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Discussion in 'RT/10 and GTS Discussions' started by Marv S, Nov 22, 2001.
<FONT face="Comic Sans MS">Another solution is to not worry about it.
From what I've been told, modern oil, especially a quality synthetic like Mobil 1, has many anti-wear additives that stay on the various parts of the engine long after the oil is back in the pan. They protect the moving parts until the calvary arrives.
Of course, you wouldn't want to be running a 50 weight oil in 0 degree weather either...</FONT f>
Howdy. First, while most of your oil is in the pan, there is always a film left on the parts. Better yet, the additives in the oil are stuck on these metal parts. There's really no difference in starting an engine after an hour and after a month. (As long as the pump and pickup tube are primed.)
What is different is sometimes the temperature. If you want to start more easily and have the oil pump quickly to all parts of the engine, use a lower "W" rated oil, like an SAE 5W-30 or synthetic SAE 0W-30.
Ha, I'm typing away and see Ron beat me to it. All oils with the API service symbol (we are now up to API SL) and the ILSAC "starburst" symbol on the front meet the proper low temperature pumping requirements.
<FONT face="Comic Sans MS">Yes, but I learned it all from you Tom.....</FONT f>
Is there any difference on the first start after an oil change? That is, do the pump and pickup tube stay primed when you change the oil?
Studies of pumping *cold* oil show the limiting feature is the diameter and length of the pickup tube. The longer and thinner, the harder the pump has to pull oil up - think of trying to slurp a milkshake through a straw. The "W" numbers, and the temperature they refer to, are pretty much determined by testing a number of engines and seeing how low in oil temperature all these engines can still slurp up the oil.
The takeaway is that the pump always stayed primed, or lubricated enough to draw a vacuum. Even if the pickup tube lost the volume of oil, (and it might, picture a straw full of liquid that you pull out of the soda- it eventually drools out) the flow rate of an oil pump without any upstream resistance is many gallons/minute, so it refills instantly. I can only imagine a problem when installing a new, dry oil pump; I suppose I would grease it a little to make sure it could suck.
One point to remember. I'm sure no Vipers are ever started in -30F temps or lower, but the most wear and tear on an engine occurs when starting a vehicle in cold and sub zero weather. That is one of the reasons synthetics are so much superior to petroleum based oils. A non synthetic petroleum based oil is basically solidified at -40 or so and starts turning to molasses long before that. There is not much lubrication happening on start up. Some synthetics will pour at -60F and can still be pumped at -40F. This, in addition to the film noted above(which is also much better with synthetics), greatly diminishes any detrimental effect on the engine at start up. For those of us who live in these 'cooler' climates, synthetics are definitely the way to go for your winter vehicles. All my vehicles have had synthetics in them since 1975.
To specifically answer your question, the following procedure comes from Team Viper guys Herb Helbig and Joe Brady and applies to a 97 Viper as the "official" procedure to allow cranking without firing:
<LI>Step 1: Remove the automatic shutdown relay which is located in the PDC (power distribution center) which is located under the hood on the driver's side, near the firewall.
<LI>Step 2: Pull fuse #10 which is located in the car under the driver'side knee blocker
<FONT size="-2">Viper Mag winter 1999 pp.41</FONT s>
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by TOM & SARAH:
IS it possible to pull the fuel pump relay when caranking over the engine and once the oil pressure is up put the fuel pump relay back in and then start the engine in the normal way.<HR></BLOCKQUOTE>
Synthetics are not inherently better at low temperatures. It is the "W" number that determines low temperature operability; the tests that determine this don't care whether the oil is synthetic or not. And "pour point" has been proven long ago to have nothing to do with the tests that show what temperature an oil will allow safe starting of your car. A synthetic will allow a wider range (i.e. 5W-50, something a mineral oil cannot achieve) but a 5W is a 5W.
The film strength issue is similarly not a starting issue- with no oil pressure, it doesn't matter what oil is (not) there. The additive package can be independent from the base oil type - you can formulate with the same addpack as the mineral oil if you want.
Yes, a mineral oil will eventually turn to molasses and go solid, but this is exactly why the SAE viscosity grade system is in place. Whether synthetic or mineral, they both pass the same tests.
Tom, I understand you are well versed in oil knowledge, but I must pose this question. Are you saying that a 10w-40 mineral based oil and a 10w-40 synthetic oil have the same low temp.characteristics for lubricating an engine and that they will each get the oil pressure up to a safe operating level in the same time frame? They may both have the same viscosity ratings, but they certainly don't lubricate the same way in extreme cold or hot temperatures. At -40F a 10W-40 mineral based oil is pretty much solidified--a 10W-40 synthetic is still able to be pumped at this temp. I once did a side by side test with 2 identical vehicles at -42F with a stiff wind. The chill factor was over -60F. Both had sat overnight outside side by side. They each had relatively the same miles on the odometer. One had 10W-40 Pennzoil, the other 10W-40 synthetic. There was absolutely no comparison between the two in starting. The synthetic vehicle turned over about twice as fast as the mineral oil vehicle(fluidity). The oil pressure in the mineral vehicle took over 25 seconds to get to 40#. The synthetic was there in about 10. The mineral oil vehicle clattered like a diesel for quite a while--the synthetic was quiet soon after getting the oil pressure up. I know this was not a scientific test, but many winters like the one above have shown me that synthetics way out perform mineral oils of the same viscosity in cold weather.
Steve is correct about the properties of syn.oil. The use of syn.oil in small piston driven aircfaft in cold climate was a blessing for them.As they have a very light weight starting and batttery system,there limited on cranking power.Amsoil synthetics have a pour point of -80F.That is there o-W-30series 2000. I wonder when the viper experts out there are going to realize the superiority of syn.oils over petro?By the way Amsoil is superior to M-1. Thats a fact not an opinion. Dont want to get going on that right now its getting late.But I can say this,the worst syn.oil out there is better than the best petro made....
Only the best way to solve the problem is put in an Accusump. It will pre lube the entire system plus if you are on banks and the oil sloshes to one side with the factory oil pan the Accusump will kick in and lubricate the engine untill oil builds up in the pan. Call SEAN ROE! For Around $300 you are in business.
Hi again. Steve, the answer is yes. The test limits do not differentiate between a mineral or a synthetic, and if a synthetic 10W were compared to a mineral 10W and found to be "really much better" then it would be classified as a 5W or 0W. A 10W classification is a range that the oil must stay within.
Take a look here: http://www.lubrizol.com/ReadyReference/6-OilClasses/physicals.htm
You are mixing comparisons by thinking only about -40C, since the "W" numbers are used to designate safe starting at different temperatures, not how well an oil lets an engine start at a single temperature. If you want safe starting at -40C, the chart in the link would say to use a 0W (whether mineral or synthetic.) Using a 10W was not the right choice, whether mineral or synthetic.
The fact that there are two tests (one simulating sucking through the oil pickup tube and the other how easily the engine can crank) indicates some engines will appreciate one characteristic more than the other. Again, for safe starting, you should have an oil that meets both requirements.
Having said all that, only synthetics will meet 0W-xx viscosity grades, so they are "better" in that they resist freezing more than mineral oils. But in regards to brands, Skipwhite, it has nothing to do with the additives.
Tom, I made that comparison in 1986 or 87? There were no 0-30's available then that I know of. There may have been a 5w-30 mineral oil, but the 10w-40 synthetic I was using at that time would have run circles around it. It is only relatively recently that 0W oils have become readily available. Synthetics have outperformed mineral based oils for decades across the entire spectrum of measuring criteria.
I read the Lubrizol page you refer to. I don't dispute their expertise, but with all due respect, I will have to stick to my statement about cold weather lubrication as I have seen dozens of real life situations where cars with the same viscosity mineral based oils would not even turn over. Maybe the viscosity standards were much less strict back then. I see these standards are from 97&99.
From my oil research--- petroleum base stock molecules consist of long carbon chains which are quite sensitive to stress and heat. In addition, paraffins contained in all petroleum products cause the oil to jell at low temperatures. High temps. can cause the base stock to boil off. For these reasons they need a substantial additive package, including viscosity improvers, to meet API&SAE standards. Additives do not do the lubricating--the oil does. The less additives the better. Today's engines, with increasing emission standards, have moved the API classification from SE in 1972 to SJ today. Engines are now lighter and run hotter. Mineral oils have struggled to keep up. All the major oil companies have finally got on the band wagon with some form of synthetic. Mineral based oils are becoming a good part additive. Synthetic base stock is made of shorter chains which, are by nature, much more stable than mineral based molecules. Good synthetics need very little additives to achieve the same results.
Synthetics have been around for a long time. The Germans picked up the prior synthetic research in WW2 with ester based stocks. They successfully integrated the technology to their military machine. Synthetic oils kept their tanks running in the fridgid Russian winter. The US started using synthetics for military aviation in the 40's. Again, it was for the extreme temperature differentials. Mineral based petroleum oils could not do the job. Today, every jet in the world uses synthetic oil. Of course we're only talking temperature differentials here. There are many other advantages of synthetic oils. Among them, potential gas mileage increase due to decreased friction, resists thermal oxidation much better, better shear stability due to better viscosity retention, better heat stability due to resistance to volativity in high heat conditions. Then there are the indirect benefits of the battery and alternator not having to work as hard on cold starts,longer engine life, & extended drain intervals using oil analysis to name a few.
Sorry for the rambling
>>There were no 0-30's available then that I know of.<<
True, that is why I brought it up. To make an apples to apples comparison, you need to compare same viscosity grades at the temperature the oil was designed for.
>> Synthetics have outperformed mineral based oils for decades across the entire spectrum of measuring criteria.<<
This is false. Synthetic *base oils* have a wider temperature range, but in most automotive uses, it isn't applicable. At the higher temperatures the oil would survive at, something else would damage your engine (melt seals, etc.) and the lower temperatures (except a 0W-xx as mentioned) the mineral is equivalent. The rest of the oil is the additive package, which really makes the difference. Example- Mobil 1 and other mineral oil pass car oils only have half the additives that diesel oils do, and only meet half the performance criteria that diesels do.
>>I will have to stick to my statement about cold weather lubrication as I have seen dozens of real life situations where cars with the same viscosity mineral based oils would not even turn over. Maybe the viscosity standards were much less strict back then. I see these standards are from 97&99. <<
Again, let's find out if the starting tests you observed were at the temperatures the oils were designed for. If the temperature was below that, then officially it's the incorrect oil. (The standards don't change every year. )
>>For these reasons they need a substantial additive package, including viscosity improvers, to meet API&SAE standards. Additives do not do the lubricating--the oil does. The less additives the better. <<
This is not true. See the diesel oil example above. Saying less is better is saying API SA oils (no additive) are best - obviously not correct. Racers used to think less additive was better when oil consumption was so high that the additives led to combustion chamber deposits and so used ashless aircraft oils. Also, in a 500 mile race, it's a little less important, since the oil is changed frequently. But additives are what make the oil perform. Another way you should recognize this is the new API category that comes out every few years. If it were the base oil, nobody would need to reformulate. But the performance comes from the additive, so the addpack is improved. In synthetics, too.
>>Mineral oils have struggled to keep up.<<
Surprise! There are now mineral oils that meet all the synthetic criteria, and folks like Castrol call their super-mineral oil (Group III base oils) a synthetic. Because the definition of a synthetic is based on *performance* and not components, the consumer will not know.
>>Good synthetics need very little additives to achieve the same results. <<
Wrong again. Synthetics are very poor at solubilizing hydrocarbon materials and therefore need more dispersant additives. The rule of thumb is "like dissolves like" and synthetics are not "like" the deposits they have to remove from engines. While the mix of additives is a little different, overall a synthetic has as much additive as a mineral oil. And if you count the additional material needed to keep the additives in oil, it's more. Because the additives are more hydrocarbon-like, you can't just dump them in and stir, you need something to help the additives stay in solution.
>>Among them, potential gas mileage increase due to decreased friction,<<
The coefficient of friction of a synthetic and a mineral is the same. Friction modifier additives can affect this, though.
>>resists thermal oxidation much better,<<
Yes, but then mineral oils then have additives to achieve good performance also.
>> better shear stability due to better viscosity retention<<
This is partially true, due to the better viscosity index of the base oil alone.
>>better heat stability due to resistance to volativity in high heat conditions. <<
See the reference to Group III base oils above.
>>extended drain intervals using oil analysis<<
Even diesel long drain tests don't show synthetics are better. Recent SAE papers show this.
Synthetics have their place for low viscosity oils (SAE 0W-30) or multigrades with wide spreads, such as a 10W-50. Otherwise, it's mostly marketing.
You sound very knowledgable on lubricants. What oil do you run in your Viper, what brand and weight.
I use a mineral oil 15W40 diesel engine oil; my local Walmart carries Shell Rotella T and sometimes Chevron Delo 400, although I would choose any major brand diesel oil. I live about 70 miles north of New York City, so sometimes my starting temperatures are about 10F. I have about 47,000 miles, bought my '94 in Nov '98 with about 20,000 miles. Except for snow, it's my daily driver.
If money is no object and you want the last very few percent consider a synthetic diesel oil - comes in SAE 5W-40 viscosity grade.
For more about this, see http://www.viperclub.org/articles/oilfaq.html
Hey, unfair. I try to explain everything I suggest, please do the same.
I am not an API spokesman. I formulated engine oils for a major US brand until some of the mega-mergers you've all read about.
Don't forget that somebody is *paying* to put the name of an oil brand on the Viper oil fill cap, it is not just based on being a synthetic. In fact, there are non-synthetics that pass the Viper-Corvette standards also.
>>But there is no comparison to synthetic oil. <<
Sorry, but a not so recent case between Castrol and Mobil resulted in a very high quality "mineral" oil being OK'd for being marketed as a synthetic. See Castrol vs. Mobil synthetic
>> And Kevin I hope you know your cars oil req. calls for synthetic oil only. <<
I think if you read the fine print, it calls for a certain performance level, not a synthetic base oil.
>> You cant wear an engine out with syn. oil,a premium quility type that is. <<
Hee, hee. Ask some Mercedes dealers about their ASSIST system and what's happening with the synthetic oil they recommend.
>> I dont understand why Tom would recomend a 15-40 weight petro oil in your car. you would loose 10 to 15 H.P. for sure. <<
Theoretically you can lose a few (not 10) HP with a thicker oil. But you have to balance that with bearing protection, additive treat rates, and formulation durability. Diesel engines go 800,000 to 1,000,000 plus miles with 15W40s....
>> Evan more after the the volitile compounds evaporate off, which would happen very quickly under the Vipers high temp operating condition. <<
Sorry, but API service categories all have volatility limits to protect against "evaporation" which never was a problem with 15W40s anyway, only the 5W-xx grades. With the use of 5W20 oils as factory fill by Ford and Honda, to meet these volatility requirements, base oil manufacturers have had to really improve the quality of mineral oils, so there is the driving force to make minerals perform more like synthetics. And with 10 quarts in the sump, I don't suspect Viper oil temps to be over 250F - anybody see this in anything less than track use?
>> Fuel milage would be decreased for sure. <<
A "fuel economy" oil gets anywhere from less than a percent to 2.0% better mileage. (Using Sequence VI-B test for ILSAC GF-3) Using a 15W40 isn't going to "lose" any more than this, either.
>> I dont really want to get into all the aspects on the subject. Just take my word and run syn. oil in your car Not a Heavy weight,diesel oil, and petro grade on top of that.If you new the difference in the two you wold not want to start your car let alone drive it using such a product. <<
In God we trust, all others must show data. (Enginerd saying)
Tom, lost my I-net until tonight. I think I see where we differ. I think your basic premise is that if an oil is rated with a certain designation or passes a certain test, then all oils meeting this requirement, whether synthetic or mineral, are basically equal. I don't happen to agree with that. The synthetic oil I use sailed into the new API SL classification with no reformulation as they have several times in the past from SE to present. This means they exceeded the SJ classification a while ago, but there was no higher rating to go to. They were also the first 100% diester based synthetic in the world to pass the API sequence tests and receive API qualification in 1972. Mobil got on board domestically 3 years later with a PAO formulation.
Let me give you another example. In the mid 70's I ran a 2-cycle synthetic oil that had the same industry rating as the mineral based oils every one was using. The recommended mineral oil mix ratio was 20:1(quart to 5 gal), the synthetic 100:1-that's 8 oz. of oil for 6 gallons of gas--scary for most people back then. I actually ran a 500cc triple cylinder Polaris at 120:1 with no problems whatsoever. That mix ratio with petroleum would have smoked the engine in no time. Running richer than 100:1 with the synthetic caused fouling. I still use this oil in my weed eater. That's 1/3 of an oz for the summer(1 quart gas). In no way, shape, or form were these two oils equal even though they carried the same rating. It is my opinion that the same holds true for synthetic automotive oils.
I don't agree with a good part of your rebuttal to my previous post, although I do respect your opinion and enthusiasm for this topic. I also believe you have a wealth of knowledge in this area. However, I do think you're a mineral oil guy at the end of the day and biased accordingly.
I would suggest a simple test. Put a bottle of 10W-30 mineral oil and a bottle of a good grade synthetic 10W-30 in the freezer-better yet get some dry ice. Monitor their temperatures down to -40F or so. The mineral oil will be jelled at this point(at least it was the last time I did it)----yet they have the same 10W rating?
One last note. If synthetics only advantage is for low viscosity applications or wide spread multigrades..ie cold weather or extreme applications, why is it that Vipers, Corvettes, Porsches, & Mercedes all come with a factory fill of synthetic. I agree with you about Mobil 1 being a complete marketing thing as I believe there are better synthetics on the market.
IMO Synthetic oils have proven themselves the last 30 yrs. as a superior product.
I certainly am not going to change your mind nor are you mine. I guess we'll have to agree to disagree.
Steve WELL SAID.............
Hi Steve,It sounds like Tom is a spoaksman for the A.P.I. It is true that the quility of petro oils have been improved over the years . But there is no comparison to synthetic oil. And Kevin I hope you know your cars oil req. calls for synthetic oil only. all Vipers since 1996 I beleive.You cant wear an engine out with syn. oil,a premium quility type that is.I know this to be true. I dont understand why Tom would recomend a 15-40 weight petro oil in your car. you would loose 10 to 15 H.P. for sure. Evan more after the the volitile compounds evaporate off, which would happen very quickly under the Vipers high temp operating condition.Fuel milage would be decreased for sure.I dont really want to get into all the aspects on the subject.Just take my word and run syn. oil in your car Not a Heavy weight,diesel oil, and petro grade on top of that.If you new the difference in the two you wold not want to start your car let alone drive it using such a product. Hope this sets you straight.
Hi Steve, thanks for the reply. Let's dissect this some more?
>>The synthetic oil I use sailed into the new API SL classification with no reformulation as they have several times in the past from SE to present.<<
I believe it, because diesel oils have also. I don't mean to keep poking you in the eye with diesel oils, but it does reiterate the point that it is the additive in each formulation (whether synthetic or not) that gets the oil to pass the test, not just the base oil. I think we'll disagree on the contribution of each, but certainly a synthetic without additive isn't going to be a good oil at all.
>>In the mid 70's I ran a 2-cycle synthetic oil that had the same industry rating as the mineral based oils every one was using....In no way, shape, or form were these two oils equal even though they carried the same rating. It is my opinion that the same holds true for synthetic automotive oils. <<
Since two stroke oils are consumed and four stroke oils are not, the additive chemistry is much different. Certainly the base oil composition means something different if it is to be burned, but this doesn't automatically mean that a synthetic base oil is better in four stroke use.
>>However, I do think you're a mineral oil guy at the end of the day and biased accordingly.<<
Actually, I'm an additive guy. The right combination and in robust quantities make for better oils. If you want the *best* oil, consider a synthetic diesel oil; but I think you'll get 98% of the benefit from a mineral diesel oil.
>>Put a bottle of 10W-30 mineral oil and a bottle of a good grade synthetic 10W-30 in the freezer-better yet get some dry ice. Monitor their temperatures down to -40F or so. The mineral oil will be jelled at this point(at least it was the last time I did it)----yet they have the same 10W rating?<<
Sorry, but this is why the SAE viscosity grade system was created. An SAE 10W means that the oil will allow satisfactory cranking speeds in the vast majority of engines for starting down to -25C. It also means that the pumpability will be satisfactory down to -30C. Using a 10W-30 at -40F (which is also -40C) is the wrong application. Further, scientific studies have shown that pour point does not predict adequate engine protection, which is why pour point is not part of an engine oil's performance specification. Lastly, a mineral oil typically "jells" at a temperature slightly below the point at which it is so viscous the engine wouldn't crank fast enough to start. A synthetic oil doesn't "jell" until very low temperatures, true enough, but it still gets very viscous. So even though the synthetic 10W-xx could be pumped (and the mineral 10W-xx may not be able to) neither oil had allowed cranking speeds to be high enough to start - if they were both true 10W-xx oils. This is exactly why the tests and specifications were set up; if something different happens, then the oil marketer has mislabeled the oil and their 10W-xx should really be called a 5W-xx or 0W-xx oil.
>>why is it that Vipers, Corvettes, Porsches, & Mercedes all come with a factory fill of synthetic.<<
First, they come with oils that meet a certain spec, like GM's 4718M, not necessarily with synthetic oils. This article shows that non-traditional synthetics are 4718M qualified. http://www.1st-in-synthetics.com/articles5.htm Second, the reason is for volatility control and fuel economy- it's hard to get both. If you want fuel economy, you need thinner oils, but thinner oils are more volatile and would escape the crankcase via the PCV system. So GM came up with their 4718M specification - which only allows 5W30 and 10W30 grades. Even though a 15W40 could meet the requirements, it could not claim 4718M performance because it's the "wrong" viscosity.
Steve and everyone, it's hard to make sure nobody is getting offended in this type of one-at-a-time conversation, and I'm certainly not meaning to. But there are interesting and non-obvious reasons for oils being the way they are. Hopefully there's a little fact here or there that helps.
Well this thread is getting a little worn, but just a little more.
I realize that 2-stroke and 4- stroke oils are different. One consumable-one not. I was merely making an analogy. In the 2-stroke case, even though rated the same, there was obviously no comparison. As for 4-stroke oils--I believe the base stock synthetic, because of it's molecular structure, to be more stable than a base stock mineral oil. I do agree there are big differences in additive quality, but from all I've read, good synthetics carry a high grade additive package.
I agree about the manufacturer spec being what determines what is permissable. In fact, it is those very specs which allowed synthetics in vehicles when they were being ostracized by everything petroleum in the mid 70's. It took many years for synthetics to get a foot hold. Mobil 1 helped because of brand name recognition. Again, I simply don't believe it is only marketing when a manufacturer recommends a synthetic. They could just as easily recommend a mineral oil and be paid for it as well.
I don't think it gets cold enough where you live to do a real test of starting and cranking power. Here, we routinely see chill factors from -20 to -50 below F. I can't speak to the Group III oils, but a regular 10W-30 mineral oil against a 10W-30 synthetic in these temperatures wouldn't have a chance.(remember that's all there was many years ago) I've seen it too many times to believe differently. Please don't go into the classification thing again. I have seen 10W synthetics work well in these temps.
----BTW we just got our first 18-24" of snow last night and today. A friend of mine 10 miles from here just told me he has almost 30" in his yard on the level. The schools close for a day, but that's about it. We had 275" last year.
I see one of the pages you refer to above is an Amsoil site. I wanted to stay away from brand names and talk synthetics in general, but what the heck. It is Amsoil I have used for the last 26 years. They were the first and I believe the best. I use synthetic everything car oil,2 cycle oil(injector and 100-1), automatic transmission fluid, gear lube, & grease. I am currently using the Series 2000 0W-30 in the Viper. Oil consumption is down from the 10W-30 I was using(quart every 2200 miles or so). I run the car relatively hard(or did till last Saturday) and have used a ½ quart in 3000 miles. This oil has a drain interval of 35,000 miles with proper filtration. I think I will run it about 6000 miles in the Viper. In my pick ups, I routinely run 20-25000 miles between changes using 10W-30 Amsoil oil and air filters. That's over 200,000 miles the last 5 years.
Many of the statements you have made in earlier posts are not necessarily fact. I would guess there's some subjective opinion in there coming from your background. I'm sure if their was a synthetic guru with a similar background on this board, he would enjoy sparring with you.
Finally -----The FAQ page you refer to states the 'at this time the technical community can't decide which is better' For my own knowledge, I am going to research additives a little closer. Maybe you could send me some links beside Lubrizol(I'm already there)
PUT HOT COCO IN THE GAS TANK.
Wow, what a discussion about oil. Tom and I have had some off-line converstaions in the past about this as well. My perspective is clearly from the automotive engineer point of view and not of oil companies. When Tom is talking about base stock for the oil he is talking about North America base stocks. Our testing clearly has shown long term advantages for ASEA (the European oil specification equivalent) higher grades like A1 oils. The increased base stock cracking results in reduced molecule lengths which have demonstrated significantly improved shear life. In high output engine (high speed, high load) and high temperatures it is the shear effect that breaks down the base oil and leads to reduced oil life. This is the primary factor behind mileage limits. For one engine that was designed for both North American and European applications the following life limits were established:
North American (API) mineral oil 7,000 miles
European (ASEA A1) mineral oil 12,000 miles
European Synthetic (note same blend US and Europe) 18,000 miles.
Note this all with the same engine. This is a personal sore point as I wanted to pursue use of an ASEA A1 equilvalent oil in the US to allow for extended oil change intervals but could not achieve it due to North American oil companies unwillingness to market equivalent oils at reasonable prices. Yes synthetics would achieve this but for standard vehicles they do not meet the "readily available and reasonable price" requirement. Note also that the ASEA A1 oil classification achieves improved fuel economy at the same viscosity as other mineral based oils. The US seems to have a lowest common denominator, one oil class for all perspective.
Regarding oil temperature, oil temperature capability is the limiting factor in todays engines. Sealing system materials have advanced beyond the temp limit for the oil. As most of you are probably aware mineral based oils are not capable of withstanding temperatures greater than 315F or extended periods of more than 300F without significant deterioration. Note some oils such as synthetics may increase this range but the auto makers must design their systems to the minimum limit. Therefor engines that would over achieve these are normally outfitted with oil coolers. In hot weather trailer tow situations I would expect that most modern engines approach the 300F oil temperature.
Regarding viscosity it would be useful to show the full temperature spectrum from -40 to 300F in comparisons, rather than at 2 specific points. I believe that would support the claims of extreme low temp capabilities of synthetics over mineral oils.
I do not want to turn this into an auto manufacturer versus oil company discussion. I merely wanted to point out that each has different perspectives and wants. And also point out that environmental pressure in Europe has resulted in significant shifts in oils, especially with regard to oil change intervals.
Thanks for the great explanations. I've read your oil FAQ a few times and done some more research, too. Currently, we run Mobil DelVac-1 in both our cars. The cars are run HARD during ViperDays events. Both cars run great and use no oil. The stronger of the 2 has dyno'd at over 440 RWHP with only K&Ns. smooth tubes and a Borla cat-back. Torque was over 480 ft lbs!!! Don't tend to think we are losing any HP there... Remember that auto manufacturers cannot tell you to use ONLY a certain product unless they GIVE you that product for free- they can only tell you a product has to meet certain standards - ergo - the recommendation for Mobil 1, but the true requirement to meet some API ratings....
I appreciate your educated responses and the lack of dire predictions without any proof. (Skipwhite)
Keep the good info coming.
I guess if your making comparisons between M-1/castrol syntec/etc and petro there is not the great degree of difference Im talking about.The oil Im refering to is Amsoil. There specs are drasticly different than other syn. brands.I have studied the specs. on oils and what they mean in real use applications. I have spent 20 years using this product in my buissness putting it to the test in severe conditions.Amsoil publishes spec comparisions against other syn. oils and they blow the others away. No one ever makes a comparision against Amsoil.They just live in the shadows of them.Synthetic oil is a very big threat to the petro industry I believe. They would like to see you keep on changing your oil every 3000 or so miles from now on.Auto makers arent to crazy about an oil that lasts 35 thousand miles and triples the the life span of your power train.Tom I hope you see my point. By the way my cummins owners manuel for my 2000 Western Star truck says change differentil oil every 50-K miles if using 75-90 petro gear lube,Then it says if using synthetic gear lube change every 250-K miles.It also says use different weight rating according to climate zone UNLESS USING SYNTHETIC GEAR LUBE.My extended warrenty is voided if I use anything but syn. gear lube. in the rear ends. But after warrenty is out I can put what ever I want in.What do you think I would do? Hope Im not offending you Tom, Just stating my case................
But wait, there's more!
Here's one big reason why I persist with this post - information. It is isn't the base oil that shears down and makes the oil behave thinner, it is one of the additives called a viscosity index improver. Deteriorating the base oil only leads to thickening (oxidation, nitration, loading with soot, etc.) Shear (breaking apart the VII molecule) is what leads to thinner oil.
Even the API SL category has changed US base oils, due to the volatility and engine requirements for the 5W-30 and new 5W-20. There are Group II, II+, and Group III base oils, and some Group IIIs are performing like synthetics. (See Castrol references in earlier posts.)
No question that European ACEA A1/B1 oils are higher performing (and higher additive treat rate!) than API performance level oils. But again, to put it into perspective of earlier discussions, there is a huge additive package difference besides the base oil differences. One reason is that most oils aren't only A1 (gasoline performance) but also B1 (passenger car diesel performance) so they need additive systems that can handle either. That makes for a robust oil, a more expensive oil, and now you can see the difficulty in marketing something like it in the US, where the average consumer has been trained to look for what has become basically a commodity product.
Here's a challenging question for the car company guys, Ron- why not increase the sump size? That would instantly decrease oil temperatures, extend oil drain life, reduce oil consumption worries, at little cost to the OEMs, I would think.
High oil temperatures, whether the oil can handle it or not, have collateral damage - running 300F in the oil means coolant temperatures have to be close by, so the coolant is near the boiling point (isn't it 284F or 264F with a 15lb cap?) Also, the intake charge is heated, so the engine is highly prone to knock or would get large amounts of spark retard. To be fair, there are requirements that all API oils must pass that run at 300F for the entire test.
It would be far beyond the typical consumer's understanding to to the viscosity at all temperatures, but the system we have isn't that bad. The multigrade values, the 15W and the 50 are indeed only two points, but on the correct graph paper, the dots make a straight line. Maybe what's needed if low temperatures are the issue is information about how low a temperature a 10W or a 5W is good for. Those that live in Florida and Canada can then make their choices smarter.
Steve makes an important point about additive packages- that good oils with synthetic base oils usually have a good additive package. And that's why it's harder to attribute the resulting performance to one or the other, since you get both together.
I'll have to look on a map, Steve, but here it gets down to "only" the low single digits; perhaps 0F. And sure, I notice the 15W40 makes things a little slower. Maybe you could revisit your experiences based on ambient rather than wind chill temperatures. Since engines don't have sweat glands, the wind chill only cools them to the ambient temperature quicker, but doesn't have the evaporative cooling to make them lower than ambient temperature.
Hee, hee, you had given yourself away as an Amsoil guy, so the article seemed appropriate. Yes, I also try to remain brand-less (how am I doing, anybody guess?) and so maybe I challenge what I consider to be marketing claims rather than technical claims. And I have thick skin, so whenever you think it's my opinion, point it out and I'll find the data.
Additive links? Here's a site of a past co-worker, he's got them all listed already.
Additive Company Links
I have been running Mobil 1 10w-30 as recommended and Mobil 1 filter and changing oil and filter every 1500 miles is this a waste of money. Should I go longer?
Jamie I would say your on the right track......