BVVHO

Screamingjimmy if you consider 15.5 to 16.5 on the Hi-way at around 70-75 than the 6.0s are bad. At least thats what I get on my 05 6.0.

99Silver6.0

iTrader: (1)

6.0's are kewl!!!

endo

Congrats on getting it done! Just curious on what it took to hydrolock the 4.8L though...i.e., what's the max fording depth for an ECSB 4x4?

treyZ28

I got through it in 2hi but engine was bogging heavily due to low rpm and exhuast underwater. in 4Lo the engine sucked up water

it was about bumper high. The SRT4 didn't make it either

treyZ28

I dont know about highway 60mph;
but I was going pretty quick through the mountains (read: death to gas milage) on pretty big mud terrains with a fair amount of weight, no skid plates or front air dam (read: death to aero) and pulled down close to 16mph.

with it better broken in Id expect better, expecially with sythetic. I'll let you know on my return drive. I'll refuel on the Ohio/PA border and drive 70mph with cruise on through flat ohio. I'll still have big tires, a good amount of weight, just one less fluid filled 4L60E w/Coverter. Keep in mind- this is winter blend crap that will hurt gas milage too.

My 4.8 always got about 16.5-17.2 through this stretch with AT's instead of MT's and less weight.

My theory is that the higher compression ratio of the LQ9 will offset its displacement gain (MPG loss).

Thing is, in a car- a bigger engine will be more detrimental than a small engine with equal gearing because the engine is the MAIN "loss." You are basically putting gas in just to keep the engine running and overcome its parasytic losses and pumping losses.

In a truck, with that weight and aero- you are actually making a lot of power relative to the car. So engine size wont hurt as much. The 6.0 doesn't need to rev NEARLY as high as the 4.8 (2000, maybe 2500rpm is just about all you need unless you are driving for fun ) and the 6.0 doesn't downshift as much. Those really help cancel out its bigger size.

screamingjimmy

hmm, thats some good points!

Thanks

treyZ28

in all honesty, gas milage be damned. worst case; 1mpg worse. dont let that hold you back.

Torque_Wrench

iTrader: (13)

Hey, so all you did was change to a diffrent trans, and 6.0 engine from a former 4.8? Only had to have the PCM remapped right?

Did you have to alter any mounting issues with the 4L65E?

treyZ28

The only things I had to do to get the new engine and trans in was

a. swap egr outlets in the intake. pretty easy. push in red thing. pull out connector. rinse and repeat.

b. pcm

c. fuel rails

d. uhh, think that was it.

GMJim

Hello guys
I posted some questions on another thread about mileage on a 2006 1500 with a 6.0 Max Vortec option and was a little concerned about gas mileage on the 6.0 versus the 5.3. I know the 6.0 will need 91 octane so there is a difference in cost there but from what I've read the 6.0 is only slightly worse than the 5.3?? I was considering the 5.3 for mileage reasons but if the 6.0 is only slightly higher in fuel consumption then it makes my decision easier. My next concern is the leather interior. How is yours (if you have it) holding up? I've noticed that the leather GM is using looks baggy after a while and cracks easy. I know this is a personal decision but I like my truck to stay nice over time. If anybody can offer any advice on my little fuel saving dilema and the leather thing, please let me know.
Thanks
Jim