Gasoline preferences

I would be interested to hear from anyone who has compared the use of regular gasoline with premium when towing over moderately high mountains, i.e. Blue Ridge, Smokies, Appalachian, etc.
I have a 29' Class C plus Ford Fiesta and am curious whether the added cost of premium is compensated by better mileage or cooler transmission output.  THANKS.

29' 2007 Winnebago Outlook equipped with Ford gas engine.

Gasoline is like shoe size. Putting on larger shoes will not make you run the 100 yard dash faster. Using octane above what the vehicle is rated for will not increase anything except cost.

I agree with Tom, use whatever your vehicle owners manual calls for. If you put in a higher octane, the computer in your vehicle will change to keep the operation the same. Net gain zero

Here is something you might find interesting,, At high altitudes.. Not only do you NOT need higher octane.. You can get buy with less.

NOW.. For this reason I may up to Mid-grade when "High" because while "Regular" is 87 here 15 feet above sea level.. I've seen 85 and lower atop mountains and the MID was 87/88/89 range, which is what the beast likes.

Wizard46 said:

If you put in a higher octane, the computer in your vehicle will change to keep the operation the same. Net gain zero

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If your engine knock sensor detects a knock, the timing and/or fuel delivery will be adjusted by the computer to prevent the knock.  No, you will not hear the knock or know if an adjustment has been made, what will happen is that performance and fuel economy will suffer.  The higher octane will help, but only if your engine develops a knock. 

Octane is very misunderstood. Higher octane fuels are not more "powerful" in the way they are advertised. The higher the octane, the harder it is to ignite.

Turbo's... high compression engines... supercharged engines... engines designed to run more "Advance" on the timing, need higher octane fuels because it is very important that the air/gas mixture ignites exactly when the engine needs it to. Pre ignition, the gas going off early due to a hot spot.. pressure.. etc... can degrade performance, if not destroy your pistons in severe cases.

Running the fuel your vehicle recommends is giving you the best bang for your buck.. the computer, the timing, everything was factored to run right at that octane level.

In some cases, running "89" if you are getting ping in older engines can help. Modern engines have knock sensors that immediately retard the timing if they sense any pre ignition.

EdS said:

Octane is very misunderstood. Higher octane fuels are not more "powerful" in the way they are advertised. The higher the octane, the harder it is to ignite.

Turbo's... high compression engines... supercharged engines... engines designed to run more "Advance" on the timing, need higher octane fuels because it is very important that the air/gas mixture ignites exactly when the engine needs it to. Pre ignition, the gas going off early due to a hot spot.. pressure.. etc... can degrade performance, if not destroy your pistons in severe cases.

Running the fuel your vehicle recommends is giving you the best bang for your buck.. the computer, the timing, everything was factored to run right at that octane level.

In some cases, running "89" if you are getting ping in older engines can help. Modern engines have knock sensors that immediately retard the timing if they sense any pre ignition.

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A lot of people don't understand this as there is a lot of misinformation about this but this is correct. Higher octane actually makes the fuel less combustible, which is important for higher compression engines. My truck has twin turbos but the manufacturer still recommends 87 octane for regular use because the turbos don't engage often. They recommend using 93 octane when towing because the turbos will be used extensively. Supposedly it gives better mileage when towing as well as better performance, but I have yet to notice a change in either. I still do it because Ford says to, but I often wonder if the extra $$ is worth it. Bottom line is read your manual and do what it says.

    Has anyone tried the ethanol free gasolines. The extra cost is not offset by the increased fuel economy but the performance makes up for it.

Good point, Will. There is more energy in pure gas than in gasahol.  Mid or premium fuel often does not have any ethanol added, so may boost performance for that reason, even though the engine itself doesn't run any better on higher octane fuel.

catblaster said:

    Has anyone tried the ethanol free gasolines. The extra cost is not offset by the increased fuel economy but the performance makes up for it.

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I tried it for a few tanks and I didn't see either a performance increase or a fuel economy increase. But then again I never floor it so I would not have noticed any performance increase.

SeilerBird said:

Gasoline is like shoe size. Putting on larger shoes will not make you run the 100 yard dash faster. Using octane above what the vehicle is rated for will not increase anything except cost.

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Agree on Octane but I run faster Barefoot.
Marvin

On several trips, traveling thru areas that we got gas with no ethanol we saw a slight increase in MPG on our 32" Class A. (454 motor)
On my Pickup truck I did a couple of tank fulls to compare and I saw a difference from 15.6 mpg to 17. mpg.
But not enough increase in MPG to justify the higher cost..

Bob

catblaster said:

    Has anyone tried the ethanol free gasolines. The extra cost is not offset by the increased fuel economy but the performance makes up for it.

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Ethanol free gasoline is good for the last fill up when storing the RV for a few months.  Less likely to turn to @#$%& in the carb/fuel system than the ethanol fuel.

yolo said:

Ethanol free gasoline is good for the last fill up when storing the RV for a few months.  Less likely to turn to @#$%& in the carb/fuel system than the ethanol fuel.

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That has been my thoughts also but what I found is the ethanol free tend to varnish just like I remember back in the 60's. The fuel stabilizer really helps or even a little 2 cy motor oil. My Ethanol fuel has been keeping longer if I keep it in an airtight container and out of the sunlight.

Since our corvette requires premium fuel anyway the ethanol free is only $.10 more a gallon and 89 octane instead of 92.  In our Tahoe that runs the cheapest fuel available it is $.60 more a gallon and is hardly worth even though the engine sure likes it.

The common E10 (10% ethanol) has about 3% less energy than pure unleaded regular gasoline, so you aren't going to notice much difference, even with the pedal floored.

I agree about going with the lowest octane that the manufacturer allows. 

Two completely different thoughts are as follow:

1.  The ethanol free concept from stations that can be found here:http://www.pure-gas.org

2.  The higher detergent concept (also mentioned in my Highlander owners manual) http://www.toptiergas.com

I guess the best of all worlds is ethanol free gas from a top tier dealer.  Poke around in both sites and come up with your own course of action.  I know here if Florida that ethanol free gas is 30-50 cents a gallon more expense (it is also listed as "boat gas") so I take my chances with E-10.

One final thought, stay away from E-15 or higher.  If you read the fine print in many vehicle owners manuals you can void your warranty if you make a claim and the dealer tests your gas and determines that E-15 up to E-85 was used.  No problem with flex fuel vehicles of course.       

I had an old truck with a heavily modified Chevy 350 engine and it required 93 octane to run properly. When they started putting 10% ethanol in the gas, I never could get it tuned to run right (carbureted). My current 2013 runs just fine on E-10 and in fact, I can't tell the difference in mileage or performance between E-10 and 100% gas, but that's because it was designed to run off 87 octane E-10. We can't get ethanol-free gas in Texas anyway, regardless of octane level. My old motorcycle was carbureted and it ran fine off of E-10, but if I didn't ride it for 3 weeks, the carbs would get gummy and it wouldn't run right for a while. Same with the carbureted lawn mower. I switched to using ethanol free gas in the lawn mower and chain saw and now they both start with one pull every time, even after winter storage. Also, a note on FlexFuel vehicles that a lot of people don't know. You can run E-10, ethanol free gas, or E-85. The caveat is that the PCM must be programmed for which fuel you're using. The default configuration is E-10/ethanol free, but you have to take it to the dealer to if you're going to run E-85. Leaving the program in either mode and switching fuel often can damage the engine.

I have a 2004 Adventure 38 Ft Chevy work horse motor.  I filled it up end of Aug 2016 with plans to travel, however life situations prevented travel so the coach has been sitting.  I live in my coach and start both the coach and generator every two weeks.  Concern about 87 octane ethanol gas being in the tank for almost 7 months with NO additive I am thinking of pumping out the gas tank.  I have access to 55 gal drums so that is not a issue.
Any advise, recommendations greatly appreciated.  What is the best way to pump out the gas? 
My thoughts after I get the gas out is to pull in REG NON Ethanol Gas and running it for about an hour and then fill it and add sea foam.  And yes replace fuel filter.

love2ride4him said:

I have a 2004 Adventure 38 Ft Chevy work horse motor.  I filled it up end of Aug 2016 with plans to travel, however life situations prevented travel so the coach has been sitting.  I live in my coach and start both the coach and generator every two weeks.  Concern about 87 octane ethanol gas being in the tank for almost 7 months with NO additive I am thinking of pumping out the gas tank.  I have access to 55 gal drums so that is not a issue.
Any advise, recommendations greatly appreciated.  What is the best way to pump out the gas? 
My thoughts after I get the gas out is to pull in REG NON Ethanol Gas and running it for about an hour and then fill it and add sea foam.  And yes replace fuel filter.

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A year or two, on the other hand, would likely cause problems, but I should not think that a few months would create a problem, but I may be missing something.

If you can move it at all (couple mile trip) I would suggest the appropriate amount of stabilizer ("Sta-Bil", avail Wal-Mart) be added to prevent varnishing. If you can't move it, and the tank's not completely full, you could add the Sta-Bil to a five gallon can, then fill with gas, then add to tank, then run both engine and genset to ensure the stabilized gas has gotten to both. Don't add Sta-Bil without mixing.


Also, if tank isn't full, condensation could be an issue. There are additives (essentially alcohol) which will blend with the gas and help hold any water droplets in suspension. For this reason I'd suggest filling tank rather than emptying.