[Z06] Octane
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Joined: Sep 2005
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From: Dumfries Virginia
Octane
Got my ears pinned back by CF readers a month or so ago for running 87 octane in my 04Z. So, I 'googled' "Octane" and found some confirming reading about octance. Octane is only a resistance to knocking. My Z does not knock or deisel. She runs great. Read the octane articles. Great information.
Now then, several readers run 93 octane. They reminded me that the GM manual calls for 91. So, here is my question: IF I am wrong at 87, aren't they as wrong at 93??
BTW, I have switched back to 91 or 93 if available.
Now then, several readers run 93 octane. They reminded me that the GM manual calls for 91. So, here is my question: IF I am wrong at 87, aren't they as wrong at 93??
BTW, I have switched back to 91 or 93 if available.
Pro
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From: MD
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Higher octane only produces more power if you need it; you can actually make more power using a lower octane fuel because it burns quicker producing a faster bigger explosion in the cylinder.
The lower the octane number the quicker the fuel burns, when fuel burns quickly, it generally burns hotter or in this case makes a bigger bang which is what produces more power. The higher the octane number, the slower the fuel burns and with a smaller explosion and less heat. The only reason you need high octane fuel is when you need a slower burn rate such as high compression, you run a lot of ignition advance or you are forced induction.
Pretty much what Romulus posted in the link but dumb'ed down.
I ran race fuel in a junk lawnmower once, used it for cutting weeds in the alley where i wasn't taking the good lawnmower. It blew up, not sure why because it should have just be a waste of good gas but it crack the block and caught fire, didn't throw a rod either.
The lower the octane number the quicker the fuel burns, when fuel burns quickly, it generally burns hotter or in this case makes a bigger bang which is what produces more power. The higher the octane number, the slower the fuel burns and with a smaller explosion and less heat. The only reason you need high octane fuel is when you need a slower burn rate such as high compression, you run a lot of ignition advance or you are forced induction.
Pretty much what Romulus posted in the link but dumb'ed down.
I ran race fuel in a junk lawnmower once, used it for cutting weeds in the alley where i wasn't taking the good lawnmower. It blew up, not sure why because it should have just be a waste of good gas but it crack the block and caught fire, didn't throw a rod either.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
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From: PNW
Got my ears pinned back by CF readers a month or so ago for running 87 octane in my 04Z. So, I 'googled' "Octane" and found some confirming reading about octance. Octane is only a resistance to knocking. My Z does not knock or deisel. She runs great. Read the octane articles. Great information.
Many cars say premium fuel is "recommended for maximum performance" ... meaning with the higher octane the engine will not retard timing if nothing shows up on the knock sensors and give you full performance potential.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
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From: NS
That's because the PCM is pulling ignition timing to keep it from knocking/pinging which could destroy pistons, rod bearings, etc. If you connected a scan tool and watched your knock retard you'll see for yourself. The knock sensors are way more sensitive than your ears.
For maximum performance you want the lowest octane that does not cause pre-ignition with optimum spark timing. GM has designed our engines to use 91 - 93 octane fuel. Sure you can use other fuel but higher or lower and you'll lose power.
For maximum performance you want the lowest octane that does not cause pre-ignition with optimum spark timing. GM has designed our engines to use 91 - 93 octane fuel. Sure you can use other fuel but higher or lower and you'll lose power.
Drifting
Joined: Sep 2008
Posts: 1,389
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From: somewhere shooting my assault rifles
Unless you are logging with a tuning program you dont even know if your car is pulling timing because of knock you cant hear. Go ahead and run the lower octane if it floats your boat and you think it works for your car.
Sure you dont hear it knocking cause its pulling timing or running off the low octane table for so long it wont ever knock or notice it.
I wouldnt run anything less than 91 in a Z06...
Try 7-11 87 octane gas cause its the cheapest and im sure your car will love it!
Sure you dont hear it knocking cause its pulling timing or running off the low octane table for so long it wont ever knock or notice it.
I wouldnt run anything less than 91 in a Z06...
Try 7-11 87 octane gas cause its the cheapest and im sure your car will love it!
Last edited by Z06supercharged; Nov 8, 2009 at 12:04 PM.
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Joined: Sep 2005
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From: Dumfries Virginia
It never ceases to amaze me. The post #8 is far and away the rudest and also one of the new dudes. Everyone else is not only more senior but so much more accommodating and provide meaningful information. I'm not a fanatic on 'Vettes but I love them and look to the CF for information. For example, I need "tars" and read about the pros and cons of each manufacturer on this site. To those who help I can only say "Thank you".
Pro
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From: Philly region SCCA
It never ceases to amaze me. The post #8 is far and away the rudest and also one of the new dudes. Everyone else is not only more senior but so much more accommodating and provide meaningful information. I'm not a fanatic on 'Vettes but I love them and look to the CF for information. For example, I need "tars" and read about the pros and cons of each manufacturer on this site. To those who help I can only say "Thank you".
/new guy
