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Discussion Starter #1
I have an '04 5.3L ECSB. When I got the truck from my dealer, he said be sure not to use 93 Octane fuel because it would be a waste of money. He said in the newer models ( like the '04) 87 Octane will make your engine run just as good as if you put 93 in it. He also said 93 could wind up damaging it. If i need to pull anything, he said i could go up to 89 octane if i needed to. Is there any truth to this, or is this guy full of crap?
 

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There is no point in running anything higher than 87 unless your manual tells you too, or its pinging, or you've got a higher octane tune. There is no difference in the quality of the gas, the only difference is that the higher octane gas ignites at a higher tempurature and is less prone to pre-detonation.
 

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HOT AIR BALLOON OWNER
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Yeah, if you look at the timing charts for these trucks on the ECU stock...they could probably use like a 76 octane fuel there is so little timing! :haha:

When my truck had no tune, I used only 87...now that I'm tuned I use 93.
 
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Discussion Starter #4
So whether I using a programmer that requires at least 91-93 octane or not, using 93 wont "hurt" my engine like the dealer said right?
 

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HOT AIR BALLOON OWNER
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Nope it will not harm anything by using 91+ fuel, you may increase emissions as the fuel isn't fully burning but these are OBDII trucks so nothing to worry about there also.
 
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