GTIRoller

I understand that DOD deletion is a popular mod, and I get why it is. I’m curious tho, how much extra MPG does DOD actually earn you vs a non-DOD engine?

SAPPER

iTrader: (10)

None for the most part unless you're driving long distances, on flat ground 98% of the time. Other than that, it's just a "lifter-waiting-to-fail" scenario.

SLOW SEDAN

iTrader: (13)

Agree, its not much. I've replaced a ton of those failed lifters, doesn't seem worth it.

G Atsma

My wife's 08 Suburban has it, and there is a display that tells whether it's running on 4 or 8. It is RARELY on 4....

pdxmotorhead

Anecdotal comment: I had a rental 2019 Tahoe that I drove from Oregon to Georgia and back in 1 week.., On the mid west part of I80 I was getting 25 on this along flat stretches and the engine was staying in 4-cyl mode all the time.. Only bumping down when I'd pass or hit a short hard grade. When the engine was in V8 mode I was getting 18-22.. My overall mileage for the trip was 23.5mpg.. I thought that was kinda cool..

I was hauling a engine in the back of it.. About 375 lbs plus camping gear.. prob another 75 lbs.

G Atsma

orYeah, the newer ones cut out a BUNCH of cylinders at times. I bet it was on only about 2 or 3 cylinders when getting 25mpg. Was it a 6.2 or 5.3?

pdxmotorhead

Was a 5.3, the dash only said 8 or 4 so no idea if it could do any other combinations, the switchover was totally invisible.. couldn't even feel it.. And I averaged 85 from the rockies to Atlanta..

G Atsma

OK, it might be just the 6.2's that cut out more, and maybe only the last year or two. You did pretty well!

pdxmotorhead

Yea for a big honking rig like that I thought that was pretty good..
MY 53 swap already has me impressed on my Jeep Wrangler, My first fill-up I'm at 22. < 200 miles on it..
(L33 with L59 flex fuel manifold and external accessories.. )

Che70velle

iTrader: (6)

Only 4 cylinders de-activate when in DOD mode on any DOD engine…1, 4, 6, and 7 go down. Thats where the DOD towers are on all Gen4 LS engines.

pdxmotorhead

Yep I think wasn't the Caddilac Motor the one that did 8/6/4 (The one that also had problems with the DOD system... LOL

SAPPER

iTrader: (10)

The common reason for failure is the VLOM, valve lifter oil manifold. Basically the valley cover on AFM engines. But when a lifter goes down, it'll let you know it.
You keepa knockin but you can't come in......and....knockin on Heavens door
The new 2020+ engines now have all 16 lifters that are AFM. The ECM can choose whatever cylinder it wants to shut down and will continuously alternate cylinders so as not to always using the same 4 cylinders.
These new engines suck. So many different variables with fuel lines, injectors, etc.

Che70velle

iTrader: (6)

Did not know this. Never been in a gen5 myself. I bought a new 2020 savannah 2500 8 months ago for the business and it’s got an LC8 6.0 LS engine in it. I was a little disappointed at first but it’s strong and I can work on it.

69-chvl

iTrader: (11)

I lost a DOD lifter in my 07 Yukon. Cost me about 800.00 to convert to non-dod camshaft and programming, and about 40hrs of my time or more. I think I saw about a 1 mpg difference, not to mention increased oil usage while on 4 cylinders. So really how much money did that 1mpg cost me on the back end?

If this was a regular-persons vehicle that has to take to to a shop or dealer - the truck would be pretty much a total loss, over a fu*cking lifter b/c the shop would want to put a reman engine engine which after fixing my truck myself - I kind of u/s why.

SAPPER

iTrader: (10)

Your LC8 is a rare breed of design. Half gen3, half gen 4. But easy to work on and all 16 lifters are standard lifters.

AgFormula02

iTrader: (13)

On my 2013 truck (LC9) I turned AFM off 6 months after I got it. MPG impact was negligible.
Happy to say 8 years later that it burns no oil, no lifters knocking, or any issues.
Regularly tow 5K plus with it. (Very grateful for the 6L80)

Jimbo1367

I had a 07 Monte SS and got 26+ MPG with 3 adults 1 child and full trunk. The DOD works. It’s just a matter of how long.