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Planning to buy my Abarth it's first tank of gas this weekend and was thinking if I should use premium or regular. Dealer told me that I should stick with one grade of fuel. His reasoning is that the engine adjusts to one grade and that it's harder on the engine to change back and forth. Is this true? In everyday driving will I notice any performance difference between the two grades?
 

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It depends on what the octane ratings of the grades you use, which vary from state to state in the US. A rating of 87 is "regular" in most places, and the owner's manual for the 124 Spider cautions against using fuel with ratings below 87, declaring that this could damage the engine. There may be places where 85 octane is "regular." I hadn't heard before that switching between grades was bad for the engine, unless you switched to a lower (87) octane where pre-ignition knock might intrude. In that case, the engine would be "adjusting" more during one tankful than in making a switch to a higher grade. But I'm no expert.
 

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From the manual (US/Canada is using the AKI number)
Fuel: Premium unleaded fuel.
Octane Rating (Anti-knock index): 91 (R + M)/2 method or above (96 RON or above) (U.S. federal law requires that octane ratings be posted on gasoline station pumps).
Regular unleaded fuel with an octane rating from 87 to 90 (91 to 95 RON) can be used, but this will reduce performance slightly, such as reduced engine output, and engine knocking.
 

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We should ask ourselves why, the European 1.4 produces 170 HP while North American only 164.HP
Maybe the answer lies on the missing 6HP.

2010 Nissan Murano has 265HP 3.5 V6 and Nissan suggests Premium gas, While 2011 nissan murano has 260 HP 3.5 V6. Nissan suggests Regular gas.

Conclusion they sacrificed 5 HP so the 2011 and on models so they can use Regular gas.

other Question re: European model, what's their specs regarding type of fuel or octane can be used.
 

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For what it's worth, I alternated between regular, mid, and premium on my 500 Abarth over 30k miles. Slight decrease in both performance and economy when running 87, but it still ran just fine (modern engine management and knock sensors are wonderful things)
 

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my understanding is that in the US the Fed requires that all cars must be able to run on 87 octane. So you could use regular. But for the best performance i always use the recommendation from the manufacturer.
 

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I use 99 RON here in the UK!
What does your manual say about which type of gas to use. Any mention of regular tia
 

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Says to use premium unleaded.
Now it makes sense why we're missing those 6HP on the North American Spider is so we could use the Regular gas. thanks
 

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In the US and Canada the "posted" octane (what's posted on the pumps) is "road" octane, the average of RON (research octane number) and MON (motor octane number) whereas pretty much everywhere else in the world the key octane number is typically RON. The two octane number tests are similar and differ only in the speed (rpm) at which the test is done. In Europe "regular" is 95 RON and although there is also a spec on MON, for most gasoline formulations at different refineries, RON is the limiting constraint. 95 RON is what the Fiat and Abarth Spiders are designed to run, with no benefit from running higher RON unless the ECU mapping is set up to adjust advance and other parameters to push up against a knock constraint. I run my modified Fiat Coupe on Tesco (supermarket) 99 RON because it's been mapped specifically for it, whereas the standard Fiat Coupe I just bought is run on 95 RON. I will run the Spider on 95 RON and will buy the cheapest available supermarket fuel. Anyone who works in or lives near a refinery knows that all the different "brands" come from the same limited number of refineries, with differences only in additives perhaps. Running higher octane in an engine that can't take advantage of it is a waste of money IMHO, it's just a placebo thing. And BTW I don't work in a refinery but work as a consultant planning new refinery and petrochemical facilities so I like to think I know a little about the subject but as you guys in the US say, YMMV ;)
 

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In the US and Canada the "posted" octane (what's posted on the pumps) is "road" octane, the average of RON (research octane number) and MON (motor octane number) whereas pretty much everywhere else in the world the key octane number is typically RON. The two octane number tests are similar and differ only in the speed (rpm) at which the test is done. In Europe "regular" is 95 RON and although there is also a spec on MON, for most gasoline formulations at different refineries, RON is the limiting constraint. 95 RON is what the Fiat and Abarth Spiders are designed to run, with no benefit from running higher RON unless the ECU mapping is set up to adjust advance and other parameters to push up against a knock constraint. I run my modified Fiat Coupe on Tesco (supermarket) 99 RON because it's been mapped specifically for it, whereas the standard Fiat Coupe I just bought is run on 95 RON. I will run the Spider on 95 RON and will buy the cheapest available supermarket fuel. Anyone who works in or lives near a refinery knows that all the different "brands" come from the same limited number of refineries, with differences only in additives perhaps. Running higher octane in an engine that can't take advantage of it is a waste of money IMHO, it's just a placebo thing. And BTW I don't work in a refinery but work as a consultant planning new refinery and petrochemical facilities so I like to think I know a little about the subject but as you guys in the US say, YMMV ;)
Here, in Montreal, we use to have several refineries, then to 3, now only 1. and they supply all the brands(Esso, Shell, Petro Canada and ect.) Before each brand use to have its delivery trucks, now same trucks deliver to all brands. figure that out
 

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Whenever it is available, use premium. You wouldn't buy low quality food for your children, would you?
 

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I honestly can't say that I follow the manufacturers recommendations although I still preach that you should. I understand that running premium on a vehicle that's meant to run on regular will provide no benefits to you, but it still doesn't do any harm either ? It's just one of those things that eases my mind and makes me go to sleep better at night lol
 

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I buy 91 octane methanol free gas for my spider. Available at some Sunoco, Velero, Keystone in my area. Availability is station managers decision; and which refinery does it come from, all the same? She's not my daily driver, so my "Black Beauty" gets the best I can find.
I am looking for critical knowledge from you people, smarter than me re: ethanal free gas.
Thanks
 

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Only ever put 98RON(93MON) in ours and that's all it will ever get. It's a turbo. Most turbos will utilise the extra octane and (at least) 95RON(91MON) is the "Fiat recommendation" here.

Our BRZ (14:1 compression ratio) has a "minimum" 98RON(93MON) recommendation!

One thing's for sure, if you've added performance bits to the car and you are then being a cheapskate on gas, you are being a bit of a dick.
 
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