ZDDP in Amsoil: good isn't it?! (another 'Don' topic)

[MarkSanne]

I stumbled upon some oil threads on the interweb and found some interesting statements:

Comparing Amsoil to Royal Purple is like comparing apples to oranges.
Amsoil 0w30 is not API certified, whereas Royal Purple 5w30 is.

It really is not fair to compare the two because Royal Purple is following the standards set forth by the API, where Amsoil has decided to "break the rules" and produce a product that has too much ZDDP (zinc-dialkyl-dithiophosphate) in it. It is the excess ZDDP that gives Amsoil the better test results, particularly in wear tests. However, the increased levels of ZDDP can also lead to premature emission control device failure, hence the reason the API sets limits on it.
Some people will say that is a risk they are willing to take, just be aware that there is that risk. You need to decide what is more important to you, using an API certified oil like all the manufacturers recommend, or use one that is not API certified and risk premature catalytic converter failure.

ZDDP and other extreme pressure additives are surface modifiers. They modify bearing and journal surface characteristics to allow lubricants to develop more "oiliness" (an old term) or lubricity and reduce the tendency to scuff and gall under heavily loaded boundary lubrication situations. Camshafts and lifters in high speed engines definitely fit this category due to the high velocities and accelerations required to open and close valves many times per second.

My conclusion from what I've read so far:

The ZDDP additive, which is very good for the engine, is now used very limited for API approved oils (Amsoil SSO is not API approved if I'm not mistaking). The point to NOT (or limited) use of ZDDP is that catalytic convertors can be harmed.

The questions that arise:

- the ZDDP apparantly does some very good things for engines, esp. older engines (I've read many topics on rebuilt car/bike engines that used the API approved oils that didn't last very long because of the lack of -enough- ZDDP). So... is it true that Amsoil still has a large(r) amount of ZDDP's in it compared to API approved oils?

- what is true on this brakedown of catalytic convertors? (as I've read quite often the VR4's in the UK have a hard time getting thru MOT, does this have something to do with it or are the UK laws on emissions very though?)

[bradc]

Don't have a cat, I'm happy

The SSO oil is a new oil, I don't think anyone in the UK is running it, and getting them to pass emissions has always been very hard in the UK anyway.

[MarkSanne]

Don't have a cat installed myself either (just for MOT's it's there), but just curious about how this kind of stuff works.

And about the SSO: I'm gonna order a few 5L cans of the new SSO oil and some other Amsoil oily goodies tonight, yippie

[amsoil]

This is a very very big subject that touches every area and aspect of the oil industry. I will answer it the best I can ,off the top of my head , so there may be an area or two that isn't perfect.
Amsoil unlike other oil companies is family owned and sets out to make the very best oil it is possible to make, this is how a small (relatively) business can survive and thrive. It will buy the very best base products from whoever has them and will change suppliers if there is better on offer elsewhere. This is a very critical starting point as it allows Amsoil the flexibility the Multi Nationals just cant have, they cannot , darent, go to their competitors for 'x' because what they have is not as good; would look good in the press I'm sure!
This leads to the API testing, which the Multi Nationals back for what will become clear in a minute. The individual tests cost about 1/3 million I am led to believe. So the bigger you are the easier this is to handle. The Muti Nationals generally sit on their laurals and generally using their own products, and the cheapest combinations necessary to meet a given standard, make the very same oil for long period irrespective of improvements that could be made. They are actually made to a price Amsoil makes continuous improvements, it has this thing about producing the very best, being top on each of the 10 recognised international tests. Every change would necessitate the retesting of the product for API purposes. (another 1/3 million not to mention the appx 6 months this would take) And of course some times updates happen faster than the API could test anyway. I could cynically suggest that if a supplier made a product 'unavaliable' to Amsoil then they would be forced to reapply for API testing with the 6 month lead in and cost, perhaps you can recognise that this could lead to a smaller business being totally controlled and to loose its freedom to go its own way.
This should now be painting a picture.
The ZDDP bit is very similar. Whilst it would be correct to say that ,all things being equal, the more ZDDP there is in your oil the more likely you are to have premature cat failure. But all things are not equal. The testing evaluates oil by amount of ZDDP with a safe maximim for cats survival using an 'average' oil as a base line. (I think this is correct rather than worse case senario) Amsoil turn around and say that there oil is not 'average' and that their tests show that their oils put out less ZDDP than others that have passed. They still however have too much ZDDP to pass the Muli Nationals backed API test. Amsoil follow by saying that its the oil being burned off that causes the ZDDP to be in the exhaust not the quantity in the oil. Amsoil has the lowest volitility of all oils so it follows that less is burned off and the emissions are therefore low, test our oils . The API just says Amsoil has too much ZDDP in it Full Stop.
So your choice really, do you want the very best oil that can be made, that has lots of the expensive ZDDP in it to prevent wear and protect your investment and which although expensive initially lassts longer and can actually pay for itself and save you money, wont harm your cats but doesn't have API certification because Amsoil have been at war with the API for years. or do you want the alternative. Your car your money your choice

[bradc]

a simple one line "it's better" would have sufficed Well done though, and thanks for another great post

[miller]

simple solution...decat

[MarkSanne]

Thanks Don, exactly the kind of response I hoped for. It's good to make these kind of statements / explanations to the 'public' as much is said about these things by people not knowing what they are talking about (like what I said on other forums).

[Beastlee]

That reminds me, I must get a de-cat pipe!