.

If you have a newer car, this becomes a warranty issue as well. Car manufacturers don’t warrant stupidi…err, owner-induced failures. So absolutely follow the recomendations that the car builder makes, and if you can’t for whatever reason take it very easy lest you turn your pimpin’ ride into a $20,000 piece of junk.

Well, assuming you have a stock car, I’d be willing to bet that even though they recommend 91+ octane gas for best performance, that you can run 87 forever with no ill effects. Your performance will suffer though, due to the knock-sensor retarding the spark to the point where knocking doesn’t happen.

With super and turbochargers, often times high octane gas isn’t enough- that’s why they have intercoolers, water injection, etc…

That’s not why they designed those systems. They designed them for the occasional knock during normal operaion, not continuous beating the hell out of your engine. If you depend on them to save your car because you want to get gas on the cheap and they fail, BOOM! And then you’ll feel pretty stupid.

Those are for thermal efficiency, not combustion. The temperature of the forced air will have an effect on efficiency but little to no effect on detonation, which is what high-octane rated gas is designed to prevent.

Techron: Yes it is superior to other gas detergents. I pretty sure there is a thread from way back if you do a search. You can always just buy the additive in a auto parts store and add it to your gas twice a year. Chevron has a patent on polyether amines which is why other oil companies can not offer the same additive in their fuel.

Lower grade gas: Read your manual. Most, if not all modern cars sense knock long before the point where it would do any damage to your engine. My 94 BMW recommends high octane fuel but allows low octane fuel with the only caveat that performance/effeciency may be less. No warranty issues despite some unsupported assertions in this thread.

And BTW, the temperature of the intake air definitely will affect detonation (as well as effeciency).

How does this fight the current price hikes? Simply by getting rid of the highest price gas so the ‘average’ price is lower?

Housing in Southern California could be affordable again if only all those expensive homes weren’t on the market! :smack:

[Johnny Carson]
I did not know that.

Sorry, but I gotta call CITE here.
Seeing as how my local filling stations have three count them three fill ports in the pavement. Also I have never seen this in any of my professional magizines in over 30 years in the auto business, my bullshit meter is pegged firmily in the red total bullshit zone. :dubious:

That’s something that he’d really have to check the owners’ manual for. My car line had anti-knock sensors added/adjusted for the 2001 model year for this very reason. All the pre-2001 guys have to put in 93. I usually put in 87. The manufacturer recommends 93, but says only performance will suffer a little bit with the 87. Really, I don’t notice any difference.