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My fuel options for my ordered 2008 LS3 are 87 octane, 89 octane with 10% ethanol, or 91 octane premium. I understand 91 octane is in the manual, but can I run any of those without causing problems?
 

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They only way you can tell is to try it out. Put the 89 octane in your car and go drive it. Take it all the way to red line. If your car does not ping at high rpm with 89 then there will be absolutely NO difference when you put 91 in it. Contrary to what most people believe, a higher octane rating is not going to make your car go any faster. If your vehicle doesn't ping with 87 then it will run the exact same on 91! I run 91 because that's what the owners manual calls for, I have never tried the 89 or 87. I have a question though......why would you consider using 89? If it's cost your worried about, I believe on a full tank of gas the difference in 89 and 91 might only be a couple of dollars......Not worth it if you ask me....
 

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:agree: go with the 91 it may be only a couple of dollars more and your baby worth it treat her right:thumbsup:
 

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The station near our lakehouse only stocks 87 and 89 ethanol. That is the only reason I wouldn't be running 91. The money is not the issue.
 

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It won't hurt anything. The engine computers have knock sensors that'll retard timing to compensate for any detonation due to the lower octane. With normal driving you probably won't notice any difference.
 

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Always 91 for me.

An anti-knock in the engine essentially detunes the engine to correct the compression ratio with the octane correct?

As far as I've always been aware the octane rating works very much like higher altitude; as far as effects to the engine's performance. Granted it could be something large as 3% from the 87 to 93 octane.
 

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Discussion Starter #7
Station near our lakehouse only has 87 Octane and 89 Octane 10% ethanol. Money is not the issue. Access is.
 

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If the 89 octane rating is before the ethanol is added, it might well be at or around 91 octane. JAT
 

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Always 91 for me.

An anti-knock in the engine essentially detunes the engine to correct the compression ratio with the octane correct?
Close- the engine computer pulls (retards) timing to protect from knocking. You lose power when this happens, but nothing will break. We're talking losing in the 50 hp range, maybe more.

Compression ratio is fixed, unless you change bore, stroke, or the heads.
:cheers: :cheers: :cheers:
 

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89 Octane OK

if you can burn 91 octane in my 04 I use 91 in my 06 Zo6 I use 91 and a mix of 100 GT sunco for a 96 octane reading.:buhbye:
 

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As we test drove the C6, my wife and I noticed that the engine was pinging terribly. :crazy: With ~1/4 tank, I knew it would be full before we left so I told the salesman to make sure he used 93 octane when he filled it while we signed the papers. The pinging has never been heard from again. Only 93 octane in the C6. :partyon:
 

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i only put 93 in every sports car i have had ..its just not worth the risk of having engine knock to me

and for those who dont know.....The octane rating of gasoline marked "premium" or "regular" is not consistent across the country. One state may require a minimum octane rating of 92 for all premium gasoline, while another may allow 90 octane to be called premium. To make sure you know what you're buying, check the octane rating on the yellow sticker on the gas pump instead of relying on the name "premium" or "regular."
 

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i only put 93 in every sports car i have had ..its just not worth the risk of having engine knock to me

and for those who dont know.....The octane rating of gasoline marked "premium" or "regular" is not consistent across the country. One state may require a minimum octane rating of 92 for all premium gasoline, while another may allow 90 octane to be called premium. To make sure you know what you're buying, check the octane rating on the yellow sticker on the gas pump instead of relying on the name "premium" or "regular."
Yup. :agree: Altitude where the gas is being sold also plays a major factor. Octane rating will be lower at higher altitude (because the engine anti-knock needs are reduced due to less O2 available, etc.)
:cheers: :cheers: :cheers:
 

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i know i will probably get yelled at for suggesting this, i don't know what would be the long term affects but what if you stocked up on some octane booster and added enough to get it to the 91 rating, it would be an extra step when you filled up but you would have the octane you need.
 

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i know i will probably get yelled at for suggesting this, i don't know what would be the long term affects but what if you stocked up on some octane booster and added enough to get it to the 91 rating, it would be an extra step when you filled up but you would have the octane you need.
yes that is a good idea and should be used if you are not going to be around 92-93 octane for a while...i am kinda shocked at how many people use 91...i thought it would be the complete opposite
 

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Well I will probably get burned from the elite on this. But I have all ways been a believer in not running any higher octane than is needed to get the job done. We have the added protection of knock sensors and the computers to keep from hurting the engine now.

I have ran 89 Octane 10% ethanol in our C6 Z06 for the last 25,000 miles and it sells for the same price as Regular fuel. I have an OBD II monitor and there is no difference in knock retard, performance, or mileage between 91 octane or 89 octane 10% ethanol in the data I have checked. but there is a 10 cent a gallon difference in price. Thats about $100 savings is it worth it who knows.

But as Grandski states it is easer to find good quality 89 octane than 91.

Just my 2 cents...:D
 
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