Valvoline Restore & Protect experiment
- Thread starter the blur
- Start date
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opfor2
Full Access Member
Why not just use regular oil and add a bottle of Rislone?
Just a follow-up on the neighbors vehicle we completed the AFM delete on. He has put 250 miles on it, and is highway MPGs have increased by 1.8 MPG. He's now at 20.1 MPG. I know he's driving it like a sane person for the first thousand miles, but commented he's never seen anywhere near 20 miles per gallon before. I'm chalking it up to using the OEM L92 camshaft. (Which is interesting, because that would suggest GM lost fuel mileage by designing the AFM system.) I can't imagine the Valvoline had that effect on it, unless it freed up some stuck piston rings and restored compression? Quite possible I suppose.
Marky Dissod
Full Access Member
Years ago, I INCREASED the V4 mode duty cycle on a 2012 Yukon XL I was leasing for NYC livery driving.
Point was to be in V4 mode as much as possible driving in Manhattan.
It was a mistake.
MpG gains were barely detectable between the first and second years.
I left it alone to try to encourage myself to drive in featherfooted style so as not to agitate my riders.
In winter of 2017-28, oil consumption went up drastically. Think the piston rings were 'coked up'.
I wonder if Valvoline Restore & Protect would've been of any help?
Truth is I should've raised the V4 mode enable temp to 235F.
I would say in the AFM deletes I have done, people on average report about a one mile per gallon increase just by disabling AFM in the ECM. Then after the AFM is physically deleted, usually there's another one half to one mile per gallon increase. Not entirely sure why. Almost all of them, the heads have been flat, and the shop I use skimmed less than a thousandth to clean and get the RA correct. In this latest case, the Valvoline may in fact have freed up a couple rings. One thing is for certain, in all cases they idle a lot better after replacing all the lifters and the cam.
the blur
Full Access Member
I bet they would idle better if you didn't touch the AFM. You are basically replacing the top half of the motor, of course it's going to idle better, and run better with a fresh cam & lifters.
It's not just the new cam and lifters improving the idle. It's getting rid of the complicated AFM system that leaks a lot of oil internally, which clearly affects how well those AFM lifters are operating in the V8 mode even. Results in a very unbalanced system, sometimes well under 100,000 miles. I think the system probably works well for the first 20 or 30,000 miles, and at some point there's a gradual process where it's efficiency drops and affects fuel mileage overall. Unfortunately, sometimes that process isn't gradual and one of those AFM lifters destroys the engine. A very risky technology in an expensive engine you would prefer to last well over 100,000 miles. The non AFM L92 is a perfect example of the same 6.2 that typically lasts much much longer and doesn't have a history of imploding. The AFM in the most basic description is a politically based technology to assist GM in meeting its CAFE requirements as the car is driven off the lot. It's benefits and fuel mileage don't last long enough to make it worthwhile, and it soon becomes a liability to the engine having the opposite effect of its intended purpose.
Marky Dissod
Full Access Member
Pretty much this - then GM doubled down by adding V7 V6 V5 V4 V3 V2 and I2 modes to their V8s ...
(My suspicion is that their intent was to make their engines more likely to fail at around 200,000 miles.)
Between 30,000 & 60,000 miles, Engine Half@$$' MpG benefits over V8 mode evaporate.
Cylinder wear differences caused by 'the lazy V4' are responsible for the MpG benefit loss over time.
People who wait to change their oil until the OLM hits 20%, or less, accelerate the Engine Half @$$ lifters' demise.
Same goes for failing to assertively maintain the PCV system.
Sooner or later, one or more of the dual-mode lifters will fail / be failed, either by the oiling system itself,
contamination of same, or the inherent design flaws of the dual-mode lifters themselves.
Although this failure can be put off further into the future by disabling Engine Half@$$ at the first opportunity,
in the long run the lifters eventually fail (an Engine Half@$$ failure after 200,000 miles is impressive, but still ...)
If you haven't yet uninstalled the feature,
raise the V4 mode enable temp over 235F if you want to save it as a defense against overheating.
Otherwise disable it entirely by raising the V4 mode enable temp over 266F.
(My suspicion is that their intent was to make their engines more likely to fail at around 200,000 miles.)
Between 30,000 & 60,000 miles, Engine Half@$$' MpG benefits over V8 mode evaporate.
Cylinder wear differences caused by 'the lazy V4' are responsible for the MpG benefit loss over time.
People who wait to change their oil until the OLM hits 20%, or less, accelerate the Engine Half @$$ lifters' demise.
Same goes for failing to assertively maintain the PCV system.
Sooner or later, one or more of the dual-mode lifters will fail / be failed, either by the oiling system itself,
contamination of same, or the inherent design flaws of the dual-mode lifters themselves.
Although this failure can be put off further into the future by disabling Engine Half@$$ at the first opportunity,
in the long run the lifters eventually fail (an Engine Half@$$ failure after 200,000 miles is impressive, but still ...)
If you haven't yet uninstalled the feature,
raise the V4 mode enable temp over 235F if you want to save it as a defense against overheating.
Otherwise disable it entirely by raising the V4 mode enable temp over 266F.
honestly I blame gm for adding afm, not any regulations. gm tried this stuff all the way back in the big carb caddy motors. gm has always chased mph number, even in their base sports cars. they also tune their throttle Map to be much softer than say Ford. I think it's just in their DNA. they spent the money and effort to certifi a small bore 305 in a camaro with half the intake port in the head blocked off because it got 4mpg better than the standard 305 they already had clear.
it's just a gm thing
it's just a gm thing
Marky Dissod
Full Access Member
Cadillac's V8-6-4 shut off the fuel but did not shut off the valves
(nevermind that V6 mode was its own rumble factory),
which made the power loss and vibrations so blatantly obvious to the driver,
that the feature got disabled before it could cause any serious costly damage.
With Engine Half@$$ / V4 mode, GM hid all sensations well enough,
that there are still people who refuse to disable the feature today.
(After it fails, they'll try to sell it, no doubt ...)
CAFE MpG test scores hit every carmaker in the US market, but I agree that how GM handles it is also off-putting.
Particularly annoying is the undergeared axle ratios.
3.90 or 4.10 would suit me & my Z71 much better, and cost very little if anything in terms of highway MpGs.
