Fuel mileage

upnover

upnover

Grumpy, decrepit Old Man
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Joined
Mar 20, 2005
Location
Morganton NC
Thought someone might be interested.

In April I went to Harlan. I filled on tank with regular gas, the other with premium. On the way back, Same thing. It took me two full tanks to get there and two full tanks back.

This past weekend I went back, same trip. I used only premium in both tanks and it took me 3 1/4 tanks total. Using premium made a BIG difference in fuel consumption. I figured some difference, but not that much.
 
Chip, recently I found the same thing on my 1989 4runner! Much more power and better fuel milage. To a 4cilinder with auto and AC, the difference amazing! Trying the same now in my old Suburban, 1996 with 174,000 miles and it runs so much better and now stays in overdrive in the hills. I'll check it soon to URE and back(116 miles round trip). It will take a while to run all the regular gas out of a 42 gallon tank and change completely over to premuim!
 
I am going to show my ignorance, but why would premium burn more? This seems like a good argument to NOT use premium.
 
BigClay said:
I am going to show my ignorance, but why would premium burn more? This seems like a good argument to NOT use premium.
Click to expand...

He is saying useing Reg and Premium burned 4 tanks.

Useing just premium burned 3.25 tanks, So better fuel mileage.


So in dollars, Just assuming your tanks are 30 gallon.

Reg - $2.50 Premium $2.75 Estimated Prices

First trip using mixed fuel - $315 in fuel cost
Second Trip using Premium - $288.75 In fuel cost

Savings of $26.25
 
Ahhh, that makes more sense. I just read it wrong.
 
I noticed this on my car awhile back...I drive the same route to work and back every day (about 40miles round trip). My Mercedes S500 gets 20mpg on the highway on the lowest octane they sell(yes it's bad, but can you put a price on being an old school pimp?)...I check it every time I fill up. One day the only gas at the station I go to was premium, the others were not working. That time I got right at 23mpg, I checked it twice more with both premium and crap gas, the results have been the same on all occasions.
 
so is there methanol in premium also? or is there not..

just curious since I have seen and heard the issues with methanol in lawn equipment?
 
Hmmm..... interesting... My (brand) new lawn mower won't start for shit... Literally, i have to push the primer button slowly to keep it running for a minute until it warms up.. I filled it with premium and it starts 1st pull now.

It seems like the gas quality just sucks recently.

Well I will give the premium gas a go in my DD slow rider truck...

Here is my mileage log on the ecomodder site...
http://ecomodder.com/forum/em-fuel-log.php?vehicleid=4009
 
BRUISER said:
so is there methanol in premium also? or is there not..

just curious since I have seen and heard the issues with methanol in lawn equipment?
Click to expand...


ETHANOL is bad for any type of stored fuel as it absorbs moisture and causes gas to varnish faster.

Ethanol also does not have the BTU's that straight gas has, ( lower heat value, so less power ) so adding it to gas reduces available power, and mileage suffers.

In the Midwest, the gas pump has to be labeled if it contains ethanol, I haven't seen many stations here in NC with the tags, but it may not be law here.
 
Most of the gas pumps I see have a sticker on them saying "May contain up to 10% Ethanol". I had the same issues with my lawn equipment. Ran 87 gas from a gascan and had to continously clean the carb bowl on a 2 yr old Deere. Switched to 93 and went away from the gascan (I fill the mower up at the gas station between my house and rental property). I have not had any problems yet and have increased my cutting range per tank.

As for my truck, I went from cheap walmart 87 octane gas to BP or Shell 93 and I got .5 mpg increase. Not really enough to warrant completely switching. I will test it again when the weather cools off and Im not running the AC.
 
Sorry to be so misleading, correct, in April 4 tanks total, (20 gallon tanks)
This past weekend, 3 1/4 tanks
On difference was in April I pulled a utility trailer with my spare TSL, Propane tanks, and camping stuff, this time I pulled my pop up camper and all the same stuff either in it, or on my truck.
 
Your Hot Dog Guy! said:
Trying the same now in my old Suburban <snip> 42 gallon tank
Click to expand...

You_just_can't_hide_money! :flipoff2:



upnover said:
On difference was in April I pulled a utility trailer with my spare TSL, Propane tanks, and camping stuff, this time I pulled my pop up camper and all the same stuff either in it, or on my truck.
Click to expand...

While not very "scientific", the mileage in April should have been better based on lighter load (unless your "utility trailer" weighs more than the camper?) and the cooler ambient temps (since cooler denser air aids in performance/efficiency)...

If I hit the lotto this weekend, I'll fill *my* 42gal tank in the 'Burb and give it whirl! :lol:
 
The reason that people are seeing such differences in mpg between different octanes has to do with the ethanol in them. I work in the Gas and Oil buisness and unfortunatly the ethanol does not carry the same octane rating as the gas. There for 87 octane is closer to 85 octane. Same reason you should always run 93 in you mower,weedeater and saws etc. Soon you will not see 89octane. They are slowly phasing it out. Same goes for the red dye diesel. Don't waste your money. Old high sulpher diesel ie. Off-road and home heating oil is no more. Red dye is not even low sulpher or 500ppm anymore. It is all ultr low diesle now just red doesn't have road taxes on it. Home heating oil is still 500ppm but I dont think the difference in price is worth it. Just some food for thought.
 
Also, just food for thought.. When we tuned my 8.1L Avalanche, on the baseline pull (stock tune, OK for 87 octane.. tank was full of 92 and had been run that way for 3 tankfuls), we were still getting some knock retard in the logs.
I can only imagine how much timing (and therefore, power, making me put the pedal down more) was being pulled when running 87!
 
HPTuners, did a tune on a local shop's dyno. Anyone who does LS1 cars can do the trucks. it's really very much the same. I absolutely would do it again. I gained across the board, anywhere from 30-50 hp & lb-ft. Dyno tunes are the only way to go IMO.

Dyno chart...
ai458.photobucket.com_albums_qq302_rquinlan3_Avalanche_dyno_20100604.jpg
 
I've got a 93 octane HP Tuners tune on my 99 Silverado. Stock I was getting 14 mpg, now with the tune, electric fans, an intake and different exhaust I average 19-20. It's got the 4.8, 5speed, 4x4, reg cab, long bed (34 gallon tank) and mine was just a mail-order tune, I'm sure a dyno tune could get a little more from it.

If nothing else, yall should at least notice a small power increase with 93 octane because the computer can advance the timing a lot more to compensate for the higher octane (harder to burn). That's a big part of what tunes do and, of course, fuel mapping, shift points, etc.
 
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