[Biturbos4] Tons of oil info (Was: Synthetic oil and coking?)

costco keman at interwolf.net
Tue Aug 30 12:13:24 EDT 2005

I would not say that synthetic impervious to coking.

You could get deep into discussions about just what IS produced with:

Hydrocarbon based oil
Ester based oil
PAG based oil

And every combination therein since all synthetics use varying amounts ...
but what you will find is that they all turn to hard crust when you get
them hot enough. Synthetic stocks do tend to resist coking more than
hydrocarbon based stocks. I think if it boils down to it though (bad pun
here) the 40 or 50 degree difference isn't going to matter, when oil cokes
up it's usually a couple hundred degrees hotter than it should be, so
really no matter what's in there it's gonna fry if it's going to fry. Does
that make sense?

You guys are gonna love this, but my fav. oil that I use in all my cars
is now Mobil Delvac 1 (Also known as Mobil 1 Truck & SUV, obtainable at
wal-mart and nowhere else that I can find for $19.88 for 5 quarts) .

It's 5W-40 weight, fully synthetic, originally designed for diesel engines
and has excellent antifoaming properties that cater well to turocharged
applications. I would strongly recommend it in the Biturbo engine. It has
much more synthetic stock in it than any other Mobil 1 oil, and does not
meet the new crippled SM oil rating that is good for catalytic convertors
and bad for longevity.

You can find out much more information than you'll ever want to read about


Just join the forums and search for M1 T&SUV or Delvac 1.

I've taken UOA (Used oil analysis) tests on my B6 with Mobil 1 0W-40 and
M1 T&SUV (Delvac 1) and the results are night and day. None of this would
really matter until, say, 200k miles ... but if you're an oil geek like
me, you might enjoy learning just what a particular oil can really do.

Does M1 T&SUV meet the 503.01 spec that our engines need? Technically, no.
Physically? Yes. M1 just hasn't passed the certifications with it but oil
analysis shows that it would pass with flying colors and several oils
which some people realy like would NOT pass.

Aforementioned Audi/VW spec sheet can be found here at my site:


FWIW: Delvac 1 used to be around $7-8/quart. Since it's been relabeled
as Truck and SUV, it's become very inexpensive and tons of people are
switching over to it with excellent UOA results in many engines.

I was originally attracted to the $19.88/5quart jug price because my B6 S4
takes 12 quarts *cough* yes THREE GALLONS of oil per change. And while I
love Redline synthetic oil .. there is just no way I'm using that every 5k

- Keman

On Tue, 30 Aug 2005, Single Malt wrote:

> Just for my own clarification, can anyone confirm that
> synthetic oil is impervious to coking?  My
> understanding (totally unfounded) is that synthetic
> oil will turn to ash when the temp reaches critical
> levels, not coke - thereby avoiding the entire clogged
> oil lines issue.
> --
> Single Malt
> '01.5 S4
> Garaged at 9200ft
> just outside Denver, CO

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