Jasonjames
Member
- :
- Mazda 2002 BJ Astina 323 1.8 L
Are you sure about that? Try gooogling burn times vs octane 
JJ
JJ
87 vs. 93
- Thread starter tweety2300
- Start date
yeah, i'm pretty sure.
here is a good, easy read (and its not Wikipedia)...
http://science.howstuffworks.com/gasoline.htm
this is the page that addresses octane:
http://www.howstuffworks.com/gasoline3.htm
here is a good, easy read (and its not Wikipedia)...
http://science.howstuffworks.com/gasoline.htm
this is the page that addresses octane:
http://www.howstuffworks.com/gasoline3.htm
INeedMoarLow
Member
- :
- slammed 02 protege5
Let's just say the a higher octane resists compression more correct?
If it takes longer to compress doesn't that mean its burning slower?
Which in turn would increase gas mileage.
Maybe only a mpg our so but it helps.
A far as burning hotter or cooler,
If its only compressing when lit versus exploding from compression it is a more controlled burn and is causing less damage whether hotter or cooler.
I run nothing but 93 in my car and I only go to one gas company to try to keep it regular.
Race fuel will increase the these results only by the amount of octane increased effectually the difference of 87-93 is the 93-race fuel.
Octane boosters are not guaranteed the results listed on the bottle and should not be relied on.
End of rant
If it takes longer to compress doesn't that mean its burning slower?
Which in turn would increase gas mileage.
Maybe only a mpg our so but it helps.
A far as burning hotter or cooler,
If its only compressing when lit versus exploding from compression it is a more controlled burn and is causing less damage whether hotter or cooler.
I run nothing but 93 in my car and I only go to one gas company to try to keep it regular.
Race fuel will increase the these results only by the amount of octane increased effectually the difference of 87-93 is the 93-race fuel.
Octane boosters are not guaranteed the results listed on the bottle and should not be relied on.
End of rant
octane resists "IGNITION" by compression. big difference from resisting compression.
tweety2300
Member
- :
- 2001 mazda protege mp3
Why do all my threads end in some sort of argument?
Jasonjames
Member
- :
- Mazda 2002 BJ Astina 323 1.8 L
Well,..it would be very boring indeed if there was no discussing, or even arguing/debate As long as the language is kept civil....
Jason
As long as the language is kept civil....Jason
Jasonjames
Member
- :
- Mazda 2002 BJ Astina 323 1.8 L
Let's just say the a higher octane resists compression more correct?
Well it resists "compression-ignition"...
If it takes longer to compress doesn't that mean its burning slower?
No,..compression acts on the fuel-air mixture regardless of type of fuel...
Which in turn would increase gas mileage.
Mileage involves many things,..however an engine designed to run on low-octane fuel will be of a lower compression, and hence not extract all the energy from the fuel-air mix.
Maybe only a mpg our so but it helps.
A far as burning hotter or cooler,
If its only compressing when lit versus exploding from compression it is a more controlled burn and is causing less damage whether hotter or cooler.
A couple of mixed ideas there,..any fuel-air mixture that ignites due to compression is bad,..as there is no timing in play [ie spark ignition] OTOH,..Diesels are designed to work with compression-ignition..
I run nothing but 93 in my car and I only go to one gas company to try to keep it regular.
Uh huh ...
Race fuel will increase the these results only by the amount of octane increased effectually the difference of 87-93 is the 93-race fuel.
Sorry,..you've lost me on this one
Octane boosters are not guaranteed the results listed on the bottle and should not be relied on.
Haven't used octane-boosters as the 1.8 is happy with 91 E10,..but from what I believe, octane boosters would include aromatic spirits like Toluene, which is pretty expensive stuff.
JJ
End of rant
I posted a response to the "burn time VS octane" thread,..but it has not appeared,..so be it
Well it resists "compression-ignition"...
If it takes longer to compress doesn't that mean its burning slower?
No,..compression acts on the fuel-air mixture regardless of type of fuel...
Which in turn would increase gas mileage.
Mileage involves many things,..however an engine designed to run on low-octane fuel will be of a lower compression, and hence not extract all the energy from the fuel-air mix.
Maybe only a mpg our so but it helps.
A far as burning hotter or cooler,
If its only compressing when lit versus exploding from compression it is a more controlled burn and is causing less damage whether hotter or cooler.
A couple of mixed ideas there,..any fuel-air mixture that ignites due to compression is bad,..as there is no timing in play [ie spark ignition] OTOH,..Diesels are designed to work with compression-ignition..
I run nothing but 93 in my car and I only go to one gas company to try to keep it regular.
Uh huh ...
Race fuel will increase the these results only by the amount of octane increased effectually the difference of 87-93 is the 93-race fuel.
Sorry,..you've lost me on this one
Octane boosters are not guaranteed the results listed on the bottle and should not be relied on.
Haven't used octane-boosters as the 1.8 is happy with 91 E10,..but from what I believe, octane boosters would include aromatic spirits like Toluene, which is pretty expensive stuff.
JJ
End of rant
I posted a response to the "burn time VS octane" thread,..but it has not appeared,..so be it
wow, long post.
sounds to me that you are trying to convince yourself that a higher octane rated fuel will give better fuel economy.
first, compression speed is a factor of the engine compression ratio and the RPM's at which the engine is spinning, not the fuel.
fuel mileage is a measurement of the efficiency of the engine to extract power from the fuel it uses. octane alone will not change that value. beside, you are only talking about gaining or losing 1-2 points of efficiency anyway. i can change my fuel mileage more than that just by changing my driving style.
one last thought from me; here's your thermodynamics instruction for the day...
when you compress a 'gas', you will also increase its temperature. when the piston inside the engine compresses the fuel-air mixture, it increases its temperature. this increase in temperature CAN cause the fuel-air mixture to self ignite, or combust, from the heat generated by compression inside the engine. this is bad for typical internal gasoline combustion engine, such as is found in the Mazda Protege. (i'm not going to get into diesel engines, since they rely on this to run)
ideally, you want the fuel-air mixture to ignite at such a time to create the maximum pressure inside the combustion chamber when the crankshaft is at an ideal position to create the most torque. (that's a VERY over simplistic explanation) there are many factors that come into play to determine when the fuel-air mixture should be ignited to obtain to best burn and most power and the best fuel economy. taking octane rating out of the equation, there is only so much ignition timing advance that you can add to any given engine to achieve the best burn. increasing the octane of the fuel will not change this, and is a factor of the engine design.
so, if you have a high enough compression ratio in your engine, the fuel-air mixture MAY self ignite before you can fire the spark plug. this is bad. to prevent this from happening, you run a fuel with a higher octane rating. the only thing a higher octane fuel gets you, is to not self ignite before the spark plug has a chance to fire.
i hope that helps you understand a little bit more about what's going on inside that cast iron lump in the front of your car. if not, well, i'm not sure what else i can do to explain it better. you really need to know all of what's going on inside the engine to see how octane rating plays its role in the whole process.
sounds to me that you are trying to convince yourself that a higher octane rated fuel will give better fuel economy.
first, compression speed is a factor of the engine compression ratio and the RPM's at which the engine is spinning, not the fuel.
fuel mileage is a measurement of the efficiency of the engine to extract power from the fuel it uses. octane alone will not change that value. beside, you are only talking about gaining or losing 1-2 points of efficiency anyway. i can change my fuel mileage more than that just by changing my driving style.
one last thought from me; here's your thermodynamics instruction for the day...
when you compress a 'gas', you will also increase its temperature. when the piston inside the engine compresses the fuel-air mixture, it increases its temperature. this increase in temperature CAN cause the fuel-air mixture to self ignite, or combust, from the heat generated by compression inside the engine. this is bad for typical internal gasoline combustion engine, such as is found in the Mazda Protege. (i'm not going to get into diesel engines, since they rely on this to run)
ideally, you want the fuel-air mixture to ignite at such a time to create the maximum pressure inside the combustion chamber when the crankshaft is at an ideal position to create the most torque. (that's a VERY over simplistic explanation) there are many factors that come into play to determine when the fuel-air mixture should be ignited to obtain to best burn and most power and the best fuel economy. taking octane rating out of the equation, there is only so much ignition timing advance that you can add to any given engine to achieve the best burn. increasing the octane of the fuel will not change this, and is a factor of the engine design.
so, if you have a high enough compression ratio in your engine, the fuel-air mixture MAY self ignite before you can fire the spark plug. this is bad. to prevent this from happening, you run a fuel with a higher octane rating. the only thing a higher octane fuel gets you, is to not self ignite before the spark plug has a chance to fire.
i hope that helps you understand a little bit more about what's going on inside that cast iron lump in the front of your car. if not, well, i'm not sure what else i can do to explain it better. you really need to know all of what's going on inside the engine to see how octane rating plays its role in the whole process.
Jasonjames
Member
- :
- Mazda 2002 BJ Astina 323 1.8 L
That post by me wasn't laid-out very well,.. It was me replying to the previous poster's statements. I should have annotated my responses. To keep it brief, lower octane fuels work best in lower-compression motors because LO fuel is more volatile. This volatility also means it burns faster, which is why its ignition timing is later [retarded] than higher octane fuel. Some folks dont get the fact that higher octane is slower burning. In addition, higher octane fuel needs to be ignited [by spark] earlier than lower octane fuels, because it takes longer to reach full cylinder pressure.
JJ
JJ
um... no.
- :
- 1989 RX-7 GXL Blaze Red
this to the max
*edit: and after reading it again I don't want to be on here during the summers when school is out anymore
