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This answers a question that I had in one of the ad nauseum threads that seems to pop ever now and then in the model forums about "oh is premium/regular ok to use" and the old mantra is still true and is NOT disputed by this AAA study: If your manual "requires" premium put in premium. But apparently now manufacturers are putting wording that distinguishes between "recommended" and "required." And this study is the 1st of its kind that tests whether following the recommendation is actually worth it IF the premium octane is not specifically required.
Summary of findings:
Fuel economy for test vehicles averaged a 2.7 percent improvement. Individual vehicle test result averages ranged from a decrease of 1 percent (2016 Audi A3) to an improvement of 7.1 percent (2016 Cadillac Escalade).
Horsepower for test vehicles averaged an increase of 1.4 percent. Individual vehicle test result averages ranged from a decrease of 0.3 percent (2016 Jeep Renegade) to an improvement of 3.2 percent (2017 Ford Mustang).
According to national averages, the price difference between regular and premium gasoline is approximately 20 to 25 percent, or 50 cents per gallon.
The modest fuel economy improvements found in AAA tests do not offset the higher cost of premium gasoline.
Interestingly, the Audi A3 loses MPG when using premium, and the Jeep Renegade loses HP when using premium.
Interestingly, the Audi A3 loses MPG when using premium, and the Jeep Renegade loses HP when using premium.
Interesting; our 2012 GTI *seemed* to get slightly better economy with Premium fuel, if (and only IF) we were able to keep our foot off the go pedal. Said another way, if we were playing up in the mountains and running the motor through its paces between curves, the economy dropped compared to running Regular, most likely because we were using the extra power afforded by the higher octane fuel, however, when on a long trip when running on Cruise Control, the economy was slightly better with Premium.
I was surprised in this study that the Mustang GT is only recommending premium and does not actually require premium fuel.
Originally Posted by Chief F1 Fan
and what happens to the engine sensors when you run regular vs. premium when the latter is required? they get trashed, that's what happens.
Indeed and AAA clearly states that for cars that specifically "requires" premium it's a no brainer to use premium.
Though for the Audi A3, they also saw knock/pinging at regular octane as well, even though technically it did not "require" premium as per the study.
They compare % increase in MPG/HP to % increase in gasoline cost. On a pure math vs math basis, the two % does not equal out (ie, the higher cost is not equally seen in higher performance/MPG, with the Audi looking real bad at regular octane). Which is one way to compare...but I' sure others will value the increase in MPG/HP differently when deciding whether to go premium or regular.
I'm pretty sure most "normal" cars these day are able to safely burn Regular (hence the "recommended" versus "required" language).
That would make sense. The level of engine management technology and engine materials engineering has probably come a long way and so the ability for most engines to tolerate or run on regular is probably quite a bit expanded than before. Even in sporty motors.
What they need to do, which would take long time/effort, would also to study if there are long-term deficits in running premium vs regular when tens/hundreds of thousands of miles are put on the motors.
We need the crabman to verify, but most engines that take premium won't bust from running regular when requiring premium as the octane isn't that different. That being said, there's definitely a point where the timing and efficiency improvements of premium gas no longer justify the price increase.
It's understandable that people don't want to fill their cars with regular when it says premium recommended in the interest of protecting their investment.
It's understandable that people don't want to fill their cars with regular when it says premium recommended in the interest of protecting their investment.
That's me right there, since I'm not an automotive engineer I feel safer going with what is recommended by the smart people who designed the engine. It's not their fault that ExxonMobil charges more than what premium gasoline is actually worth.
Originally Posted by Saintor
Oddly, the other previous Bimmer, a 2005, ran rough cold on regular so I sticked to premium on that one.
When we had our Bimmer we ran 93 through it, but it still spuddered. The dealership told us to use Shell gas. After a few cycles the spuddering was gone. Talk about weird (and finicky).
It's understandable that people don't want to fill their cars with regular when it says premium recommended in the interest of protecting their investment.
at people trying to save roughly $125 per year. If it says premium recommended, I'll go with premium.
15,000 miles/yr with average 30 MPG = 500 gal/year x $3.00/gal for regular = $1,500
15,000 miles/yr with average 30 MPG = 500 gal/year x $3.25/gal for premium = $1,625
It's actually less for me since the price difference between regular and premium is $0.10 to $0.15 and I drive less than the national average of 15,000 per year.
9,000 miles/yr with average of 25 MPG = 360 gal/year x $3.00/gal for regular = $1,080
9,000 miles/yr with average of 25 MPG = 360 gal/year x $3.15/gal for premium = $1,134
Those could be used for general numbers, but some cars got better gas mileage and some got worse gas mileage. Overall there was roughly a 3% increase in gas mileage with premium.
After flow testing fuel injectors from cars using both premium and regular, I have noticed that the additional detergents in premium help maintain better flow. After 75k miles on premium, flow was still 98-99% of rated flow. After 75k miles on regular, flow was as low as 80% of rated.
The cleanliness of the injectors would suggest similar cleanliness of valves. Both would affect the airflow and therefore overall performance of the engine.
If you choose to run regular, I would highly recommend regular use of a good fuel system cleaner like techron. By regular use I would say right before every other oil change.
After flow testing fuel injectors from cars using both premium and regular, I have noticed that the additional detergents in premium help maintain better flow. After 75k miles on premium, flow was still 98-99% of rated flow. After 75k miles on regular, flow was as low as 80% of rated.
The cleanliness of the injectors would suggest similar cleanliness of valves. Both would affect the airflow and therefore overall performance of the engine.
If you choose to run regular, I would highly recommend regular use of a good fuel system cleaner like techron. By regular use I would say right before every other oil change.
I'm not at all buying what you've written; I've worked with three different automotive manufacturers and have had hands on several long-term tests of fuel injectors, and not one of them support your argument for Premium.
I'm not at all buying what you've written; I've worked with three different automotive manufacturers and have had hands on several long-term tests of fuel injectors, and not one of them support your argument for Premium.
when I pulled my heads, I found carbon deposits on the pistons. at that time, I had extensivley used Premium fuel, but from Sam's club.
would your experience lend towards different tiered fuels?
Since then, Ive switched to Shell...(no difference in perceived performance or fuel economy.)
but would be interesting to pull the heads to see if any carbon buildup
I'm not at all buying what you've written; I've worked with three different automotive manufacturers and have had hands on several long-term tests of fuel injectors, and not one of them support your argument for Premium.
You certainly don't have to buy anything I say. I simply post what I've experienced.
I've sent several sets of injectors from s2000's that have only seen premium fuel. 98% is the least flow compared to rated I've ever seen back.
Conversely I've sent several sets of injectors from 4g civic's/2g crx's that only ran regular. 80% is the least flow, and I've never seen as high as 98% on any from them.
Always sent off around 75k, +-5k
This is not a scientific test with controlled environments by any means. However, it's what I've seen in my experience, so it's meaningful to me. For everyone else take it for what it's worth, just another internet opinion to add to the millions of others out there.
I was always under the impression that each grade at the same gas station (Shell or Exxon) had the same additives. Turns out that they only put the detergents and additives in the premium gasoline.
Perhaps that is the larger reason why premium fuel is more expensive. Having a cleaner engine over time may be more of a value proposition then just saying that you get little to no MPG or HP gains from higher octane fuel.
I run premium in the F150, manual calls for it when towing & carrying a load. Not a huge jump in the price of a tank.
Our Flex runs on 87 only, never tried anything higher.
I was always under the impression that each grade at the same gas station (Shell or Exxon) had the same additives. Turns out that they only put the detergents and additives in the premium gasoline.
Not quite correct; there are a huge number of additives and detergents in non-Premium fuels. The thing is, some companies opt to put even more in Premium; the benefit of these extra additives is more than a bit dubious.
I run whatever is recommended. If it's 87, that's what I use. If it's Premium (93), that's what I use.
That said, I typically put ethanol-free in the Tundra, FJ, and Jeep since they are not driven as much. The Bimmer and E63 get Premium. Only reason they don't get ethanol-free is b/c the stations here that have it only have either 89 or 90. If I do find 93 ethanol-free I will put it in the other two... otherwise it's just standard Premium as recommended.
From their analysis, they found that some companies (Shell, Speedway) put double the amount of detergents in premium vs regular while with others (Mobil) it's a negligible difference. Things may have changed since then though.
Learn something new every day. I had no idea that premium fuel potentially had more detergents. I simply stick to premium due to the same logic as AZuser; it's not that much more expensive in terms of operating costs per year and the science of compression ratio and knock makes sense.
What I find interesting is that oil companies and gas stations don't tend to promote premium fuel. Following the money, maybe it's because the profit margin may not be all that much better. It's true that the premium fuel is usually termed something like "supreme" or some other description that leads consumers to believe it's better. But otherwise, their main promotion tends to be their fuel cleaning your engine, being fresh or helping performance.
I'm with horseshoez in the difficulty in believing that premium fuel would somehow be better for fuel injectors. At least in my experience, my Pilot's FI's look exactly the same as the TL's. Granted, we typically use Chevron or Shell. Maybe that makes a difference.
And again, following the money, I'm not sure what the incentive would be for auto manufacturers to promote the use of premium fuel if the car didn't need it. Are they getting some kick back from the oil companies? I kind of doubt it. Auto makers are making more and more efficient vehicles, along with hybrids and electrics, yet fool the consumer into using premium as some sort of conspiracy with oil companies? That's a hard pill to swallow.
I guess the question is how much detergent is sufficient to properly keep injectors clean and from whom you're buying gas from because you're worse off with premium Marathon gas vs regular Exxon gas since the Exxon gas has more detergents per mL
I really don't understand the mental gymnastics some people do to try to save a hundred bucks or so over the course of an entire year.
Chances are if your vehicle requires premium, it is either a luxury vehicle, relatively high performance, or both. You paid more for a premium vehicle, yet want to try and cheap out?
I really don't understand the mental gymnastics some people do to try to save a hundred bucks or so over the course of an entire year.
Chances are if your vehicle requires premium, it is either a luxury vehicle, relatively high performance, or both. You paid more for a premium vehicle, yet want to try and cheap out?
the last time I tried to cheap out, I tried one-ply toilet paper.
Never again! my tooshie deserves at least 2-ply!
at people trying to save roughly $125 per year. If it says premium recommended, I'll go with premium.
15,000 miles/yr with average 30 MPG = 500 gal/year x $3.00/gal for regular = $1,500
15,000 miles/yr with average 30 MPG = 500 gal/year x $3.25/gal for premium = $1,625
It's actually less for me since the price difference between regular and premium is $0.10 to $0.15 and I drive less than the national average of 15,000 per year.
9,000 miles/yr with average of 25 MPG = 360 gal/year x $3.00/gal for regular = $1,080
9,000 miles/yr with average of 25 MPG = 360 gal/year x $3.15/gal for premium = $1,134
$54 difference.
.
with more and more FI cars... how much is Smile per gallon worth? I think at the end running 91+ will come out on top.
I think the only time i put in 87 is in loaners i mean i am sure the person before me used 87 too.
Last edited by oonowindoo; 12-20-2017 at 06:15 PM.
I found the Engineering Explained video and AAA's report fascinating. The spread between regular and premium in the Northeast is 60 cents to almost a dollar, but I'm not in to save a few bucks. I'm in it for the same reason I visit Acurazine -- knowledge.
I found the Engineering Explained video and AAA's report fascinating. The spread between regular and premium in the Northeast is 60 cents to almost a dollar, but I'm not in to save a few bucks. I'm in it for the same reason I visit Acurazine -- knowledge.
Well, not in the entire Northeast; I live in New Hampshire and the station down the road from me only has a thirty-cent delta between Regular ($2.319 last night) and Premium ($2.619 last night). Lucky me.
12-18-2017, 03:12 PM
i mean i am sure the person before me used 87 too.
