What is the best synthetic oil? Best oil filter?

[Gary Wells]

[quote=kck;1945584]...................Gary: I’m sorry I am so dense on this topic, but I’m struggling to reconcile your two posts to me (which I really appreciate you taking the time to do). In the first one you seem to suggest that GM includes considerable factory-installed EOS-type additives in their Z06 engines – which would lead me to include a pint or so of GM EOS in all the engine oil changes I do for my (Vette-based) V engine, especially for the first two or so oil changes during the “break-in” period. But then in your second post to me, I get the impression that you are concerned that the EOS supplement (and its high Zinc content) might damage the CATS. However, if that is true, then why would GM use EOS in their Z06 engines? You also note that modern camshafts & valve trains do not need EOS. So, in your first post regarding the E0S that GM puts in the Z06, did you possibly mean that GM used to put EOS in the older-style Z06 engines, but now GM does not include EOS their current (more modern) Z06 engines?

KCK:
Sorry for the delayed response back. I don't feel that GM necessarily runs GM EOS as an oil additive in their ZO6 motors during break-in, I think that the assemblers use an abundant amount of it for engine assembly purposes realizing that most ZO6 owners are still changing their first "original" oil out very early in the game, and think that it can only help in the break-in process.
I find it hard to believe that GM EOS or any of it's commercial counterparts such as ZDDP+ only benefits older motors due to running flat tappet camshafts and it has no benefit as an anti-scuff agent to a modern day motor. However, modern day motors are built to more exacting tolerances, thereby having more nominal clearances of friction producing internal parts.
I do think it possible though that GM EOS or any similar type engine oil supplement can plug up your cat given enough time & mileage.
I did not intentionally mean to give mixed signals, but I am on the fence myself for my new '09 CTS-V as to what oil, what viscosity, what filter, and what , if any engine oil supplement is best for it.
I have run Mobil 1 since about '86 or so, and believe that it is one of the best readily available synthetic oils on the market. And I do believe in running a bottle or two of GM EOS in every oil change in my 26K mile '87 turbo Buick. What the more knowledgeable CTS-V owners on here decide to run in the way of oil, filter, & additive will probably give me some insight into what I will run. I might try Amsoil for a while when I run out of Mobil 1. Dunno, & sorry again for the delayed & tardy response.
I wasn't hiding, I was just taking cover for a while and thinking. But I do have faith in this forum & it's members on deciding a clear cut path for the less informed like myself to follow. HTH

[kck]

Gary: Thanks for the clarification! Although it would be nice, of course, to have definitive answers to this question regarding use of “supplementary oil additives,” I’m encouraged that even knowledgeable persons like yourself are struggling with this issue, as well as the more general one of how best to care for ones V. In other words, I’m feeling a little less “stupid.”

Kyle

[kck]

marktanner: I agree with you that it seems highly unlikely that using 0w40 Mobil 1 would result in voiding the V’s GM warranty. If you read the web pages regarding the various Mobil 1 oils (see my later posts below), it seems fairly clear that the 0w40 formula is Mobil’s “premier” engine oil for high performance street cars – designed for the most extreme cold to the most extreme hot environments. Additionally, I’m very impressed that 0w40 Mobil 1 is the recommended spec for Porsche, Dodge Viper, Mercedes-Benz AMG, Aston Martin, GT-R, and the Z06s sold in Europe.

So why is 5w30 (instead of 0w40) Mobil 1 the spec for the Z06s sold in the U.S.? Is it possible that Z06s sold in Europe do not have to meet as stringent standards regarding the longevity of their CAT systems as compared to Z06s sold in the U.S.? Brad’s web link to the Mobil 1 spec sheet (see C66 Racing’s earlier post on this thread) shows that the zinc content of the 0w40 Mobil 1 is higher than the 5w30 Mobil 1 – and it’s my understanding (based on web information that Gary and Dallara suggested I examine) that the better lubricating properties of “higher-Zinc” oils can only be realized, if the phosphorous content is proportionately increased, and it’s the phosphorous that clogs CATS.

Kyle

[kck]

Guys: Thanks again for all the information you have provided. Based on those various comments, I have now added a third oil – 0w40 Mobil 1 – to my list of 3 potential oils (also including 5w30 Mobil 1 and 0w30 Amsoil) from which to choose. I’d like to select among these 3 oils based on both “engine protection” and “horsepower” considerations. I’m going to assume that the best index of engine protection – at least under the “stress” of all-out-performance (e.g., W.O.T. in desert heat) -- would be maintenance of viscosity at high oil temperatures. I’m also going to assume that an oil’s relative “drag coefficient” (or “fluidity”) at normal operating temperatures would be the best index of its effect on both gas mileage and (more importantly in a performance car like the V) horsepower.

Do any of you know what specific “indexes” would measure an oil’s “drag coefficient” at normal operating oil temperatures and an oil’s engine protection (viscosity?) at high operating temperatures?

As backdrop for my above questions, I’m going to cite some information I ran across and my initial (“newbie”) interpretations of this data. I realize, of course, that any of the 3 oil formulas I’m evaluating is likely to provide good performance in my V. I guess what I’m really trying to do here is satisfy my intellectual curiosity, and to see where my reasoning may be flawed. Please feel free to point out my errors. As a social and behavioral scientist, I have developed the requisite “thick skin” that is a necessary part of the scientific endeavor. So fire away!

Mobil provides technical specs for their 0w40 vs. 5w30 products (see the specs listed under “Typical Properties” on the two web pages below), but I don’t have the background to interpret the numbers, nor to single out which spec (if any) is the most direct measure of the relative “drag coefficient” at normal operating temperatures or the best spec to determine engine protection at extremely high oil temperatures. So any help you guys can provide here would be much appreciated.

0w40 Mobil 1: http://www.mobil.com/USA-English/Lub...il_1_0W-40.asp

5w30 Mobil 1: http://www.mobil.com/USA-English/Lub...bil1_5W-30.asp

In the absence of knowledge regarding the best direct measure of the relative “drag coefficient” for a given oil, I would have assumed that the upper-end (“hot”) viscosity number for a given oil would be the best indication of the relative drag that it produces. However, in my next post I provide some additional background information regarding why I think the low-end (“cold”) viscosity number, surprisingly, may be more important than the upper-end number in determining relative drag and corresponding gas mileage and horsepower. Based on the information contained in my later post (and my ignorance of the specs contained in the Mobil web links above), I’m going to “speculate” that the “drag coefficients” for the two Mobil 1 oils are roughly the same – given that the 0w40 Mobil 1 oil has a lower “low-end” (“fluidity-enhancing”) viscosity than the 5w30 Mobil 1 oil, but a higher “upper-end” (“fluidity-degrading”) viscosity. If, in fact, it turns out that the two Mobil 1 formulas produce about the same “drag coefficient” under normal operating conditions, then the choice between the two oils would seem to come down to which potentially provides the best “engine protection.” In this regard, it is possible that the 0w40 formula gains the overall “upper hand” because of its greater potential to enhance engine life in more extreme hot (and cold) environmental conditions. Indeed, when evaluating this engine protection, I’m guessing that the most important index in the Mobil 1 spec sheets is “HTHS Viscosity” @ 150 degrees C (302 F). If true, then the relevant comparison is an index of 3.7 for the 0w40 versus 3.09 for the 5w30 oil. (Interestingly, with regard to “cold weather” performance, Mobil reports an “MRV” index for its 0w40 oil at minus 40 degrees C [-40 F], but no such index for its 5w30 oil.) But, again, I need our “oil experts” to provide guidance in interpreting the indices contained in the Mobil tables.

So what about comparisons of the Mobil 1 oils with the 0w30 Amsoil formula? Based on “viscosity range” only, the Amsoil product would seem to have the best potential for maximizing gas mileage and horsepower – given that it matches the 0w40 Mobil 1 oil on viscosity at the low-end, but has less viscosity on the upper-end. But, again, it would be very helpful to know if there is a specific technical specification that provides a direct measure of the relative drag coefficient for the Amsoil vs. Mobil 1 oils.

Brad: Assuming that the Mobil web pages I provide above contain the appropriate “drag coefficient” (and “extreme heat engine protection”) indices for the Mobil 1 products, would you have access to this same information for your Amsoil products?

It would also seem important to be able to “translate” the “drag coefficient” index scales for different oils into a measure of “real-world” horsepower (and gas mileage) differences. For example, on a scale of, say, “0 to 100” (with a higher number indicating more “drag”), if 0w30 Amsoil is a “50” and 0w40 Mobil 1 is a “60,” would the 10-point lower drag coefficient for Amsoil translate into “meaningful” differences in horsepower (and gas mileage), or would this 10 point difference suggest “trivial” differences in power (e.g., 1 h.p.) and gas mileage (e.g., 1/10th m.p.g.)?

Assuming that the 0w30 Amsoil does have a meaningfully better “drag coefficient” than the 0w40 Mobil 1 (or 5w30 Mobil 1) oil, than the choice would seem to be between selecting the 0w30 Amsoil oil for its potentially greater “fluidity” and correspondingly better gas mileage and horsepower enhancement versus selecting the 0w40 Mobil 1 for its potentially greater engine protection.

Bottom line: If any of you guys have insight into the actual “drag coefficient” and “engine protection” numbers (and to what extent differences in these numbers might translate into meaningful differences in engine protection, gas mileage, and horsepower) for the Amsoil vs. Mobil 1 oils, this might help me (and other forum members) to determine which engine oil to choose.

Kyle

[kck]

Below I’ve included a couple of additional web pages from the Mobil 1 web site with information that I found interesting with regard to its potential implications for oil performance. As in my previous post, I’m trying to satisfy my intellectual curiosity here and to determine flaws in my interpretation of this information.

Below is a web page on Mobil 1’s “advanced fuel economy” oils. If you read through this web page, It would appear that Mobil concentrates on decreasing the lower-end (“cold start”) number (i.e., going from 5w20 to 0w20, or going from 5w-30 to 0w-30) to increase gas mileage (and, I would assume by implication, a corresponding increase in horsepower). Before seeing this comparison, I would have guessed that decreasing the upper-end (“hot”) viscosity number (e.g., going from 5w-40 to 5w-30) would be what is most important to increase gas mileage (and corresponding horsepower).

https://www.mobiloil.com/USA-English...AQs.aspx#FAQs3

The importance of the low end of the viscosity scale for enhancing potential horsepower (and, by implication, gas mileage) would also seem to be implied by a careful analysis of Mobil’s discussion of their “racing oils” on the following web page:

https://www.mobiloil.com/USA-English...AQs.aspx#FAQs5

Interestingly, both of their racing oils -- 0w-20 and 0w30 -- are based on “0” for the lower-end number. And the intent of Mobil to create a “thinner” (“higher-horsepower”) oil by formulating both their race oils with this lower-end number is clearly seen in the title of one of the sections on the above web page: “Zero weight oils are thinner. Will using a 0W oil cause excessive engine wear while racing or qualifying?” Mobil then goes on to note that using these two racing oils will not promote excessive wear because: “Mobil 1 Racing 0W-30 and 0W-20 oils are formulated with anti-wear (Zinc/Phosphorus) chemistries at twice the level of automotive street oils to protect race engines including highly loaded flat tappet designs used in the NASCAR series.”

Also of interest, on this same web page they note that “street cars” should not use these race oils (see the section titled “You say the new Mobil 1 Racing oils are not for street use“) because the high zinc/phosphorous content is not compatible with “emission control equipment” (i.e., CATS). Instead, for a car designed for both “road and track use” (i.e., a high-performance street car such as the V), Mobil recommends using either 0w40 Mobil 1 or 15w50 Mobil 1. (See the bottom of the web page at https://www.mobiloil.com/USA-English...cing_Oils.aspx.)

I would interpret this latter recommendation to mean that, to compensate for the loss of the lubricating (“engine-protecting”) qualities of the higher zinc/phosphorous content in the racing oils, engine oils designed for performance street cars should continue to use (“thinness-promoting”) 0w formulas for the low-end of the viscosity range, but increase the (“engine-protecting”) upper-end of the oil’s viscosity range (e.g., move from 0w30 for pure racing applications to 0w40 oil for high-performance street applications).

Although maintaining a “0w” low-end number for street car oils will help retain some of horsepower-enhancing oil “thinness” found in racing oils, going to a thicker (engine-protecting) 40w viscosity for the high-end number in street applications will likely sacrifice some oil thinness and corresponding horsepower. The effect of the upper-end viscosity number on horsepower is most clearly seen in Mobil’s description of their two different race oils:

0w20 Mobil 1 racing oil: https://www.mobiloil.com/USA-English...ing_0W-20.aspx
0w30 Mobil 1 racing oil: https://www.mobiloil.com/USA-English...ing_0W-30.aspx

To summarize the information on these two above web pages: Mobil’s description of their two race oils indicates that the 0w20 is geared more towards (shorter) “qualifying runs,” whereas the 0w30 is intended for the (longer) race itself. I interpret this to mean that the “20w” version of the race oil will provide maximum horsepower and the corresponding speed especially needed in qualifying, but the “30w” version of the race oil will sacrifice a small amount of horsepower to provide a bit more engine protection especially needed for the longer period in which cars conduct the race itself.

In sum, one possible interpretation of Mobil’s descriptions of their various viscosity oil formulas (“race” oil, “road & track” oil, and “advanced fuel economy” oil) is as follows: (1) the lower-end viscosity number is potentially the most important determinant of how much a given oil will affect gas mileage and horsepower, but that the upper-end number also has some, potentially smaller, effect on gas mileage and horsepower; and (2) the upper-end number is a more important determinant of engine life, at least under the “hot” conditions such as generated in racing.

Assuming my above “interpretation” is even approximately true with regard to lower-end and upper-end viscosity effects on m.p.h. and h.p., then what are the implications for selecting between the 0w40 Mobil 1 vs. the 5w30 Mobil 1 formulas? One possible implication is that the lower (“fluidity-enhancing”) range of the 0w40 Mobil 1 compared to the 5w30 Mobil 1 might be roughly “counter-balanced” (offset) by the higher (“fluidity-degrading”) range of the 0w40 vs. the 5w30 oil formulas. In other words, the two formulas might generate a net “push” with regard to gas mileage and horsepower – with the 0w40 formula decreasing the lower-end (potentially more important) viscosity number by 5 points, but also increasing the higher-end (potentially less important) viscosity number by 10 points.

However, although the two Mobil 1 oil formulas might be comparable in generating horsepower-enhancing “oil thinness,” as I’ve noted earlier, the higher (“engine-protecting”) upper-end viscosity number for the 0w40 Mobil 1 formula would seem to give it the nod as the superior oil for high-performance street cars. Recall, too, that Mobil’s own web pages would seem to suggest that the best oil formula for a high-performance street car (such as the V) is the 0w40 (or 15w40) Mobil 1 oil – and not the (GM-recommended) 5w30 Mobil 1 oil.

Alternatively, one could use 0w30 Amsoil to (potentially) generate a bit more horsepower (and gas mileage) than the 0w40 (or 5w30) Mobil 1 oil. Furthermore, to overcome the loss of some “engine-protection” under “race” conditions (i.e., using the 30w spec of the Amsoil, as opposed to the 40w spec of the Mobil 1), one could add EOS (zinc/phosphorous supplements) to the Amsoil. But the downside to using this alternative strategy is that you may very well shorten the life of your CATS.

Kyle

[kck]

Originally Posted by C66 Racing

Kyle,
Appreciate the kind words. I really do appreciate the dialogue with guys like Dallara and work hard to clearly separate my opinions from more factual info.

That said, here are some opinions. I've been a long time member of several Corvette Forums (bought my Z06 in Aug 01) and I do not remember seeing what I consider concrete info on any break-in additive used in LSx engines by GM. I am confident that in the Corvette and my CTS-V (V1) there is no mileage recommendation, even for the first oil change. GM strongly advises to follow the OLM. Additionally, your post is the first I remember reading about a coating on the ring/pinion.

Over the past four years or so, I've seen several articles put out by AMSOIL indicating that early diff fluid changes help prevent long term wear similar to this one:
Change Gear Lube after Break-in for Long Differential Life

My general practice has been to change all the factory fluids out at about 1000 miles, which is what I did with my Z06 way back when. My CTS-V was a little different as I bought it as a used corporate car with about 7k miles on it, but I still changed out all the fluids not too long after I bought it.

Brad: Your web link to the article recommending an early fluid change for the differential is very interesting. I did not realize that the differential has no filter. This fact would seem to support not only an early fluid change but also the use of the (internal) differential magnet from FilterMag. I’ve posted (see http://www.cadillacforums.com/forums...you-using.html (Which size Filtermag are you using?)) on this company and their products. I’d be very interested in your reaction, as well as other forum members (i.e., our other oil experts) participating in the present thread, to the FilterMag product line of magnets for the oil filter, transmission, and differential.

Also, jwa999 has posted questions on a current CAI thread regarding your Amsoil air filter products (see http://www.cadillacforums.com/forums...-intake-3.html (Best Cold Air Intake?)), in a response to a post I made there in which I noted that you (and 1BlinkGone) had raised concerns about the filtration capabilities of high-performance air filters such as K & N. Hopefully, you might be able to answer Jwa999’s questions.

Kyle

[21rouge]

I havent read through this entire thread but a direct injection engine makes it a bit more problematic re dilution by fuel and deposits. There has been some discussion elsewhere that Biosynethic oil made by "Renewable Lubricants" specifically RLI 0W30 or 5W30 might help combat these difficulties.

[Looney100]

Originally Posted by 21rouge

I havent read through this entire thread but a direct injection engine makes it a bit more problematic re dilution by fuel and deposits. There has been some discussion elsewhere that Biosynethic oil made by "Renewable Lubricants" specifically RLI 0W30 or 5W30 might help combat these difficulties.

Fuel dilution isn't a problem with gasoline engines. Gas has a flash point of -40 degrees, so any small amount of fuel that might leak into the oil, would evaporate and wouldn't accumulate to any amount that would cause trouble.
Oils are made to handle the small amount of deposits that would come from normal use.

Coolant contamination is another issue. If any significant amount gets into the oil, the oil will be near useless.

[21rouge]

Originally Posted by Looney100

Fuel dilution isn't a problem with gasoline engines.

That isnt true...especially in DI engines. See here for example:

http://www.sae.org/technical/papers/2002-01-1647

Originally Posted by Looney100

Oils are made to handle the small amount of deposits that would come from normal use.

Again there is increasing evidence that DI engines are more susceptible to carbon buildup. Google for more info.

[Looney100]

I'm not saying that fuel doesn't get into the oil, but is there any evidence that it is accumulating to the point that it is affecting the performance of the oil?
With all the guys doing used oil analysis out there, I would suspect this would have been clearly visible if it was happening.

[CTS-V-TWIN]

GM states in the owner's manual to NEVER USE A THICKER OIL THAN 10w30. Stick to 0w30 or 5w30. Remember GM's dreaded crankshaft failures that caused them to only run 5w30 motor oils?

SG

[21rouge]

Originally Posted by Looney100

With all the guys doing used oil analysis out there, I would suspect this would have been clearly visible if it was happening.

For whatever reason I see very few UOAs posted for this GM 3.6 Direct Injection Engine. Do you have any links?

But many UOAs are available for European DI engines and Mazda DI engines and it is very usual to find excess of fuel in the oil. Fuel in engine oil degrades the protective properties of the oil of course leads to excessive engine wear.

As well it appears that deposit buildup goes hand in hand with DI engines.

http://www.bobistheoilguy.com/forums...517650&fpart=1

[kck]

Originally Posted by AERO1

GM states in the owner's manual to NEVER USE A THICKER OIL THAN 10w30. Stick to 0w30 or 5w30. Remember GM's dreaded crankshaft failures that caused them to only run 5w30 motor oils?

SG

AERO1:
Thanks for your post. Could you elaborate on your statement regarding “GM's dreaded crankshaft failures” when using engine oil that exceeds 30 weight? As a total “newbie,” I have no knowledge of this issue.

Also, if this “heavier weight” is a problem for GM engines, why would 0w40 Mobil 1 be the spec for Z06s sold in Europe (as C66 Racing has noted in an earlier post on this thread)?

Kyle

[C66 Racing]

Originally Posted by marktanner

Does anyone really think that a dealership or even GM could tell the difference between 5W30 and 0W40 without an expensive analysis, especially if the oil was used for a few thousand miles?

I do. For about $20, labs like Blackstone could easily tell the difference. The two keys are viscosity, which will be higher for the 0w40, and the dead giveaway is phosphorus and zinc. The API SM 5w30 must have phosphorus less than 800 ppm and the 0w40 is listed by Mobil 1 to have phosphorus of about 1000 ppm and zinc of about 1100 ppm. Take a look at some of the used oil analysis reports on my CTS-V I linked higher in this thread (here for convenience: Cadillac CTS-V Used Oil Analysis – Mobil 1 5w30 & AMSOIL 0w30 )

These tests only cost me about $20 or so and clearly indicate the zinc and phosphorus. If you lost a $$$ motor, I wouldn't put it past GM to deny coverage based on using the wrong oil.

Kyle,
Answered a few of your questions in your dyno thread, so won't repeat here totally.

For your comments on cold vs hot viscosity, I think that there are two issues here. First, if you look at the data for most fuel efficient motor oils, you'll find that their hot viscosity is very low in the applicable grade. Second, I believe that the EPA mileage test which is used to determine CAFE ratings starts from a cold engine, cold oil. Thus to improve CAFE, they must lower cold viscosity. Overall, whether hot or cold, lower viscosity equals less fluid friction, equal more net Hp and better mpg.

However, on the other end of the spectrum is protection. Whether we will ever note the lower viscosities drop in protection in daily driver's is something we can debate forever. In my opinion, the corporate answer is not the same as the individual answer. Said another way, while it might be okay for GM if 1 in a 1000 engines fail to improve their CAFE rating, I don't want to be the one.

Of the three oils you've listed Kyle, I personally would rank them on their HTHS rating, as Mobil 1 0w40 (3.7), AMSOIL 0w30 (3.2), Mobil 1 5w30 (3.09). But, as only the later two meet GM Standard 4718M, I went with the AMSOIL 0w30. Where that standard doesn't apply, e.g. my track day 02 Z06, I have been running the AMSOIL Premium Protection 10w40 which has an HTHS of 4.3 (and I don't care about the cold protection because I always warm my oil before going on the track).

[Bandit1]

Originally Posted by AERO1

I am going to run strictly Amsoil 0w30 Signature Series Synthetic Motor Oil and the Amsoil EA oil filter. Which other oil guarantees protection for up to 35,000 miles in normal driving conditions? Amsoil seems to be the only one.

Amsoil is 10 years ahead of everyone else in lubricant technology.

I have used Red-Line, Royal Purple and probably most of the synthetics on the market and based on the research and testing results I have seen, Amsoil always comes out on top.

SG