[Mgs] ZDDP (Again)

[PaulHunt73]

My thoughts exactly ever since I started looking into this about four years 
ago, which is why I just don't trust it.  Castrol GTX even though sold under 
it's original API spec only seems to contain half the zinc and phosphorus it 
did originally.  I've seen a letter purporting to be from Royal Purple 
stating that RP XPR 10W40 has over 1500-1600 ppm of ZDDP and goes on to say 
"we could take all of the ZDDP out of our engine oils and still have 4 times 
the wear resistance of even the VR-1 oil due to our Synerlec additive 
technology".  It which point the whole thing degenerates into farce.  What 
was apparent when I was looking is that Diesel oils, if they had a petrol 
API rating as well as a Diesel, contained more ZDDP than oils with only that 
petrol rating, but that was also under review.  In the UK I use Comma Sonic 
which is to API SL but has .2% zinc and .19% phosphorus 
http://www.commaoil.com/productsguide/file/367670c3e9a411571893883585a71863

PaulH.


----- Original Message ----- 
> Can someone explain how Valvolene's VR1 meets the (claimed) SN/SM/SL
> rating, yet contains the claimed 0.14/0.13 Zinc/Phosphorus? As far as
> I can see, any oil rated higher than SL MUST contain less than .12%
> Zinc and Phosphorus.