worse mpg with 93 octane
#1
#2
#6
Without a tune, you are wasting your money, polluting more and clogging you Cat. If you can tell a difference you are feeling what you want to feel.
http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm
~HJ
http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm
~HJ
#7
#8
What you are feeling is all in your head. It is actually degrading performance. It is degrading your MPG. And if you keep using it, it is going to degrade the rest of your engine with carbon and screw up your entire emissions system.
You computer must be reprogrammed to properly use any octane other than 87.
You computer must be reprogrammed to properly use any octane other than 87.
#9
#10
I doubt it, Just hitting your wallet.
#11
#14
Which means there is something wrong with your engine. You should fix it rather than continuing to make it worse and throwing money in it.
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#16
Look in your manual. It will say 87. Rangers don't have high compression engines or boost. You don't need the extra octane.
#17
your truck isn't designed to run 93 octane. its not high compression like a corvette where it needs slower burning fuel. 93 is a little bit thicker so it burns slightly slower than 87. when you have high compression you have more horse power but high compression makes the fuel burn faster. semis run completely off of compression which is why diesel fuel is so thick and thats why semis don't have sparkplugs. your engine assuming it is the stock motor is designed to burn most efficiently on 87 octane and anyting else your basically wasting money.
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#21
your truck isn't designed to run 93 octane. its not high compression like a corvette where it needs slower burning fuel. 93 is a little bit thicker so it burns slightly slower than 87. when you have high compression you have more horse power but high compression makes the fuel burn faster. semis run completely off of compression which is why diesel fuel is so thick and thats why semis don't have sparkplugs. your engine assuming it is the stock motor is designed to burn most efficiently on 87 octane and anyting else your basically wasting money.
No, but higher octane can advance the timing. The closer to TDC you spark it, the more energy out of it you are going to get. Hence why running E-85 doesnt give a 30% drop in mileage when E-85 has 30% less energy than 87 oct gas. Ethanol has an "octane" rating of 110 IIRC.
#22
There is so much misinformation in this post and I hope nobody reads it and believes all of it.
I have never read anywhere that high octane fuel has a temperature of ignition. It does tend to burn slower and more uniformly. It also resists pre-ignition. High octane fuel cannot change timing but advancing the timing is done when using higher octane if the engine does not have higher compression to utilize the higher octane fuel. Advancing the timing is not closer to TDC, it is farther away from TDC.
High octane fuel is not thicker. I use 110 to 112 octane in my race car at 14:1 compression and that fuel is no thicker than 87 octane pump gas.
Be careful about using 100 octane Av-gas. It is my understanding that even though it is called unleaded, it still has a very small amount of lead in it which can damage your catalytic converter. I don't know this for fact but I would recommend investigating this a little before trying it.
The slight miss you get at idle with 87 may just be a lean miss. They run the engine lean to reduce emissions. A slightly rich mixture will will run smoother. Using higher octane will have a tendency to run slightly rich because you don't get a complete burn due to the slower burn. This is hypothetical and may not be fact. Just a suggestion based on a few facts.
I have never read anywhere that high octane fuel has a temperature of ignition. It does tend to burn slower and more uniformly. It also resists pre-ignition. High octane fuel cannot change timing but advancing the timing is done when using higher octane if the engine does not have higher compression to utilize the higher octane fuel. Advancing the timing is not closer to TDC, it is farther away from TDC.
High octane fuel is not thicker. I use 110 to 112 octane in my race car at 14:1 compression and that fuel is no thicker than 87 octane pump gas.
Be careful about using 100 octane Av-gas. It is my understanding that even though it is called unleaded, it still has a very small amount of lead in it which can damage your catalytic converter. I don't know this for fact but I would recommend investigating this a little before trying it.
The slight miss you get at idle with 87 may just be a lean miss. They run the engine lean to reduce emissions. A slightly rich mixture will will run smoother. Using higher octane will have a tendency to run slightly rich because you don't get a complete burn due to the slower burn. This is hypothetical and may not be fact. Just a suggestion based on a few facts.
#23
Aviation fuel is not called unleaded at all. It is called 100LL which stands for 100 Octane low lead. It is in fact leaded gasoline and shouldn't be used in autos designed for unleaded fuel.
Gary, this octane thing comes up a few times a year and i must say it is funny to read all the various misconceptions. I blame the fuel companies advertising. They always call it premium or super or whatever. When in reality, there is nothing premium or super about it other than the cost.
Gary, this octane thing comes up a few times a year and i must say it is funny to read all the various misconceptions. I blame the fuel companies advertising. They always call it premium or super or whatever. When in reality, there is nothing premium or super about it other than the cost.
#24
There is so much misinformation in this post and I hope nobody reads it and believes all of it.
I have never read anywhere that high octane fuel has a temperature of ignition. It does tend to burn slower and more uniformly. It also resists pre-ignition. High octane fuel cannot change timing but advancing the timing is done when using higher octane if the engine does not have higher compression to utilize the higher octane fuel. Advancing the timing is not closer to TDC, it is farther away from TDC.
I have never read anywhere that high octane fuel has a temperature of ignition. It does tend to burn slower and more uniformly. It also resists pre-ignition. High octane fuel cannot change timing but advancing the timing is done when using higher octane if the engine does not have higher compression to utilize the higher octane fuel. Advancing the timing is not closer to TDC, it is farther away from TDC.
Incase you missed automechanics 101, advancing the timing is moving it closer towards TDC. The spark plug fires before the piston reaches TDC.
Knocking happens because of two reasons, hot spots, and charge temperature. Longer carbon chains have a higher temperature of combustion. In theory, longer carbon chains also have more energy, but the way they blend it, there is actually less energy.
Thus, a higher octane will allow you to advance timing which results in a quicker, more complete combustion.
So if you are so dumb as to think that I was saying changing the fuel changes its timing as if spark timing were magic....well god save your soul and perhaps a reading comprehension class and giving people the benefit of the doubt would would benefit you in life.
Last edited by CBFranger; 01-20-2009 at 12:19 PM.
#25