i can’t be the only one who runs regular in a GT right?

[m3incorp]

Wait, you aren't paying to ship in some 93 octane from the East coast...

I'm kidding. I live in both GA and CO and in Colorado, 91 is the best it gets for the normal stations.

I have to run the 93 on the East coast and I'm good with that. My cars in CO are ok with the 91 there.

Nothing wrong with that… I would not even spend 15 minutes waiting in line to get .50c off a gallon, my time is worth much more than 5 bucks.
But I get it, we are all different and everyone’s financial situation is different too.

Would I buy a 55K performance vehicle and put the cheapest gas or wait hours just to save a few bucks ? NO.

If someone is concerned about saving $4 a tank (let’s say $10-12 a month), this person should not be pursuing a performance vehicle, not to mention a V8.
I don’t know, that’s just me.

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[Bikeman315]

It does not even recommend the use of 91 or 93 octane.

Really?

 

[WildHorse]

if the knock sensors are triggered, it retards timing. does the car wait until its refueled to restore full timing? is there some other interval? is it constantly trying to restore timing? how much more knock with 87 is the car enduring than with 93?
honest questions. not rhetoric.

I should answer in the same ungrateful childish way you answered @sk47. But I won't. FORD calls it ADAPTIVE OCTANE LOGIC. The next time you add fuel, it resets and depending on the octane content, it will use 'xx' timing map.

 

[sk47]

Really?

Hello; When I was shopping for a GT I asked the dealers several times about using 87 octane. Even went to the gas cap and fuel door to see what was listed. This is news to me. Is it part of normal use or perhaps a section about special conditions? I did not get to look at an owners manual.

 

[K4fxd]

When I was shopping for a GT I asked the dealers several times about using 87 octane.

The car is designed to run 91, it will de-tune itself to run 87 safely.
From what I have seen logging, it adds spark up to 94 octane.

 

[ICU812]

Hello; When I was shopping for a GT I asked the dealers several times about using 87 octane. Even went to the gas cap and fuel door to see what was listed. This is news to me. Is it part of normal use or perhaps a section about special conditions? I did not get to look at an owners manual.

Many sales people don't want to say, you should run 91 or 93 in a vehicle as that alone will cause many buyers to walk away, They know it will run on th 87 swill but be down on power from the claimed specs. But People are stupid, they'll cry over pump gas going up 3 cents while buying that 5 dollar+ 20 ounce cup of joe.
I mean look at this thread.
Last time I looked the price swing from 87 swill to 93 was 48 cents a gallon, so from empty running on fumes, it is a 7 dollar difference for 15 gallons of gas. So a v8 gt getting say 20mpg it is a whopping 2.4 CENTS per mile in "extra"fuel cost. It is most likely closer to under 2 cents as most get at least 20mpg or more and the 87 swill and ecu pulling power, you'll be deeper in the throttle to drive at your normal pace lowering the mpg because of this.
Many drivers will never feel the 50-80 hp drop in power from the retarded timing maps. As they rarely if ever get on it.
And for some that are already living beyond their means A gas price hike can make them cry. 5 dollar a gallon plus will hurt those that budgeted for 3.399 and only had 2 bits left over and now have to pony up for 5.00+ or hit the 87 swill button and pay 4.299gal.
When I had a long commute and in the mid 2000's and fuel went to 4 bucks plus for 87 swill, I traded in my truck for a fwd 4 banger that got double the mpg. I could afford the weekly fuel bill, but decided I'd rather not in a daily.
If fuel holds at the higher prices or even goes up even more and stays the course , you will see a bunch of soccer moms dumping those crew cab trucks for mid to small suv's with 4 bangers.

 

[WD Pro]

Interestingly, our Euro cars specify a minimum of 95 (RON) :

Which is your 91 :

V-Power over here is 99 RON / 94.5

WD

 

[tal]

I like the option of having 87 octane as an option.

I even had Steeda make a 87 octane tune. I normally run the 93 octane tune but just wanted to have this as "just in case". I may not be in an area with 93 octane or it gets too costly. Here in the Chicago area the swing between 87 & 93 octane can be .80 cents. That adds up after awhile.

Just for gags I loaded the 87 octane tune and the car actually ran pretty good. I could tell it was down on power but all the other tuning parameters that Steeda does with the 93 octane were there. I'm talking about trans shift firmness, top speed removal (didn't try that one yet!), and general responsiveness with the engine.

If I need to run 87 octane, I will be happy to use it because of the performance tune with 87 octane.

If you currently have a 93 octane tune, you may want to ask your tuner if they can do a 87 octane tune. They may look at you funny but if you tell them the reasons (as stated above) they will understand. And it was a no cost for the extra 87 octane tune.

For my wife's 2020 Nissan 370z I have a 87 octane tune in addition to the 93 octane tune. Tuner said it was the first one he has done for 87 octane. He did understand my reasoning. The car does REQUIRE 91 octane & up but with experience with 370z tuning (he's done hundreds) he was able to do a 87 octane tune. However; I have not run the 87 octane tune. And he did this as a no-cost option.

I'm just glad we have options from these tuners and hope the EPA doesn't come down too hard.

 

[velocityblue5.0]

Many sales people don't want to say, you should run 91 or 93 in a vehicle as that alone will cause many buyers to walk away, They know it will run on th 87 swill but be down on power from the claimed specs. But People are stupid, they'll cry over pump gas going up 3 cents while buying that 5 dollar+ 20 ounce cup of joe.
I mean look at this thread.
Last time I looked the price swing from 87 swill to 93 was 48 cents a gallon, so from empty running on fumes, it is a 7 dollar difference for 15 gallons of gas. So a v8 gt getting say 20mpg it is a whopping 2.4 CENTS per mile in "extra"fuel cost. It is most likely closer to under 2 cents as most get at least 20mpg or more and the 87 swill and ecu pulling power, you'll be deeper in the throttle to drive at your normal pace lowering the mpg because of this.
Many drivers will never feel the 50-80 hp drop in power from the retarded timing maps. As they rarely if ever get on it.
And for some that are already living beyond their means A gas price hike can make them cry. 5 dollar a gallon plus will hurt those that budgeted for 3.399 and only had 2 bits left over and now have to pony up for 5.00+ or hit the 87 swill button and pay 4.299gal.
When I had a long commute and in the mid 2000's and fuel went to 4 bucks plus for 87 swill, I traded in my truck for a fwd 4 banger that got double the mpg. I could afford the weekly fuel bill, but decided I'd rather not in a daily.
If fuel holds at the higher prices or even goes up even more and stays the course , you will see a bunch of soccer moms dumping those crew cab trucks for mid to small suv's with 4 bangers.

i’d love to see a dyno on 87 vs 91 vs 93 to see what the exact HP drop is at the wheel ya know? that would be cool. i’ll search youtube later lol

 

[ICU812]

i’d love to see a dyno on 87 vs 91 vs 93 to see what the exact HP drop is at the wheel ya know? that would be cool. i’ll search youtube later lol

Most likely not much, remember the octane rating is the min. that fuel out of that grade will be.

 

[Bikeman315]

Hello; When I was shopping for a GT I asked the dealers several times about using 87 octane. Even went to the gas cap and fuel door to see what was listed. This is news to me. Is it part of normal use or perhaps a section about special conditions? I did not get to look at an owners manual.

This is normal use. One top of that Ford makes it very clear that all performance and gas mileage numbers are rated using 91.

Minimum Required is 87
Minimum Recommended is 91

 

[sk47]

Interestingly, our Euro cars specify a minimum of 95 (RON) :

Which is your 91 :

V-Power over here is 99 RON / 94.5

WD

Hello; I will use this image as an example. It states the fuel requirements near the gas cap. This is what I looked at when shopping for the mustang GT. I did not simply take a salespersons word for it. The GT, as I recall, did not say 91 recommended on the gas cap.
Some of the cars I shopped for did say such. Some used the word required. It has become my understanding there are generally three levels with required meaning you must use the specified or greater octane fuel. That recommended, means you should use the specified or greater octane rated fuel, but might get away with a lower octane fuel from time to time if you could not find the suggested fuel. Personally, I would use the suggested fuel in both cases where the words required or recommended were used.

I looked at a few gas caps/door areas to see and do not recall the words recommended on the Mustang GT. I do not know about the turbo model as I never shopped for it. I did ask a dealer about the issue in Clinton TN. He dug out a manual and read from it, telling me 87 is OK.

I do figure the gen III engines can be set up to run on 87 as used in the pickup trucks. One thing is sure now. That being I will have to look into this some more if things ever settle down in the car markets and I start to shop again for a new Mustang. I do not want to risk any damage to a new vehicle by using a too low octane rated fuel. What some are saying on this thread is the 87 fuel rating for a new Mustang is not correct and it should be at least 91 to be safe.
I can be comfortable with less HP on 87 octane fuel, but not at the risk of damage. Knowing how to determine the risk appears to be much harder now.

 

[K4fxd]

What some are saying on this thread is the 87 fuel rating for a new Mustang is not correct and it should be at least 91 to be safe.

87 is perfectly safe. You are overthinking it. Ford did not want to require 91. They did want the car to perform on it. Think of it like the car has 2 tunes built into it. It senses the gas and runs the correct tune for it.

If 87 was not safe to use the gas cap and owners manual would state that 91 was required. The electronics on these cars are amazing, you could probably use 83 octane and not cause damage.

 

[331GT]

I always use 91 (highest octane rate here in California) on my GT. I did the same with my EcoBoost.
Typically, the difference between grades is 10 cents / gallon. With a little bit of math:

Filling a 14.5 gallon tank with:
*87: 4.70*14.5 = $68.15
*89: 4.80*14.5 = $ 69.60
*91: 4.90*14.5 = $71.05

So, you are saving $2.90 per tank. Is it really worth it? To me, it's not. Even if the difference between grades would be 20 cents you are saving $3.80 per tank.
Sometimes the only thing we "care" is the price per gallon, but when you do the math you realize that there is not that much difference between the lowest and the highest grade.

while i understand your point 100%, for some reason the days of a 20 cent different seem to be gone near me. sometimes it can be as much as a dollar difference between 87 and 93. i dont recall if i saw that difference at one gas station/one pump or say 87 is 3.30 and half a mile away i saw 4.30 or over for 93. ill pay closer attention next time. suddenly filling up that tank at a dollar more per gallon does begin to add up, especially if you're doing more than one tank a week. could i afford it? of course. do i want to when just cruising down the highway with cruise control set? not always. but yea, if it were a simple 20 cent difference as in your example, id likely never bother with 87. i actually remember it being that way around me, not sure when they wiggled these 50 cent or more differences in.

 

[sk47]

while i understand your point 100%, for some reason the days of a 20 cent different seem to be gone near me. sometimes it can be as much as a dollar difference between 87 and 93. i dont recall if i saw that difference at one gas station/one pump or say 87 is 3.30 and half a mile away i saw 4.30 or over for 93. ill pay closer attention next time. suddenly filling up that tank at a dollar more per gallon does begin to add up, especially if you're doing more than one tank a week. could i afford it? of course. do i want to when just cruising down the highway with cruise control set? not always. but yea, if it were a simple 20 cent difference as in your example, id likely never bother with 87. i actually remember it being that way around me, not sure when they wiggled these 50 cent or more differences in.

Hello; There are three grades in my area. There has been for years at least a 20 cent per grade jump. So from 87 to 93 would be at least 60 cents. I think I saw a bigger jump recently. I will check again.

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