87, 89 Octane... or E85 ????
CF Junior Member
Joined: Oct 2009
Posts: 45
Likes: 0
lol, so what your saying is that you trust the OIL pressure guage, the Tachometer, the Speedometer, the gas guage, the temp guage, the voltage guage, the tranny temp guage, the odometer, and you trust that the fuel injector's accurately measure fuel in the thousandths of a gallon, hundreds of times a minute, yet... darn it, somehow that silly MPG guage is off...
yea man, I don't know... I'd much prefer an abacus and some 1 gallon milk jugs to measure the gas usage. Then we can drop string out the window and see how far we went
. We can count the knots
Sorry, it's just funny...
the DIC MPG can't lie. it's a machine. the ECM measures fuel very, very accurately... and it knows how far you drove... it even knows you rolled that stop sign 2 miles back leaving your home...
Also, don't use E85, I hate it so much, there isn't enough room here for me to explain how bad it is...
yea man, I don't know... I'd much prefer an abacus and some 1 gallon milk jugs to measure the gas usage. Then we can drop string out the window and see how far we went
. We can count the knots Sorry, it's just funny...
the DIC MPG can't lie. it's a machine. the ECM measures fuel very, very accurately... and it knows how far you drove... it even knows you rolled that stop sign 2 miles back leaving your home...
Also, don't use E85, I hate it so much, there isn't enough room here for me to explain how bad it is...
DIC mpg is a good approximation but when it tells me that I've used 18 gallons and it takes 20 gallons to fill, it makes me wonder about the mpg calculation.
Administrator
Joined: Apr 2006
Posts: 11,337
Likes: 194
From: KC, MO area
Well you have to fill at the same pump every time and stop when it shuts off.
Looked at my data and the DIC data is right on about 5% of the time and the rest, it usually is about 0.5-1.0 mpg optimistic. I suspect it's probably due to tolerances on the sensors more than an effort to present a better mpg figure.
Looked at my data and the DIC data is right on about 5% of the time and the rest, it usually is about 0.5-1.0 mpg optimistic. I suspect it's probably due to tolerances on the sensors more than an effort to present a better mpg figure.
CF Junior Member
Joined: Jul 2013
Posts: 30
Likes: 0
From: Scottsboro,AL
Milage
In my 1997 Tahoe 5.7 L I tried the 89 then the 93 and my mileage really was really bad. On the 93 I got 9 mpg average and using the 89 I got 10.5 mpg. Then I read the manual and it said use regular (89), so I started using it. Then I happened upon the Lucas ethanol treatment ( a little pricey ). So I decided to give it a try is because I drive a 18 wheeler and we use Lucas in our trucks. I have been keeping up with the fuel millage,( 6 months )I am now averaging between 16 to 17 mpg. That is in what they call city driving. I have to drive up a large hill. The grade is around 5% and it is 3 miles 5% ( speed limit 55 ). So now it really seems to be cheap as I recoup the money with the millage.
Administrator
Joined: Apr 2008
Posts: 7,573
Likes: 47
From: Austin, Texas
It's not so much the octane rating as it is the amount of alcohol in the fuel...
But along that line, with some unscientific testing and discussing via this forum others have concluded that using a higher octane fuel can in some cases provide better MPG... that said I believe it's due to a lower ( in some cases not all) alcohol content of the higher octane fuel....
If you have marine grade 100% gas available to you, give that a try in a couple of tanks and you will see better MPG....
Go with what is recommended for daily driving, also change up where you get your gas, some stations can have more alcohol added then others...
Alcohol is basically used a filler or extender to reduce the cost of fuel so that farmers get a cut of the government subsides....(I mean it's to help the environment and reduce pollutants and show the world that we really want to address global warming)
But along that line, with some unscientific testing and discussing via this forum others have concluded that using a higher octane fuel can in some cases provide better MPG... that said I believe it's due to a lower ( in some cases not all) alcohol content of the higher octane fuel....
If you have marine grade 100% gas available to you, give that a try in a couple of tanks and you will see better MPG....
Go with what is recommended for daily driving, also change up where you get your gas, some stations can have more alcohol added then others...
Alcohol is basically used a filler or extender to reduce the cost of fuel so that farmers get a cut of the government subsides....(I mean it's to help the environment and reduce pollutants and show the world that we really want to address global warming)
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