quackattack

with the recent crunch, I have had to use this lesser grade fuel ... any major issues/

Kracka

Just drive gentle & easy, stay out of the gas the best you can until you can fill back up with premium (91+).

JerryU

Yep, GM says minimum 91 octane required. You lose power versus 93 BUT OK. Below 91 could void warranty! It's NOT just "take it easy," can't lug the engine at low rpm! Delicate balance. I would not do it! You couldn't operate 11.5:1 compression with cam providing 495 hp even with all the timing GM can pull out when it detects knock! Heck, back-in-the-day needed Sunoco 260 100+ octane with that compression ratio even with a lumpy cam that didn't give much volumetric efficiency at low rpm!

Quoting the Owner's Manual, pp204
"Use premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 93 — (R+M)/2. If unavailable, unleaded gasoline with a posted octane rating of 91 may be used, but with reduced performance and fuel economy. If the octane is less than 91, the engine could be damaged and the repairs would not be covered by the vehicle warranty."

Yep detonation recorded and GM can tell! In a real pinch might drive in Manual Mode, no V4 and keep rpm above 2000 maybe 2500 AND drive like you have a raw egg between your foot and the throttle!

srobert910

Couldn’t you add some octane booster from a auto store?

thill444

Why not just add octane booster?

Kracka

If you want to go the octane booster route (most of which is junk), you're better off adding a gallon or two of E85. Cheaper & more effective...

RKCRLR

The ingredients in octane booster can also void the warranty. Most contain some items that are in the prohibited fuels section of the manual.

steve8

I've avoided buying cars, or the 6.2 in a pickup due to the cost of super.
But you can be sure super goes in my current and future Vette!

IMO you're asking for trouble at some point not using super.

thill444

I think he is referring to the pipeline issue and lack of available gas. 87 may be the only option available for many folks over the next couple days/weeks.

steve8

My bad. Sorry.

quackattack

what is a good one for this situation?

WEBDZYNER

Octane boost is tricky, with their description. Some say something like "will raise octane up 4 points". This does not mean your 87 octane is now 91, it means your 87 octane is now 87.4. Make sure you get one that says raises your octane by numbers, not points. I buy gallon jugs from a company called Klotz, for my 69 Oldsmobile, that still needs leaded gas. Although they do have unleaded options.

Also, look up Sunoco race fuel sellers. Comes in 5 gallon cans, so you can boost up the average. Just bought 5 gallons of 116 octane for 80.00 (leaded and unleaded options, so make sure you grab the right one)

I cannot speak to voiding of the warranty though, as mentioned above. Weigh your risk.

Hope all turns out well.

GB1099

Just put 91 in it and forget about octane booster. I know gas is high but that small difference is worth it and will keep your engine problem free (knock on wood) for the most part. That could be a very expensive lesson if something happens to that engine and GM refuses to cover it. And they can tell if you used lower octane gas from the diagnostics.

quackattack

as previously addressed, higher octanes are not available due to the pipeline crisis

Phil1098

He's on the east coast and they don't have any fuel in places and where he's at all he can get is 87. (because of the pipeline thing)

Andybump

I just looked up the Klotz product. It raises a related question. I also read the stuff in the manual about the danger of certain fuel system additives. The Klotz product says it also will act as a fuel stabilizer for long term storage etc. So...what about fuel storage products? I use fuel stabilizer in all of my other collector cars because over the winter month they dont get driven so much. And, in 2020, nothing I have got driven much, so I used fuel stabilizer in my regular cars too. Will that be an issue for the C8? What, if any, fuel stabilizer products are safe, or approved, for use in the C8? I dont know what is in stabil, but it smells like it has hydrocarbon type stuff in it. Star-tron is claimed to be "enzymatic". Maybe its safer?

GB1099

Sorry...I live in Texas where we have lot's of fuel at all octanes. That's a tough one.....if it were me I'd park the car and not drive it until 91 returns, but I know that is not an option for everyone. If you have to then just drive is as few miles as possible. I had an SL-500 that was very clear on the gas door not to put lower octane in the tank or engine damage can occur....but in the owners manual it stated in an emergency you could drive it up to 50 miles on lower octane....they said no more than 5 gallons in the tank.

I know this sucks....but that's an very expensive car that you waited a long time to get...and an engine swap could take a very long time to get done if that one goes sideways.

tunaman

Chevy has to put it in the manual to CYA. I’d be willing to bet a good sum that a tank of 87 isn’t going to hurt it, especially if driven responsibly.

Id expect it may ping a little under load, no different than getting a bad or old batch of 91.

TXFlyGuy

Am I missing something here? Won’t the ECU prevent any detonation/damage while running 87 Octane? It’s a computer controlled engine.

Red Mist Rulz

Read the owners manual:

There's a limit to how much retarding the timing (which is what the ECU does in response to pinging or knock) can do.

I'd park it before I'd run 87 octane, especially in hot weather.