89 Octane Worked Fine, Hope Okay

[fine69]

My original L46 was tamed-down somewhat with its overhaul. For example, the compression ratio was lowered to (I believe) slightly less than 10:1.

I have been using 91 octane fuel. However, today I Inadvertantly filled her up with 89 octane petrol... but to my surprise, she seems to run just fine. Strange, hu? I hope I am NOT screwing something up..... Should I purchase an additive to boost the octane?

Like I stated, it seems to perform fine with this gasoline... hmmmmm.

Also, the local WAWA gas station mixes methanol (or ethanol) to their gasoline pumps. I've steered clear of this gas for fear of how this could affect the ports/valves, etc.... any thouhts?

Thanks.

 

[Vettefan87]

If it is less then 10:1 I would assume you would be ok with that. You said it seems to run fine, as long as there is no spark knock or anything I don't see why there would be a problem.
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[Vettehead Mikey]

Many people use too high an octane rating in their Corvettes- most smog era C3s run just fine on regular grade. That's what they were designed for.

If yours doesn't 'ping', then you're fine and can use this grade of gasoline from now on.

The old stories that premium gas gives better mileage, starts better, smoother idle, cleans engines etc.etc. are just more marketing BS.

 

[BarryK]

as Mikey & Vettefan said, as long as she ain't pinging or knocking you are fine with the lower octane. Since that's the case be glad to save the extra money per gallon over what premiun or mid-grade costs you.

BTW, don't bother with those octane boosters you see for sale at the auto parts store - they are nothing but a waste of time and money and do not significanly increase your octane. I believe I've seen JohnZ (if it wasn't you John I apologize) mention that at best they may increase the octane a FRACTION of a single point.

:

 

[JJS]

I can't use anything less than 93 in my LT-1. Not even a little bit. In fact, I get pinging if I use Mobil 93, so the only brand of 93 I use is Sunoco, as I've never had pinging issues using their fuel. I used to use Sunoco 94 when it was available.

 

[BarryK]

JJS, I know the feeling - I need to use 93 in my '65 L76 also with it's 11:1 compression.
with the sidepipes on the car (loud!) I can't even risk trying 91 octane to see if it would work or not since chances are I wouldn't be able to hear any pinging over the loudness of the sidepipes anyway to know if i'm starting to detonate so I just keep using 93 to keep it safe.