GF6 motor oil

[xstuntman]

A new oil coming out in the spring of 2020 for direct injection engines. It seems modern synthetic isn't up to the stresses and higher pressures of direct injection engines. The oil breaks down rapidly causing excessive valve train/timing chain wear which might explain the LLT timing chains issue and the reason why the LFX takes so much oil at change. I wonder if Chevy knew and made 6 quarts a bandaid?

I'll be the first guy in line.

[G8One2]

What higher pressures, and stresses are a result of DI engines?

[DSX_Camaro]

I would imagine anyone could go over to Camaro6 or Corvette7 forums and see what those guys think considering the LT1 and LT4 are direct injection and blah blah blah. Considering SS guys here do oil analyses frequently I'm sure those guys do too.


(The LT1 takes 8 quarts, right? Same as the Coyote 5.0L? Is that a bandaid? Does the LS3 take 8 quarts? It isn't even DI)

[xstuntman]

Unlike port injection DI engines have a very short time to inject fuel into the cylinders so they typically run around 2,200 psi fuel pressure at injection. Yes, 2,200 - not a typo. Couple that with an already high compression engine and internal pressures get stupid but that's how you make 323hp from a tiny 217 cubic inches.

There are soot and fuel dilution issues too but it leads too oil viscosity failure.

[DSX_Camaro]

Originally Posted by xstuntman

Unlike port injection DI engines have a very short time to inject fuel into the cylinders so they typically run around 2,200 psi fuel pressure at injection. Yes, 2,200 - not a typo. Couple that with an already high compression engine and internal pressures get stupid but that's how you make 323hp from a tiny 217 cubic inches.

There are soot and fuel dilution issues too but it leads too oil viscosity failure.

Doesn't the LT1 / LT4 run like 2900 psi? Don't the 3/4 ton truck diesels run like 25,000+ psi? Are "modern synthetics" not good enough for them?

[xstuntman]

No they aren't and that's the whole point.
DI has known issues.
Apparently you aren't aware?
Anything else you'd care to argue about?

[G8One2]

Originally Posted by xstuntman

Unlike port injection DI engines have a very short time to inject fuel into the cylinders so they typically run around 2,200 psi fuel pressure at injection. Yes, 2,200 - not a typo. Couple that with an already high compression engine and internal pressures get stupid but that's how you make 323hp from a tiny 217 cubic inches.

There are soot and fuel dilution issues too but it leads too oil viscosity failure.

The DI system has absolutely nothing to do with cylinder pressures and compression. I don't know why you would think that. And I don't mean that in any way to verablly attack you, or question your skill, it's just what you said makes no sense, at least to me.

[DSX_Camaro]

I'm really not trying to argue, you just aren't offering any counterpoints. DI's known issues to my knowledge revolve around the fuel never coming in contact with the intake valves, leading to carbon deposits. This is well known across any car manufacturer.



Or the LFX oil capacity. The Pentastar and Cyclone V6's in the Challenger and Mustang both use port injection and have 6 quart oil capacities. Is this a coincidence? If oil capacity was a bandaid wouldn't GM have made the LFX 8 quarts like the 5.0L and LS3?

[G8One2]

Originally Posted by DSX_Camaro

I'm really not trying to argue, you just aren't offering any counterpoints. DI's known issues to my knowledge revolve around the fuel never coming in contact with the intake valves, leading to carbon deposits. This is well known across any car manufacturer.



Or the LFX oil capacity. The Pentastar and Cyclone V6's in the Challenger and Mustang both use port injection and have 6 quart oil capacities. Is this a coincidence? If oil capacity was a bandaid wouldn't GM have made the LFX 8 quarts like the 5.0L and LS3?

You are absolutely correct about the DI systems not having a PFI system to piggyback, causing carbon build up issues. I suspect the oil capacities have nothing to do with anything other than oil change intervals. I'm still wondering though, what cylinder pressures and compression have to do with the conversation here. I can only assume, there are people on the internet who really have no clue how the DI system works or how the engine as a whole works. Not to fault anyone though, there is a TON of bad information on the net that is preached as if it were true, making it difficult for others to know the difference between fact and bull*hit.

[Elite Engineering]

xstuntman is correct. And here are the issues:


GDI engines are far higher compression ratio than old port injection, 11.5:1 and higher in some cases. You would need to run 100 octane in a port injection engine to run that CR.


GDI engines (again depending on which ones) introduce the fuel directly into the combustion chamber milliseconds prior to spark ignition, so 2,000-3,000 PSI plus is not unusual. This results in 8-12 times the raw fuel pushed past the rings compared to a port injection engine. Not only does this wash the cylinder walls and piston skirts, but also dilutes the engine oil, and unless an oil analysis sample is drawn immediately at shut-down through the dipstick tube such as this (there are several brands you can choose):


https://www.jglubricantservices.com/...lysis-kit.html


you will not get an accurate fuel dilution reading if taken when draining!!


Now, what else is occurring that stresses the oil? ALL GDI engines have intake valve coking issues as no fuel is sprayed onto the backsides of the valves keeping them cool and clean, so they operate at far higher operating temperatures and the deposits are NOT the "soft carbon" of the past that a Seafoam or similar could easily remove without damage to the engine. These deposits are baked into a hard abrasive crystalline structure so those solvent based cleaners cause damage in every case we have studied. While most is expelled out the exhaust, some is always forced between the pistons and cylinder walls and that contaminates the engine oil as well, further overwhelming an oils ability to protect. The premature timing chain and other internal parts wear was caused by GM using the cheap syn blend oils until recently (many dealers still use it for the "free" oil changes that you paid for up front in the price, so that is a gamble) as it results in much greater coking deposits building compared to a good full synthetic.


The other issue? LSPI. (Low Speed Pre Ignition). This is when fuel and oil is pushed behind the rings and if ANY amount of petroleum based oil is used as in a blend or the cheaper full synthetics and it ignites, the resulting explosion will break the ringland. This can be as simple as a broken land that stays in place so slight misfires and oil consumption to complete piston failure.


Now, the new oil mentioned will be a better option, but Amsoil and most other "premium" synthetics have already addressed much of this. One is the additives. Amsoil was one of the first, and others have followed suite in reformulating the oil so it is far less prone to ignition in these situations. That is part of the new spec for GDI engines (M1 also has this now).


So, this oil specification is specifically to address some of the problems inherent with GDI engines, but are not a "fix all".


Here is an example of one of our field testers with a GDI twin turbo engine making 20# of boost that is driven hard. With our E2-X air/oil separating crankcase evacuation system at 13,000 miles. Next sample will be drawn at 20,000 miles and we will share it as well. Note the comments by the lab technician:






As our E2 and E2-X dual valve systems convert the factory PCV system to full time flushing and evacuation vs factory part time, and we separate app. 95% of all these substances, it keeps the oil clean far longer. Especially the fuel dilution. It is not unusual for a GDI engine to reach 5% fuel dilution in as little as 2-3k miles. 5% is where oil is considered "condemned" and no longer able to protect. Google: "GDI engine failure issues" and read how widespread this is.


So no, you can't compare the old engines to today's engines. And this is a main reason there are no longer 100,000 mile engine warranties as in the past. These are subject to so many issues that shorten engine life unless you the owner take the steps needed.


Questions? Please ask, and as always, email our Engineering and Technical support team direct at: Tech@EliteEngineeringUSA.com

[ChibiBlackSheep]

Originally Posted by xstuntman

I'll be the first guy in line.

According to Mobil, their current Mobil 1 formulation seems to be meeting GL6 standards. So if you are experiencing DI issues and using Mobil 1, I don't know if the oil next year will magically start to fix things.

https://mobiloil.com/en/article/why-...nes/ilsac-gf-6

...Our initial tests indicate our current formulations are GF-6 capable

I really hope that they can work on making this work, but DI and short trips seem to always allow fuel to dilute and not get taken away, and I think it's a bigger issue with DI and not something that can be solved by oil. Hopefully though they just make the oil a little more resistant to the dilution?

I had to move away from my LFX, I loved the car, but I was having a lot of issues with my direct injection, and I'm big on early and frequent oil changes with high quality oils.

[G8One2]

The only reason a DI system runs a tad bit higher compression, compared to a PFI system, is that the DI system adds a cooling effect to the combustion chambers.

[Russell James]

Originally Posted by G8One2

The only reason a DI system runs a tad bit higher compression, compared to a PFI system, is that the DI system adds a cooling effect to the combustion chambers.

There are a few more reasons... i.e. timing of the fuel charge, increased atomization, less fallout from vapor to liquid, compressing only air....

If you spray and atomize the fuel in the microsecond before ignition spark, this eliminates the possibility of detonation way before ignition. So you can compress the bejesus out of the air without risk of detonation.... cuz, it's only air. Then inject high pressure atomized fuel within milliseconds of spark into chamber shaped to focus the fuel charge right at the spark plug... and you get a more efficient combustion. Leaner too, because you don't have to account for the % of fuel that would normally fall out of vaporization traveling in the ports.

[xstuntman]

[QUOTE=Elite Engineering;10625866]xstuntman is correct. And here are the issues:


This results in 8-12 times the raw fuel pushed past the rings compared to a port injection engine. Not only does this wash the cylinder walls and piston skirts, but also dilutes the engine oil,

ALL GDI engines have intake valve coking issues as no fuel is sprayed onto the backsides of the valves keeping them cool and clean, so they operate at far higher operating temperatures and the deposits are NOT the "soft carbon" of the past that a Seafoam or similar could easily remove without damage to the engine. These deposits are baked into a hard abrasive crystalline structure so those solvent based cleaners cause damage in every case we have studied. While most is expelled out the exhaust, some is always forced between the pistons and cylinder walls and that contaminates the engine oil as well, further overwhelming an oils ability to protect. The premature timing chain and other internal parts wear was caused by GM using the cheap syn blend oils until recently.


The other issue? LSPI. (Low Speed Pre Ignition). This is when fuel and oil is pushed behind the rings and if ANY amount of petroleum based oil is used as in a blend or the cheaper full synthetics and it ignites, the resulting explosion will break the ringland. This can be as simple as a broken land that stays in place so slight misfires and oil consumption to complete piston failure.

Now, the new oil mentioned will be a better option, but Amsoil and most other "premium" synthetics have already addressed much of this. One is the additives. Amsoil was one of the first, and others have followed suite in reformulating the oil so it is far less prone to ignition in these situations. That is part of the new spec for GDI engines (M1 also has this now).
So, this oil specification is specifically to address some of the problems inherent with GDI engines, but are not a "fix all".
It is not unusual for a GDI engine to reach 5% fuel dilution in as little as 2-3k miles. 5% is where oil is considered "condemned" and no longer able to protect. Google: "GDI engine failure issues" and read how widespread this is.

So no, you can't compare the old engines to today's engines. And this is a main reason there are no longer 100,000 mile engine warranties as in the past. These are subject to so many issues that shorten engine life unless you the owner take the steps needed.


- That's even more info than I've been able to find, thanks for posting.

The big question in my mind now is will we need to convert to the GF6A or B version in our cars? I believe both are 0W16 weight.