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View Full Version : 87 octane or 91 (premium) ???



Cammilla500L
07-23-2013, 01:42 AM
Ok, I have a 2014 500L with the duel clutch and my owner's manual says "87 octane preferred, 91 optional" on the internet Fiat sights and reviews say 91 is preferred and 87 is optional. The dealership said to use 87 octane.

I've been using 87 and its getting 32 mpg on the highway and about 20 mpg in town. Should I switch to 91? I love my little car and I want to use the right gas. Its at the most an extra $1.00 to a $1.20 per fill up....so thats not a problem for me.

Help?

ScorpionSkins.com
07-23-2013, 01:58 AM
One very important thing to look at is the ethanol content of the fuel you're pumping into the vehicle. I'd recommend using a pure blend of gasoline (ethanol free) as higher concentrations of ethanol commonly found in 87 blends will reduce mileage by as much as 10%. A 91 blend will allow the engine within our vehicles to operate at optimal timing and has improved knock-resistant qualities within those parameters. A higher quality fuel blend is also (typically) better formulated to assist in removing and preventing carbon build up over time. For my vehicle, I refuse to pump anything but ethanol free 91 octane fuel (be sure to verify the gas station you visit offers an ethanol free variety).

One additional important factor to note is that should you encounter a gas station offering fuels with an octane rating higher then 91, it would serve of little benefit to use these blends with our vehicles unless the ecu were reprogrammed to take advantage of the higher octane rating (of which no ECU tunes currently exist). Hope that helps! :)

Cammilla500L
07-23-2013, 02:39 AM
Thanks Scorpion!
I was also wondering about ethanol too. I don't have a problem with finding ethanol free gas but I go to Nebraska about once a year and have found most of the gas stations carry ethanol in the Midwest. I noticed the other day that Sam's Club has 10% ethanol in their gas....so no more gas from them.

What would happen if I accidentally put ethanol mixed gas in my car? I've heard that there will be more and more stations are going to be going ethanol in the future.

My Dad put gas with ethanol in his motor home and it vapor locked and wouldn't run....he had to drain the tank.

ScorpionSkins.com
07-23-2013, 03:52 AM
Not to worry. :) Our vehicles are designed to accept fuel blends with up to 10% ethanol without issue (aside from the energy loss), although straight from the service manual are some details on what you may encounter if you use a fuel with an ethanol concentration of higher then 10%:



E-85 Usage In Non-Flex Fuel Vehicles
Non-FFV vehicles are compatible with gasoline containing
10% Ethanol (E10). Gasoline with higher Ethanol
content may void the vehicle’s warranty.
If a Non-FFV vehicle is inadvertently fueled with E-85
fuel, the engine will have some or all of these symptoms:
• operate in a lean mode
• OBD II “check engine light” on
• poor engine performance
• poor cold start and cold driveability
• increased risk for fuel system component corrosion
To recover from a Non-FFV vehicle inadvertently fueled
once with E-85 perform the following:
• drain the fuel tank
• change the engine oil
• replace the fuel filter and oil filter
• disconnect the battery to reset the engine controller
long term adaptive memory
More extensive repairs will be required for prolonged
exposure to E-85 fuel.


and per the owners manual recommendation for performance and fuel economy:



FUEL REQUIREMENTS
This engine is designed to meet all emission
regulations and provide satisfactory
fuel economy and performance when using
high-quality unleaded “regular” gasoline
having an octane rating of 87. For
optimum performance and fuel economy
the use of 91 octane or higher is recommended.


(These were pulled from the Abarth owners manual, but the same rules should apply.)

panther76
07-23-2013, 07:47 AM
One very important thing to look at is the ethanol content of the fuel you're pumping into the vehicle. I'd recommend using a pure blend of gasoline (ethanol free)

unfortunately, in many states in the U.S. finding ethanol free gas can be difficult to impossible in some states.

for the OP, while there have been documented performance gains (though VERY minor) with the higher octane gas for these engines, I don't see the same with gains in fuel economy. if you are concerned only with fuel efficiency id save your money and look into altering you driving style.

Corrnaus
07-23-2013, 10:52 AM
One very important thing to look at is the ethanol content of the fuel you're pumping into the vehicle. I'd recommend using a pure blend of gasoline (ethanol free) as higher concentrations of ethanol commonly found in 87 blends will reduce mileage by as much as 10%. A 91 blend will allow the engine within our vehicles to operate at optimal timing and has improved knock-resistant qualities within those parameters. A higher quality fuel blend is also (typically) better formulated to assist in removing and preventing carbon build up over time. For my vehicle, I refuse to pump anything but ethanol free 91 octane fuel (be sure to verify the gas station you visit offers an ethanol free variety).

One additional important factor to note is that should you encounter a gas station offering fuels with an octane rating higher then 91, it would serve of little benefit to use these blends with our vehicles unless the ecu were reprogrammed to take advantage of the higher octane rating (of which no ECU tunes currently exist). Hope that helps! :)


For us in Canada.. Shell V Power 91 is the only ethanol free fuel that i can find and the only one that I use.. You also get some good air miles when buying 91.

Robert Nixon
07-23-2013, 10:53 AM
My 13,000 miles tells me that there is no difference in 87 or 91 octane in MPGs. Not much difference in ethanol free premium either, so for now I'm sticking with the cheap gas. As far as I'm concerned, when the manual says either gas is OK and the ocmputer can adjust to it, then both are OK.

Cammilla500L
07-23-2013, 11:00 AM
unfortunately, in many states in the U.S. finding ethanol free gas can be difficult to impossible in some states.

for the OP, while there have been documented performance gains (though VERY minor) with the higher octane gas for these engines, I don't see the same with gains in fuel economy. if you are concerned only with fuel efficiency id save your money and look into altering you driving style.

Thanks Panther! Fuel economy isn't an issue with me, just want what's best for my Baby! ;)

I lived for several years in Nebraska and we pretty much used 10% ethanol in all our cars (because that was what choice we had). We found our cars had better performance and lower mpg with ethanol.

My husband passed away in 2009 and now you guys are my "go to people" For my new Fiat! My husband and I owned a 1967 Fiat Abarth and love it! We have always loved Fiats. The Volvo in my signature was my husbands pride and joy....still got it, I just couldn't part with it.
Thanks again guys!

Ryephile
07-23-2013, 11:12 AM
The engine computer will tailor its performance to at least an 87 to 93 octane range. Higher octane allows more ignition timing and more power. Running 87 won't hurt anything, you'll just lose a few HP when you've got the throttle to the floor.

E10 is pretty much unavoidable. Here in Michigan the law allows E10 to be sold without any notification to the end customer. As such, you can only assume it's 100% gasoline if that specific station advertises it, which is rare since Ethanol is cheaper and they can pad their wallets.

sbulla
07-23-2013, 01:33 PM
So if your only choice in ethanol free gas is either 87 or 93 which would be better to put in the 500L? Those are the only two choices I have, the station I use does not have a 91 octane option.

panther76
07-23-2013, 01:46 PM
Thanks Panther! Fuel economy isn't an issue with me, just want what's best for my Baby! ;)

I lived for several years in Nebraska and we pretty much used 10% ethanol in all our cars (because that was what choice we had). We found our cars had better performance and lower mpg with ethanol.

My husband passed away in 2009 and now you guys are my "go to people" For my new Fiat! My husband and I owned a 1967 Fiat Abarth and love it! We have always loved Fiats. The Volvo in my signature was my husbands pride and joy....still got it, I just couldn't part with it.
Thanks again guys!

if I could find ethanol free gas, that is all I would ever use. the few times ive used in on trip my fuel efficiency would go up by around 10%.

you've probably already seen this site with ethanol free gas stations....but in case you haven't.


http://pure-gas.org/

ReconTopher
07-23-2013, 01:46 PM
So if your only choice in ethanol free gas is either 87 or 93 which would be better to put in the 500L? Those are the only two choices I have, the station I use does not have a 91 octane option.

You would need to define "better". What are you looking for? performance or mileage? Then you'd need to figure out if the extra mileage you get from 93 is equal or greater to the added cost over 87.

Using the pure-gas site, there is a 93 station somewhat close to me in So Cal, and in May it was at $6 a gallon, ouch!

sbulla
07-23-2013, 03:07 PM
Well really just what would be better for the car. I'm happy with the performance so would probably lean more towards getting the best mileage. In my area the 93 octane without ethanol is $3.99 a gallon. Overall ethanol free is about 30 to 40 cents a gallon more than gas with ethanol. It looks like it would cost more to add something to the gas than to leave it pure. Not sure why it costs more.

Felnus
07-23-2013, 06:03 PM
Corn is cheaper than oil. 93 octane 100% gas was $3.85 at my last fill up.

Cammilla500L
07-23-2013, 06:07 PM
Thanks everyone for all your input! I just noticed at a station near my home also has 89 octane for 5 cents a gallon more than the 87. I just might split hairs and use the 89.

It is good to know that the computer will adjust to the octane. I'm not an aggressive driver but do like to have power when I need it.

Mario500L
08-20-2013, 12:25 PM
Scorpoin, that is the same question I have, since the car's manual is kind of not 100% clear on that. @ page 274, "For optimum performance and fuel economy the use of 91 octane or higher is recommended. But sounds , for other replies here, a 91 does not give that boost on miles/gallon to be at least even with the prince range between 87 and 91.

ScorpionSkins.com
08-21-2013, 01:07 AM
Scorpoin, that is the same question I have, since the car's manual is kind of not 100% clear on that. @ page 274, "For optimum performance and fuel economy the use of 91 octane or higher is recommended. But sounds , for other replies here, a 91 does not give that boost on miles/gallon to be at least even with the prince range between 87 and 91.

I've found a substantial difference in mileage by using 91 octane (31-32mpg vs 27-28mpg on regular). As I mentioned earlier in this thread, in my opinion it's more about the overall package of benefits: higher formulation of cleaner additives, no ethanol content, increased performance, and better mileage. An extra $5 per fill up doesn't scare if it means the optimal output and health of my engine.

Vaejovis carolinanus aka lowconabarth
08-21-2013, 09:46 AM
I use 93 octane only in my Abarth and I have noticed that I get 50 to 60 miles more on a tank of real gas than a 10% ethanol blend. So it really cost about the same in the end and the power is better with real gas. This is with a RRM ECU piggy back on setting #8. When I drop to a #4 setting and drive highway miles the MPG increases to @ 41 to 42.

bryanintowson
08-21-2013, 10:27 AM
with the current summer blends available now, I have been averaging 36.5mpg on 93 octane in my automatic Lounge.

Mario500L
08-26-2013, 09:20 AM
An update.

I am using now 93/10% ethanol (only one available at VA) (Costco has 93, the same price as 91 on some places), and I can see the improvement in performance. Going to post my average soon, so far , using 87/91 is around 31 (highway).

Luv2byte
08-26-2013, 10:22 AM
I don't have possession of my trekking yet, does the evic or unconnected have a read out for avg mpg?

n00dle
08-26-2013, 10:27 AM
yes

Luv2byte
09-04-2013, 01:35 AM
So far, around town driving only, I'm avg 28.2 per evic. Not bad for around town & where I live are many hills. We filled up w 89 octane, will watch how it goes, next tank we are going to use 91-92 octane then compare fuel economy.

Richard in Idaho
09-07-2013, 06:24 PM
Corn is cheaper than oil. 93 octane 100% gas was $3.85 at my last fill up.

That's what we pay for 87 with 10% ethanol.

Indie500L
09-07-2013, 07:16 PM
I have found about a 10% difference in MPG with different brands of 87 octane gas so that's the first thing to consider. Often the higher octane fuels have a better cleaning package and guess what ... the gas makes the engine dirty just like the oil breaking down makes the sludge. Around here I do not think there is any ethanol free gas so we have to live with our governments decision on that. A little gas fuel additive injector cleaner is good for your engine as is the oil you use - keep to the recommended oil that the studio uses since you have a turbo!

n00dle
09-07-2013, 07:51 PM
I'll use whatever the circumstances call for. Most of my commuting is in the city where my average speed according to the EVIC is 20 mph and 87 octane suffices for that. I've been using that since day 1 with the Trekking and it's been running fine. If I plan on romping on it I'll fill it with 91 octane, the highest readily available to me. I always try to fill with a Top Tier supplier, currently it's been Shell.

Mario500L
09-08-2013, 06:45 PM
Using 93 (10% ethanol) , U$ 3.769 (Costco) , the average in 23 days has been around 32 miles/gallon [ around 75 miles per day, yes I know, sucks ] (most of my commute is highway , that sometimes or almost of the time is bad). We just completed a 350 miles round trip to the beach and the average was 33.9 miles/gallon. The trip was very nice, the 500L was really nice during all trip, we just loved. The funny note was when we went to the "Deck" at Ocean city, and when I told the girl at the front desk if was fine to park on a particular spot, she asked the car brand to tell the security guy, I told is a FIAT 500L, she smiled , and "oh a FIAT , nice..."

On a side note, the GPS at least for this trip sucked , I used Google Maps on my iPhone instead. Even trying short/fast trip mode, the GPS insisted to use a route that was at least around 1/2 longer, just trying to use some "shortcuts" that didn't make sense at all.

Indie500L
09-08-2013, 10:31 PM
Yup you have to watch out for the short distance calculations as it does NOT take into account stopping at all - great if you are walking however. Usually the fastest route works best and then you can always just drive the little variations you know will save time and let it recalculate. I remember coming across the Mass Pike from upstate NY and watching how taking different exits to get down to RI would affect the trip time and distance - plus the price of the tolls! On two trips to NY City the GPS has totally failed just when I needed it and even rebooted at the exit next to the Studio where I purchased it when we went back for the license plates... going to see if the TSB for the non-existent XM Radio fixes the GPS.

Mario500L
09-09-2013, 12:43 AM
On the GPS I did some small experiences, like "pretend" to go to "current location" to point "A", or "B", and unfortunately the way the GPS is calculating the route is kind of weird for some routes. Even going to my wife's work to home the GPS tries to do some "fault" short cuts. I am going to do some more tests, but well, Google Maps is the best routing system available , no match in the market. What is a pity, since the internal GPS has a nice interface, bigger of course as my iPhone, but so far , sucks on routes. Going to do some more tests and see, but so far, going to use my phone for navigation on places I don't know.

Indie500L
09-09-2013, 10:53 AM
What are you all listening to when using the GPS . . . MP3 files or the radio? I am wondering if the computer in the unit is getting overloaded decoding MP3 music that we listen to and that is causing it to crash more often.
A note about google maps - it seems to give unrealistically short travel times like 2 hours 15 minutes to Long Island from RI (173 miles) when it really takes 3 hours 15 minutes.

Fazzster
09-09-2013, 11:48 AM
I am only on my 2nd tank of gas. Not sure what the dealer put in but I am using 93. The L averages 31.1 mpg "city" but have not done a hwy trip yet. Car has the dual clutch auto.

Mario500L
09-09-2013, 12:22 PM
I am going to report some use cases when I get home. About the "listening to when using the GPS . . . MP3 files or the radio?.." , I can assure you that on the unit software stand point, that doesn't matter at all (this is my area of expertise). Is just the way they use the database , and how good are the database/routing algorithm. About Google Maps report "wrong" ETA, I never had that issue, with a 1 hour drift. The "mistakes" I noticed on the routing pattern are pretty bad.