Better Gas Mileage with 87

[Jordan Arthur]

I've switched back and forth between 87 and 93 many times. I've heard most people justify the cost which here is about .60/gal difference by the increase in gas mileage they got with 93 but it's been the opposite for me. I try to drive the same with both and maybe but rarely I romp it a bit more with 93 but I don't exactly baby the throttle with 87.

Has anyone else gotten better mileage with 87? I know the 87 vs 93 debate has been beat to death but I just can't justify the cost difference at this point with the slightly better performance you get with 93 which to be honest I can't notice either. I rarely use sport mode but when I do and having a PP car it's night and day almost in terms of acceleration but that's the same with both octanes.

Is it truly better for our cars to run 93 for longevity and reliability?

 

[krewat]

Longevity and reliability? Probably not, unless you count the process that the PCM goes through every so often of advancing the timing until it knocks and then backs off. This allows you to run 87 without pinging. On the other hand, I'm not even sure this PCM does that, it might just run off the knock sensor, someone else will have to chime in.

But the PCM is listening for a ping, and that ping will happen more with 87 than 93. But I doubt it's really a longevity issue.

Do your gas pumps say it contains ethanol or "may" contain ethanol? The one thing that might be going on is, there's more ethanol in the 93 to raise the octane, so in affect, it's causing worse gas mileage.

I don't know about anyone else, but when I once tried 87 in my 2013, it was such a slug I couldn't stand it. I never went back to it ever again...

 

[Jordan Arthur]

I'll check the whole ethanol thing but my 2014 runs like a bat out of **** with either octane.

 

[Poppa Diezal]

I've been wondering the same thing. I was afraid to put 87 in. Going on a 200 mile trip this weekend. I'll try 93 on way and 87 back the other. Record my gas mileage. Itll be a highway cruise both ways with little stomping.

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[bpopilek]

Are you guys running custom tunes and switching back and forth between octanes? I have a Livernois tune and it says to run 93 Octane. I've never tried running 87 with the 93 tune active. I didn't want to cause possible damage. I'd like a little more insight in to this too.


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[Jordan Arthur]

No tune, im all stock w/pp

 

[Eric Morris]

I'll check the whole ethanol thing but my 2014 runs like a bat out of **** with either octane.

My runs just fine on 87 too. I see no reason to spend $0.60+ per gallon more. If I was trying to race people all the time, or had a tune, sure- but for a stock DD, it's a total waste of money IMO.

I've driven mine for 10,400 miles so far and have averaged 22 MPG. 10400/22= 472 gallons of fuel. 472 * 0.60 = $283. Personally, I'd rather have $283 in my pocket.

Looking at the numbers further- I've paid an average of $2.34 per gallon over those miles. The $283 will buy 125 gallons of fuel at that price. At 22 mpg, that gets me 2,750 miles further down the road.

So for the premium to be worth it solely as increased MPGs (which I know is unrealistic) it would have to deliver 13.150 miles in the same 472 gallons, which would be 27.8 MPG. So in my case premium would have to deliver 25% more MPG just to break even cost wise.

 

[jman1200]

I alter between 87 and 93 tunes by Unleashed. Haven't noticed any difference in mpg between the two.

 

[Jordan Arthur]

My runs just fine on 87 too. I see no reason to spend $0.60+ per gallon more. If I was trying to race people all the time, or had a tune, sure- but for a stock DD, it's a total waste of money IMO.

I've driven mine for 10,400 miles so far and have averaged 22 MPG. 10400/22= 472 gallons of fuel. 472 * 0.60 = $283. Personally, I'd rather have $283 in my pocket.

Looking at the numbers further- I've paid an average of $2.34 per gallon over those miles. The $283 will buy 125 gallons of fuel at that price. At 22 mpg, that gets me 2,750 miles further down the road.

So for the premium to be worth it solely as increased MPGs (which I know is unrealistic) it would have to deliver 13.150 miles in the same 472 gallons, which would be 27.8 MPG. So in my case premium would have to deliver 25% more MPG just to break even cost wise.

Nice break down sir and i agree with u 1000%. I don't race people and i can get in and out of traffic as good as anyone. In my case i think i would only see the performance difference if i tracked the car but i def don't feel a drastic difference on power between the 2.

 

[Lostneye]

Longevity and reliability? Probably not, unless you count the process that the PCM goes through every so often of advancing the timing until it knocks and then backs off. This allows you to run 87 without pinging. On the other hand, I'm not even sure this PCM does that, it might just run off the knock sensor, someone else will have to chime in.

But the PCM is listening for a ping, and that ping will happen more with 87 than 93. But I doubt it's really a longevity issue.

Do your gas pumps say it contains ethanol or "may" contain ethanol? The one thing that might be going on is, there's more ethanol in the 93 to raise the octane, so in affect, it's causing worse gas mileage.

I don't know about anyone else, but when I once tried 87 in my 2013, it was such a slug I couldn't stand it. I never went back to it ever again...

I don't know enough to talk details but yes the ECU does adjust. OAR short for Octane Adjust Ratio can be datalogged. It's not just timing it can affect multiple strategies.

 

[Jeff2017]

93 is more important in hot climates. I fill up with 93 at Costco which is already about .20 a gallon cheaper and it has detergent. I figure I might be spending about $100 more per year. I see no reason to be putting 87 in a twin turbo. If you cannot afford the cost difference then maybe NA engine would make more sense.

 

[SHOdded]

Yup, the PCM uses knock sensor data to adjust timing. If you drive your SHO "normally" and use good quality fuel, 87 should be fine. One note of caution: pay attention to the car! If it starts to ping or misfire, the car has no room to adjust DOWN. This could result in an irreversibly damaging knock condition. So, since 87 is the minimum octane fuel that is required, do not cheap out, and you will be fine.

 

[Christian]

Up here in the Pacific Northwest, higher octane fuels have LESS ethanol, no the other way around. For example, I often use Chevron 94 octane , which has ZERO ethanol.

The difference in performance is very noticeable as well. It feels like a completely different car. Fuel economy? No idea. Its pretty bad (for a v6) either way. I certainly don't use the higher octane for the economy. The higher octanes also have higher levels of detergent in some cases (though not with Chevron...it's the same across the grades).

There is at least one video online that shows before and after 0-60 times with lower and higher octanes in a Ford (I think a Focus ST). If I recall, it was about .3 seconds quicker.

As for longevity? Nah...I doubt it. My manual in Canada here, says 87 octane. It recommends 94 only to get the advertised 365 hp numbers and 0-60 claims.

 

[Jordan Arthur]

93 is more important in hot climates. I fill up with 93 at Costco which is already about .20 a gallon cheaper and it has detergent. I figure I might be spending about $100 more per year. I see no reason to be putting 87 in a twin turbo. If you cannot afford the cost difference then maybe NA engine would make more sense.

Lol...you are right, i'll sell the sho, roll a few thousand in negative equity and just go buy a charger to avoid the .60 extra cost at the pump. Thanks for the sound advice!

 

[SM105K]

I remember when I used to get 22 mpg combined.....I get a solid 30.3 combined mpg now.

 

[6500rpm]

I also saw better mileage with the 87 untuned. Shortly after buying the car I switched over to Shell V Power, not so much for the higher octane, but for the cleaning properties that I'd read on line even with GDI. Unfortunately almost every Shell station in St Louis recently sold out to Circle K leaving me looking for another Premium brand, right now it's Mobil, but I'm not sure about what's in there blend and how it compares to Shell.

 

[Jordan Arthur]

I also saw better mileage with the 87 untuned. Shortly after buying the car I switched over to Shell V Power, not so much for the higher octane, but for the cleaning properties that I'd read on line even with GDI. Unfortunately almost every Shell station in St Louis recently sold out to Circle K leaving me looking for another Premium brand, right now it's Mobil, but I'm not sure about what's in there blend and how it compares to Shell.

That's good to know on the Shell, I try and get Mobil if I can as I get points as a reward member of theirs but i'll def go Shell if it's better.

 

[SHOdded]

I like the Exxon/Mobil Synergy too. It is in all octane grades. V Power is only in Premium/93 octane grade.

 

[Jeff2017]

Lol...you are right, i'll sell the sho, roll a few thousand in negative equity and just go buy a charger to avoid the .60 extra cost at the pump. Thanks for the sound advice!

LOL!

 

[jman1200]

I fill up about once a week so it's 70 liters x 52 weeks @ 0.2 l difference, it comes to $ 728/year... ouch !
That is why I load the 87 tune during Winter to save about half of that.
Totally worth the extra cost using the 93 when weather permits, otherwise why tune it if you won't use it.