<VV> Best Oil & STP

[James Davis]

An Internet search shows the the concentration of Zinc in STP (blue 
bottle) is 165 ppm and phosphorous  225 ppm as of a 2009 independent  
test.  STP is a viscosity index improver.   It makes oil thicker at all 
temperatures until it breaks-down.  Deterioration starts at about 270 F. 
   One thing that is never discussed, is the amount of calcium in the 
base stock oil.  Calcium is an antagonist to phosphorous and as such 
defeats much of the good phosporous does.  Calcium is a main ingredient 
in oil detergents.  If an oil is high detergent, it requires more ZDDP 
to counteract the detergent qualities.  Too much ZDDP can actually 
increase the wear in an engine.  No engine oil manufacture am familiar 
with had approved any additive to their oil.

By the way, the screwdriver trick works with castor oil, also but I 
wouldn't add it to my oil either.
Jim Davis

On 1/4/2012 5:24 PM, J R Read wrote:
> Odd that the oil topic came up just after a little "experiment" at work.
>
> A few days ago, one of the guys had Regular oil 5W30, Mobil1 5W30, A bottle
> of STP and a flat edge (relatively heavy) screwdriver.   He dipped the blade
> of the screwdriver into each and had several of us (taking turns and
> cleaning hands and screwdriver each time) holding the screwdriver tip
> between thumb and forefinger with palm above and handle of screwdriver
> hanging down.  Easy to do with nothing on the blade AND with oil on it AND
> with Mobil1 on it.  But, even though it was more viscous to the touch, it
> was virtually impossible to keep the screwdriver from falling when it was
> dipped into the STP.
>
> Now, this makes me think that it might be a good idea to add some (how
> much???) STP at oil change time.  I looked at their web site and could not
> find any specifications for STP.  I was looking to see if there was a
> statement about ZDDP content, but was unable to find anything.
>
> Does anyone on VV have a clue as to ZDDP content of STP and what would be an
> appropriate ratio of oil (either type) to ZDDP if adding at oil change time.
> I'm not condoning this, just trying to investigate at this point.
>
> Thanks.
>
> Later, JR