Octane curiosity - anybody running 87 octane?

[spectreman]

a little shouty, are we?

Nobody 'feels' HP, they feel torque and that's where the big impact is.

You asked a 'loaded' question and got sensible answers as well as snide ones. It's the Internet. Who cares what forum jockies say anyway? If the manual says you can run 87 that's the definitive answer. We/you pissed away 35-50 grand on a completely impractical 4-wheel conveyance and so it naturally follows that the fuel bill doesn't even register as a consideration.

Not seeing how a Costco etc. a mere >15 miles away is some kind of great difficulty. Do you live at the wrong end of a goat track where gramps on a walker makes better time than you can because of traffic?

AH, AND THERE COMES THE SOUND OF AN SVT FORUM SITE MEMBER!

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[onebad58]

Out of curiosity, I loaded up w/a tank of Sunoco's good ol' 87 octane today in the '19. Saved myself more than $7 for the 11 gallons over their 91 octane's price. Would've been even more if I had gone as I often do w/their 93 octane.

Doesn't sound like much but over time that could add up, especially since I tend to fill up twice per week. It could mean more than $60 a month, or almost $700 a year, more if I compared to 93! That's six months of auto insurance costs for me.

Mindya, my car is a daily driver, not a track or race car. I'm not looking for ultimate performance/HP, etc. Anyway, the car ran fine. In the routine powerband I normally drive in, I felt zero difference in engine performance. And amazingly, I had to do some highway miles and got my highest mileage yet- 28.6 MPG cruising at 77 MPH.

So there ya go- that's my experiences from today.
Lee

i use 87 octane aal the time. works just fine in my 19 gt a10. in the summer ill use 93 and only on the drag strip. my car with only 500 miles on it ran 12.63 @116mph i totaly stock mode .my gt 350 has to have at lest 91 octane.

 

[nustang]

Use 87 in my V6 and it runs very well. tried a nearly full tank of 91 with no discernible change.
bit of googling you will find 87 has more bang (bigger explosion) than higher octanes.
Higher octanes are harder to light off, ie for higher compression engines, so the fuel doesnt ignite prematurely and prevents knock. They arent more powerful.
If you have knock issues, Id investigate that first (plugs, heat range, etc).
Hashtag - owners manual.

 

[shogun32]

They arent more powerful.

1cc of 87 and 1cc of 93 have the same BTUs in their unburned state. "powerful" engines use timing advance etc. to extract more of the BTUs (or Joules) per unit of fuel than "less powerful" engines can. The v6 Mustang engine is an antique. But if you put a tune on it and teach the ECU how to properly leverage 91/93 it makes a very noticeable difference than it can safely/reliably generate if fed 87. Whether or not you care, or the (im?)perceptible difference is worth the cost hike is up to each driver.

 

[nustang]

1cc of 87 and 1cc of 93 have the same BTUs in their unburned state. "powerful" engines use timing advance etc. to extract more of the BTUs (or Joules) per unit of fuel than "less powerful" engines can. The v6 Mustang engine is an antique. But if you put a tune on it and teach the ECU how to properly leverage 91/93 it makes a very noticeable difference than it can safely/reliably generate if fed 87. Whether or not you care, or the (im?)perceptible difference is worth the cost hike is up to each driver.

They may have same BTUs, but the burn is more explosive with 87 (faster)
Yep , you sure can mod the engine/tune etc to get more ponies, and use higher octane with advantage.
However in stock form, anything other than the MFGR's recomendation is false economy if hoping for better performance. High performance vehicles tend to recommend 91/93. So the association is it gives more power if you use it in stock commuter cars. And oil companies exploit that association to sell you a higher profit product.

 

[Elp_jc]

One of the things that appeals to me in the V-8 Mustang is to be able to use 87 octane fuel. I passed on the Subaru BRZ and Toyota 86 because they require premium fuel.

with all due respect, that is a lousy excuse. Either of those cars would cost you less in fuel, even with premium, than a V8 Mustang on regular. Just saying .

And yes, Ford might recommend regular fuel and 5/20 oil, but that doesn't mean they're the best for the engine. Remember auto manufacturers do anything appease the EPA, save thousands of dollars by saving 1/10 of a MPG with thinner oil, and make their cars more attractive to more people (cheaper to run). So yes, you can run your GT with regular fuel and 5/20 oil, but it doesn't mean it's the best for the engine. Having said that, would I run regular if fuel was $4 a gallon? Most of the time, probably yes (except on trips, when I run it harder). Now? No way.

 

[sk47]

with all due respect, that is a lousy excuse. Either of those cars would cost you less in fuel, even with premium, than a V8 Mustang on regular. Just saying .

Hello; You may be correct, I have not done the math. Around here the difference is always at least 40 cents a gallon at the cheaper stations. I guess either of the two cars mentioned should get a bit better MPG, driven normally, than the Mustang. I think the Mustang is heavier so will require more energy to move it around. If the power of the V-8 is used then for sure it will take more fuel to create the greater horsepower. Not sure how calm ordinary driving would play out.

I have a friend with a VW Jetta diesel. He gets between 45 to 50 MPG. I have had gas cars which get 40 MPG. Most of the time his fuel is a lot higher per gallon. I have done the math and he loses much of the time in terms of just cost. This is not much of an argument for my side tho, is it.

These secondary arguments aside, to me the bottom line is if the 87 octane will in some way damage the engine. In the dark mid-times mainly during the 1970's and 80's pre-ignition was a problem. Before then emission controls did not exist and by the 1990's or so the new computer run systems were getting a grip on detonation. Pre -ignition can do damage to an engine and is worth doing something about.
If an engine will run without damage on 87 octane, then those who want to give up some power and torque are not losing anything permanent. At any time they can get a tank full of premium and be back to full power.

 

[cactus_kid]

I was at a Sam's club getting 93 gas and an old boy who worked there told me they test the gas every week and the 87 has never tested less than 90. That's interesting. In my Bullitt I only use Shell, Chevron, or BP 93.

Not surprised. Same issue here in TX. That is why I run mid grade. Seems to work great year round. Here in TX, CO and, CA ..... both ends of the state.

 

[Elp_jc]

I haven't tried regular yet, but the engine should run fine if octane is in fact at least 87, but how worse it'd drive compared to premium, I don't know... and don't want to find out. Ha ha.

 

[blackk3389]

I had asked James the question of running 87 in the BULLITT a few weeks ago when i saw him, his reply was in the face he made.......lol. it was all i ran in my '16 GT without a hitch
he did say it was not a problem to some, but that there would be a power difference. harm to your engine i dont think so. harm to some ego's here yes. if you want power and low cost fuel go E85, like james wanted me to go. its all he runs in his '03 mach1. and the price difference between 93 and E85 is even bigger up to a $1.00 a gallon
i dont drive the car enough to hit me in the wallet to make these changes or go low octane

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