20/50 Semi-Synthetic Oil - Where?

Discussion in 'Technical' started by NDSinBKK, Mar 28, 2009.

  1. At the last oil change (26K KM) on my 1150GS, we switched from dino oil to semi-synthetic. The manual and the mechanic (K. Yut, Dynamic Motors, BKK) specify 20-50 Semi-synthetic, but I have looked everywhere and only found 10-40 in semi-syn. Yut has advised that if I have to choose between topping up with 20-50 dino and 10-40 semi-syn, to go with the semi-syn, which I did today.

    I'd rather put the right thing in there - anyone seen 20-50 Semi-Synthetic for sale anywhere?

    Tks much.
  2. Mate

    i know Khun Yut for long time and he is ok and give good advice always.

    i use Penzzoil Gold 20/50 semi syntetic(Heavy duty), that can be found fron any car spare part shop
  3. Thanks for the pointer, Marco. I've tried every petrol station I've passed to no avail, but I'll try what you are suggesting. Tks and regards.

    Off tomorrow on a 3-day meander through Chacheungsao, Rayong, and Chantaburi.


  4. I had the same problem a few months ago - no more Shell Diesel Helix Plus 20/50semi synthetic. Didn't like the 10/40 option so have swapped to PTT 20/50 dino.
  5. If you read this it asserts that semi-synthetic is a waste of money. It is neither fish nor fowl. You pay for the word synthetic but get little in return.

    Better to go with fully-synthetic. But read the bit about modifiers.
  6. Did little research as well and i would not say it waist of money as guys are using semis in BMW M5 cars all the way in the Africa how ever they do recommend that it's "advisable to use "Fully" synthetic. I use “Fully” synthetic when it’s available, but that time so I took Semis, no difference for me,, how ever look interesting underlined sentence in Semi-Synthetic section.

    Im no Oil experts so i do need to relay for experts comment's and recomendations :wink:

    Here is what i found and explain all kind of oils

    I will paste it here as well so save you for an other click.

    Conventional Oil

    What is it ?

    Conventional oils are refined from petroleum crude oil that has been pumped from the ground.

    What are the inherent problems ?

    All conventional oils contain naturally occurring substances such as sulfur, sulfur compounds, reactive hydrocarbons and other materials, that can not be completely removed from the petroleum crude and thus end up in the final product.

    What happens ?

    High oil temperature in excess of 240°F (115°C) will break down petroleum oils and cause oxidation, which in turn forms deposits, varnish and increases wear.

    Low oil temperatures will cause formation of sludge, which can block oil passages.

    Very low temperatures of -40°F (-40°C) will make oil too thick to flow.

    What must be done ?

    For dependable performance and long-term engine protection in all motor vehicles in all climatic conditions petroleum oils MUST be supplemented with expensive "additives" which prolong the oil service life and reduce the wear to an "acceptable" level.

    Why is it used ?

    PRICE - it is cheap; less than 50 cents per quart in bulk and about $1.00 per quart in consumer packaging.

    Typical Motor Oil Service Life:

    3,000-mile (5,000 km) or 90 day oil changes are recommended by Oil industry and car mechanics.


    In USA 94% of consumers use conventional oil in over 188 million vehicles.

    Synthetic Oil

    What is it ?

    Synthetic oils are produced either by a chemical reaction (synthesis), severe refining or other complex chemical processes, that yield molecular uniformity and purity that is impossible to achieve through normal refining process.

    What are the inherent problems ?

    All consumer level "synthetics" are still produced from petroleum and although more uniform and better performing at the temperature extremes, they still suffer from the same problems that petroleum does. Additionally many "pure" synthetics are very poor lubricants and cause excessive wear. They also have poor solubility for additives.

    They do NOT offer extended oil service life.

    What must be done ?
    All "synthetic" oils MUST be also supplemented with "additives" which prolong the oil service life and reduce the wear to "acceptable" level.

    The "additive package" is normally dispersed in petroleum carrier oil and is blended-in, even in "FULLY" Synthetic oils at a rate of 10% to 20%.

    Why is it used ?

    Superior protection in low temperatures as many synthetics will still flow at -40°F (-40°C).

    Enhanced high temperature durability, reducing oxidation rates and wear on some engine parts because many synthetic will tolerate temperatures up to 400°F.

    Typical Motor Oil Service Life:

    Not more than the maximum, which is recommended by vehicle manufacturer – usually 5,000 to 7,500 miles or 6-month oil changes, are recommended by the producers of Synthetic Oils. (ExxonMobil, Castrol, Shell)


    In USA 4% of consumers use Synthetic oil in over 8 million vehicles
    (60% of them use Mobil 1 – ExxonMobil claim)

    Synthetic Blend Oil

    What is it ?

    Synthetic Blends, also known as semi-synthetic, use mix of non-conventional oils in combination with conventional petroleum oil.

    The "synthetic" content is usually less than 10% and sometimes as low as 2%.

    What are the inherent problems ?

    Synthetic Blends offer NO advantage to consumers as they are priced two to three times higher than petroleum, they however offer much greater profits to marketers as they are much less expensive to produce than fully synthetic oils.

    What must be done ?

    For dependable, long-lasting performance and long-term engine protection in all motor vehicles in all climatic conditions "semi-synthetic" oils also MUST be supplemented with "additives" which prolong the oil service life and reduce the wear to "acceptable" level.

    Why is it used ?

    Huge investments in advertising and promotion of Synthetics benefit the sales of Synthetic Blends as consumers do not realize that they are getting very little extra performance over petroleum at much higher per quart price.
    Typical Motor Oil Service Life:

    Same as Conventional Petroleum Oil:

    3,000-mile (5,000 km) or 90 day oil changes are recommended by Oil industry and car mechanics.


    In USA 2% of consumers use Synthetic Blend oils in over 4 million vehicles.
  7. I think MikeRust and DavidFL both have it right. Semi-syn is a bit of a waste of money mainly because it is 50%+ more expensive than a pure dino, but most semi formulations only contain 10% "synthetic" basestock. The other 40% goes right to the oil company profit margin.

    Using a good 15W/40 or 20W/50 diesel rated, or better yet, turbodiesel rated, dino is about as good as it gets for bang for the buck (or baht). And no need to worry about friction modifiers or anything since you got a dry clutch in that GS.

    If you got a hyper performance 14K revving GSXR etc and you ride it like you stole it, then the pure synth makes sense due to ultimate shear and temp stability. But that boxer motor will be plenty happy with a good diesel dino for many years to come.
  8. "dino" = petroleum-based (non-synthetic) motor oil. As in derived from dinosaurs. Not exactly the case since it really is from microscopic plankton and other organic goo.

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