Dexos 1 and dexos 2 clarification

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Went to a website stating the list of approved oils is changing for dexos warranty soon. It seemed at first glance they were eliminating most syn blends and paring down the approved oils (I assume many companies don't want to pay to be dexos approved).

Based on how I read this list only euro pennzoil platinum would be on the dexos 2 list for pennzoil, Is this right?

http://www.centerforqa.com/dexos-about/
 
If these car makers are testing oil to certify it to meet thier specification's that's Great but if they are just selling certification like Dodge did Pennzoil then it's just side cash for the auto maker and bull.
Iam not a GM guy but I go for the Dexros oil certs if I can.
Dodge perturbs me with the Pennzoil Ultra deal.
 
Dexos 1 is a passanger car motor oil spec.
Dexos 2 is a diesel oil spec.

I am guessing you asking about the upcoming Dexos 1 Gen 2 spec?

I had read that to meet the Dexos1Gen2 spec, the oil will have to be mostly synthetic, it is near impossible to meet with conventional, and very hard for even a blend.
 
You have that right. But also, the dexos1 gen 2 spec does not become the standard till September. And then, it will only be the standard required for 2018+ model year vehicles. Everything up till then still has a dexos1 gen 1 recommendation. One can use gen 2 in a pre-2018 MY vehicle, but not required. I don't use any oil on the dexos1 gen 1 or gen 2 list anyway in my GM vehicles and don't worry about it. I understand other's concerns for doing so, but they don't need to overthink the issue.
 
You guys are right. My 14 chevy equinox would fit into the broader category. Geez I'm not the smartest guy in the world but at first glance that is a bit confusing.
 
Dexos 2 seems to be going the same way as most European OEM recommended oils; more and better synthetic, more and better additive, more stringent engine/rig/lab tests. Of course this makes the oil significantly more expensive which naturally the OEMs don't give tinker's cuss about because they don't have to pay for what they recommend. I'll concede that if you're going to move to very long OCIs or drive like a maniac, these 'super oils' can make sense. However if all you're going to do is tootle around in your rather ordinary car and change your oil every 5k - 7k, then the technical case for using a Dexos 2 oils fall apart completely.
 
One significant driver for the Gen 2 upgrades is LSPI, which is why they are mandated for new engine designs. This puts focus on the additive mix, particularly the detergents, to reduce or eliminate LSPI events.
 
Ahh answered my own question. So am I to gather that to reduce lspi the oil essentially has to be a certain clinginess to the engine upon startup?
 
Yes, the Dexos 2 spec does contain an LSPI engine test, but with tens of thousands of TGDI engined vehicles out there on the roads today, functioning quite happily on NON-LSPI certified engine oils, it naturally begs the question, so what? And let's not forget that the extensively reported problems with the Hyundai/Kia Theta II GDI engine were absolutely nothing to do with LSPI.
 
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Originally Posted By: kenpoed
Ahh answered my own question. So am I to gather that to reduce lspi the oil essentially has to be a certain clinginess to the engine upon startup?


No, it's about the additive pack uses. Certain additives appear to increase the chance of LSPI events
 
Originally Posted By: kenpoed
Ahh answered my own question. So am I to gather that to reduce lspi the oil essentially has to be a certain clinginess to the engine upon startup?


(Note: I think when SonofJoe mentions "Dexos 2" he really means "dexos1 Gen2". dexos1 is never capitalized. dexos1 is for gasoline engines. Am I right? Seems that way from your text SonofJoe.)

About LSPI, "clinginess" is not relevant to it. You might be referring to the polarity of oil and additives which stick to the surfaces enabling a tribofilm to form.
LSPI technical papers and GM's own dexos1 Gen2 claims indicate it is a complicated detonation issue which can be influenced by some additive combinations in oils, so dexos1 Gen2 oils are usually better at avoiding LSPI in most engines.
 
Originally Posted By: oil_film_movies
Originally Posted By: kenpoed
Ahh answered my own question. So am I to gather that to reduce lspi the oil essentially has to be a certain clinginess to the engine upon startup?


(Note: I think when SonofJoe mentions "Dexos 2" he really means "dexos1 Gen2". dexos1 is never capitalized. dexos1 is for gasoline engines. Am I right? Seems that way from your text SonofJoe.)

About LSPI, "clinginess" is not relevant to it. You might be referring to the polarity of oil and additives which stick to the surfaces enabling a tribofilm to form.
LSPI technical papers and GM's own dexos1 Gen2 claims indicate it is a complicated detonation issue which can be influenced by some additive combinations in oils, so dexos1 Gen2 oils are usually better at avoiding LSPI in most engines.


Appy polly loggies!. Yes, I did mean dexos 1 Gen 2, not dexos 2 (the diesel spec).

Oh, and while 'dexos' might not be capitalised, BITOG autocorrect always annoyingly puts in the capital D, so it's basically not my fault!

And yes, I've seen the various studies that suggests overbased Calcium detergent contributes to LSPI events and that you're better off with one based on Magnesium. If I'm honest though, I do question why you need a new specification to make this happen. Under the existing Minor Modification rules, you're allowed to interchange a certain amount of Ca for Mg with Level 1 support and more if you have Level 2 support. I also seem to recall you can legitimately add Mg under the TBN Booster rule.
 
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Originally Posted By: SonofJoe
And yes, I've seen the various studies that suggests overbased Calcium detergent contributes to LSPI events and that you're better off with one based on Magnesium. If I'm honest though, I do question why you need a new specification to make this happen. Under the existing Minor Modification rules, you're allowed to interchange a certain amount of Ca for Mg with Level 1 support and more if you have Level 2 support. I also seem to recall you can legitimately add Mg under the TBN Booster rule.


I've wondered how GM gets away with using only 1 engine design to test for dexos1 LSPI. Seems LSPI is also a function of piston & chamber shape unique to every engine.
They came up with something that kind of tests for it anyway! At least GF-6 will use another separate engine design to test of LSPI on top of dexos1's one engine.
 
Originally Posted By: oil_film_movies
Originally Posted By: SonofJoe
And yes, I've seen the various studies that suggests overbased Calcium detergent contributes to LSPI events and that you're better off with one based on Magnesium. If I'm honest though, I do question why you need a new specification to make this happen. Under the existing Minor Modification rules, you're allowed to interchange a certain amount of Ca for Mg with Level 1 support and more if you have Level 2 support. I also seem to recall you can legitimately add Mg under the TBN Booster rule.


I've wondered how GM gets away with using only 1 engine design to test for dexos1 LSPI. Seems LSPI is also a function of piston & chamber shape unique to every engine.
They came up with something that kind of tests for it anyway! At least GF-6 will use another separate engine design to test of LSPI on top of dexos1's one engine.


Gasoline with a heavy back-end also seems to be complicit in LSPI. This would logically fit with the theory that at low speed, you're randomly 'throwing off' a mixture of engine oil and unburnt fuel that has accumulated between the top land and the bore. Funny how all the argument has focussed on the engine oil with not the faintest whisper about limiting the 95% point or FBP of gasoline.
 
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Originally Posted By: SonofJoe
Funny how all the argument has focussed on the engine oil with not the faintest whisper about limiting the 95% point or FBP of gasoline.


Wondering if we'll see anti-LSPI touted in future Shell commercials, like this one with TCP-Platformate in the gas:
 
Gasoline has a set of ranges for most of the distillation specs, and is a varied multicomponent mixture at all times with a boiling range, not a single boiling point of a pure substance like water for example.

A heavy end gasoline would be one blended such that the distillation range falls nearer the maximum values for 90% point and end point than the minimum specifications. However, a "heavy end gasoline" will have a higher energy content per unit volume as well.

Refineries with Fluid Catalytic Cracking Units (FCCU's) can have a "swing cut" of catalytically cracked heavy naphtha. When gasoline production economics are more favorable than diesel production economics, this stream is routed (or "swung") to gasoline blending. When diesel production economics are more favorable than gasoline economics, this stream is routed or "swung" to the diesel blending pool. The other refinery units that produce gasoline blend stocks will in general experience undesirable catalyst fouling and liquid hydrocarbon yield to coke if they attempt to produce "heavy end gasoline".

This "swing cut" can either be a physical heavy naphtha side draw off the FCCU Main Column fractionator (most desirable), or the distillation cut point can be adjusted within the FCCU Main Column fractionator to achieve the same effect if it has sufficient hydraulic capacity.
 
Yeah. All of the above!

One other thing to bear in mind is that all things being equal, gasoline Final Boiling Points (FBPs), and back-ends in general, tend to be heavier in winter than in summer. Gasoline volatility (as measured by Reid Vapour Pressure) tends to be less restricted in winter. This allows you to stick more light stuff (like Butane) into the blend. A lighter front-end allows you to get more heavy stuff into the back-end. There are many other factors that might impact on this (like season demand) but in general, the principle is true.

The thing is LSPI, if my understanding of the basic mechanism is right, is more likely to be a 'winter thing', as opposed to a 'summer' thing'. That's because direct injection of cold gasoline into a cold cylinder to mix with cold air is more likely to leave the heaviest bit of the gasoline in the liquid phase. This non-evaporated fuel could potentially accumulate in the top land space be later 'thrown-off' at low engine speed. Now if you add in on top of this that winter gasoline might contain MORE heavy stuff, well, you risk getting caught with a double whammy effect which can't be a good thing.
 
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