WRONG OCTANE

[59-62USNVET]

Went to the local Sunoco to fill up needing about 12 gallons. I handed the attendant my credit guard and said "93 fill it". I looked at the pump after about 6 or 7 gallons and realized he was putting 87 in. I reached out and shut the pump off and started complaining. The boss came over and volunteered to put in a bottle of STP octane boost, gratis. I filled the rest of the car up with about 5 gallons of 93 and the octane boost. The bottle gave no info except that it would boost the octane and recommending its use with 14 gallons. Did I do the right thing? I don't hear any pinging and the book says 91 is OK. I have a bottle of NOS Octane booster that will boost it up 6 octane numbers. It says it will treat 8-16 gallons. Am I doing any harm to the engine by using the booster?I really don't want to drain the tank. Any comments or ideas out there? This really ticked me off. Thanks for any help.
59-62USNVET

 

[wishuwerehere82]

The 7 gal. of 87 plus the 5 gal. of 93 average to a combined octane of 89.5.
Combine that with what you had left in the tank, and it's probably close to 90.5.
I think the can of STP got you well over 91.
If it starts pinging, add some NOS, but not the whole thing. Maybe 1/4.
But it shouldn't ping. The knock sensor will retard the timing automatically if it does.

 

[jhecox]

I think the computer will automatically de-tune the engine to prevent any ping or knock. So there shouldn't be any engine damage for running the lower octane.

Hecox

 

[Marlar]

Sounds like a very good excuse for a road trip to get rid of that tank of fuel to me!!!

 

[NORTY]

Sounds like a very good excuse for a road trip to get rid of that tank of fuel to me!!!

Yup, that's what I'd do.

 

[catbert]

I think the computer will automatically de-tune the engine to prevent any ping or knock. So there shouldn't be any engine damage for running the lower octane.

Hecox

erd: I had to run a whole tank of 87 in the middle of New Mexico, cuz that's all they had. The Vette didn't seem to mind at all - no ping.