Dex III thinner than DexVI

Status
Not open for further replies.
G

GMorg

Joined
Jan 29, 2006
Messages
2,435
Location
Mizzou-land
Recently I posted the viscosity of PetroCanada DexVI and Amsoil ATF over a range of temperatures. I did the same calculations today with Mobil1 Synthetic ATF which is a DexIII fluid approved for the "H specification". I was pleasantly surprized to see that this DexIII fluid is actually less viscous at low temps than the DexVI approved fluid. All temps are degrees C. All viscosity units are cSt.

Code:


temp amsoil ATF petrocanada Mobil1 Synthetic ATF

-40 8820 9535 4708

-20 1074 1052 762

0 237 220 200

20 77 70.2 73.6

40 33.5 29.8 34

60 17.4 15.4 18.5

80 10.4 9.1 11.4

100 6.8 6 7.6

120 4.8 4.24 5.44


 
So, any guesses on wether we are seeing a difference in base (PAO vs Group III) or is Mobil using more VII's. Pour point on Amsoil ATF is -52C and on Mobil1 is -54C.
 
I have added Redline D4 to the table:

Code:


temp Amsoil ATF PetroCanada Mobil1 ATF RedlineD4

-40 8820 9535 4708 5111

-20 1074 1052 762 798

0 237 220 200 205

20 77 70.2 73.6 74.3

40 33.5 29.8 34 34

60 17.4 15.4 18.5 18.4

80 10.4 9.1 11.4 11.2

100 6.8 6 7.6 7.5

120 4.8 4.24 5.44 5.36


 
Don't overlook the additive package. That is a primary part of the Dex VI spec improvement.

I'm just guessing that the PetroCanada and M1 are both GIII bases.
wink.gif
 
Pablo, I made one graph with 4 lines (viscosity on log scale). If you need something else, let me know. Notice how difficult it is to differentiate between Amsoil ATF and PetroCanada DexVI.

ATFviscosity.jpg
 
Ah. Discussion solved. Thank you VERY much.

Any of those four fluids would pretty much be identical in real world viscosity related performance. Really cold extreme edge goes to Redline ATF and M1 ATFas it has in the past. (Nothing new).

As for what each oil company is using for a basefluid - anyone's guess! It is interesting.......
 
Toss in some more numbers. RoyalPurple Max-ATF, Valvoline ATF+4, and Pennzoil multivehicle ATF have pretty decent info on their websites that you should be able to calculate/compute with. I also love to see how other Dexron-VI's compare. Conoco, Schaeffers, Cam2, and Pennzoil, have datasheets that you can also work with.
 
Pablo wrote: "pretty much be identical in real world viscosity"

While I agree for the most part, keep in mind that a log scale can be deceptive. At -40C, the PetroCanada DexVI is nearly twice as viscous as the Mobil1 product. At -20C, the PetroCanada DexVI is about 50% more viscous.
 
Below are numbers for Pennzoil DexIII(H)/Mercon, that's enough for me for now. If others want to add data, please feel free.

Code:


temp Pennzoil

-40 6779

-20 940

0 225

20 77.4

40 34.35

60 18.2

80 11.0

100 7.25

120 5.14


 
Volvohead wrote: "Don't overlook the additive package. That is a primary part of the Dex VI spec improvement."

I understand that the GM/PetroCanada collaboration led to a GM approved additive package. However, I thought that the specs were performance based and that the major changes in those specs were in heat/oxidation and viscosity stabilities. Can anyone offer any addtional info? Does GM now require a formulation spec instead of performance only specs? A formulation spec would create some real legal issues.
 
I doubt there is an exclusive additive formulation spec, and if there is one, it would likely be freely available to blenders as the approved "recipe". Otherwise, there would be problems.

But I do understand the additive package in the Dex VI to be far more robust than that in mainstream mineral Dex III(h) formulations. Whether the existing premium synthetic grades of Dex III are as robustly designed, I do not know. I also do not know how that will impact on the viscosity curves as the fluids age in service. I fully expect Dex VI to be more stable than III, however. As we all know, the conventional III's thin out at 100c in a hurry.

But no matter how you frame it, the performance bar has been significantly raised under Dex VI. I'm looking forward to using it in our next 850 flush.
 
It's not a formulation spec but if you take a look it specifies the approved additives, and at the moment it seems that there is only one. However, since there seems to be a growing number of DEXRON-VI fluids I would assume that the additives are available to anyone.
On the low temperature issue I agree with Pablo in saying that in the real world those 'differences' are not an issue.
 
I looked at cold viscosity a little more for other DexIII and DexVI products. To my surprize, DexIII fluids are "thinner" than DexVI in the -20C to -40C range. I cannot say that I have made an exhaustive comparison, but I have not been able to find a DexIII that the is "thicker" than DexVI in this temp range. Above zero, all DexVI fluids are "thinner" than DexIII. This may be due to the higher shear stability requirements for DexVI that may result in less tolerance for VIIs.

As for additives, the only reference that I can find for a performance characterisitic that is not related to stability/degradation is that DexVI fluid specs appear to be more stringent in a test for pitting.
 
Are you taking actual fluid measurements? or are you just calculating the viscosity using formulas and manufacturer data sheets?

I just don't see how mineral Pz DexIII is thinner cold then DexVI:
http://pennzoil-quakerstate.com/Tech/Pds...issionFluid.pdf

http://pennzoil-quakerstate.com/Tech/Pdsheet/DomesticMarketing/Gear&Transmission/pdf/ATF4.PDF

http://www.pzlqs.com/Tech/Pdsheet/DomesticMarketing/Gear&Transmission/Pdf/dexronvi.pdf

http://www.pzlqs.com/Tech/Pdsheet/Domest...issionFluid.pdf

Just compare the above OEM numbers @-40.
 
I was calculating the values, so there will be a significant error on the cold end of the scale. However, I just looked at the Pennzoil products that unDummy listed. DexVI is thicker than the mutipurpose ATF!

The multipupose ATF which includes DexIII (H), -40C measured, 8,600 cP
DexVI, -40C measured, 12,030 cSt I don't know the density of this product at -40C, but I would estimate that the DexVI would be at least 10,000 cP.

The DexIII(H)/Mercon product is 17,200 cP. So, this DexIII product is measured as thicker than the DexVI. So, I now know of one. I assume that there are others. I am still amazed that the trend is still that DexVI is thicker than DexIII in extreme cold.
 
I have done some more looking. There are more "thick when cold" DexIIIs than "thin when cold" DexIIIs. I haven't found enough DexVIs to know much. A list of actual measurments as provided by the manufacturers is below. They are listed by name, then viscosity at -40C. Units are noted most are cP. With at least two exceptions, most are "approved" DexIII formulations.

Mobil1 synthetic ATF, 5190 cP
Mobil multi-vehicle ATF, 12000 cP
Mobil ATF D/M, 16670 cSt

RedLine D4, 5200 cP

Amsoil ATF, 9326 cP

Kendall DexIII/Mercon ATF, 14400 cP
Kendall VersaTrans ATF, 8600 cP

Mystik Power DexIII/Mercon ATF, 17500 cP

Conoco DexIII/Mercon ATF, 18000 cP

76 Super ATF, 17000 cP

UniLube, 18730 cP

Shell DexIII/Mercon, 17200 cP

GulfPride Dex/merc, 17500 cP

Esso Merc/Dex III, 9500 cP
 
Mineral DexronIII and ATF+3 have pretty pathetic cold performance. Actually, only obsolete not popular anymore Type-F(some as high as 50000 cP) is worse.

Typical DexronIII/Mercons/ATF+3's range from 15k-20k cP at -40.
MerconV, usually a synth blend, improves it by requiring the spec at originally 12000cP or from what I understand now ATF+4, one of the earlier full synth OEM ATF(mostly group III), improved on the MerconV by spec'ing even better cold flow performance, or maybe its just possibly a side effect of quality baseoils. Its usually
If you look at the DexronVI specs, most brands' cold weather performance are no better then Mercon-V. I understand that the fluid has a new fancy longer life HFM additive and newer AW/EP additives. But, I just don't see DexronVI as something so special. And, I can't understand why they want so much for it when compared to the boutique synthetic ATFs, the multi-vehicles ATFs, or ATF+4.
Also, GM has a super full synthetic DexronIII. Its called Transynd. Anyone want to compare DexronVI to TES-295?

Until ATF UOAs and VOAs(looking into additive packs) show up here, I personally don't care for all the fuss on how superior DexVI is.
 
unDummy wrote: "I personally don't care for all the fuss on how superior DexVI is."

Currently, I agree with this statement. However, I will specify that my position reflects a willingness to change out some fluid every now and then. I don't have enough information to come to conclusions for the "fill for life" strategy.

As for TES-295 fluids, they appear to be little thinner than PetroCanada's DexVI at -40C. Castrol TranSynd and Mobil Delvac Synthetic ATF are each 8400 cP and Cognis EMGARD 2805 is 8600 while PetroCanada's DexVI is 12030 cP. All four values are measured (as opposed to extrapolated) and were supplied by the manufacturer.
 
Status
Not open for further replies.
Back
Top