PQIA tests five oils, including Royal Purple SL

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Thanks Tom. Royal Purple's sulfur concentration is around 4 times most oils, which validates, but does not confirm, the possibility that a sulfurized ester is used. The high detergency and moderate ZDDP concentration is not high enough to increase sulfur by 4 times.

The nitrogen comes largely from dispersants. The other 3 oils have much less dispersancy than the Royal Purple.
 
It`s a shame that RP watered down their oils (removed the Synerlec and lowred the zddp content). If you want *good* RP you`ll have to mail order the HPS version,or find some nos Synerlec.
 
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Originally Posted By: JAG
Thanks Tom. Royal Purple's sulfur concentration is around 4 times most oils, which validates, but does not confirm, the possibility that a sulfurized ester is used. The high detergency and moderate ZDDP concentration is not high enough to increase sulfur by 4 times.

The nitrogen comes largely from dispersants. The other 3 oils have much less dispersancy than the Royal Purple.


I think so too. It may be their Synerlec additive which some have said is a sulfurized ester.

Thanks Tom!
 
Originally Posted By: Tom NJ
The Royal Purple SL is quite interesting.



Does interesting mean good in this case or just different? I am currently using the Royal Purple 5W30. Yes, it is the SL rated mixture, and my car can use SL per the Owner's Manual.

I'm not knowledgeable enough to pick the numbers apart, other than TBN. And I realize that just because an oil starts with a high TBN, it may not necessarily retain it long term.

The engine does seem to be the quietest over other oils I've tried (Mobil 1 SM, PP SN, PU SM, and Castrol Syntec SM) but I'm not sure if this is real or placebo.

Thoughts?
 
Originally Posted By: CATERHAM
That's a very old (SL) RP bottle.


I have a half quart of RP SJ 20W50 :^)
 
Originally Posted By: Rand
I thought you could purchase both still?



Discount Auto Parts closest to home had a case of 5W30 SL and no more 5W30 at all. They had plenty of 10W30 SN in the new bottles.
 
Originally Posted By: Rand
also Tom you has a typo

All tests conducted on this sample meet the specifications for SAE 10W-40 and are consistent with API SL engine oil.


OOPs - will have it fixed.

Thanks!
 
Originally Posted By: CATERHAM
That's a very old (SL) RP bottle.
Interesting but hardly applicable to the current SN formulation that no longer uses the so-called Synerlec sulferized ester additive.


There will still be a bunch of the old stuff coming down the pipes for a while. My supplier has both HPS and the old SL stuff. The only surprise was that I expected the zinc levels to be a bit higher.

So, for my old truck, instead of an obsolete synthetic 10w-30, I'll probably use an antiquated dino HDEO in 5w-30.
wink.gif
 
This RP looks pretty good.
Holy TBN, Batman.
Also, highest VI, as well as lowest NOACK volatility.
Nice additive levels, too.
I guess that the very high sulfur is an artifact of the additive package?
RP SL may be better stuff than many of us have given it credit for being.
 
RP has always been an impressive oil - lots badmouth it, but there is really no reason to if you want a no-hold-barred oil...
 
Originally Posted By: dparm
High TBN again points to ester content.

How come Red Line oils dont have high TBN then?
 
Originally Posted By: dparm
High TBN again points to ester content.

Esters don't have basic behavior. The high TBN is from the high concentration of magnesium and calcium detergent combination.
 
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