2017 Escalade/Denali L86 "requires" 93 octane - your experience?

gtrslngrchris · Jul 24, 2024

I'll throw in my 2 cents to further muddy the waters. I got my Denali with the 6.2 two and a half months ago and the previous owner clearly did not take care of it. It drove sluggishly when I got it even in manual and was just completely uninspiring. Over the course of the next 2 weeks the motor really woke up and while my transmission was busy being bipolar at least the motor regained its' senses. I think it was pretty clear it was run on 87 as money was not spent to maintain the rest of the vehicle.

It makes me nervous thinking that my 6.2 was run for who knows how many miles on 87 with 11.5:1 compression when my LS1 is 10.2 or 10.5 and I know that it wants nothing but 91 or better in the heat.

CMoore711 · Jul 25, 2024

RobH said:
The 2017 Denali and Escalade Owners Manuals say

"Fuel (L86 6.2L V8 Engine). Use premium 93 octane unleaded gasoline in your vehicle. Unleaded gasoline with an octane rating as low as 87 may be used, but it will reduce performance and fuel economy."

I know that the engine computer can enrichen the mixture and dial back the spark advance to prevent knock with lower octane fuel. And that most driving is with moderate to low load with these engines anyway which reduces pre-ignition/knock.

My perception is that, yes, 93 octane has more energy per gallon and more knock resistance than 87 octane, but not enough more energy and gas mileage to justify the price premium.

Since I don't plan to operate the engine above 3,000 RPM or at higher loads practically ever, will running 87 octane pose a problem?

If I buy the 2017 with the L86 with 37,000 miles,
I would get the transmission fluid flushed, and,
A tune with the AFM delete, which means the engine would be running at lower manifold pressure in V8 mode with eight cylinders working than it does in V4 mode with four cylinders working. I've seen that on my ScanGauge II with my 2016 L83 by running in M5 which disables the AFM.

What are your thoughts and experience on less than 93 octane?

If you're plan would be to invest in a tune that disables AFM and your spending that money for the tune; Why not just spend a little more to do the E85 Flex Fuel conversion? It can be accomplished with all GM OEM Parts and shouldn't impact the cost of getting the tune it would just be the additional money in the GM OEM Flex Fuel parts. There are plenty of threads on this forum as well as other GM full-size truck sites (Silverado/Sierra owners) installing E85 flex fuel conversion kits pre-assembled from vendors with GM OEM Parts or there's a few threads with GM OEM Parts lists and how to's to build/assemble your own conversion kit.

Not only does this help keep your 6.2L L86 happy and healthier, but it allows you to save some money at the pump. Since it sounds like your intent would be to keep the vehicle for the long haul this would continue to pay you back in dividends throughout your ownership.

2017 Escalade/Denali L86 "requires" 93 octane - your experience?

gtrslngrchris

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CMoore711

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