Noob with a 6.0 swap question for those who have done it...

[MrFleming007]

Hey guys, new guy here coming over from GMFS. I've got a question for those that have done the 6.0l swap- What are your real world mpgs?

A little background... I've got a 2000 Suburban with the 5.3l. Its got 185,000 miles now and I've got a failed lifter on the #3 cylinder exhaust. Ticking is driving me nuts. I can't justify the cost of a rebuild compared to a low mileage drop in motor, so that is the route I want to go. However, the local wrecking yards around here have the LQ4 motors for only a couple hundred above the cost of the 5.3l.

I've heard rumors of guys getting better city and highway mpg with the lq4 swap vs the stock 5.3, so I want to see if its true, especially on the slighter heaver 'Burbans. Thanks in advance everyone!

 

[M3PO]

I haven't done the swap, but I had a '02 Z71 a few years ago, and now I have a '06 Denali.
The Denali is a thirsty truck to say the least. In the dead of winter, with bad gas, defrosting windows, and long warm up times combined with short trips, I was getting as bad as 10 mpg. We are in a cool Spring and I now getting about 15, but dont use the truck as much for the short trips, so I would say the 15mpg is 50/50 city/highway.
This is JUST A GUESS, but my Denali has full time AWD which adds some drag, I am guessing having a slightly heavier Burb will net you similar MPG's??
If you can find a 6.0 for just a couple bucks more, I say "go with it". While the 5.3 was no slouch for a heavy truck, the 6.0 is terrific in the HP, torque, and sound departments.

I think the Denalis have a bigger/heavier transmission, but I am not sure. You might want to ask some that have done it, if they switched the trans or had any problems keeping their other, IF the 6.0s did get a heavier trans.

Good luck!

 

[J-dub]

Go with the 6.0

 

[zaathur]

i go with the 6.0 you will love the extra power

 

[bkboatnsleds]

6.0 .. stock trans... NO issues. LQ9

 

[Nickleahy23]

i love my 6.0..

my city mpg are down from my 5.3, but i also went with a yank tt3000 converter...which is why they are down..

highway i get better..im up around 18 on the highway..never downshifts on a hill even with 7 people in the truck and the 24s on it..the 5.3 was always downshifting...

I would at least do a shift kit and a servo in the trans...I blew my stock trans up right after the motor swap..3/4 clutch pack went out, which is common with that many miles...denalis and eskys came with a 4l65e..which is an "upgraded" 4l60e, but its not much better stock for stock..i did the shift kit and servo, and mine lasted about 2 months after the swap with 155k on it..I now have a built 4l65e

 

[bkboatnsleds]

What differences did you notice with the yank tt3000 converter ? Whats the stall on it?

 

[Nickleahy23]

3k is the stall speed...well you can brake stall it to just over 3k with a 6.0, so take off is way better, shifts stay higher in the power band when at full throttle (say shifting at 5800, instead of dropping down to 2500, they stay up near 2900-3100 ish) and just better response..but it kills the city mpg a bit because you have to give it more gas to get it goin...

 

[MrFleming007]

Good information. Guess I'll be on the lookout for a LQ4 then! Sounds like I may want to keep an eye out for a 4l65e too. My Stock tranny has 188k on it now. Still shifts like new, so I may be ok short term on it...