[Johnfin]

my 2023 v6 LGX says it has 11:5 compression ratio yet still recommends 87 octane gas. How can that be?

[Gen6cyl]

I used 87 from new to 18 k miles. It smelled when I ran it hard and made some stranger noises sometimes.I thought I had an exhaust leak. So I changed to 93 at 18 k miles,now at 5Ok miles. No more exhaust smell or bad sounds, runs stronger, better. I guess it pulls timing for 87. Some say 93 is a waste but it is all I use in my v6. Some reputable tuners recommend 93 for the lgx. My experience is it will run on 87.It will be happier and run better on 93.

[Matt1LE]

Originally Posted by Johnfin

my 2023 v6 LGX says it has 11:5 compression ratio yet still recommends 87 octane gas. How can that be?

They say that to meet emissions and mileage standards. But you are correct. You need to run 91 min. Better performance, mileage,better on the engine.

[dpevans]

Never had an issue running 87 even at the track. No timing knocks or funny smells and great gas milage. Putting high octane is like taking a sugar pill it really does nothing for the LGX except waste your money. It's a fact that higher octane fuel doesn't create more energy it increase the resistance to knock. Gm engineers recommend 87 for the 3.6 and 91 for 2.0 and 6.2, but what do engineers know right.

[Alan47717]

Originally Posted by dpevans

Never had an issue running 87 even at the track. No timing knocks or funny smells and great gas milage. Putting high octane is like taking a sugar pill it really does nothing for the LGX except waste your money. It's a fact that higher octane fuel doesn't create more energy it increase the resistance to knock. Gm engineers recommend 87 for the 3.6 and 91 for 2.0 and 6.2, but what do engineers know right.

This thread gives me PTSD symptoms from my days on the Equinox forum regarding running 87 or 91 in the 2.0t. I tried running 87 in mine (would never do it in the Camaro) and saw definite performance and trans shift degradation so nothing but 91 for mine. But a determined group insist that running 87 is not only fine but see no difference. Besides, if there was was any detonation they would hear it. Before the knock sensor with their (mostly old, like mine) ears? Not a chance.

I ran into a guy gassing up a 1994 454 motorhome the other day. He was putting 91 into it and was not happy he couldn't find 93 in the SW. Insisted premium was necessary because of how "hard" his engine had to work. Those engines had such low compression and output (I owned one) that they would probably run fine on kerosene. But you can't keep some people from wasting their money.