Should I use premium gas in a 2015 Ford Focus SE?

[tamedcowboy]

My owner's manual for my 2015 Ford Focus SE recommends 87 octane, but also states that, "Premium unleaded gasoline will provide improved performance and is recommended for severe duty usage, for example a fully loaded vehicle."

So I went on the Ford website and the performance and fuel economy figures for a Focus SE are presented with an asterisk, (*Using 93-octane fuel). I'm wondering, should I use premium gas in my 2015 Focus SE?

Thank you in advance for your replies.

 

[horse123]

Do you have a heavy foot and love to feel every bit of acceleration? If you do, go for it, if you don't, then use whatever is cheapest.

 

[gathermewool]

I run the highest recommended octane.

 

[HTSS_TR]

If the price of premium is no more than 20 cents a gallon more than regular in your area you may try few tanks premium to see if your Focus is running better(quicker acceleration, quieter ...).

 

[NMBurb02]

What engine is that? The 1.0L or 2.0L EcoBoost?

 

[901Memphis]

If there mention of using premium I'd do it.

 

[Wolf359]

I don't think you'll get any better gas mileage so I would just use regular instead of premium. If the car is fully loaded, I could see how premium might help especially if it's an ecoboost.

 

[tamedcowboy]

2.0L Ti-VCT I-4 Flex Fuel. No Ecoboost, but it does have direct injection and 12:1 compression.

 

[BikeWhisperer]

87 works fine in mine, still get 38 mpg hwy and around 28 city which actually beats the smaller (car and engine) Scion I had before.

I haven't run premium in it since I got it in February so I can't tell you if there is a noticeable difference, just Top Tier 87 (usually Chevron).

 

[tamedcowboy]

That's a big help. Thanks.

 

[Danh]

This will just demonstrate how we're still trying to figure out DI technology...

I use premium in my 2012 Focus, principally because it just runs better with it (crisper throttle response, etc.) and it seems to get slightly better fuel economy. Fuel dilution can be an issue with DI engines and some believe 87 octane is more likely to cause detonation that prompts a richer mixture, which in turn could cause fuel dilution. And low speed preignition is a cause of combustion chamber deposits in DI engines - something premium may help to prevent.

So, I'd say try a few tanks of each and see if the car behaves better with premium. If it does, it's up to you whether the cost is worth the better behavior and the other "maybe" advantage of premium.

 

[wemay]

Both GDI...

My Sonata pings slightly on 87, mostly during hot weather. The Santa Fe 2.0T runs on anything without a hiccup. I mostly use 93 oct in both, rarely 87. I prefer to have control over detonation in these very high compression GDI engines by using higher octanes instead of relying on the ECU.

 

[aquariuscsm]

I'd only use premium if you're experiencing pinging under heavy throttle.

 

[wemay]

Originally Posted By: aquariuscsm
I'd only use premium if you're experiencing pinging under heavy throttle.


Oddly enough, i do in the naturally aspirated Sonata because of it. My wife drives the Turbo and sometimes uses 89 octane. But again, that vehicle has never hinted at having issue with mid-grade. The manual recommends 87 or above in each.

 

[raytseng]

Agree with the people saying just try it for a few tankfuls. There's no barrier to entry to just find out.

 

[bvance554]

Or you may find a happy median with mid grade.

 

[badtlc]

I would and do use it in my similar Mazda 3 DI skyactiv.

What is the compression ratio on that Focus DI? If it is above 11, i'd definitely run premium.

 

[CT8]

Run the gas tank down to below a quarter and run a half dozen tank fulls of premium and find out.

 

[gathermewool]

I'd recommend against changing from high to low octane on a regular basis, if the ECU can indeed advance timing and change fueling to account for higher-than-87 AKI. The ECU will respond by knock sensor input to very quickly retard timing and possibly enrich the mixture, but I'd prefer not to require the ECU to have to respond like that.

So, if I wanted to switch from the highest octane the ECU could account for to 87, I'd reset the ECU to reset the learned ignition advance and fueling tables.

I assume that each knock scheme is different, but it might be that the ECU is ALWAYS trying to add back timing, even if you always use 87 octane, which means that it's always operating at the threshold of knock. Personally, that would bother me, knowing that my engine always having to react to account from knock instead of allowing for max timing and not having to react at all.

IMO, the OEM's worked hard to provide robust enough knock schemes so that they could provide turbo-charged or higher-powered engines to people that will run on 87 octane, because they can't stomach the EXORBITANT cost of running 91+ octane. I really don't know how running 87 AKI in a car designed for 87-93 octane will affect longevity, but I have no intentions of finding out. If the manual recommends 93, I'll run 93.

 

[KeithS_NW_Ohio]

Track your fuel cost using this spreadsheet. Do 3 or 4 fill ups with 87 and then 3 to 4 fill ups with 91-93 octane. The spreadsheet will show you your cost per mile on different fuels.
http://www.vertex42.com/ExcelTemplates/mileage-calculator.html