5.3 vs 6.2 octane

[h2100]

How heavy is the boat you are towing?

My 2002 Tahoe works hard to pull our trailer up hills. Loaded, we had a total loaded weight (truck, trailer, people, cargo etc) of about 10,000 lbs. The engine worked hard and tended to overheat in the summer heat unless I turned off the AC. I know there are many factors involved such as transmission coolers, external oil coolers, etc etc etc. But, the engine did work hard pulling that load.

A couple of years ago, we towed our trailer with our 2008 4.6L Ford Explorer. It has VVT, and a 6 speed transmission. The trucks are similar in weight. This engine, in spite of being smaller, pulled the trailer with greater ease. We didn't have to turn the ac off going up the CA Grapevine.

I'd say if you are alright with the 5.3 in your 2010 5.3, you will be even happier with a 2018 5.3. However, I suspect that you'd have even more fun with the 6.2.

The boat is about 5,000 lbs.

Thanks for everyone's reply. Gives me things to think about.

 

[intheburbs]

This is straight out of the owner's manual for my 6.2 Sierra Denali (2009):

If the vehicle has the 6.2L V8 engine (VIN Code 2),
use premium unleaded gasoline with a posted octane
rating of 91 or higher. You can also use regular unleaded
gasoline rated at 87 octane or higher, but the vehicle’s
acceleration could be slightly reduced, and you might
notice a slight audible knocking noise, commonly referred
to as spark knock. If the octane is less than 87, you might
notice a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you could damage the
engine. If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, the engine needs
service.

Yes, it says you can use 87. I don't. Why? Because the 6.2 is a "high-compression" engine that inherently needs higher-octane gas. And frankly, I don't trust the knock sensors and the computer to be able to adjust the timing well enough to fully control knock/ping. The manual even says that, you might hear a "slight" knock. Using 91+ octane gas is, IMHO, cheap insurance against possible engine/piston damage.

That, plus the fact that when I floor the throttle, I want all 400 ponies present and accounted for.

I'm actually tempted to take it to the other extreme and run E85 in it. If I'm willing to tolerate the abysmal mileage and limited range (10 MPG with a 26-gallon tank), E85 has an effective octane rating over 100.

 

[h2100]

This is straight out of the owner's manual for my 6.2 Sierra Denali (2009):



Yes, it says you can use 87. I don't. Why? Because the 6.2 is a "high-compression" engine that inherently needs higher-octane gas. And frankly, I don't trust the knock sensors and the computer to be able to adjust the timing well enough to fully control knock/ping. The manual even says that, you might hear a "slight" knock. Using 91+ octane gas is, IMHO, cheap insurance against possible engine/piston damage.

That, plus the fact that when I floor the throttle, I want all 400 ponies present and accounted for.

I'm actually tempted to take it to the other extreme and run E85 in it. If I'm willing to tolerate the abysmal mileage and limited range (10 MPG with a 26-gallon tank), E85 has an effective octane rating over 100.

thanks. Need all those ponies!! funny.

 

[PG01]

 

[Larryjb]

Good thing he doesn't have the Turbo diesel then, or ....

 

[h2100]

View attachment 245837

funny

 

[John McElligott]

Hello All,

I'm an owner of a 2010 Tahoe with 185,000 (middle aged!) and will be upgrading in the next 3-4 months to a new-to-me model. Probably a 2017-2018 Tahoe/Yukon/Escalade. I have a 23 ft boat that I travel with 6-7 times a year plus other trailers many time. The 5.3 does good enough but it does work hard. An Escalade (Denali too) is interesting to me since the 6.2 comes standard.

Question, it seems many web pages/articles indicate the 6.2 needs 92 octane to run properly. Who has experience here?

Is this true?? Please share thoughts.

I own a 2019 Tahoe that I purchased new last year. It has the 6.2L engine and the 10 spd trans. My previous vehicle was a 99 suburban with the smaller v8, but with a 3.73 rear end. I do tow a 20 ft fiberglass boat and had no problems with that combination, other then extremely bad mileage. The Tahoe also has no problems towing and the 10 spd transmission is as smooth as butter. I absolutely, hands down would recommend that you get the 6.2L, and if possible the 10 spd trans. I run premium 91 gas almost all the time and have noticed better mpg then with mid-grade fuel. I barely had 1200 miles on this Tahoe and I took in on a 2200 mile vacation to Colorado, with a lot of mountain driving. At the end of the trip, my average was 23 mpg. This was without towing the boat, but even still was quite impressive!

 

[andy desch]

I have a 2012 yukon xl denali with 175k and only use the cheapest gas I can find. Unless I tow something, then I'll put in the premium.

 

[h2100]

I own a 2019 Tahoe that I purchased new last year. It has the 6.2L engine and the 10 spd trans. My previous vehicle was a 99 suburban with the smaller v8, but with a 3.73 rear end. I do tow a 20 ft fiberglass boat and had no problems with that combination, other then extremely bad mileage. The Tahoe also has no problems towing and the 10 spd transmission is as smooth as butter. I absolutely, hands down would recommend that you get the 6.2L, and if possible the 10 spd trans. I run premium 91 gas almost all the time and have noticed better mpg then with mid-grade fuel. I barely had 1200 miles on this Tahoe and I took in on a 2200 mile vacation to Colorado, with a lot of mountain driving. At the end of the trip, my average was 23 mpg. This was without towing the boat, but even still was quite impressive!

great info, thanks. do you think the 2017 & 2018 have the 10 sp tranny too?

 

[petethepug]

6.2L can & does run on 87. The motor dials things back to accommodate the loss of energy being supplied vs demand.

“IF” you’re running 87 towing, under load (hills), taxing the motor w/ in high temps or speed, your normal margin of safety gone.

My folks can’t fathom paying for premium fuel. It’s something that truly upsets them. They feel premium fuel is a rip off. Because of that, they only purchase vehicles made to run on 87 here in Cali.

I have another buddy that feels the same way but also felt that his wife’s Lexus RX300 was ok to run on 87 driving up to 6k mountain roads w/ heavy loads. When the alternator bearing went out the dealer offered them $10k+ toward a RX350 on trade. They laughed and said jay fix the alternator. The dealer let them know they prolly had a cracked piston. They did.

If you don’t want to pay for premium fuel, no biggie. Just don’t purchase a premium fuel (recommended) vehicle and run 87. The road you’ll go down may be expensive. It’s a roll of the dice.


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