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Which Gas grade do you use in your Fiesta?

  • 87

    Votes: 124 91.9%
  • 89

    Votes: 5 3.7%
  • 91

    Votes: 6 4.4%

Which gas grade do you use in your Fiesta?

63K views 66 replies 36 participants last post by  daftinn686 
#1 ·
87, 89, or 91?
 
#4 ·
I only use Top Tier fuel, mostly Conoco Phillips/76.
However I always use 89 octane.
As all Top Tier fuels meet the highest standards the 87 octane fuel usually only meets the minimum requirement for Top Tier.
The 89 and 91 octane fuels have the highest amount of additives by brand and only differ by the octane itself.
The cost difference between 87 and 89 is normally only 10 cents per gallon.
Most people, as do I, only by 10 gallons or less per fill up. I fill up less then once a week now so this is less than $50.00 per year.
I think my car is worth it.


Dave
 
#7 ·
Waste of money, don't make the oil companies rich!

Question!

Do any of those who use better than 87 octane (or any octane rating as specified by the manufacture) have any engineering or scientific fact that you're getting a better product for the car? My belief is that if the engineers designed the car for 87, then that's what you should use. All the expert information I have read over the years have always said that higher octane rating gas than what is recommended is always a waste of money! I have never seen, head or read any FACTS indicating anything different! And I might add my own experience over the years has proven to me that the recommended octane rating for any car I owned always gave me the best performance and the most economical situation. Its a known fact that higher than recommended octane is a waste of money. And no it does not clean an engine!

Now will someone prove me wrong!

Before you gang up on me, I do understand that there are a few unique instances that might warrant higher octane than recommended. The particular car that might ping because of manufacturing anomalies for instance. Or higher elevation might cause knocking IF you're using gas from a lower elevation purchase.

Before anybody replys please look at the first few articles as listed here:

Google

A few of these articles show testimony of people swearing that higher octane made a difference but not one gave any scientific proof or statistical proof (data comparison).
 
#9 ·
Question!

Do any of those who use better than 87 octane (or any octane rating as specified by the manufacture) have any engineering or scientific fact that you're getting a better product for the car? My belief is that if the engineers designed the car for 87, then that's what you should use. All the expert information I have read over the years have always said that higher octane rating gas than what is recommended is always a waste of money! I have never seen, head or read any FACTS indicating anything different! And I might add my own experience over the years has proven to me that the recommended octane rating for any car I owned always gave me the best performance and the most economical situation. Its a known fact that higher than recommended octane is a waste of money. And no it does not clean an engine!

Now will someone prove me wrong!

Before you gang up on me, I do understand that there are a few unique instances that might warrant higher octane than recommended. The particular car that might ping because of manufacturing anomalies for instance. Or higher elevation might cause knocking IF you're using gas from a lower elevation purchase.

Before anybody replys please look at the first few articles as listed here:

Google

A few of these articles show testimony of people swearing that higher octane made a difference but not one gave any scientific proof or statistical proof (data comparison).
Placebo effect.

You are correct in that 87 is the way to go. Timing maps are set up for 87 and higher octane means longer burn means performance degradation.

As for gas, Arco and Chevron use the exact same gas as everyone else. Literally. It even comes out of the same pipeline.

The only difference is the additives.


As for if they work for cleaning or not, the reason engines built up crap in the past had to do with seepage from looser clearances and impurities in the gas. Also the craptastic ignition systems by comparison that wore out plugs in 15-25k but were only changed every 50k because "it still runs good."

You can believe all you want but the fact is, your engine will tank from wear or lack of maintenance before it breaks from something related to cheap gas. Just keep up on your filters and oil and you'll be just fine. If it makes you feel better, run a bottle of BG fuel cleaner through every oil change. It's a hell of a lot cheaper than paying 10 cents for the next octane level.


That being said, I have noticed better performance running Chevron and Shell over Arco or Costco gas when I had my Tacoma. Whether or not it's worth the extra couple bucks every time I fill up (well, extra dollar with this car), I don't know. I'm just a creature if habit on that one... I've never tried cheaper stuff in the Fiesta.
 
#15 ·
I use the 89 ethanol blend because it's cheaper than 87. Has nothing to do with anything other than price. It's what I've used in every vehicle since I've been driving (11 years). I've had many different types of vehicles over the years and everything has ran just fine on it. :)
 
#17 · (Edited)
I have to admit, I am the guy that voted 91 octane. The cars I have owned prior to these were just crap cars I didn't care much about and put as little money into as possible. Then I got the bimmer which requires 91 octane and will actually run like crap without it.....don't ask me how I know (it wasn't from reading). When I got the Fiesta, I used 91 because I got use to it and assumed it'd be better in the long run without thinking too much about it.

So, I started reading and thinking more about it and it seems pretty clear. The car was made to burn 87 completely. Anything higher is a slower burning fuel requiring more spark and timing that is not there. Not only will you not be getting any benefits running a higher octane, but looks like you're not burning it completely so it's less HP, worse MPG and you're leaving crap behind to dirty up the motor. Maybe if you got a tuner chip that adjusts everything to take advantage of higher octane fuel and dynoed everything to show the difference between their tune and different octanes? I dunno, my motor will pretty much remain stock and I'll be switching to 87 on my next fill up.
 
#18 ·
I also worked at 76 stations for many years. My father even owned one for a time.
Yes, 76 does now only use two tanks and 89 is a blend of 87 and 91.
That being said, you still get the extra additives by using 89 octane.

Chevron, Arco, and 76 have their own refineries (at least here in So. Cal) and blend there own gasoline. They do however use the same OIL.

Yes higher octane fuel does burn slower to prevent detonation but it also burns more completely and cleaner. This not only results in lower emissions but by a more complete burn means that your catalytic converter and O2 sensors will last longer. So if you don’t care about emissions then save money on parts.

My wife switched from 87 to 89 in her FIT and MPG was increased by 3-5 miles.

Don’t take my word for it, try it your self, or ask your Smog Tech.


Dave,
Retired ASE Master Tech and California smog guru.
 
#19 ·
My wife switched from 87 to 89 in her FIT and MPG was increased by 3-5 miles.

Don’t take my word for it, try it your self, or ask your Smog Tech.
I put almost 300 miles on my car yesterday with 89 in the tank. At an average of 70-72mph I got approximately 41mpg. More than happy with my car's performance on 89. :)
 
#20 ·
I'm a bit skeptical now about this. I think when i get back from my vacation (from soon-to-be snowed in Kansas City to already snowed in Erie, PA) i'll throw in some 89 and see what happens....
 
#28 ·
Too many variables for one individual to claim (even with data) that higher octane gives better performance than what is recommended. Andrew and One4MeToo are correct. The scientific method is needed. Also until a recognized institute such as API, ASME, Good House Keeping, UL, or other such organization says so, it ain't true. One would think that if it was true one of these organization would publish findings. And why oh why would the auto manufactures lie? They don't need to lie. They are all playing on the same level field and all must meet EPA and mileage minimums. If using a higher octane would improve mileage and the auto companies could substantiate it, I'm sure people would be willing to use the higher octane. I don't understand it but people don't seem to care about price. When gas goes to $5 a gal, we will pay the price and continue to drive just as many miles as we always do. What I also don't understand is why a person will buy a sub-compact high efficiency mileage car for economy sake and then spend hundreds extra on higher gas prices that the designer says not to. What don't they understand about buying a car that is suppose to save you money?
 
#30 ·
What constitutes 87 octane varies across the U.S.

Thanks to the E.P.A. our nation is a patchwork quilt of fuel formulation "regions". What one person fuels up their Fiesta with in the L.A. basin is going to be different than what they refuel with in Vegas and very different from what they get in Nebraska or Denver Colorado! I use premium because I am not a fan of ethanol. Premium has the least percentage of ethanol. I have done one round trip drive on regular and then refuled with premium. it was a calm day and the trip was 135 miles of highway and 17 miles of city/suburban. low wind. no rain either way. I maintained steady 70mph on the highway. fuel economy was 1.3 mpg average higher on premium. Ethanol is less efficient than true gasoline(sic). The higher percentage of ethanol you put in, the less fuel economy you will get. I must say that My Fiesta was still very "new" last August when I took this trip. I don't think Regular fuel will hurt Fiesta unless you store the car with a tank of it! It is very short lived as a useable fuel. It is also a damn poor fuel for lawn mowers and garden tractors. It has no shelf life if kept in a can in a hot shed or garage. I cant speak to any definitive fuel economy result that is universal. I am certain that there are so many variations of Reformulated fuels/oxygenated fuels out there that a blanket comparison is difficult.
 
#31 ·
I don't think Regular fuel will hurt Fiesta unless you store the car with a tank of it! It is very short lived as a useable fuel. It is also a damn poor fuel for lawn mowers and garden tractors. It has no shelf life if kept in a can in a hot shed or garage. I cant speak to any definitive fuel economy result that is universal. I am certain that there are so many variations of Reformulated fuels/oxygenated fuels out there that a blanket comparison is difficult.
Well, I won't say you're right or wrong (I don't see any data). However, I fill up 3, 2 gal gas containers about once every 3 to 4 months and run all my lawn and garden tools including 4 & 2 cycle engines. Regardless of how old the gas might be I have never seen even a hint of poor engine performance from any of my gas powered items, including snow thrower or lawn tractor. Not sputter, skip or spurt. And it doesn't seem to affect how often I need to refill the appliance. I will however, dump any stored gas into the cars when change of season takes place between warm and cold.
 
#41 ·
Agreed. When I first got into racing M/C, I got a 60 hp sv650 to get around the track, just to learn the fundamentals.
The reasons were that it was easy to set up for the track, and if you went down, it was cheap to fix. It was a $1500 investment, for a 4-5 year old bike, just to learn the tracks ins and outs.
Of course the Fiesta is used, not cheap, and still needs alot of money into it to be track ready.
 
#44 ·
just wanted to say that I tried a tank of 89 from the same station I normally fill up with 87 at. Same time of day (6am) same day of the week and I dropped from 34mpg to just a tick over 31 since the last fillup. Same drive everyday.

Back to 87 for me.
 
#46 ·
I also filled up with 89 Thursday night. It was almost empty, 34 miles to empty according to the dash. I still only put in 10.6 gallons. Dashhawk reported 7% fuel left.
After 150 miles today, I had to drive 55 just to get it to 37 mpg.
 
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