Jump to content
LegacyGT.com

Rotella T6 Zinc decrease


Recommended Posts

I am hearing that the recipe has changed slightly for Rotella T6 5W-40 and it now has less zinc.

 

Has anyone heard of this?

 

Has anyone done an oil analysis with the new blend?

Link to comment
Share on other sites

I have no clue if Rotella specifically is reducing ZDDP but on the whole, I believe diesel oil is following the same trend that auto oil is, due to exhaust aftertreatment that is being installed these days.

 

I personally do not believe that ZDDP is anything more than one solution to a problem,and it is the cheapest solution (that being an EP additive). Engines that most people would perceive as needing ZDDP have been around and running for years without it.

Link to comment
Share on other sites

I was going back and forth about whether or not to reply to this again, since it's such a complex subject. Here are a few additional thoughts though. I don't think the reason why rotella does so well in turbo subies is because of the extra ZDDP. I think the main reason rotella does so well is because it has a fairly high HTHS value. Shell does not publish the HTHS number for rotella t6 5w-40, but based off some of the certifications it meets, it is thought to be at least 3.8 mPa•s.

 

So what is HTHS? HTHS is sort of like the film thickness of the oil on moving parts. Lower HTHS is great for fuel economy, but higher HTHS values are better for engine protection.

https://commercial.lubrizoladditives360.com/high-temperature-high-shear-viscosity-of-engine-oils/

 

For comparison sake, here's the HTHS of a few oils. One thing to note is last I knew, the minimum allowable HTHS of an oil was 2.6, mostly seen in 0w-20 oils. Note that 5w-40 and 0w-40 oils will generally have a higher HTHS value than a 5w-30 or 0w-30 oil.

 

Rotella T6 5w-40 – Suspected at least 3.8 mPa•s, because of some of the certiifications it meets.

Mobil 1 5w-30 – 3.1 mPa•s.

Mobil 1 10w-30 – 3.0 mPa•s.

Mobil 1 0w-40 – 3.8 mPa•s.

Mobil 1 Turbo Diesel Truck 5w-40 – 3.8 mPa•s.

 

Castrol Edge 5w-30 – At least 3.5 due to ACEA C3 spec

Pennzoil Platinum and Ultra Platinum 5w-30 – Between 2.9 – 3.5 mPa•s. due to ACEA A5 spec

Pennzoil Platinum Euro 5w-40 – At least 3.5 mPa•s. due to the ACEA A3 spec

 

Amsoil Signature 5w-30 – 3.1 mPa•s.

Amsoil XL and OE 5w-30 – 3.3 mPa•s.

Amsoil European car formula 5w-30 – 3.6 mPa•s.

Amsoil European car forumula 5w-40 – 3.7 mPa•s.

 

Red Line 5w-30 – 3.7 mPa•s.

Red Line 5w-40 – 4.4 mPa•s.

 

Castrol, Pennzoil, Havoline and Valvoline don't publish their HTHS values on their product/technical data sheets, so that's why the list is a bit limited. When I look at the list above, there is probably a difference of at least .8-.9 mPa•s between Mobil 1 5w-30 and Rotella T6 5w-40, so that might help explain why some people don't like Mobil 1 in their turbo subaru's. .8 - .9 might not sound like much, but when you consider the tight range of 2.6 - 4.4 mPa•s mentioned above, it is a pretty big step up in my opinion.

 

High amounts of ZDDP is just one aspect of an oil like Rotella. I was very active on bitog from 2004-2009. During that time, two things were very popular, high molybdenum oils and German Castrol. The funny thing is, German Castrol had 0 ppm of molybdenum in it. So what I'm trying to say is, there are many different ways to formulate a quality oil. If shell reduced the ZDDP, maybe they boosted other additives to make up for that. You can't just focus on one aspect of a motor oil, even something like HTHS like I've talked about here.

 

Couple articles that talk about HTHS and ZDDP.

http://www.redlineoil.com/news_article.aspx?id=291

 

The article below mentions that HTHS is important, but the additive package is very important as well, which is true. But again, there are other additives out there aside from ZDDP which can help reduce wear.

http://viewer.zmags.com/publication/d4e8e0b9#/d4e8e0b9/16

part 2

http://viewer.zmags.com/publication/20213322#/20213322/49

 

http://www.amsoil.com/newsstand/classic-and-vintage/articles/flat-tappet-cams-in-classic-cars/

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use