View Poll Results: What brand of gas do you like most for your IS
Chevron
8
53.33%
Shell
6
40.00%
Sunoco
0
0%
BP
2
13.33%
Exxon/Mobil
2
13.33%
What ever is cheapest
1
6.67%
Any top tier station
0
0%
Oh no, not another poll - who cares
0
0%
Multiple Choice Poll. Voters: 15. You may not vote on this poll
Favorite Gas for your IS?
11-09-09, 06:12 AM
#76
And just to save you guys some time, here's a decent, non-Wiki, explanation of what Octane actually is-
http://auto.howstuffworks.com/fuel-e...question90.htm
That's it.
resistance to knock.
That's the only thing octane level indicates.
So you should -always- use the lowest possible octane that causes no engine knock.
Which for a 2IS is 91.
Anything higher is a 100% waste of money because it's not doing anything else
Anything lower will cause engine knock, which besides being bad, which cause the ECU to pull timing and reduce power.
But once you're running high enough octane to not have any knock (again, that's 91 for a 2IS) anything higher does nothing for you, because the only thing it CAN do is avoid something you've already avoided.
There are many changes you can make to an engine to produce more power (raising the compression ratio, adding some sort of forced induction, advancing the timing, etc) and THOSE changes can cause the engine to produce more power, and those changes can then require a higher octane fuel to avoid the engine knocking. Here again the only thing the higher octane is doing for you is resisting the knock that might otherwise be caused by the _other_ changes you made to the engine.
If you're making no such changes than the higher octane can not do you any good, because the only thing higher octane fuel does differently is resist knock better. If the motor isn't knocking to begin with the "extra" octane does nothing.
Claiming higher-than-needed octane "makes your car faster" is akin to claiming adding a second volume **** makes your radio louder. What you already had is already doing all it needs to.
http://auto.howstuffworks.com/fuel-e...question90.htm
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.
That's it.
resistance to knock.
That's the only thing octane level indicates.
So you should -always- use the lowest possible octane that causes no engine knock.
Which for a 2IS is 91.
Anything higher is a 100% waste of money because it's not doing anything else
Anything lower will cause engine knock, which besides being bad, which cause the ECU to pull timing and reduce power.
But once you're running high enough octane to not have any knock (again, that's 91 for a 2IS) anything higher does nothing for you, because the only thing it CAN do is avoid something you've already avoided.
There are many changes you can make to an engine to produce more power (raising the compression ratio, adding some sort of forced induction, advancing the timing, etc) and THOSE changes can cause the engine to produce more power, and those changes can then require a higher octane fuel to avoid the engine knocking. Here again the only thing the higher octane is doing for you is resisting the knock that might otherwise be caused by the _other_ changes you made to the engine.
If you're making no such changes than the higher octane can not do you any good, because the only thing higher octane fuel does differently is resist knock better. If the motor isn't knocking to begin with the "extra" octane does nothing.
Claiming higher-than-needed octane "makes your car faster" is akin to claiming adding a second volume **** makes your radio louder. What you already had is already doing all it needs to.
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corradoMR2
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09-15-23 08:18 AM
