gas quality decline?

[Uncle-A]

I have not checked actual numbers but it does seem like I'm getting less gas mileage. Always using "Regular" gas at 87 octane, so no idea about premium fuel. Some of the high end vehicles require better fuel at least the "Plus" fuel level 89 octane and not necessarily the "Hightest" 91 octane.

 

[scott43]

Yeah cars have knock sensors...if it detects detonation it'll modify the engine parameters..basically giving you less power. When someone says their car runs better on 91 or 93, chances are they're telling the truth. 90% of the herd don't care..they're just trying to get to daycare without losing their minds..

 

[Uncle-A]

Yeah cars have knock sensors...if it detects detonation it'll modify the engine parameters..basically giving you less power. When someone says their car runs better on 91 or 93, chances are they're telling the truth. 90% of the herd don't care..they're just trying to get to daycare without losing their minds..

Who is selling 93? I thought it is 87, 89, and 91.

 

[scott43]

Who is selling 93? I thought it is 87, 89, and 91.

Up here we have 93 and 94 octane in some Sunoco and PetroCan stations.

 

[cantunamunch]

Up here we have 93 and 94 octane in some Sunoco and PetroCan stations.

Yeh, this is a perfect example of localist differences - no problem finding this selection in Western MD though of course it no longer costs that little

 

[Uncle-A]

View attachment 172402

Yeh, this is a perfect example of localist differences - no problem finding this selection in Western MD though of course it no longer costs that little

It is an old photo $2.439, was it early 2021?

 

[François Pugh]

Is that per US gallon? looks more like our CAD per L.

 

[cantunamunch]

Is that per US gallon? looks more like our CAD per L.

It's more like $5.059 now.

 

[Uncle-A]

It's more like $5.059 now.

Paid $4.699 cash today in NJ for Regular 87 Octane.

 

[snwbrdr]

Who is selling 93? I thought it is 87, 89, and 91.

When I lived in NJ, premium was 93, except for Wawa, which was 92

 

[François Pugh]

I used to spoil my bike with Sunoco Gold. 94 IIRC. No need, it wasn't modded for higher compression or anything like that (just geared lower and tuned for more valve overlap). I haven't noticed a Sunoco station in years. Where'd they go?

 

[Jim Kenney]

Can you use E15 (15% ethanol) gas in a regular car? I'm not that familiar with it, but was tempted to try it this week on a 300 mile (each way) drive from Wash DC to the Finger Lakes region of NY. In the state of PA around Gettysburg and Harrisburg the stations were selling it for $3.99 a gallon, almost a dollar less than regular gas.

 

[dbostedo]

Can you use E15 (15% ethanol) gas in a regular car?

Yes if it's fairly new (like from 2000 or newer). But you'll get worse mileage which may offset the cheaper pump price.

 

[scott43]

E15 is ok in most newer vehicles. Ethanol does deteriorate some materials, like rubber and aluminum. Most newer vehicles though are fine with E10 and E15 ain't much different. But it does have less energy than full gas and you may not see much cost savings. YMMV...

Oop db beat me to it!

 

[Eleeski]

There is a significant mileage difference between California gas and Nevada gas (~10% in my experience) so how gas is blended makes a tangible difference. Summer blend in California is different than the winter blend and I have noticed a slight difference in mileage but the switch was a while ago.

Ethanol has a much lower energy content than gasoline so you will see a decrease mileage with more alcohol added. Alcohol might be farther removed from conflict gasoline so it makes sense that more would be blended in the fuel.

Octane does not correlate to better fuel economy in most vehicles. Specialty engines designed for high octane have no choice but normal engines are fairly tolerant of low octane fuel. My Cessna 182 was designed for 80 octane fuel. I ran a lot of 87 cargas in that plane instead of the 100 octane low lead avgas (with the proper STC). I found that the engine had more power and got better fuel economy on the lower octane fuel. Perhaps the additives to make it low lead avgas had less energy. Note that they have been working unsuccessfully on removing all the lead from avgas for decades - and many aircraft engines are in the group that must use the high octane.

Diesel has a very low octane equivalence but the most energy per gallon. I'm not ready to blend in some diesel looking for better mileage in my car. But I have added a bit of gasoline to old diesel for my tractor with no problems. Not recommended for newer diesels with clean fuel.

Eric

 

[cantunamunch]

There is a significant mileage difference between California gas and Nevada gas (~10% in my experience) so how gas is blended makes a tangible difference.

Absolutely.

Going back to my octane number <-> height analogy, having a 5'11" average blend of Peter Dinklage and Penn Jillette copies is going to give you massively different performance results than a 5'11" average team of Jessie Diggins copies.

 

[snwbrdr]

There is a significant mileage difference between California gas and Nevada gas (~10% in my experience) so how gas is blended makes a tangible difference. Summer blend in California is different than the winter blend and I have noticed a slight difference in mileage but the switch was a while ago.

Ethanol has a much lower energy content than gasoline so you will see a decrease mileage with more alcohol added. Alcohol might be farther removed from conflict gasoline so it makes sense that more would be blended in the fuel.

Octane does not correlate to better fuel economy in most vehicles. Specialty engines designed for high octane have no choice but normal engines are fairly tolerant of low octane fuel. My Cessna 182 was designed for 80 octane fuel. I ran a lot of 87 cargas in that plane instead of the 100 octane low lead avgas (with the proper STC). I found that the engine had more power and got better fuel economy on the lower octane fuel. Perhaps the additives to make it low lead avgas had less energy. Note that they have been working unsuccessfully on removing all the lead from avgas for decades - and many aircraft engines are in the group that must use the high octane.

Diesel has a very low octane equivalence but the most energy per gallon. I'm not ready to blend in some diesel looking for better mileage in my car. But I have added a bit of gasoline to old diesel for my tractor with no problems. Not recommended for newer diesels with clean fuel.

Eric

CA has a requirement for Reformulated gas, which is one of the reasons why gas costs so much. And today, the gas tax just went up slightly. Next time I fill up at Costco, I'll have to check the price.

Diesel's octane equivalent rating is Cetane, which relates to ignition delay period, and higher is shorter.

 

[James]

Absolutely.

Going back to my octane number <-> height analogy, having a 5'11" average blend of Peter Dinklage and Penn Jillette copies is going to give you massively different performance results than a 5'11" average team of Jessie Diggins copies.

The most bizarre analogy in the history of ski talk.

 

[cantunamunch]

The most bizarre analogy in the history of ski talk.

So, it's completely fitting for a bizarre fixation on the artificial fiction of octane number when there are so many actual compositions.

Hell, just octane has 18 structural isomers, all of which have different octane numbers, different volatility and different heat content.

And you thought conflating titanium and Titanal was stupid. Blanket discussion of performance of 87 vs 90 octane number gasoline is exactly analogous to blanket discussion of track & field performance of a 5'11" average team vs a 6'0" average one.

 

[Bill Miles]

100 Octane Avgas is still leaded, although less than the old days, and the oil companies, FAA, EPA, independent suppliers, and users are going through a rather chaotic process about what to do about. Apparently some states/and/or airports have already banned it or are about to. Sure glad we didn't have to fight WWII on unleaded avgas.