GM Truck Club Forum banner

2021 Silverado 6.2l - regular gas?

606 Views 6 Replies 3 Participants Last post by  RayVoy
I've searched the site, and the threads found discussing premium vs regular in the Chevy 6.2l V8 are quite old.

The specs I've found online say this engine has a compression ratio of 11.5:1, which in the "old days" would mean premium fuel.

My owner's manual says:

Recommended Fuel (6.2L V8 Engine)
Premium unleaded gasoline meeting ASTM specification D4814 with a posted octane
rating of 93 — (R+M)/2 — is highly recommended for best performance and fuel
economy. Unleaded gasoline with an octane rated as low as 87 can be used. Using
unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration
and fuel economy
(underlining is mine)

I've experimented with regular gas for a recent trip with my truck, and did not notice any issues.

I assume the engine control is adjusting the timing.

I didn't time any 93 vs 87 acceleration numbers, but I noticed no (obvious) power reduction and the gas mileage (calculated by the truck - I did not verify) did not materially change (it is still in the vicinity of 20 mpg for highway cruising @ 65 mph).

Does anyone else here run regular gas with this engine?
1 - 2 of 7 Posts
I think what Mike was trying to say was: yes you can use 87; but the engine will knock. Spark knock will burn holes into the top of the pistons.
This isn't as big a problem as it once was, today's trucks have computers that will dial back the spark timing and let the engine operate with a lower possibility of knocking.
And I know you know that.

What Mike was trying to point out was that yes the computer will retard the timing when the knock sensors hear knocking; but, the knock has to have occured before the computer changes the timing. You may not hear it, or feel it; but a knock has occured

And, how often will the process repeat? i don't know, I'm sure it's a number of times in a driving cycle. Maybe the program locks down the timing after a set number of occurrences per drive; I don't know what the program specs are.

But at any rate, using 87 gas will cause knocking that you do not want to have.

Your gas is cheaper than Canadian gas; but even up here the extra cost is worth it in my opinion.
See less See more
I think I'm done with this topic
1 - 2 of 7 Posts