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View Full Version : Premium Gas - Does the Brand of gas make a big difference in acceleration?



rtwolfe
09-21-2011, 10:41 PM
Just noticed something today. Full disclosure. I am NOT trying to get high MPG with my manual Fiat Cabrio. Am looking to get the maximum acceleration and fun from the car. I picked the manual Pop cabrio vs the Lounge because I expected the manual would give more zip.

Have learned that high RPMs are your friend. So, am shifting between 4000 and 6000 vs 2000 and 4000 in my last vw. Also, I always click on the Sport button when I drive. The 500 Madness High Flow drop in air filter that I ordered, just arrived, so will soon know how that impacts performance.

But how about the gas you use? I knew that the Fiat does best, acceleration wise, if you fill it with premium gas. I previously thought premium gas is premium gas. So I filled up with the local SuperAmerican Premium brand. It is is relatively cheap, but it's Premium. Today, my tank was very low so I stopped in a nearby BP station and filled up with BP premium gas. Trust me, I have no love for BP after the Gulf oil spill but....

That BP gas seemed to have made a big difference. The car quickly responded and with some torque, when I stomped on the gas. So question, if you too are looking for the best performance (aka Speed), have you found that that 'Brand' of premium gas makes a significant difference? If so, which brand works the best for you?

Ciao

Nero
09-21-2011, 11:56 PM
Just noticed something today. Full disclosure. I am NOT trying to get high MPG with my manual Fiat Cabrio. Am looking to get the maximum acceleration and fun from the car. I picked the manual Pop cabrio vs the Lounge because I expected the manual would give more zip.

Have learned that high RPMs are your friend. So, am shifting between 4000 and 6000 vs 2000 and 4000 in my last vw. Also, I always click on the Sport button when I drive. The 500 Madness High Flow drop in air filter that I ordered, just arrived, so will soon know how that impacts performance.

But how about the gas you use? I knew that the Fiat does best, acceleration wise, if you fill it with premium gas. I previously thought premium gas is premium gas. So I filled up with the local SuperAmerican Premium brand. It is is relatively cheap, but it's Premium. Today, my tank was very low so I stopped in a nearby BP station and filled up with BP premium gas. Trust me, I have no love for BP after the Gulf oil spill but....

That BP gas seemed to have made a big difference. The car quickly responded and with some torque, when I stomped on the gas. So question, if you too are looking for the best performance (aka Speed), have you found that that 'Brand' of premium gas makes a significant difference? If so, which brand works the best for you?

Ciao


I switched from 87 octane to 93 octane and felt a noticeable difference in my 500's performance as well as 3-4 more miles per gallon. Well worth the additional 3 bucks per tank. Best results with Chevron
brand.

luckymoi
09-22-2011, 12:19 AM
Ok. I am gonna try Arco 91 see what happens...

SeaDawg
09-22-2011, 12:40 AM
Ok. I am gonna try Arco 91 see what happens...

Probably be standing at the pump with no clothes in California.:joyous: I would suspect that even using 87 octane you would have to empty all your pockets and raise your hands when you pull up to the pump.

I get Premium here in Orlando for $3.75 per gal and if I use WM Discover at the onsite Murphy Oil station I get a .10 a gal discount on top of that price.

I haven't really noticed any difference between different brands of Premium here, but I did notice the difference between 87 and 93 Octane when the selling dealer filled it up with Regular once after they had Road Tripped it (about 150-175 miles) back from Sarasota.

Doodles
09-22-2011, 08:38 PM
Ok. I am gonna try Arco 91 see what happens...

The only real problem is you don't really know what your putting in your tank.
There is no guarantee what octane your getting.
Too bad there wasn't a litmus test for you to check ....

SeaDawg
09-22-2011, 09:11 PM
The only real problem is you don't really know what your putting in your tank.
There is no guarantee what octane your getting.
Too bad there wasn't a litmus test for you to check ....

The one thing here you can be sure of is that gas sold in Florida contains up to 10% Ethanol (and sometimes more I suspect). When I start the 500 and back out of the garage the exhaust fumes smell like burning alcohol.

WIBOB
09-22-2011, 09:17 PM
I discoverd that Shell Premium here is 91 octane with ethanol and the 500 does good on that. But I did one better and put in Citco 93 octane no ethanol and it did seem to make a difference. I do not run regular or ethanol in the 500 because it takes a lot of the zip away and the mileage goes way down. I am constantly getting 41 to 43 with the premium.

F500
09-23-2011, 01:13 PM
I've been running Shell 93 octane from the beginning in my Sport. the last fill-up I went for the regular 87 'just for the heck of it'. honestly, I've seen no difference in performance (acceleration, idling, etc) but my mpgs are slightly better. my 'normal' driving (not caring how if I'm saving gas or not) I had been getting on average 34.6 but on my first fill-up with the 87 I averaged over 35.3. same driving conditions, etc. now I know its only one tank, but it certainly doesn't look like it dropped off.

now I HAVE seen a difference in 'brands' affecting my mileage. using BP 93 octane gave me MUCH better mileage than the Shell 93, but that was my 08 Charger. haven't tried it yet with the 500. maybe next month........




btw.....my 500 is a 6sp Auto, not a manual.

fiat for life
09-23-2011, 02:10 PM
Ive used both 93 and 87 in multiple 500s and as far as I can tell I dont see much of a difference. Unless a car is tuned for a specific octane you wont really notice anything.

pchop
09-26-2011, 09:04 PM
Ive used both 93 and 87 in multiple 500s and as far as I can tell I dont see much of a difference. Unless a car is tuned for a specific octane you wont really notice anything.

+1. If anyone can notice such a difference, you are either Michael Schumacher or are having a placebo effect.

EugeneS
09-26-2011, 10:09 PM
+1. If anyone can notice such difference, you are either Michael Schumacher or are having a placebo effect.

I am definitely not Michael Schumacher, ;) but the first time I used Shell 91 (we don't have 93 in SF) my Fiat became noticeably more responsive! My first tank was courtesy of Fiat of Fremont and I am sure the filled it with regular... though I should not complain, free tank is free tank :)

Freedomland
09-26-2011, 10:31 PM
So far in the Fiat I've been running 87 though I actually try to put BP in (also no love for BP as previously mentioned)
but on my Mini which only wants premium.. Ive used different premiums and also once in a while 87 BP as well as 89 and 93 BP
and I have to say Ive noticed in the Mini better response with the BP gas vs other brands (tried shell but it didnt make as much as a difference as BP did)

i dont know why but Ive heard their "Invigorate" is a lot of detergent.. but no matter what. it actually does make a difference when I drive,, still cant find out exactly what their "invigorate" is but it does!!

luckymoi
09-26-2011, 11:47 PM
Just filled up with ARCO 91... will let you know how mileage plays out.... was doing 87 and getting 28.9 ... so far 33.5 MPG with 91 but not a wholely valid test yet as the drive was mostly freeway with some but not enough local streets to be my typical drive. Today 91 octane was 3.999/ gal (we will see $5 gas I have no doubt). Certainly 91 will give zippier performance but a mileage boost for where/how I drive is unclear... any bets?

Nero
09-27-2011, 07:52 AM
The Owner's Manual states that the minimum octane is 87 but they recommend 91. I don't think they do that just so we can spend more money on gas. The Fiat 500 engine must perform better on higher octane. My Cadillac SRX on the other hand only requires 87 octane and performs quite well. We don't have 91 octane in my area so I use 93. For about $3.00 a tank, it's worth it to me.

Scorpion
10-03-2011, 10:48 PM
If a manufacturer gives a minimum and a recommended octane level, it's because the car's ECU will allow the car to run on the lower. But, it will need to slightly retard the timing to do so. By using the recommended, you are allowing the engine to perform at the level for which it was designed.

Using anything above the recommended, on an unmodified engine, provides no advantages.

However, this may sound like an advertisement, but I've documented a 5+% increase in fuel economy using Shell V-Power. And have done so in more than one of my cars.

I don't know what brand/octane came in the Prima from the factory. But, it's only had V-Power every tank since. :D

Fiat500USA
10-04-2011, 01:27 AM
Just as some people don't feel a difference with the sport button, some won't feel a difference between regular and premium. Hey, that's cool, it is what makes the world go around, everyone has their own priorities. But if your priority is performance, you are really missing the first step in getting the most out of the engine by using regular gas. It is not a huge difference, but every little bit helps with a car with modest power levels, and besides outright HP there is the increased throttle response that advanced ignition timing brings.

The maximum HP rating on the 500 was achieved with premium fuel.

cmj912
10-04-2011, 12:50 PM
I have been using 93 since there is no such thing as 91 anywhere around here that I can find. We don't have additive free "pure gas" either.

I assume the dealer filled the car with the cheapo stuff when I got my free tanks but my driving style doesn't really lend itself to being able to tell the difference!

talindsay
01-20-2012, 11:53 AM
Sorry to revive a zombie thread, but does anybody know if the 500's ECU actually changes the timing based on quality of gas? Typically, it wouldn't be safe to run 87 octane gas in a car with nearly 11:1 compression unless the timing were quite retarded, which itself can introduce problems such as higher heat. Coming from the motorcycle world, it's considered a bad idea to run an air-cooled carbureted engine with even 9.5:1 compression on 87, as the knocking and heat can cause problems. Of course, liquid-cooled engines with fuel injectors and sensors in the exhaust can detect predetonation and adjust accordingly, which I'm assuming is what our engines do. If that's true, then the engine will be running in a significantly degraded state with 87 octane gas in all but the most neutral of weather - too hot and it has to retard to avoid knocking, too cold and it has to retard and/or remix to avoid a lean condition.

Does anybody know what exactly the 500's ECU does to make 87 octane gas safe in a very high compression engine? All told, I would guess that our engines with 87 octane in them would be lucky to generate 90 horsepower given the significant timing and/or mix changes it would require.

FiatPhil
01-20-2012, 12:03 PM
Just as some people don't feel a difference with the sport button, some won't feel a difference between regular and premium. Hey, that's cool, it is what makes the world go around, everyone has their own priorities. But if your priority is performance, you are really missing the first step in getting the most out of the engine by using regular gas. It is not a huge difference, but every little bit helps with a car with modest power levels, and besides outright HP there is the increased throttle response that advanced ignition timing brings.



The maximum HP rating on the 500 was achieved with premium fuel.

Was the maximum Horsepower rating achieved with premium 100% gasoline or premium 10% ethanol/ 90% gasoline? Can you find out for me?

Mini Cord
01-20-2012, 06:59 PM
Taken of the Internet:

My gas isn t better for your car; it s just more expensive.

Oil companies spend lots of money explaining why their gas is better than the competition s. Chevron s gas, for example, is fortified with Techron, and Amoco Ultimate is supposed to save the planet along with your engine. But today more than ever, one gallon of gas is as good as the next.

True, additives help to clean your engine, but what the companies don t tell you is that all gas has them. Since 1994 the government has required that detergents be added to all gasoline to help prevent fuel injectors from clogging. State and local regulators keep a close watch to make sure those standards are met; a 2005 study indicated that Florida inspectors checked 45,000 samples to ensure the state s gas supply was up to snuff, and 99 percent of the time it was. There s little difference between brand-name gas and any other, says AAA spokesperson Geoff Sundstrom.

What s more, your local Chevron station may sell gas refined by Shell or Exxon Mobil. Suppliers share pipelines, so they all use the same fuel. And the difference between the most expensive brand-name gas and the lowliest gallon of no-brand fuel? Often just a quart of detergent added to an 8,000-gallon tanker truck.

Source: http://www.smartmoney.com/spend/rip-offs/what-gas-stations-wont-tell-you-19750/

And another good read:


A Chemists View on Octane and Gasoline Brands

Brand of gasoline:
Some of you probably know this, others may be shocked by it. Oil companies swap base gasoline all the time. Let's say I have a refinery in Houston and you have one in Dallas. It makes little sense for me to truck my Houston gasoline to Dallas and for you to truck your gasoline from Dallas to Houston when gasoline is a commodity product. So, I let you draw 100,000 gallons of base gasoline from my storage tank in Houston for your Houston gas stations, and you let me draw 100,000 gallons of base gasoline from your Dallas holding tanks for my Dallas gas stations. That way, we both save on shipping. Yup, Texaco gasoline may have come from a Shell refinery and vice-versa. At a gasoline terminal you may see trucks from up to six different companies all loading at the SAME terminal (that for example may be supplied exclusively by Shell). What comes next, however, is what makes Texaco Texaco and Shell Shell. Additive. Each company has its own additive and adds it to the base gasoline. So while the base gasoline may be the same, the additive is different, and hence the brand of gasoline you use is different because of the additive, not the base gasoline.

Which additive is better?:
Given the above discourse, it's obvious that we all want the gasoline with the best additive. Unfortunately, it's not that simple. Additves respond differently in different base gasolines (even of the same grade). Also, some additves work better with gasolines used in a carbureted car vs one that uses fuel injection. On a practical level, additives are going to be developed today for today's cars -- meaning fuel injected cars. For Corvette owners who have carbureted Vettes (like me), this is unfortunate. Carbureted engines leave a LOT more deposits behind than fuel injected cars. From a regulatory stand point, California was the first to call for all gasolines to pass the BMW test (port-fuel-injected engine) in all grades of gasoline. Like all regulations, this one had various massages put to it, but the net effect was that all oil companies went to work developing additives that are a LOT better today than 10 years ago AND they are used in all grades (not just premium -- hence the argument to use premium to get a better additive went out the window).

Insider's trick on gasoline additives:
No matter what you do or what you drive, this trick will help you keep down deposits inside your engine. You see, additives themselves will make deposits and/or create a deposit that is different from the one made by base gasoline alone. If you think about this for a moment, you'll come to realize that your engine will build some kind of deposit based upon what additive you are using. Yes, it will build at a slower rate, but it will build deposits. At some level this will taper off (but this is maximum deposits and what Corvette owner wants that!). So what do you do? Simple, switch to a different brand of gasoline (this will almost assure you of getting a different additive but not always. Some companies buy additives from other companies, so it could be the same. More on this later). What this will do, is the new additve will look at the deposit formed from the old additive as foreign and begin removing it. Now after 5000 miles, you'll be rid of this deposit but you'll have a new one from your most recent additive, so switch back and start the process all over again. As an analogy, this is like building an immune response to an anti-biotic, so your doctor gives you a new one. I know of absolutely no additive that will work as well as switching back and forth between additives. On a molecular level this makes perfect sense.

Source: http://www.vettenet.org/octane.html

SeaDawg
01-20-2012, 07:31 PM
Was the maximum Horsepower rating achieved with premium 100% gasoline or premium 10% ethanol/ 90% gasoline? Can you find out for me?

My understanding is that ALL EPA ratings are achieved with 100% GASOLINE, but I'm sure the Moderator is much closer to the definitive answer.

Fiat500USA
01-21-2012, 02:09 AM
My understanding is that ALL EPA ratings are achieved with 100% GASOLINE, but I'm sure the Moderator is much closer to the definitive answer.

That is an interesting question...

On a different note, I asked the man in charge about premium and regular making a difference with the mileage and he said it didn't. I was surprised, but I'm not an engineer. :)

SeaDawg
01-21-2012, 06:02 AM
That is an interesting question...

On a different note, I asked the man in charge who would know about premium and regular making a difference with the mileage and he said it didn't. I was surprised, but I'm not an engineer. :)

I switched to regular for a few tanks and didn't really notice a difference in mileage. I did however notice a difference in the 'sound' of the engine. It also seemed to 'labor' more under regular gas than it does when running premium. I decided to stick with premium; plus I think I'm going to spring for the RRM Timing Controller.

F500
01-21-2012, 06:26 PM
....Today, my tank was very low so I stopped in a nearby BP station and filled up with BP premium gas. Trust me, I have no love for BP after the Gulf oil spill but....

That BP gas seemed to have made a big difference. The car quickly responded and with some torque, when I stomped on the gas. So question, if you too are looking for the best performance (aka Speed), have you found that that 'Brand' of premium gas makes a significant difference? If so, which brand works the best for you?

Ciao

I ran BP for years in my Jeeps, smart car and Dodge Charger. got the best gas mileage and performance seemed to be the best as well. BUT, like you, along came the Gulf Oil Spill and my BP card ended getting cut up and in the trash. enter Shell Oil.

since that time, I've used Shell gas and Pennzoil Synthetic Oil in my Charger and now my 500. the difference in MPG's and performance with my Charger was very noticable. haven't tried BP in my 500 yet, but I'm really considering going back to them. with my Charger, my gas mileage dropped about 10% and if thats the case with my 500, then I could be averaging 36+ instead of the 32-33 I'm getting now.

my experience is that BP is MUCH superior to Shell. when I was using BP gas before, I was also using Mobil 1 Synthetic. I'm seriously thinking about returning to BP Gas and Mobil 1 Synthetic Oil. saving money on gas, getting better performance AND protection is a no-brainer in my book.

sjmst
01-21-2012, 06:48 PM
That is an interesting question...

On a different note, I asked the man in charge who would know about premium and regular making a difference with the mileage and he said it didn't. I was surprised, but I'm not an engineer. :)

No diff in mileage with 87 or 91 for me.

FiatGusto
01-21-2012, 08:16 PM
Taken of the Internet:

My gas isn t better for your car; it s just more expensive.

Oil companies spend lots of money explaining why their gas is better than the competition s. Chevron s gas, for example, is fortified with Techron, and Amoco Ultimate is supposed to save the planet along with your engine. But today more than ever, one gallon of gas is as good as the next.

True, additives help to clean your engine, but what the companies don t tell you is that all gas has them. Since 1994 the government has required that detergents be added to all gasoline to help prevent fuel injectors from clogging. State and local regulators keep a close watch to make sure those standards are met; a 2005 study indicated that Florida inspectors checked 45,000 samples to ensure the state s gas supply was up to snuff, and 99 percent of the time it was. There s little difference between brand-name gas and any other, says AAA spokesperson Geoff Sundstrom.

What s more, your local Chevron station may sell gas refined by Shell or Exxon Mobil. Suppliers share pipelines, so they all use the same fuel. And the difference between the most expensive brand-name gas and the lowliest gallon of no-brand fuel? Often just a quart of detergent added to an 8,000-gallon tanker truck.

Source: http://www.smartmoney.com/spend/rip-offs/what-gas-stations-wont-tell-you-19750/

And another good read:


A Chemists View on Octane and Gasoline Brands

Brand of gasoline:
Some of you probably know this, others may be shocked by it. Oil companies swap base gasoline all the time. Let's say I have a refinery in Houston and you have one in Dallas. It makes little sense for me to truck my Houston gasoline to Dallas and for you to truck your gasoline from Dallas to Houston when gasoline is a commodity product. So, I let you draw 100,000 gallons of base gasoline from my storage tank in Houston for your Houston gas stations, and you let me draw 100,000 gallons of base gasoline from your Dallas holding tanks for my Dallas gas stations. That way, we both save on shipping. Yup, Texaco gasoline may have come from a Shell refinery and vice-versa. At a gasoline terminal you may see trucks from up to six different companies all loading at the SAME terminal (that for example may be supplied exclusively by Shell). What comes next, however, is what makes Texaco Texaco and Shell Shell. Additive. Each company has its own additive and adds it to the base gasoline. So while the base gasoline may be the same, the additive is different, and hence the brand of gasoline you use is different because of the additive, not the base gasoline.

Which additive is better?:
Given the above discourse, it's obvious that we all want the gasoline with the best additive. Unfortunately, it's not that simple. Additves respond differently in different base gasolines (even of the same grade). Also, some additves work better with gasolines used in a carbureted car vs one that uses fuel injection. On a practical level, additives are going to be developed today for today's cars -- meaning fuel injected cars. For Corvette owners who have carbureted Vettes (like me), this is unfortunate. Carbureted engines leave a LOT more deposits behind than fuel injected cars. From a regulatory stand point, California was the first to call for all gasolines to pass the BMW test (port-fuel-injected engine) in all grades of gasoline. Like all regulations, this one had various massages put to it, but the net effect was that all oil companies went to work developing additives that are a LOT better today than 10 years ago AND they are used in all grades (not just premium -- hence the argument to use premium to get a better additive went out the window).

Insider's trick on gasoline additives:
No matter what you do or what you drive, this trick will help you keep down deposits inside your engine. You see, additives themselves will make deposits and/or create a deposit that is different from the one made by base gasoline alone. If you think about this for a moment, you'll come to realize that your engine will build some kind of deposit based upon what additive you are using. Yes, it will build at a slower rate, but it will build deposits. At some level this will taper off (but this is maximum deposits and what Corvette owner wants that!). So what do you do? Simple, switch to a different brand of gasoline (this will almost assure you of getting a different additive but not always. Some companies buy additives from other companies, so it could be the same. More on this later). What this will do, is the new additve will look at the deposit formed from the old additive as foreign and begin removing it. Now after 5000 miles, you'll be rid of this deposit but you'll have a new one from your most recent additive, so switch back and start the process all over again. As an analogy, this is like building an immune response to an anti-biotic, so your doctor gives you a new one. I know of absolutely no additive that will work as well as switching back and forth between additives. On a molecular level this makes perfect sense.

Source: http://www.vettenet.org/octane.html


Who in the heck can we believe anymore. I trust this post, but then some of you swear by your brand choice and
say you really can see the differences.
So, whose on first!

Felnus
01-22-2012, 07:44 AM
Who in the heck can we believe anymore. I trust this post, but then some of you swear by your brand choice and
say you really can see the differences.
So, whose on first!

It is pretty much correct but there are other variables to consider at the gas station level as well. Is the stations equipment well maintained? How old are the tanks in the ground? Do the tanks have water seepage? If all the gas in your area comes from the same refinery (and it probably does) which brand has newer and better maintained trucks? Contamination of the fuel during shipping is a big issue. Also, if you use premium (like me), does that station sell a lot of premium or does it sit in the underground tank for months?

You could drive yourself nuts figuring it out. Or do what a female co-worker of mine does. She buys her gas at the station that has the cleanest restrooms. Priorities matter!

FiaTED
02-01-2012, 07:17 PM
So why shouldnt I switch brands every fill up then?

krayzielilsmoki
03-07-2012, 10:03 PM
Difference between 87 and 93 is quite noticeable on my 80cc scooter, so I would imagine there would be some (even if miniscule) difference in a car :).
I live in Florida so there is the ~10% ethonal thing, but there is a gas station around here called Racin' Gas that sells 100% gas at 90 octane. By law they had to put a label on the pump that said "not for highway use" and "for recreational purposes only" etc. Thought that was pretty funny :highly_amused:.
This 90 octane is slightly pricier than 93.
I might try it when I get my Abarth...
They also sell racing gas, maybe I'll mix in a gallon of that :chuncky:

I have a friend who owns a Honda S2000, and I swear he notices the tiniest differences in that car.
He swears by some gases, but he might be just able to notice more of a difference when he hits VTEC.
Sometimes it will be sluggish, other times it will be loud and occasionally knock a drink out of his cup holder :smug:

I think there are many variables that affect the feel of your car, so play around with what you can change to find what suits you best.

P.S. Have you SEEN the selection of smilies here??? :surprise:

Felnus
03-07-2012, 10:26 PM
VTEC....last century technology...how quaint....:smug:

Fix it again Tony
03-07-2012, 10:57 PM
If your engine knocks, get Premium. If it doesn't, use regular. There is no more actual energy in one than the other. Just hype.

talindsay
03-08-2012, 11:02 AM
If your engine knocks, get Premium. If it doesn't, use regular. There is no more actual energy in one than the other. Just hype.

First off, you are absolutely correct that octane has nothing to do with amount of energy; however, different fuel blends *do* have different amounts of energy. Because ethanol has a much higher octane rating than regular gasoline, many fuel companies achieve higher octane ratings in their higher-octane gas by using larger percentages of ethanol (which they don't have to state on the label as long as it's still within the "up to 10%" claim). This of course means that often, higher octane gas actually has *lower* amounts of energy, since ethanol has less energy per gallon than dino gas.

With that stated, I still think it's a bad idea to run 87 in these cars, and here's why: by the point you, the driver, can actually detect the knocking it's pretty severe. The car has sensors to adjust engine properties (valve timing, ignition timing, a/f mix) according to what's happening in the engine and exhaust, and it will start degrading the engine's performance as soon as it detects predetonation, long before you can tell it's going on. So running lower-octane gas will have the effect of the engine retarding timing and/or adjusting mix long before predetonation gets to a point you notice it. This means that running low-octane gas *will* rob you of performance, even though (as stated above) the lower-octane gas may actually have more energy in it.

This is based on general knowledge of how a car like this, with such very high compression, makes it safe to run low-octane gas; it is not based on specific knowledge of Fiat's engine programming. It would be really great to hear from a Fiat engineer exactly what strategies our engine uses when confronted with 87 octane gas; but of course we know it involves some variation of retarded ignition, modified valve timing and/or modified a/f mix because those are the options available. In all three cases, changes would de-tune the engine to keep it from predetonating, which means lower performance and most likely (though not necessarily) lower fuel economy.

Fiat Forever!
03-08-2012, 06:07 PM
First off, you are absolutely correct that octane has nothing to do with amount of energy; however, different fuel blends *do* have different amounts of energy. Because ethanol has a much higher octane rating than regular gasoline, many fuel companies achieve higher octane ratings in their higher-octane gas by using larger percentages of ethanol (which they don't have to state on the label as long as it's still within the "up to 10%" claim). This of course means that often, higher octane gas actually has *lower* amounts of energy, since ethanol has less energy per gallon than dino gas.

With that stated, I still think it's a bad idea to run 87 in these cars, and here's why: by the point you, the driver, can actually detect the knocking it's pretty severe. The car has sensors to adjust engine properties (valve timing, ignition timing, a/f mix) according to what's happening in the engine and exhaust, and it will start degrading the engine's performance as soon as it detects predetonation, long before you can tell it's going on. So running lower-octane gas will have the effect of the engine retarding timing and/or adjusting mix long before predetonation gets to a point you notice it. This means that running low-octane gas *will* rob you of performance, even though (as stated above) the lower-octane gas may actually have more energy in it.

This is based on general knowledge of how a car like this, with such very high compression, makes it safe to run low-octane gas; it is not based on specific knowledge of Fiat's engine programming. It would be really great to hear from a Fiat engineer exactly what strategies our engine uses when confronted with 87 octane gas; but of course we know it involves some variation of retarded ignition, modified valve timing and/or modified a/f mix because those are the options available. In all three cases, changes would de-tune the engine to keep it from predetonating, which means lower performance and most likely (though not necessarily) lower fuel economy.

I am told that these cars don't even know the difference between 87 and 91 octane, and that you would need 93+ octane before any performance would be altered.

davidl
03-08-2012, 06:52 PM
From my limited experience with my 500 sport, before mods, 93 octane improved performance over 87. The difference was noticeable bearing in mind we are taliking about a 101 bhp car. I had similar results with my 08 911 ( I will always regret selling that car and so will the State Troopers). Whether the hefty premium is worth it is another matter and a personal choice. The cost differential is a lot lower than between a 24 mpg SUV and the Fiat and for me worth the increased fun factor.

Fix it again Tony
03-09-2012, 12:46 AM
From my limited experience with my 500 sport, before mods, 93 octane improved performance over 87. The difference was noticeable bearing in mind we are taliking about a 101 bhp car. I had similar results with my 08 911 ( I will always regret selling that car and so will the State Troopers). Whether the hefty premium is worth it is another matter and a personal choice. The cost differential is a lot lower than between a 24 mpg SUV and the Fiat and for me worth the increased fun factor.

Yes, 93 octane....anything less might as well be 87 octane, because as Fiat Forever! stated, your car won't even know the damn difference.

FiatGusto
03-09-2012, 01:41 AM
I discussed octane ratings with an old car guy, and he raised an interesting point. With gas prices up, few folks buy anything but the cheapest fuel; 87 octane.
So, he feels, that premiums sit in the storage tanks so long that they pick up moisture, and they change. (His words, not sure I understand.)
Anyway, I asked my local Safeway gas stop how many buy premium...91-92 octane.
He said, very, very few.
So, to you experts on this forum. Are we paying more money and not getting the advantage of the higher octane due to what my car guy said???

Piccirillo
03-17-2012, 02:29 AM
I just have to say that, tonight I filled up with 93 for the first time and it felt like it was alive!


No kidding and I'm coming from turbo induction/performance tuned vehicles and lots of power as a result....

It was fun (no placebo there, real fun)

GoHack
01-05-2014, 02:49 AM
Not all gasoline brands are the same.

http://www.toptiergas.com/retailers.html

Here in the Northwest, the best gasoline is seen as Chevron, thanks to it's Techron additive, w/ARCO considered the worst. Chevron is a Top Tier Rated Gasoline, while ARCO isn't. Chevron is also a little more expensive than ARCO, so you get what you pay for.

Techron is available in Texaco and Caltex gasolines, in all three grades, as well.

There are many other good gasolines out there as well, including Shell, which I also use when I can't find a Chevron station. It too is a Top Tier Rated Gasoline.

zyxelenator
01-05-2014, 10:05 AM
I usually fill up at Shell and Costco, sometimes at Speedway with 93. Don't feel or see any difference. Also tried 92 pure gas without ethanol while in FL. Same here didn't notice any improvements in mpg or performance other than higher price. But there were many variables during vacation.

slowbird
01-05-2014, 11:48 PM
^^^ You can never keep an old Gas or oil thread dead for long.

I don't know how it is down in America, but up here our Shell V-Power is listed as having ZERO Ethanol in it. I tend to use that for the Abarth and the VFR.

....even my snow-blower says not to use Ethanol fuels in it.

bryanintowson
01-06-2014, 09:44 AM
most states have their own laws requiring ethanol blends. In Maryland where I live, it's kind of a crapshoot because we have different zones of the state with different smog laws. Overall tho, you can count on getting 10% ethanol when you fill up in MD.

Personally, I always fill up Dante with 93 Octane from BP.

rustbucket
01-14-2014, 03:58 PM
Hope this might help those looking for ethanol free fuel ...

http://pure-gas.org/index.jsp

4carbcorvair
01-15-2014, 12:06 PM
We usually run 87 octane. I stopped getting gas from where I usually do because I noticed three of our vehicles, including the Fiat, spark knocking on acceleration/up hills. Started using a different brand/station and it went away. So now I avoid the place. I have run 91, highest around here, a couple times. I too noticed a bit of power according to the seat of the pants dyno and a slight increase in MPG's.

gincar96
01-15-2014, 04:56 PM
. I have run 91, highest around here, a couple times. I too noticed a bit of power according to the seat of the pants dyno and a slight increase in MPG's.

Same story here from Reg to mid grade. Have not seen much change from mid grade to prem though. Generally run mid grade.