Schaeffer Supreme 15w40 vs 10w30 in cold weather

[Patman]

I'm a bit confused after looking at the specs of these two oils in terms of cold weather performance.

They both seem to be very close in terms of how they pump at low temps, as their CCV at -25c is almost the same (4500 for the 10w30, 4877 for 15w40) but yet their viscosities at 40c are drastically different (15w40 is 108-111cst, while 10w30 is much thinner at 62-70cst) So how can the 15w40 flow almost as good at low temps when it is so much thicker on the 40c viscosity test? Different base oils perhaps?

When I am done my long term test on the 10w30 I may just go to the 15w40 to compare, as it seems like it can handle the cold weather we get here (which as I've said before rarely goes down below 0F)

I've heard it mentioned before that the 15w40 Schaeffer would actually qualify as a 10w40 and based on the numbers I believe it. Would you guys recommend the 15w40 for my daily driven and drag raced 95 LT1 Firebird? What benefits would I get with the 15w40 compared to 10w30 in terms of the additive package and long drain capabilities? I notice the 15w40 has a TBN of 10.0 compared to 7.1 on the 10w30, how are they achieving the higher TBN on the 15w40 and does it maintain it's TBN as well as the 10w30 does?

 

[MolaKule]

Here's the short answer:
Regarding pour-point and pumpability, they use more PAO in the 15W40 than in the 10W30.

tbn is determined by the magnesium/calcium detergent/dispersant additives and stabilized by the anti-oxidants, such as moly DTC, penetro, and ZDDP.

 

[G-MAN]

quote:

---

Originally posted by Patman:
I'm a bit confused after looking at the specs of these two oils in terms of cold weather performance.

They both seem to be very close in terms of how they pump at low temps, as their CCV at -25c is almost the same (4500 for the 10w30, 4877 for 15w40) but yet their viscosities at 40c are drastically different (15w40 is 108-111cst, while 10w30 is much thinner at 62-70cst) So how can the 15w40 flow almost as good at low temps when it is so much thicker on the 40c viscosity test? Different base oils perhaps?

---

The 108-111cst and 62-70cst is what you'd expect from 15w40 and 10w30 oils, respectively. Those numbers are right on the money for 40 and 30 weight oils. The 15w40 oil almost matches the 10w30 numbers because it undoubtedly has a higher VI than the 10w30.

 

[Patman]

But I have also heard that the 15w40 is actually a 10w40, since it does qualify to be labelled as a 10w based on it's CCV performance.

 

[dragboat]

Quote:
"Would you guys recommend the 15w40 for my daily driven and drag raced 95 LT1 Firebird? What benefits would I get with the 15w40 compared to 10w30 in terms of the additive package and long drain capabilities? I notice the 15w40 has a TBN of 10.0 compared to 7.1 on the 10w30, how are they achieving the higher TBN on the 15w40 and does it maintain it's TBN as well as the 10w30 does?"

If I were you with the miles on your motor would certainly swicth to the 15/40 oil. It has better HTHS numbers and a better Noak of the tough ASTM # 5800 " showing more PAO" . Those along with the higher TBN should make for a longer drain interval imo and better overall protection of a motor like you have and how you use it.
Not to take away from the 10/30 but I just think the 15/40 is a step up for a hi-performance engine. I also think it is as race worthy for some moderate road racing and the bracket racers as oil that cost much more.It is a oil worth every penny you pay for it imo and seems to get many jobs done well to include use in the old grocery getter

EDIT:
The 15/40 is on my list for the next order along with some # 148 Valve Clean that meets BMW spec.

I also must have a 30 gallon drum of the cool #256 Pure PAO single grade 30wt,,have you guys seen this oil/Data sheet and MSDS ? I am a bit surprised it is not mentioned more often.I believe it desrves a look at the possible merits of using this oil in another thread

http://www.schaefferoil.com/data/256.htm
http://www.schaefferoil.com/msds/256.htm

[ December 18, 2002, 11:44 AM: Message edited by: dragboat ]