Will 5.3 to 6.0 (LQ4) make a big difference in towing?

[S33k3r]

Boosted or not, premium fuel is a decent idea when towing.
My dad always ran low grade in his 2002 6.0 2500hd always. Once we had to run to pick up my cousins truck in Minnesota with the trailer. About halfway back on a fuel stop the station was having pump problems and only could sell 93 premium. Needless to say dad was pretty pissed bit my cousin was reimbursing him so a tank of 93 it got.
Never again when towing did he use anything but 93 octane. He said he could feel it pull better.
And after seeing how the timing tables work with knock tables and calculations with doing a little playing with tunes, ill bet it did. Running 85-87 can easily put you in the low octane timing table if the ecm sees knock pulling upto 8 or even 10 degrees of timing. That could be as much as 20 hp and just as much tq. 93 octane when towing has the potential knock resistance to keep the truck in the high octane table and not lose power if loaded down more than usual. Anyone towing a decent load needs to run a tank of premium even if the vehicle doesn't specifically call for it.
But in the long run, even with a 6.0 4.10s are needed in mild to medium hilly areas. If he is foothill/mountain towing he really should go to 4.56s.

I only mentioned the premium fuel because I, too, suggested forced induction. THAT is also an answer to high altitude. Towing, overall, yes -- more gears. [EDIT] Just posted this in a hurry, THEN reread it. Many apologies if it comes off snarky -- it is not intended to be.

 

[Mudsport96]

I only mentioned the premium fuel because I, too, suggested forced induction. THAT is also an answer to high altitude. Towing, overall, yes -- more gears. [EDIT] Just posted this in a hurry, THEN reread it. Many apologies if it comes off snarky -- it is not intended to be.

Nah no snark. Its good,

 

[Buggdave]

I also tow a 5500# TT (with 4 boys and two dogs) with a 6.0, 4l65 at high altitude. This summer, I was towing a long 10% grade in Wyoming (final elevation was about 11,000') and it was the first time I felt that the 6.0 was struggling. I have a BB tune, TBSS intake & 87mm TB with MIT intake tube. I could not get it to stay in 2nd gear, so I was pulling at about 35 mph. I also have 3.73 gears and stock 265-70-17 tires. I only run 91 when I tow and can notice a difference when I use 87. I have 205,000 miles on the engine and this has been the only real issue. My research has shown what others here are advocating, better gears, forced induction, or what I found was to run a high compression engine. I am currently building a higher compression engine, because why not more HP & TQ.Gears are in my future but i am not doing FI because I do a lot of back country exploring and did not want the added headache of FI maintenance.

 

[S33k3r]

Gears are in my future but i am not doing FI because I do a lot of back country exploring and did not want the added headache of FI maintenance.

Ok... Now I feel SUPER ignorant. I'll go Google, but what kind of maintenance?

 

[Fjs0001]

Ok... Now I feel SUPER ignorant. I'll go Google, but what kind of maintenance?

I put a turbo on my Miata. I love it, but it's a never ending project. There's always more needed than the kit you buy provides. My next Miata project is upgrading the transmission and rear end because I'm on borrowed time for them to fail. The same would be true for the 4l60e in our GM rigs.

 

[S33k3r]

Ok. I feel less stupid now. I understand supporting mods, more powerful fuel pump, bigger injectors, hardening the drive line, etc. I thought there was some magical maintenance thing I'd never heard of; you know -- like blinker fluid...

 

[Buggdave]

I may have been mislead, I heard that your oil change intervals should be less than every 3000 miles and that rebuild intervals on turbos was about 30k to 50k.

 

[Larryjb]

Ok. I feel less stupid now. I understand supporting mods, more powerful fuel pump, bigger injectors, hardening the drive line, etc. I thought there was some magical maintenance thing I'd never heard of; you know -- like blinker fluid...

You did change the air in your tires to Winter Air didn't you? Cans of it are available at your local auto parts store, just ask for it.

 

[Fjs0001]

I may have been mislead, I heard that your oil change intervals should be less than every 3000 miles and that rebuild intervals on turbos was about 30k to 50k.

I don't think you've been mislead. My turbo'd car doesn't follow schedules well and I probably do change the oil every 3000 miles or less. It doesn't see a ton of miles because it's not my daily driver. I generally change the oil because I know that I'm going to be giving it the beans all weekend. Or something broke and I'm working on it anyway. Then there are the times where it's developed an oil leak and I'm constantly topping it off. I've also blown up a motor and took apart the turbo to confirm it wasn't messed up.

You can only pick two
Fast, reliable, or cheap.

 

[jrdecat]

I had this same dilemma about a year ago. 2003 Yukon XL w/ 3.73 gears and the 4L65e tranny. I live near Denver and Fat Konnie was a slug when I headed into the mountains...or drove up anything steeper than a 1% incline.

So I bought a rebuilt LQ4 with upgraded Comp Cam roller setup, upgraded springs and trunion bearings, and decked 241 heads with appropriately sized gaskets. I replaced some wear items like water pump, thermostat, belts, spark plugs, wires and threw on a set of speed engineering long tubes and Y pipe. I hit up Black Bear for a tune and hit the road.

Now she runs like a spotted ape and will pass anything but a gas station. BB told me I'd have to run premium fuel with his tune, especially at altitude and having some engine mods. So now I get to pay more for gas and I get gas mileage (11-13mpg)! She's not my daily driver so that should play into your decision.

Bottom line...is it worth it? !!!YES!!! Now Fat Konnie has plenty of power in the mountains and can even downshift and pass people on the interstate. Will I blow up my tranny? Maybe. But GM put the 4L65E behind plenty of 6.0 motors so I'll report back if it grenades like a G80.

DO IT!

 

[BG1988]

My 2003 Suburban with 5.3L has 225k and I just upgraded my boat. 3.73 rear axle. Boat is about 6500 lbs on trailer. Love my Suburban but at 6000 ft elevation I lose about 30% of my power. 5.3L struggles bad with the new boat, especially on hot days and loaded down. Looking at dropping in an LQ4 (salvage or reman) if it will make a significant difference. Not willing to go LQ9 as 85 octane is expensive enough. I know fuel economy will fall off a cliff as my folks have a Silverado 2500 with LQ4, but I'm mainly trying to avoid buying a new truck altogether. Anyone done an LQ4 swap for improved towing?
Also,I bought a 2013 Tahoe this year with the Gen IV 5.3L. After CAI, straight through exhaust, and Diablosport tune, it didn't tow any better than my old Suburban. 5.3 isn't the answer for me at this elevation.

8.1L

 

[S33k3r]

This might inspire you: Turbo 8.1 Build for 2001 Silverado

 

[Sam Harris]

This might inspire you: Turbo 8.1 Build for 2001 Silverado

I enjoy his videos and work. Looking forward to some final results re: the 4.8 vs. 8.1 comparison…

 

[fasteddy]

A built 6.0 will tow it easy. I have an LQ9 with shaved 317 heads and a torque focused cam. I get 350lbs of TQ at 1500rpms and 490lbs at 4900rpms (crank)
And I still get 19mpg on highway at 80mph.....not towing. towing is around 12-13.
A stock 5.3 in 2003 put out 315lbs of TQ Max around 5000rpms.
A new 6.2L pushes around 460lbs and that easily tows my trailer with race car and spares about 6500lbs.

The only engine that will beat a built 6.0 towing is an SC6.0 or duramax...... superchargers are expensive, get heat soaked in summer, they will suck more fuel, and they need a very beefy transmission.
I stayed N/A with my 6.0 as I need dependability, and less parts is more dependable.

Torque moves a car and pulls trailers, horsepower is computed.

 

[Mudsport96]

A built 6.0 will tow it easy. I have an LQ9 with shaved 317 heads and a torque focused cam. I get 350lbs of TQ at 1500rpms and 490lbs at 4900rpms (crank)

And that is the key. Im pretty convinced that GM crippled the 6.0 with the wrong cam from the factory.
Why on earth would you put a cam from a f body in a truck meant to pull and carry loads.

 

[fasteddy]

I've decided to put the 6.0 Tahoe to the test on towing......Trailer + car inside + spares + tools is about 6K lbs.
Towed it no problema....I was worried most about the tongue weight. As you can see it is squatted a bit but not much.
I have Z71 springs in the rear. But it handled great!
If this Tahoe had an 8 or 10 speed trans it would be perfect. Towed about 200 miles round trip. 10-11mpg. temps were fine.
19+ chevy 4P calipers worked awesome.