What Octane do you run?
4th Gear Member
Joined: Apr 2007
Posts: 1,612
From: S.Florida
RE: What Octane do you run?
of course the car doesn't sense the higher octane, buti thinkit does sense something in the emissions/exhaust that is a result of higher octane that tells the computer to adjust timing.
since we're quoting things, chevron says this:
"Q. Which octane grade should I use in my car?
A.Use the recommendation in your car owner's manual as a starting point for selecting the proper gasoline. If you notice engine knock over an extended time and your engine is adjusted correctly, try a higher octane gasoline. Also, higher octane may provide a performance benefit (better acceleration) in cars equipped with knock sensors. Many late model and high-performance (turbo-charged and supercharged) cars fall into this category."
to tell you the truth though, you're probably right, but my thinking is this:
a car that can take out timing when it senses knocking also has to have the ability to add timing back automatically otherwise your car is permanently detuned once it knocks and adjusts. now, i'm wondering, when they take out timing to prevent knock, does the timing reset everytime you restart the car or what? i would think it wouldn't be safe for the car to add timing back everytimeuntil it senses knocking again, this can be harmful over time. the other scenario is that you bump up the octane, and your timing will be restored (automatically increased). some other mechanism must add timing back under the right conditions. i always assumed this was sensors in the exhaust, but hell, i really don't know much about this stuff.
btw, that's a hot '08 man!!!
since we're quoting things, chevron says this:
"Q. Which octane grade should I use in my car?
A.Use the recommendation in your car owner's manual as a starting point for selecting the proper gasoline. If you notice engine knock over an extended time and your engine is adjusted correctly, try a higher octane gasoline. Also, higher octane may provide a performance benefit (better acceleration) in cars equipped with knock sensors. Many late model and high-performance (turbo-charged and supercharged) cars fall into this category."
to tell you the truth though, you're probably right, but my thinking is this:
a car that can take out timing when it senses knocking also has to have the ability to add timing back automatically otherwise your car is permanently detuned once it knocks and adjusts. now, i'm wondering, when they take out timing to prevent knock, does the timing reset everytime you restart the car or what? i would think it wouldn't be safe for the car to add timing back everytimeuntil it senses knocking again, this can be harmful over time. the other scenario is that you bump up the octane, and your timing will be restored (automatically increased). some other mechanism must add timing back under the right conditions. i always assumed this was sensors in the exhaust, but hell, i really don't know much about this stuff.
btw, that's a hot '08 man!!!
5th Gear Member
Joined: Oct 2006
Posts: 3,115
From: Baytown, TX
RE: What Octane do you run?
ORIGINAL: lldsandsll
of course the car doesn't sense the higher octane, buti thinkit does sense something in the emissions/exhaust that is a result of higher octane that tells the computer to adjust timing.
since we're quoting things, chevron says this:
"Q. Which octane grade should I use in my car?
A.Use the recommendation in your car owner's manual as a starting point for selecting the proper gasoline. If you notice engine knock over an extended time and your engine is adjusted correctly, try a higher octane gasoline. Also, higher octane may provide a performance benefit (better acceleration) in cars equipped with knock sensors. Many late model and high-performance (turbo-charged and supercharged) cars fall into this category."
to tell you the truth though, you're probably right, but my thinking is this:
a car that can take out timing when it senses knocking also has to have the ability to add timing back automatically otherwise your car is permanently detuned once it knocks and adjusts. now, i'm wondering, when they take out timing to prevent knock, does the timing reset everytime you restart the car or what? i would think it wouldn't be safe for the car to add timing back everytimeuntil it senses knocking again, this can be harmful over time. the other scenario is that you bump up the octane, and your timing will be restored (automatically increased). some other mechanism must add timing back under the right conditions. i always assumed this was sensors in the exhaust, but hell, i really don't know much about this stuff.
btw, that's a hot '08 man!!!
of course the car doesn't sense the higher octane, buti thinkit does sense something in the emissions/exhaust that is a result of higher octane that tells the computer to adjust timing.
since we're quoting things, chevron says this:
"Q. Which octane grade should I use in my car?
A.Use the recommendation in your car owner's manual as a starting point for selecting the proper gasoline. If you notice engine knock over an extended time and your engine is adjusted correctly, try a higher octane gasoline. Also, higher octane may provide a performance benefit (better acceleration) in cars equipped with knock sensors. Many late model and high-performance (turbo-charged and supercharged) cars fall into this category."
to tell you the truth though, you're probably right, but my thinking is this:
a car that can take out timing when it senses knocking also has to have the ability to add timing back automatically otherwise your car is permanently detuned once it knocks and adjusts. now, i'm wondering, when they take out timing to prevent knock, does the timing reset everytime you restart the car or what? i would think it wouldn't be safe for the car to add timing back everytimeuntil it senses knocking again, this can be harmful over time. the other scenario is that you bump up the octane, and your timing will be restored (automatically increased). some other mechanism must add timing back under the right conditions. i always assumed this was sensors in the exhaust, but hell, i really don't know much about this stuff.
btw, that's a hot '08 man!!!
although the knock sensor does work it is still posible to get a knock as it tryes to add timing
so using a higher octane will prevent any knocking and protect the engine as well as cause the timing adjustment to be at the highest proformance setting
it can't go so far as to go to 93oct timing on its own (a tune is needed for that) but it will go to the highest within a range
I use 93 always in any car I own and I've never had any trouble with emmisions infact many emisions places will suggest use of a higher octane to clean carbon out to pass testing
5th Gear Member
Joined: Oct 2006
Posts: 3,115
From: Baytown, TX
RE: What Octane do you run?
BTW by talking to some people that have tryed to go from 93 to 87 all at once is
93 will cause the knock sensor to be maxed out and that'll go alittle past 87 which means if you then put in 87 it'll knock for a little as it tryes to readjust to the lower octane so they end up running 89
93 will cause the knock sensor to be maxed out and that'll go alittle past 87 which means if you then put in 87 it'll knock for a little as it tryes to readjust to the lower octane so they end up running 89
3rd Gear Member
Joined: Feb 2006
Posts: 523
From:
RE: What Octane do you run?
ORIGINAL: fairlane292
Basic question for ya, a bit subjective I know... my car is not a daily driver so annual miles are very lowl. I am planning on CAI and tune and would think I should go 93 since the extra cost of the fuel each year would be miniscule. I suppose the big question is how much of a gain can you get from 87-93 tune and would you actually feel the difference the first time you run the 93 vs the 87? ..just your thoughts since I see you run the 93 tune. I do have 93octane readily available here. Thanks for any input/insight you might have. I'm assuming there are no mechanical drawbacks (engine wear) etc to be concerned with but if you've heard of any, do let me know. ...pretty sure this is the route I'm going to take. Thanks much!
ORIGINAL: thxultra
Stick with 87 for that intake. You will only benifit from 93 if you are running a tune built for 93.
Stick with 87 for that intake. You will only benifit from 93 if you are running a tune built for 93.
BTW, I run 93