Which Grade of Fuel Do You Use?

[Ravi_1992]

Re: Which Grade of Fuel Do You Use?

what are the other benefits of using a better fuel?

[tcope1]

Re: Which Grade of Fuel Do You Use?

If all gasoline is the same then why do I get 18.5 mpg on Mobil gas , 18.0 on Shell gas and 17.0 on BP. This is all stop and go city driving. I check my mileage after every fill up, and this testing took 4 months.

There is really no difference in .5mpg... even if you filled up 50 times, it could still vary this much. Driving habits and temperature could account for this. The other difference I can think if is the amount of ethanol that station uses. If less, then your mpg is going to go up. But these stations usually charge a higher amount to compensate.

Bottom line, 1mpg is not a significant amount.

[roushstage2]

Re: Which Grade of Fuel Do You Use?

I used 87 for awhile but my car says use 91 octane on the fuel door so thats what ive been using lately , Ive noticed a significant power increase but I don't know weather I get more milege or not

Between these two links, you should have a pretty good understanding of octane ratings. That being said, using say 91 octane in a car that can use 87 is essentially throwing money away as the car will run with the less expensive gas. If you car needs 91, use it. The newer Dodge Hemi engines require mid-grade (89) IIRC.

http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm

http://www.associatedcontent.com/article/296800/what_does_gasoline_octane_rating_really.html

[Fly Bye]

Re: Which Grade of Fuel Do You Use?

Bottom line, 1 mpg is not a significant amount.

1 mpg is 5.5 percent of 18 mpg. 5.5 percent of 1,000 miles (aproximately 3 fill up's) is 55 miles. 55 divided by 18 equals 3.0 (gallons)


That's about 10 dollars

[sdprius858]

Re: Which Grade of Fuel Do You Use?

My Eclipse requires Premium, 91+ so thats what it gets and usually returns 20-24mpg mixed.

The 2010 Ram with the 4.7 flex fuel usually gets 87 and returns 15mpg mostly city, occasionally we'll take it down to the old Pearson Ford in El Cajon Blvd. and 15 and put E85 in it which returns 14mpg but only costs $2.39 a gallon.

The G35 coupe also gets 91+.

The Camry gets 87 and runs fine.

[Tuck91]

Re: Which Grade of Fuel Do You Use?

One of my clients is kind enough to give me free fuel out of his junkyard cars.

[cnfowler]

Re: Which Grade of Fuel Do You Use?

Since you don't have 85 listed, I chose 87. However, here in Colorado we don't have 93. Our premium is 91. Our regular is 85. Its because of the altitude.


Colin

[STG]

Re: Which Grade of Fuel Do You Use?

My car was tuned in California on 91 octane. I now live in Wyoming at 5,100 feet and can use 89 octane with absolutely no problem.

Octane requirement decreases as altitude increases. From Conoco Phillips:

Why are octane ratings lower at high altitude areas?

Lower octane number is required for carbureted engines at high altitudes because the lower air density results in lower combustion pressures and temperatures, the fuel/air ratio becomes richer due to the lower air density, and the spark advance is less due to lower manifold vacuum.

Knock sensors and altitude compensators in fuel-injected engines have lowered the octane requirement reduction at increasing altitude. Studies show an average altitude difference of 0.2 and 0.5 (R+M)/2 per 1000 ft (300 m). Consumers may experience slight power and acceleration reductions.

Practically speaking no new car sold in the United States requires more than 91 octane as states with large populations like California have added so much anti-emissions **** to gasoline that 91 octane is the highest available even near sea level in Los Angeles and San Francisco.

MAYBE you car's ECU can boost performance on 93 octane, but do not assume this. My 2004 Mach 1 cannot take advantage of higher octane unless I have it custom tuned. I know because I spoke with the Ford Calibration Engineer who wrote the programming for the 2003-2004 Mach 1 and the 2001 Bullitt Mustangs.

I've noticed the international posters on this thread. Please note octane is calculated more than one way. The USA uses AKI (Anti Knock Index), Europe uses RON (Reasearch Octane Number). The same fuel's octane is about 4-5 points higher using RON.


I can't believe **** was edited out of my post. Should I carp about **** being censored? After all, carp has the same four letters as ****!

[new2detailing]

Re: Which Grade of Fuel Do You Use?

I use 87 octane for all my vehicles. It is pointless to use a higher grade unless the owner's manual suggests it. Remember, the ECU will help determine the proper fuel/air ratio and adjust accordingly. Unless, one plans on remapping the ECU, it is a fruitless exercise to step up on Octane ratings. Even cars listed for 91 or above octane can run on lower octane in a pinch. The ECU will simply adjust for the lower octane(the car will lose a touch of power to compensate) to avoid premature combustion.

The same methodology applies to when someone adds an intake and exhaust to a vehicle but doesn't pay to remap the ECU. The gains are modest without the remapping. If you want the sound fine, but for performance it is imperative to unlock the potential in the ECU.

As an earlier poster stated, if you go up in elevation, lower octane fuels will assist in decreased oxygen levels. The ECU will automatically adjust for the altitude.

[smack]

Re: Which Grade of Fuel Do You Use?

I use what the manufacturer recomends. In my case its 91. I use chevron.

[ANeat]

Re: Which Grade of Fuel Do You Use?

I use diesel in my car

[e85 bish]

Re: Which Grade of Fuel Do You Use?

i use e85 on my evo
Pros-higher octane rating(105) by switching form 91 to e85 my car gained 95hp and 105torque
Cons-it lower my mpg's so now i have to stop more @ the pump

[rcktpwrd]

Re: Which Grade of Fuel Do You Use?

depends on the vehicle... the regular driver only gets 87 as that is what the manufacturer recommends and anything above that is wasted money. The high performance vehicles get 93 as that is what is needed for the higher compression engines in them.

[Shootist]

Re: Which Grade of Fuel Do You Use?

Only use regular these days, but will occasionally put a tank of Shell Premium in the Infiniti. I can't tell a difference unless I put my foot to the floor and even that may be in my head. The Infiniti says "Premium Only' everywhere...hogwash. I don't think I'm allowed to post links yet, so here's a quote from a 2003 USA Today article, 'Why use premium gas when regular will do?":

All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.

I do use Top-Tier fuels exclusively unless I'm in the boonies with none available. If you're unfamiliar with that, go to toptiergas.com. Of course, old muscle-cars or cars w/o knock sensors which retard the engine timing may very well require a higher octane fuel. I've been told by engineers, however, that a slight ping when under load means the engine is operating at peak efficiency.

[Zeta Detail]

Re: Which Grade of Fuel Do You Use?

Diesel in my case, I regret not seeing it listed. I ride a US-built Jeep, by the way.

In Europe premium is 98 octane and regular 95. I'm surprised to see that in the U.S. 87 octane gas is still sold, but I've heard that the composition of car gasoline varies widely depending on the country.