Help me decide Royal Purple ATF vs Pentosin ATF 1

[Turkeybaster115]

Hi guys, I have a ZF6hp19 transmission in my 2007 335I auto. I changed the fluid at 50K, with pentosin ATF1. Its been fine so far, but I wanted to know how you guys felt it compares with Royal Purple ATF. MSDS states that the pentosin is mineral oil based+additives, while the Royal Purple is Synthetic based+additives. Here are the specs

PENTOSIN ATF1
Density at 15 °C kg/m³ 850 DIN EN ISO 12185
Kinematic Viscosity at 100 °C mm²/s 7.6 DIN EN ISO 3104
Kinematic Viscosity at 40 °C mm²/s 38.0 DIN EN ISO 3104
Viscosity Index 171 DIN ISO 2909
Dynamic Viscosity at -40 °C mPa*s 14000 ASTM D2983
Pour Point °C -51 ISO 3016
Flash Point °C: 210

Royal Purple ATF
Kinematic Viscosity at 100 °C 7.5 cST
Kinematic Viscosity at 40 °C 32.5 cST
Viscosity Index 164 SSU
Dynamic Viscosity at -40 °C 3,852cP
Pour Point °C -51
Flash Point °C 226

It turns out the units of measure here are directly cross-comparable. So my question is this:

Which ATF would be best for year round highway use in weather with hot summers (105F), and cold winters (-10F), plus 3 full track days during the summer. (299 ft/lbs of torque at the wheels stock)

Thanks

 

[JHZR2]

If the pentosin holds the BMW approval and the rp doesn't, I'd go with the approved ATF. The rp does seem to flow better in extreme cold, but at temp both are fine.

The biggest thing I'd be looking for is viscosity retention. I'd pull a uoa of the pentosin you have in there and see how it did.

 

[Turkeybaster115]

Yes, pentosin ATF1 is on the official TE ML 11B approved oils list, where as the Royal Purple doesn't. Its also similar to synthetic based castrol transmax Z which is also 11B, in specification:

Castrol Transmax Z

KV @ 40C(cSt) 36
KV @ 100C(cSt) 7.1
cP @ -40C Approx: 8400
Density@150C Approx: 0.836
Viscosity Index Approx: 170
Pour Point(0C)Below -60
Closed Flash Point (0C): 226 C

However, I'm wondering what some people think of the difference in base oil types. also what is better higher or lower dynamic viscosity numbers in the cold? I was thinking the higher number would be better in cold because it denotes a better shear resistance?

 

[unDummy]

Its a coin toss. More important to change out the ATF in regular intervals.

RP is easy to find at various stores like M1. Ams/RL are available too.

Don't sweat the decision.
For the colder climates, and Illinois is northern enough for me to want the fluid with the best flow when cold.

 

[Turkeybaster115]

Anyone else with transfluid experience wanna chime in?