5.3 vs 6.0 Vortec?

[Rayyy]

Anyone have experience with both the 5.3 and High Output 6.0 that came in the Denali, Sierra and Esky.

How is reliability compared?

Power bump worth the mpg loss?

 

[Mudsport96]

Both gen 3 engines so reliability should be the same. Mpg with a tune should be fairly negligible for an otherwise identical vehicle i would think. As the 6.0 was either an awd only or 3/4 ton option it would be hard to tell because both suck fuel more than selectable 4wd and 1500 weight vehicle

 

[iamdub]

Anyone have experience with both the 5.3 and High Output 6.0 that came in the Denali, Sierra and Esky.

How is reliability compared?

Power bump worth the mpg loss?

The ** 6.0 (LQ9) requires 91/93 octane. With it set up for the vehicle it's going in and primary driving environment, the LQ9 could actually achieve the same or better MPG. Even if it's a small loss of MPG, the jump in power from even the ** 5.3 (L33) is quite a lot. I'd happily burn a couple extra bucks in fuel with the LQ9 since I'd have power I could actually feel and use. Comparing the standard 5.3 (LM7) to the LQ9 is comical.

I'd say the reliability is even among the two.

It really depends on what it's going in, where and how it'll be used, what you're willing to put into it and what you want out of it.

 

[BatsTDK]

The ** 6.0 (LQ9) requires 91/93 octane.

It does? My owner's manual says to use regular 87.

 

[iamdub]

It does? My owner's manual says to use regular 87.

Now that you mention it, I recall this being a discussion here not long ago. I don't recall the outcome (or if there ever really was one), but maybe it was a year model thing or maybe the book said 91 was recommended but 87 was acceptable or something like that. Maybe someone will remember.

Regardless, I'd run 91/93 in an LQ9. Maybe not during colder weather, but definitely during the spring and summer.

 

[drdave81]

It does? My owner's manual says to use regular 87.

You have an LQ4 (9.4:1 compression) in your Denali, not an LQ9 (10:1 compression) that came in the Escalade. Yours takes 87 octane. The LQ9 was higher.

 

[Bill 1960]

I had the LQ4 in a 2500 Sierra. It was somewhat stronger than the 5.3 I had of the same generation in a 1500. Noticeable, but not awesomely different.

 

[Tonyrodz]

Now that you mention it, I recall this being a discussion here not long ago. I don't recall the outcome (or if there ever really was one), but maybe it was a year model thing or maybe the book said 91 was recommended but 87 was acceptable or something like that. Maybe someone will remember.

Regardless, I'd run 91/93 in an LQ9. Maybe not during colder weather, but definitely during the spring and summer.

Why not during the colder weather?

 

[iamdub]

Why not during the colder weather?

After re-reading it, I see what I wrote is confusing. What I meant was I'd run high octane exclusively. But, if I wanted to run the cheap stuff, I'd do so only during colder weather. I didn't mean that I'd intentionally run 87 because of the colder weather. If 87 was just "acceptable" but 91-93 was recommended, then I'd be apprehensive to run 87 at any time. During colder weather would make me feel better about it. I'd still be leery and listening for pinging if I were giving it any moderate to hard throttle.

 

[rockola1971]

LQ9 10.1:1 Compression Ratio
LQ4 9.4:1 Compression Ratio

I dont own a LQ9 but I do own a LQ4 and (4) LM7's. The difference between my 6.0 and 5.3's is night and day. The 6.0 pulls alot harder than the 5.3. Its just a matter of what you want the engine to be able to do. For just around town , travel and towing a boat to the lake then the 5.3L works fine. The 6.0 will make it more fun. For pulling larger loads then no doubt the 6.0. LQ4 works will do fine for that and you can even cam it and headers with a tune if you feel froggy. I prefer the iron block of the LQ4 for every application except a maybe a track queen to save some weight by using the LQ9 Alum block.