5.3 vs 6.0 Vortec?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Rayyy

Full Access Member
Joined
Jun 4, 2020
Posts
299
Reaction score
133
Location
Northern California
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

Full Access Member
Joined
Jun 6, 2020
Posts
1,145
Reaction score
1,736
Location
40.923,-89.488. Illinois
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

Full Access Member
Joined
Apr 23, 2016
Posts
20,712
Reaction score
44,431
Location
Li'l Weezyana
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.
 

iamdub

Full Access Member
Joined
Apr 23, 2016
Posts
20,712
Reaction score
44,431
Location
Li'l Weezyana
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.
 

Bill 1960

Testing the Limits
Joined
Dec 17, 2020
Posts
1,480
Reaction score
2,857
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

Resident Resident
Joined
Feb 16, 2012
Posts
30,958
Reaction score
45,061
Location
Central Jersey
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

Full Access Member
Joined
Apr 23, 2016
Posts
20,712
Reaction score
44,431
Location
Li'l Weezyana
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

Full Access Member
Joined
Dec 29, 2016
Posts
2,376
Reaction score
2,972
Location
Indiana (formerly IL)
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.
 
Last edited:

Forum statistics

Threads
128,781
Posts
1,805,301
Members
91,760
Latest member
MyCleftNut

Latest posts

Top