6.2 vs 5.3 and premium gas

[waynehead99]

Honestly, I don't really miss the 6.2 or regret opting for the 5.3 and feel its sufficient. Wont be racing off the line at the light or for passing and believe me the passing capability on the 5.3 is pretty good and not lacking anything. If I felt I needed a need for speed I'd have opted for the 392 wrangler or Jeep SRT. Even considered the 392 charger but those are due for a refresh soon and was coming from a jeep already so...Tahoe it is

Agreed... the 5.3 for me is plenty. I didn't by this vehicle to take people off the line... I have other cars/motorcycles for that .

 

[gaffster01]

I should have data next week on this. Got the reader and app just haven’t had time to do anything. Will be good comparison as the truck has 91 octane in atm for pulling and will put 87 in after.

 

[wsteele]

Just a few data points driving my 5.3L flex and recording engine data with my Tech 2. With E10 87 (Costco), driving around town, my engine has knock sensors going off all the time with correlated timing adjustments. I have concluded this is how the engine is tuned, to "ride the knock sensors" for timing adjustments when running 87.

I haven't tried E10 91 yet, but I did run a tank of E85 through (it was actually 80% Ethanol, which has a very high octane rating relative to the E87-E91 range) and the knock sensors did still kick off once in a while, but much less.

I will try running the Costco E10 91 next and maybe post the two snapshots side by side for comparison, but I suspect the knock sensors will be more active with the 91 than they were with the E85.

It would be nice to have one of the guys who have a 6.2L and a Tech 2 post up similar results. I suspect even with 91, the engine will be riding the knock sensors some, if my results with the 5.3L is any indication. I definitely wouldn't ever consider running 87 in the higher compression 6.2L.

The caveat I would offer is my engine is high time, so likely is more prone to knock than a new engine with less build-ups, etc.

My opinion on the 6.2L and the additional cost of Premium is, I wish my engine was a 6.2L.

 

[Gibby13]

We had a 6.2 in our '11 Escalade and then a 5.3 in our '15. For our '21 Yukon XL Denali we went with the 6.2. The Suburban was a little bit of a turd.

Also we ran premium for the first 3000 miles or so in the '21 and then went with regular for 3000 miles. The MPG gain was around 14% but premium cost 35% more here. We run just cheap regular now as we always have before.


And from the manual you can run as low as 87.

 

[gooffeyguy]

We had a 6.2 in our '11 Escalade and then a 5.3 in our '15. For our '21 Yukon XL Denali we went with the 6.2. The Suburban was a little bit of a turd.

Also we ran premium for the first 3000 miles or so in the '21 and then went with regular for 3000 miles. The MPG gain was around 14% but premium cost 35% more here. We run just cheap regular now as we always have before.


And from the manual you can run as low as 87.

View attachment 349997

Yes, as the highlighted sentence says, it can be used. Then continue reading after the highlighted part

 

[wsteele]

We had a 6.2 in our '11 Escalade and then a 5.3 in our '15. For our '21 Yukon XL Denali we went with the 6.2. The Suburban was a little bit of a turd.

Also we ran premium for the first 3000 miles or so in the '21 and then went with regular for 3000 miles. The MPG gain was around 14% but premium cost 35% more here. We run just cheap regular now as we always have before.


And from the manual you can run as low as 87.

View attachment 349997

I would probably be using 87 as well if I planned on sending it back under the lemon law anyway.

 

[Gibby13]

I would probably be using 87 as well if I planned on sending it back under the lemon law anyway.

 

[swathdiver]

We had a 6.2 in our '11 Escalade and then a 5.3 in our '15. For our '21 Yukon XL Denali we went with the 6.2. The Suburban was a little bit of a turd.

Also we ran premium for the first 3000 miles or so in the '21 and then went with regular for 3000 miles. The MPG gain was around 14% but premium cost 35% more here. We run just cheap regular now as we always have before.


And from the manual you can run as low as 87.

View attachment 349997

And you too ought to buy a little OBDII adapter and get an app for your phone so you can "see" what you cannot hear, that the engine is knocking and pinging with that swill gasoline you're using.

 

[michome]

My 2021 Denali has 18560 miles on it now without any engine issues I have been reading about recently. It has only ever seen 91 to 93 octane and gets a can of berryman every second tank.
I change the oil every 6000 miles with mobile 1 or at 10% whatever is first. I have been lucky with my vehicles since buying a denali since 2008. The only TSB I ever did was my 2018 trans flush to get rid of the shudder. The compression is borderline high, 91 octane always but you could get by with 89 with no towing in my opinion. Spending 80 grand for a vehicle takes me out of price per gallon concerns.

 

[swathdiver]

Took the Sierra out for a 0-40 on straight pump gas. 93 octane at 0% alcohol content from Racetrac.