93 Octane push by Shell & Exxon/Mobil

PhilF said:

Ok, short-term update, switched to the "New" Shell 93, now on 3rd fill-up (should be pretty much all 93 by now)
Observations so far: slight measured mpg increase, maybe 1-2 mpg. Engine seems to accelerate more smoothly with less hesitation, seems a bit quieter at idle, overall difference is, at best, subtle. Will run two more fill-ups and calculate mileage. Not seeing any magic or mystical differences yet.

Click to expand...

I'm very aware of the placebo effect and I completely don't trust my judgement after knowing that I took some sort of "pill." But.... When I first filled up with this, I didn't pay much attention, just another piece of same old advertising. Forgot about it just after leaving the gas station. Then after a couple days I noticed the car runs really well (my car always runs well, but it was a bit above average feel). I still didn't think about the fuel. Then I had this impression again the next day and only then I remembered about this allegedly new gasoline and the TV ads. So I take it as a more credible impression, because I wasn't actually aware I filled up with any different fuel than usual when I noticed how nice the car drives.

I wouldn't be surprised if Shell added some additional octane and maybe doubled some higher quality more expensive components only for a limited time after the ad campaign. If I was a marketing boss at an oil company I would easily have this sort of an idea.

Gruber said:

I'm very aware of the placebo effect and I completely don't trust my judgement after knowing that I took some sort of "pill." But.... When I first filled up with this, I didn't pay much attention, just another piece of same old advertising. Forgot about it just after leaving the gas station. Then after a couple days I noticed the car runs really well (my car always runs well, but it was a bit above average feel). I still didn't think about the fuel. Then I had this impression again the next day and only then I remembered about this allegedly new gasoline and the TV ads. So I take it as a more credible impression, because I wasn't actually aware I filled up with any different fuel than usual when I noticed how nice the car drives.

I wouldn't be surprised if Shell added some additional octane and maybe doubled some higher quality more expensive components only for a limited time after the ad campaign. If I was a marketing boss at an oil company I would easily have this sort of an idea.

Click to expand...

Your observations are pretty much spot-on, overall I'm noticing subtle differences in smoothness & quietness, however measured mpg is really not improved, possibly 1-2 mpg. Certainly not enough to justify .60 cents/gallon cost. As far as long term results, who knows. I'm going to try one more fill-up then go back to Shell 87 which is Toptier. Weather here in Central Pennsylvania is in kind of a flux situation and I don't have any extended trips in the near future so meaningful comparisons aren't really possible. Overall, my thoughts are that an engine designed and programmed to run on 87 doesn't benefit all that much from 93. The extra $350+ dollars/year is better spent elsewhere.

Well, finally was able to get some purely highway miles on the 93 octane, actually computed to 2-3 mpg less.
Again, slight differences in smoothness, but no real verifiable mileage increase, in fact some loss. I've started the transition back to Shell Toptier 87. All the ads, the hype & claims, in the end, just ain't worth 60 cents a gallon more. Still prefer Shell, but I'll stick with what Honda recommends, 87 octane.

Over the years I've heard Mobil premium was a high detergent gasoline. That being said, my cars ran on regular & I used to buy the cheapest regular grade. After a year or two they would start idling just a little bit rough. I'd run 2-3 tanks of Mobil premium through the system & the idling smoothed out. Then I'd go back to the cheapest stuff. I never noticed any difference in power/acceleration with the premium grade. But I do think premium grade does have more detergents than regular grade, at least for some brands.

Here's a AAA study on gasoline quality. Be sure to click on the "full report shows" link for lots of photos & graphs.
https://www.thetruthaboutcars.com/2016/07/aaa-study-finds-drastic-difference-in-quality-of-gasoline/

Several years ago I started using only Top Tier gas, regular or premium depending on the car. The study shows not all Top Tier gas is the same so I try to rotate between a few different brands.

The higher octane itself may or may not make a difference, but the extra additives that could be in a premium grade might affect performance by keeping the engine cleaner. The same for using a Top Tier gas.

PhilF said:

Well, finally was able to get some purely highway miles on the 93 octane, actually computed to 2-3 mpg less.
Again, slight differences in smoothness, but no real verifiable mileage increase, in fact some loss. I've started the transition back to Shell Toptier 87. All the ads, the hype & claims, in the end, just ain't worth 60 cents a gallon more. Still prefer Shell, but I'll stick with what Honda recommends, 87 octane.

Click to expand...

Well, Honda may recommend 87 to you, but they recommend premium to some other customers of theirs, like me. So you do you, I will continue with 93 only, Shell or not Shell.

I don't trust your computation, because it is not easy to do a scientific comparison with all other factors being equal. 2-3 mpg less (less than what?) is unlikely.

All fuels have to meet minimum standards. Top tiers will have more of a detergent pack. Higher octane fuel can allow more advanced timing and the closer the piston is to the moment just after TDC when the pressure from the combustion event happens... the piston is going to have effectively have force applied to it longer. It'll make you have a little more power and efficiency for the same volume of gas burned. 20 years ago, the cost of premium wasn't, percentage-wise, higher than regular like it is today. Premium is easily 20% or more the cost of regular... when I remember it being maybe 10-15% more. For a premium fuel recommended car, I'd buy it for the power... but if you interested in efficiency, I'd always buy the cheaper gas. I'm more interested in miles/dollar than miles/gallon for efficiencies sake. I bought the Si and reflashed it... so I gave up from premium recommendation for a premium requirement on TSP Stage 1. It's a relatively cheap but good car I'm asking more from than it was asked to do in it's factory form... so using 93 all the time is warranted.

So far as detergents and cleaning? There is a lot of marketing that Shell 93 is 'better'... but then again, non-top-tier is technically good enough. Any top-tier should be better. I'd buy the cheapest top-tier if I was going for efficiency and cleaning but wasn't chasing power. When I see pictures at the pump or on the back of fuel injector cleaner of injector spray patterns/valves... I don't really get hooked by it. It's marketing. I've cleaned parts in diesel on the farm for a long...long time. Petrol-products are pretty good solvents and dissolve most anything. I've taken apart a few engines, mostly small, and they've always been as clean as a whistle. I've never seen something with coked up valves first-hand... other than some stuff where the oil was never changed... it was just added. For years.

Currently some states don't have 93 octane & 91 is the highest available, unless you buy racing gas. IIRC Calf has 91 octane as the highest premium grade. By me in ILL all the premium is 93 octane & 91 is nowhere to be found.

BriteBlue said:

Currently some states don't have 93 octane & 91 is the highest available, unless you buy racing gas. IIRC Calf has 91 octane as the highest premium grade. By me in ILL all the premium is 93 octane & 91 is nowhere to be found.

Click to expand...

Here in Central Pennsylvania, we have 87 , 89, & 93, we're starting to see some grades that have 15% ethanol, mostly at places like Sheetz. The Toptier stations, at least around here are Shell, ExxonMobil, Sunoco and Costco, we had a Valero, but think it closed. I've seen 91 in upstate NY.

But then, I don't get out and around as much as I used to, most of my gas is purchased at 2 local stations, Shell & Sunoco, my wife's Fit has only had ExxonMobil. Did fill up at a Shell in Hunt Valley Md today, $2.35 vs $2.69 here in Pa, which has either the highest or second highest gas tax. There may very well be some 91 locally, just never seen it.