Join Date: Jul 2003
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Location: SE PA
The definitive Castrol TWS 10W-60 thread
First some history on 10W-60 TWS
. This is a quote (with his permission) from a PM discussion last week with Doug Hillary on BITOG. He worked for Castrol at the time and he's written at least one book on automotive lubricants:
"This lubricant started off in the late 1970s as Castrol R Synthetic 15W-50 - it was castor oil based, red in colour and with that lovely exhaust odour. I worked with Castrol in refining the lubricant until the mid 1980s. It was used by me in a variety of high utilisation engines, diesel, petrol, flat, inline, vee, aircooled - almost the lot! I used it in some gearboexs etc too
It changed from a castor base around 1980-81
The lubricant as "Formula R Synthetic" had a long history with race teams around the World in the 1980s and 1990s. It won at LeMans a number of times commencing in the 1980s with the likes of Sauber Mercedes and was used by Porsche and BMW. It was marketed by Castrol as a Race oil and recommended for a wide range of "sporting" applications including Porsche. It became a "quck fix" for high temp applications and where fuel dilution was common
So very early on it had serious development by a series of Race Team engineers from the major Euro Manufacturers. These people are on site of course and experimentation with formulations is widespread and very thorough
As Castrol and BMW have a very serious Technical liaison now that goes back many years I believe that BP-Castrol created a special formulation version of the 10W-60. This was to solve some "issues" for BMW and to ensure a unique FF lubricant. I can't confirm the details but IIRC this occurred about the time of the BP takeover of Castrol when all Contracts were up for grabs
This type of thing is not uncommon. It happens with FF lubricants were extra chemical dosing is needed for specific reasons which include the metallurgy in a certain engine family - and even in gearboxes and etc as you will be very aware of"
In case you're missing the timing here, the BP take over of Castrol and then subsequent making a custom formulation of 10W-60 for BMW was in 1999-2000. The e46 M3 came out in late 2000 as a 2001 model year. Making the connection?
From Castrol's web site
RESEARCH AND DEVELOPMENT
Castrol is committed to working together with BMW, using lubricants technology to improve the performance of new models. This brings benefits to BMW drivers worldwide.
More technical info from BITOG:
a friend from BITOG sent me this info. Thought you guys would appreciate the insights.
1 - ALPINA worked on its formulation with Castrol/BMW
2 - It suits DI engines due to its viscosity namely HTHS @ 5.4cP
3 - It has an excellent Pour Point (-42C) which is much better than some lighter viscosity lubricants
4 - It was progressively developed from 1997 as a low chlorine/minimised phosphorous lubricant
Its part ester/part PAO base has been constructed over a period of 30 years on an excellent development path
In its early life is was used by Sauber-Mercedes winning at LeMans and in Formula 1 engines (Ford-Cosworth). It was used at one point by Porsche in some race engines. It was also used here in the V8Supercars ZF six speed gearboxes with great success
It is a bit like a heavy weight version of M1 0W-40 or Delvac 1 5W-40 in its formulation.
Some thoughts by one of the M engineers:
I was fortunate to attend a BMW sponsored track day a few years ago and they had a factory engineer/advanced driver from Germany in attendance.
I and others were able to pick his brain through out the day and the 10W-60 spec oil of course came up. The real concern of most was the use of that oil in our Canadian winters.
He justified it's use in M engines when specified, for track days like the one we were currently enjoying and high speed driving when oil temps can easily exceed 150C.
He was asked to define high speed driving and he said sustained speeds in the 250 kmh range. When asked, what if you don't track your M3 and never exceed 150 kmh? He honestly found the question puzzling and answered "why would you buy an M3 if you didn't plan on driving it fast; there are other less powerful but more suitable 3 series choices available"? I told him my dentist who had an M3 was typical of most M3 owners in N/A. He likes the performance looks of the car, the status of it but he's never driven it faster than 140 kmh and typically cruises in the 120 kmh range. He found this 'poser mentality' very strange but agreed an M3 driven in such a manner would never see higher oil temps than a regular 3 series BMW and consiquently the regular BMW spec' oil would be more appropriate.
So, per BMW M engineers, If you're a poser you can run other oils. If not, stick with the TWS
Recently posted by YemThwee on why BMW's recommendations have changed, for those of you who claim this was not designed for the engine as it wasn't originally speced:
Originally Posted by YemThwee
After countless oil threads, endless arguments, and much entertainment, I was still none the wiser about WHY, in March 2000, BMW changed their S62 oil recommendation from 10W60 TWS / Edge to the 5W30 that they recommend for all their other models.
Bored of this endless cycle, and being the curious sort, I decided to call BMW and get an answer straight from the horses mouth. I explained the endless debate on the m5board, and the guy I dealt with got quite interested himself, as he is a huge E39 M5 fan. Over the last couple of weeks, on our behalf, he has contacted Customer Services in Germany, the engineering dept at Bracknell (BMW UK HQ) and he even ended up talking to the design team in Munich. Quite a few calls went back and forth between us. In the end we pieced together what we could from all the emails and conversations he had had, and came to a very simple conclusion.....
BMW engineers were adamant that the S62 was developed along side TWS and no other oil should be used. (year was not an issue as far as they were concerned - it is 10W60 or nothing, whether it is pre, or post March 2000.
However, as is far too often the case these days, the BMW marketing team had different ideas to their engineers. The problem was, that back in '98 & '99, there were a growing number of complaints from customers, who were finding they needed to top up the oil rather more often than they had expected. This in itself was not a huge issue - the problem was that they could not just grab a bottle of oil when they filled up with fuel. They had to keep making special trips to the dealer, and this may be many miles away. This was bothering people a lot.
BMW did 2 things in response to these complaints:
The engineers tried changing the piston rings. BMW will not provide any documentation regarding the ring change or why it was done - this is just from conversation. Assuming it was an attempt to reduce oil consumption, then from what I can gather from the board, they only had limited success.
The marketing team however, ignored the engineers and simply changed the oil recommendation to match the rest of their products. This meant you could now pick up a bottle of oil at the motorway service station and feel good that you were using the "recommended oil" and you hadn't had to stockpile it at home, or go out of your way to a dealer on your way to the in-laws for thew weekend.
We could not extract anything in writing from ANYONE at BMW in the UK or in Germany regarding the reasons why all this had happened. People at BMW were even quite reluctant to talk about it to the customer service guy, and were keen to know why he was digging all this up. All I did manage to get in writing was this -
Dear Mr MacDonald
Thank you for contacting BMW Customer Information.
I have contacted BMW Munich on your behalf and they confirmed to me that Castrol developed this special oil with BMW "M" specifically for these engines. The running characteristics and performance are reliant on this oil being used.
Normally engine changes (piston rings) denote new engine model numbers, however this has not happened in this case. Therefore the recommendation would be to continue to use the TWS oil only as instructed. BMW UK also confirmed to me that in March 2000, more oils were tested for the vehicle but they did not have any information on piston rings affecting the oil type required.
I am sorry that I have been unable to find any further information on the subject and thank you for your patience whilst I researched this matter on your behalf. Please do not hesitate to contact me if I can be of any further assistance.
BMW Group UK
Customer Information Advisor
Bracknell RG12 8TA
So there you go. Make of that what you will.........
A PDF from Castrol, stating that the TWS
formula is specific to M engines: http://www.lindvigs.com/obioban/EDGE_10W-60.pdf
BMW SIB which was the official oil change over document and the official BMW reasoning: http://www.lindvigs.com/obioban/BMWEngineOils.pdf
Some points I'd like to add.
-As seen above, engine may have indeed been originally designed for castrol 10W-60, and marketing took it away... briefly
-oil technology has indeed changed in the last 10 years. Fun fact: the TWS
spec has not remained constant-- they have been updating it
-the castrol engineers work on the TWS
spec WITH BMW M engineers. M engineers have input on what goes into. Now, admittedly they're focusing most of that development effort on the newer M cars, but I'm sure they're not doing it at our expense
-IMHO, redline products ARE HORRIBLE
. Their fluids feel great at first, and then quickly degenerate. Even if I did venture from TWS
, Redline would be my absolute last choice in aftermarket oils. (if you're wondering, I'd probably go with Motul).
At the end of the day, I'm sticking with the TWS
because there's no compelling reason to use anything else. It's plenty cheap, it provides good protection, and it works in every environment I drive the car. If I lived somewhere where it got absurdly cold I'd probably switch for the winter months, but other than that I just don't see any possible benefit to switching. What are you hoping to GAIN in exchange for the gamble you're making? (and yes, it certainly is a gamble, as it's absolutely more risk than the tested, proven, factory recommended TWS
How many cars get to have an oil specifically designed for them? Very few! In TWS
, we are getting a very high quality oil that should cost MUCH more than it does, for a very reasonable price. ANYTHING you switch to is going to be for a more generic application, regardless of it's quality.
Edit: Just found this on another site. I think people considering switching should have a good read over this and realize that was have an oil specifically tailored to our engine. That's not very common, and something I certainly want take advantage of:
What Goes Into an Oil: AdditivesWhat Goes Into an Oil: AdditivesWhat Goes Into an Oil: AdditivesWhat Goes Into an Oil: AdditivesWhat Goes Into an Oil: AdditivesWhat Goes Into an Oil: AdditivesWhat Goes Into an Oil: AdditivesWhat Goes Into an Oil: Additives
Although the basestock of an oil will be a major determining factor in the lubrication quality of an oil, chemical additives play a major part in making sure that it does all that it is supposed to do. In fact, the chemical additive package of an oil is just as important to insuring the quality of a lubricant as is the particular basestock used.
The chemical additive package of an oil is designed to perform a number of tasks and each task is performed by a particular type of chemical. The quality of the chemicals used and the manner in which they are blended plays a large part in determining how well the additive package does its job.
As you can well imagine, as the quality of the additive chemicals increases, so does the price. In addition, proper blending takes a great deal of research. This requires much time and, again, money. Therefore, manufacturers will, of course, charge more for motor oils which contain a high quality additive package than those with lower quality additive packages. They simply can't afford not to.
As mentioned above, each chemical within an oils additive package plays a different role in boosting the beneficial properties of it's host lubricant (basestock). Each of those roles is described below along with a brief description of the types of chemicals that are used to accomplish those roles.
Additives Improve Viscosity Characteristics
Basestock lubricants have a certain temperature range over which they will flow adequately. The wider this temperature range the better. Cold temperature starting requires an oil that will flow well at low temperatures. The higher engine temperatures of todays smaller, higher revving engines requires an oil that will perform well under high temperature conditions.
Viscosity Index Improvers
As a lubricant basestock is subjected to increasing temperatures it tends to lose its viscosity. In other words, it thins out. This leads to decreased engine protection and a higher likelihood of metal to metal contact. Therefore, if this viscosity loss can be minimized, the probability of unnecessary engine wear will be reduced. This is where viscosity index (VI) improvers (sometimes called viscosity modifiers) come in.
VI improvers are polymers that expand and contract with changes in temperature. At low temperatures they are very compact and affect the viscosity of a lubricant very little. But, at high temperatures these polymers "explode" into much larger long-chain polymers which significantly increase the viscosity of their host lubricant. So, as the basestock loses viscosity with increases in temperature, VI improvers negate that viscosity drop by increasing their size.
The higher the molecular weight of the polymers used, the better the power of "thickening" within the lubricant. Unfortunately, an increase in molecular weight also leads to an inherent instability of the polymers themselves. They become much more prone to shearing within an engine. As these polymers are sheared back to lower molecular weight molecules, their effectiveness as a VI improver decreases.
Unfortunately, because petroleum basestocks are so prone to viscosity loss at high temperatures, high molecular weight polymers must be used. Since these polymers are more prone to shearing than lower molecular weight polymers, petroleum oils tend to shear back very quickly. In other words, they lose their ability to maintain their viscosity at high temperatures.
Synthetic basestocks, on the other hand, are much less prone to viscosity loss at high temperatures. Therefore, lower molecular weight polymers may be used as VI improvers. These polymers are less prone to shearing, so they are effective for a much longer period of time than the VI improvers used in petroleum oils. In other words, synthetic oils do not quickly lose their ability to maintain viscosity at high temperatures as petroleum oils do.
In fact, some synthetic basestocks are so stable at high temperatures they need NO VI improvers at all. Obviously, these basestocks will maintain their high temperature viscosities for a very long time since there are no VI improvers to break down.
Lubricant Stability Maintained by Additives
Lubricating oils are not only prone to viscosity loss over time. They are also susceptible to breakdown due to contamination and/or oxidation which decreases the useful life of an oil. Additives are often used in order to inhibit the susceptibility of a basestock to this breakdown over time.
Detergents and Dispersants
Contamination due to sludge and varnish build-up within an oil can often be one of the limiting factors in determining the useful life of an oil. If this build-up can be minimized and contained, the life of the lubricating fluid can be increased. Detergent and dispersant additives are utilized for this purpose. There is some debate as to whether those additives considered to be detergents actually "clean" existing deposits, but at the very least they aid dispersants in keeping new deposits from forming.
Detergent and dispersant additives are attracted to sludge and varnish contaminants within a lubricant. They then contain and suspend those particles so that they do not come together to form deposits. The more contamination within the oil, the more additive that is used up. Since synthetic oils are less prone to leave sludge and varnish, these additives are used up much more slowly within a synthetic lubricant.
Some oils use ashless dispersants which are more effective at controlling sludge and varnish contamination than metallic dispersants. In addition, some ashless dispersants are actually long chain polymers that serve a dual purpose as VI improvers in multi-grade oils. Detergents are all metallic in nature.
Although necessary for engine cleanliness, detergents and dispersants can have a negative effect on the lubricating fluid within your engine as well. Sometimes, these oil additives can play a part in oil foaming. In other words, air bubbles are produced within the oil. These air bubbles, if not neutralized, will reduce the lubricating qualities of the motor oil. Anti-foaming agents such as small amounts of silicone or other compounds are used to control this phenomenon.
As you probably can guess, oxidation inhibitors are additives that manage to reduce the tendency of an oil to oxidize (chemically react with oxygen). They are also called antioxidants. There are two types:
One type of antioxidant destroys free radicals. In fact, you may have heard of antioxidants which can be found in vitamin supplements. In human beings, free radicals can cause cell damage and even cancer. Antioxidants neutralize these free radicals in the body to reduce the chance of them causing any damage. In motor oil they serve a similar function by destroying free radicals that aid in the process of oxidation.
The other type of antioxidant reacts with the peroxides in the oil. These peroxides are involved in the process of oxidation. Reaction with the antioxidant removes them from the oxidation process, thereby lessening the chance of motor oil oxidation.
Oxidation inhibitors also serve one more very important purpose. They protect against bearing corrosion. You see, bearing corrosion is caused by acids within your motor oil. These acids come from combustion by-products, but they can also be the result of oxidation. So, by inhibiting motor oil oxidation, antioxidants also protect against bearing corrosion.
Additives Improve Engine Protection
Although antioxidants prevent the acids caused by oxidation, they do nothing to neutralize the acids caused by combustion by-products. Therefore, other additives must be used in order to keep these acids in check and to protect engine components from their effects.
Some corrosion inhibitors are designed to protect non-ferrous metals by coating them so they cannot come in contact with acids within the oil. Other corrosion inhibitors are designed to actually neutralize the acids within the oil. The acid neutralizing capability of an oil is expressed by its Total Base Number (TBN).
Since diesel engines tend to have more acid build up within the oil, these oils generally have TBN between 9 and 14. Gasoline oil TBN levels are normally lower at 5 to 8. Generally, higher quality oils and/or those that are designed for longer drain intervals will have higher TBN numbers.
Synthetics will almost always fall at the high end of the scale for both gas and diesel oils, while petroleum oils will typically fall at the low end of the scale because they are changed frequently anyway. There is normally no need for petroleum oils to have high TBN values.
Even with the best of oils there is always the possibility of metal to metal contact within an engine, however slight. Some oils (especially premium synthetics) will cling to metal surfaces better than others, but engines that are left to sit for any period of time may have very little lubricant protection at start-up. This is especially true in cold conditions when petroleum oils do not pump well. To minimize the engine component wear caused by these situations, anti-wear additives are used.
Additives such as zinc and phosphorus will actually coat metal surfaces forming a protective barrier against wear. They do not eliminate the metal to metal contact. They simply minimize the wear that occurs during those instances. Typically, zinc and phosphorus come as a package called ZDDP (zinc dialkyl dithiophosphate). They work together.
Additives Help to Alleviate Compatibility Issues
Some additives are included in an oil to deal with compatibility issues between the oil and certain engine components. For instance, as was mentioned when discussing basestocks, there are certain types of lubricant basestock that will cause seals and gaskets to swell or to shrink. These effects have to be minimized. Sometimes basestock blending will alleviate the issue, but in other cases additives might be used.
Moreover, depending upon the particular application the oil will be used for, some additives may be left out while others may be left in. For instance, in order to meet API SJ through SM fuel economy requirements, oils are now formulated with special friction modifiers (reducers). However, these friction modifiers are typically left out of motorcycle oils and higher viscosity oils that are not used for their fuel economy benefits anyway.
Seeing the Big Picture
When considered as a whole, lubricant oils are comprised mainly of basestock fluids. Only a small percentage of the oil is comprised of additive chemicals. However, as is evident from the information presented above, additives can play as important a role as the basestock fluid itself.
A high quality basestock blended with a cheap additive package is still junk oil. A high quality additive package added to a cheap basestock is no better.
Of course, a motor oil as a whole is far greater than the sum of its parts. In other words, even a high quality basestock combined with a high quality additive package isn't necessarily going to yield a premium oil. The company manufacturing the oil has to know how to correctly blend those basestocks and additives so that they perform well together.
If you want your engine to last, don't be cheap - Your vehicle wasn't. Spend the extra to get a high quality oil. If you're going to stick with a petroleum oil, don't by "John Doe's No-Name Cheapo Oil". It might meet API specifications, but that doesn't mean much.
The same goes for a synthetic oil. If you're going to spend the bucks, why purchase synthetic oil from a manufacturer that's only been blending synthetics for a few years? Wouldn't you rather purchase a synthetic oil from a company that's been doing it for a while.
As an example, if you were waiting to have triple bypass surgery, who would you want operating on you - the first year eager-beaver medical resident or the guy who's been doing it for 15 years and gets a write-up in a different medical journal every week for his expertise in the field? Do I even have to ask? There are companies out there that have been manufacturing synthetic lubricants for over 20 years.
Don't you think they probably know a little more about it than some company that just started selling synthetic oil a few years back to increase their bottom line? If you want the better oil, generally you can purchase it from the company that's been doing it the longest. Of course, that's not always true, but it is generally a good rule of thumb.
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Last edited by Obioban; Tue, Dec-22-2009 at 04:44:50 PM.