It's only 20 more cents per gallon (in most cases) for premium. If you can't afford that you probably shouldn't have gotten the Z-28.

 

Its at 4 bucks/gallon now.

I also have a truck which it takes about 90 bucks to fill it up.

Even with super 93 in the Z, its still less $$ than to fill up the truck.

 

.20 x 15 gallons = 3.00 per fill up not that big of a deal, why risk knock? any knock is not good knock! just run what is needs!

 

Why would 93 octane in NY (where the OP says he lives) be somehow different than 93 octane in some other location? The owner's manual references 91 octane, and that's based on sea level conditions. He's at sea level. The octane rating of the fuel doesn't change at altitude, but the octane of the fuel that the engine needs is reduced at higher elevations.

Now, if he was in Europe, they would be using Research Octane, which is different than the (R+M)/2 octane system used in the US.

91 should not make his engine "run like crap". Depending on coolant temperature and ambient air temperature, plus altitude, he may be able to run somthing lower, without getting knock retard. The only way to know is to run a real time scanner, and monitor knock retard.

 

Maybe im wrong please correct me if I am, but the reason some people have only 93 in there town and others have only 91 is because at a higher (or lower not sure which) you need more octane to prevent detination. The guy said that if he could get ahold of some 91 (where he only has 93) then it will be cheaper and he will be ok. I thought the only reason we had 93 is due to we needed higher octane at our sea level to eqaual out to the other peoples 91. If you dont understand wtf im talking about due to terrable wording sorry.

 

its not going to knock , it has a knock sensor that will just keep retarding your timing untill you start loosing performance

 

Appears its faulty wording. Yes, you don't need 93 octane in Denver, so they don't sell it there. They only offer lower octane fuels at most stations. But that's not what your orignal post said. You said that 93 purchased in one location would not be the same as 93 purcheased at another location. It will be the same... but it its not needed at that elevation, most stations won't offer it. The OP is in New York, on Long Island, which is basically as close to sea level as you can get.

 

it is almost getting more cost affective to make your own high octane fuel using toluene.

 

This raises my next question, would 93 octane be "better" at sea level then, lets say above sea level. Im confused because at higher elavations we need 93. So would 91 where he lives (sea level) act like 93 where others live (above sea level).

 

You have it backwards.... as elevation increases, octane requirement decreases. When you are in Denver, what started out as a 10.5:1 LT1 engine only fills the cylinders with 80% of the design air mass, meaning the octane requirement only has to satisfy the equivalent of an 8.5:1 engine. And the engine only makes 80% of the HP it would make at sea level.

You need at least 91 octane at sea level, if you believe the Owner's Manual. You need a lower octane fuel at higher elevations.

 

Oh, makes sense now, thanks. I was confused lol