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Discussion Starter · #1 ·
Found this interesting article on Porsche's dual clutch transmissions that shows they all use Pentosin FFL series fluid:
http://www.just-auto.com/analysis/zfs-new-...s_id101268.aspx

"In fact, two separate DCT ranges or 'platforms' have been developed by ZF, both fitted with wet clutches, for use in Porsche's various longitudinal applications. The first is for use in the mid- and rear-engine sports cars (the 911, the Cayman and the Boxster), while a completely different platform has been developed for use in the larger Panamera. For each platform, two different torque options are available, with the 500N.m versions using an 'ND2015' clutch pack, and the 780N.m versions using an 'ND2216' clutch pack, both supplied by ZF Sachs......
.....In terms of the oil circuit itself, two completely different approaches have been employed for the two platforms. The 7DT45 and 7DT70 have two oil circuits, and hence two different oils; the first is Pentosin FFL-3 for the clutch and hydraulics, and the second is ExxonMobil Mobilube PTX 75W-90 for the gear-set and bevel gear. The oil levels have been kept as low as possible, to reduce churning losses for those moving parts that are immersed in oil. Conversely, the 7DT75 has a single oil circuit and a dry sump (to minimise churning losses), with an 'active lubrication system' to feed oil to each gear-set and clutch. This version uses only the Pentosin FFL-3 lubricant, which was developed exclusively for the ZF DCTs. One of the main reasons for using a single oil circuit is that clutch cooling is required at both ends of the transmission, for the main dual-clutch module and for the hang-on clutch used in the four-wheel-drive variant. This would have presented significant sealing complications had multiple circuits been chosen."

And this: "All of the 7DT transmissions were developed (and successfully tested) to use a lifetime oil fill, but Porsche decided to err on the side of caution and opted for a 90,000km oil change interval."

And 780 Nm of torque is 575 ft-lbs. Pentosin is good enough for Porsche as a factory fill, so....
 

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Found this interesting article on Porsche's dual clutch transmissions that shows they all use Pentosin FFL series fluid:
http://www.just-auto.com/analysis/zfs-new-...s_id101268.aspx

<snip>

.....In terms of the oil circuit itself, two completely different approaches have been employed for the two platforms. The 7DT45 and 7DT70 have two oil circuits, and hence two different oils; the first is Pentosin FFL-3 for the clutch and hydraulics, and the second is ExxonMobil Mobilube PTX 75W-90 for the gear-set and bevel gear.

<snip>
There was another blurb in that piece that's interesting...

Conversely, the 7DT75 has a single oil circuit and a dry sump (to minimise churning losses), with an 'active lubrication system' to feed oil to each gear-set and clutch. This version uses only the Pentosin FFL-3 lubricant, which was developed exclusively for the ZF DCTs.


Interesting that they used two oil circuits where the application allowed (the 7DT45/7DT70) but a single oil circuit when crunched by packaging (the 7DT75). Be really interesting to see a cut-away showing the "active lubrication system" on the 7DT75 to compare to the GR6.

Claude, have you seen anything on what's different between FFL3 and FFL4 and why Porsche/ZF didn't just use FFL4 like BMW, etc? Wonder if FFL3 is a better choice for the GR6 than FFL4?
 

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^^^That is what I was wondering. It seems the GT-R owners who adopted Pentosin have opted for FFL4. What is the difference between FFL3 and 4? Is it simply a difference of viscosity or are they completely different formulations?
 

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Interesting article thanks for posting.

The Sport Plus mode also includes a launch control function, which allows the driver to build the engine speed to maximum before releasing the brake for an exceptionally quick getaway. When this happens, the transmission oil is circulated over the clutch much more quickly than normal, to prevent it from overheating.
How many launches can be done on the 911 before it needs to cool off?
Do the GTR borg warner clutches also get increased lubrication under Launch?
 

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Discussion Starter · #6 ·
Recommendation I got direct from Pentosin was that FFL-2 would be fine for the GT-R, and that they had recommended FFL-4 to tuners who wanted something better than OEM, as this was their latest generation fluid. If using FFL-2, then it was recommended to replace it at 90,000 km. Also stated was that FFL-2 was not as good as FFL-4. And the FFL-4 is a life time oil for the M3, the 335i and the Z4, all sports cars. No mention from them about FFL-3 for the GT-R. And this in terms of it's high temperature performance:

"We vex the FFL-4 for 192 hours at 170°C by bringing in air. It is still okay after this treatment. But this is an aerobic treatment whereas in the gear box the FFL-4 sees an unaerobic atmosphere most of the time. If you take an hour of this lab test and estimate that it is equivalent with an hour of the car running at 200 km/h you get a milage of 38400 km. But obviously one hour at 170°C under air stands for more than 1 hour at 200 km/h. According to BMW it is 5 hours at 200 km/h."
 

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Recommendation I got direct from Pentosin was that FFL-2 would be fine for the GT-R, and that they had recommended FFL-4 to tuners who wanted something better than OEM, as this was their latest generation fluid. If using FFL-2, then it was recommended to replace it at 90,000 km. Also stated was that FFL-2 was not as good as FFL-4. And the FFL-4 is a life time oil for the M3, the 335i and the Z4, all sports cars. No mention from them about FFL-3 for the GT-R. And this in terms of it's high temperature performance:

"We vex the FFL-4 for 192 hours at 170°C by bringing in air. It is still okay after this treatment. But this is an aerobic treatment whereas in the gear box the FFL-4 sees an unaerobic atmosphere most of the time. If you take an hour of this lab test and estimate that it is equivalent with an hour of the car running at 200 km/h you get a milage of 38400 km. But obviously one hour at 170°C under air stands for more than 1 hour at 200 km/h. According to BMW it is 5 hours at 200 km/h."
Not a lot of information on the Pentosin site, however the "spec sheets" for FFL 3 and FFL 4 seem very close. FFL-3 talks about it being specifically for Porsche and ZF gearboxes, while FFL-4 says its specifically for GETRAG boxes. Is the GR6 more closely resemble the GETRAG or ZF double-clutch design?

The FFL-2 specific reference is for Audi/VW, and it seems to be a bit of a different beast. Viscosity is a bit different (Kinematic Viscosity @ 40C is 36.3 mm2/s for FFL-2 vs 34.7 mm2/s for FFL-3, viscosity index is 173 (FFL-2) vs 168 (FFL-3). Pour point for FFL-2 is-51C vs FFL-3 at -54C. No boiling point listed for FFL-2 but is "> 200C" for FFL-3

So why the 3 different fluids if, as has been suggested before, FFL-4 is appropriate in for any DCT box? Certainly be interesting to better understand which of the three designs and clutch packages (Audi/VW vs ZF vs GETRAG) that the GR6 most closely resembles...
 

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When given the option, though, Porsche used a GL spec oil for the gearset. While any oil will work for lubricating gears (truly, honestly, no kidding, Honda used to spec 10W-30 for its manual transmissions), only certain fluids will work for clutches AND gears at the same time. Under ideal circumstances, GL based fluids are used for gears (no matter what kind), and hydraulic compatible fluids are used for clutches (ATF type fluids, Pentosin, Nissan GR-6 "special").

The real difficulty is Pentosin keeps their design process very proprietary. No one knows for sure what the long term effect of using these fluids in our gearboxes will do. But, heck, nobody knows about long term for WillAll or Dodson either. I'd really like to see an oil analysis from a Pentosin using gearbox.

Shawn
 

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I'd really like to see an oil analysis from a Pentosin using gearbox.
Shawn
I have been running FFL-4 in my car for about the past 9,000 miles. (Changed from OEM at 18,000.) Would now be a good time for an analysis Shawn? What would the process be? (I am not an "oil geek" and have never submitted anything for analysis before.)

Matt
 

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I have been running FFL-4 in my car for about the past 9,000 miles. (Changed from OEM at 18,000.) Would now be a good time for an analysis Shawn? What would the process be? (I am not an "oil geek" and have never submitted anything for analysis before.)

Matt
www.blackstone-labs.com

Now would be an excellent time for an analysis. While not 100% guaranteeing that you are getting protection, an oil analysis WILL detect a badly chosen lubricant. Lots of dissolved metal indicates poor protection, and one can even detect syncho wear (due to excess copper from the brass synchronizers). The best analyses also produce a filtergram in addition to a spectrogram, but a basic spectrogram is a cheap and way to tell if you are WAYYYYY off, or at least in the ballpark.

You simply drain a sample and send it off. You might need to wait for the next change, unless you are regularly "cracking" your tranny drain plug for other reasons.

It requires at least one ounce, and they send a container that will hold three.

I think the community would LOVE to see some of your results.

Shawn
 

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I think the community would LOVE to see some of your results.
I'm planning on changing front and rear diffs as soon as my washers / gaskets order arrives, so I'll drain a little tranny fluid at the same time. I'll keep everyone posted.

Matt
 

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I've been running Pentosin FFL4 now for almost 10k miles. Will be doing a flush and refill in the next month or so, so I'll be sending a sample off to Blackstone then.

Definitely improves driveability/shifts... they are much quicker, smoother, and more crisp. I thought it was just the usual "placebo effect," but another local owner who has been using GR6 for over 20k miles just switched over to FFL4 and said he felt an immediate improvement. In fact, like me, he used to drive in R mode almost all the time with GR6, but since the change, rarely feels the need to as the shifts are so smooth in regular mode.

I don't track, but for spirited everyday driving, the car just feels so much better on the FFL4. I'll post the Blackstone report after my tranny flush.
 
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