talldude100

2010 4.6 question: have been using ARCO regular fuel (1) and the mpg has been going down! Is it better to use the next (2) or highest (3) octain to get the higher compression for better mileage more power, and less pull on the engine...getting more mpg....thnks

as in more bang for the gas buck.....

talldude100

in other words what octain do you use everytime you fill up..easy huh!
are you happy with your mileage...????

Nuke

Higher octane doesn't give you higher compression, nor will it give you any noticeable mileage improvement. You'll waste more money in the cost per gallon of a higher octane (i'm sure some will disagree).

Fuel mileage can vary due to so many things that you could drive the same stretch of 400 mile road at the same speed using gas from the same pump and still vary by as much as 4 MPG. I know this for a fact because I did just that every 2-4 weeks for almost 2 years with the Stang.

What are you basing your drop in mileage on and how many data points? Have you taken the weather conditions into consideration (at the very least)? Are you hand calculating or relying on that god-inaccurate on-board?

Did you buy your Stang for economy? I doubt it. If you want to save fuel do all the basics: maintain the engine, keep your tire presuure up, ease off on the gas pedal, coast more and time your distances.

If you're looking to save money, better to start drinking water instead of soda, packing your lunch instead of buying those Happy Meals (I miss the toys, too) and make your own coffee and take a thermos instead of buying StarBucks.

I bought my Stang for the wood it gives me, NOT for economy.

siggyfreud

Generally you want to use the lowest octane rating your car can run on without having to pull timing due to detonation.

sactown

LOL! No offense, I get about 13.8mpg average running 91 octane. If your mileage is going down it is cause by 2 things driving habit, and tune up. BTW Arco gas is crap IMO, I know some people will say it does not make a difference, but I don't run the cheap ****.

Bmr4life

Run the minimum octane your car is meant to run. Stock, out cars are meant to run 87. Anything higher is a waste unless you have octane recognizing ecu (like on the Bullitt). Once you put an aftermarket tune on, run what the tune is meant for, any higher is again a waste.

alkemist

Don't have ARCO around here, but I always run name brand gas such as Shell, BP, Exxon, etc and willing to use mid-range brand names if I'm traveling.

I use 93 due to my tune. It's a waste of money otherwise if you were stock and put higher octane in the tank.

GT Nate

OCTANE BTW

Ethanol in gas doesn't help mileage in the least. Bad idea to ever put that **** in our gas supplies.

Bmr4life

Please look at the age of a thread before replying. Also, everyone knows E85 doesn't help MPGs and is worth running if you want those power gains especially with FIs.

outceltj

the resurrection