What is your favorite gear lube?
03-01-2013, 01:34 PM
#31
Rennlist Member
Sounds about the same as my setup. For the trans pump switch, I used a 3 pole switch and put an idiot light on the "off" circuit so when the trans pump is off, the light is on to hopefully prevent me from forgetting to turn on the pump. I usually just leave the pump on all the time though.
03-01-2013, 01:57 PM
#32
RL Technical Advisor
03-01-2013, 05:22 PM
#33
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Well, I'm highly biased, given that I sell the stuff (i.e. full disclosure here), but look at Millers. Here are two articles from techincal magazines about it:
Race Tech Magazine July 2009, Tiny Technology: Big Breakthrough and Racecar Engineering June 2010, Grinding Back the Gears. The same technology will be in the Bryan Herta IndyCar gearboxes next year, and in all likelihood in one of the most successful F1 teams. The BTC and WRC cars that have been using it have seen their gearbox lifespan typically double, but up to four fold in a couple of cases. Those two articles I linked get into some of the mechanism for how it protects the gearboxes.
We've had one of our customers who runs a shop start converting the older 901's from the PAG based oils to our di-ester synthetic with nanotechnology. The older PAG based stuff was used because when the transmissions came out, EP additives were not as capable as they are today, and PAG was the most capable. The PAG is not compliant with typical petroleum based stuff, but conversion can be done with a simple flush (drain, add conventinoal gear oil, run it warm for a short period of time, drain and add the good stuff). If you've got the gearbox apart and cleaned up, then you are pretty much already there.
Also, I should mention heat. Due to the NT not shearing down nearly as readily as typical MoS2 types of EP additives, the transaxles tend to run much cooler. 20-25 degrees is pretty typical for closed system gearboxes (i.e. those without an external cooler). On the F1 application, they have been repeatedly and consistently measureing a 500Watt reduction in heat put into the oil.
Race Tech Magazine July 2009, Tiny Technology: Big Breakthrough and Racecar Engineering June 2010, Grinding Back the Gears. The same technology will be in the Bryan Herta IndyCar gearboxes next year, and in all likelihood in one of the most successful F1 teams. The BTC and WRC cars that have been using it have seen their gearbox lifespan typically double, but up to four fold in a couple of cases. Those two articles I linked get into some of the mechanism for how it protects the gearboxes.
We've had one of our customers who runs a shop start converting the older 901's from the PAG based oils to our di-ester synthetic with nanotechnology. The older PAG based stuff was used because when the transmissions came out, EP additives were not as capable as they are today, and PAG was the most capable. The PAG is not compliant with typical petroleum based stuff, but conversion can be done with a simple flush (drain, add conventinoal gear oil, run it warm for a short period of time, drain and add the good stuff). If you've got the gearbox apart and cleaned up, then you are pretty much already there.
Also, I should mention heat. Due to the NT not shearing down nearly as readily as typical MoS2 types of EP additives, the transaxles tend to run much cooler. 20-25 degrees is pretty typical for closed system gearboxes (i.e. those without an external cooler). On the F1 application, they have been repeatedly and consistently measureing a 500Watt reduction in heat put into the oil.
I've run synthetic gear lube in 901 transmissions before without trouble, so I would hope it works.
03-01-2013, 06:19 PM
#34
Race Car
I may shoot Mark Bates a note, too, to see what they run. Info on his outfit - http://www.eb-motorsport.co.uk/
03-01-2013, 06:31 PM
#35
I lot of people are going to make authoritative statements about what gear oil to use in 901, 915, and 930 transmissions without understanding the differences between a Borg-Warner cone system and a Porsche balk ring system. The Porsche system needs more friction to work which is why synthetic oils are a problem.
Scott
Scott
03-01-2013, 07:25 PM
#36
RL Technical Advisor
I lot of people are going to make authoritative statements about what gear oil to use in 901, 915, and 930 transmissions without understanding the differences between a Borg-Warner cone system and a Porsche balk ring system. The Porsche system needs more friction to work which is why synthetic oils are a problem.
Scott
Scott
These early gearboxes will still work with a synthetic, however the brake bands, operating sleeves, and hub teeth simply don't last as long. One should avail themselves about prices on these components before making a decision about which type product to use.
03-01-2013, 08:08 PM
#37
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I know people have all different experiences, but our is just that the pinion shaft, input shaft bearing and ring/pinion were hurt. Thebands, puppy teeth, and everything else are just fine.
03-01-2013, 11:37 PM
#40
Matt, I am currently putting in a trans cooler in my 901. I made all the lines today. I have had good successes with the swepco 201. Last year when I installed the limited slip I found after about five laps of a sprint race low gears would be very hard to engage until it cooled down. I am hoping the cooler setup keeps it from wearing on the bearings and gears. I am pretty certain if you swith to the swepco 201 per the recommendation of gt gears you will have no problems with the trans cooler. A open diff in a 901 does not create the heat of a limited slip unless you have some serious HP. By the way put that banana in pca gt 4 and give me somemone to play with . Racing is wayyyyyy more fun then DEs.
. Racing is wayyyyyy more fun then DEs.
03-01-2013, 11:46 PM
#41
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Well said & true words,....
These early gearboxes will still work with a synthetic, however the brake bands, operating sleeves, and hub teeth simply don't last as long. One should avail themselves about prices on these components before making a decision about which type product to use.
These early gearboxes will still work with a synthetic, however the brake bands, operating sleeves, and hub teeth simply don't last as long. One should avail themselves about prices on these components before making a decision about which type product to use.
Thanks
03-02-2013, 10:46 AM
#42
Race Car
I lot of people are going to make authoritative statements about what gear oil to use in 901, 915, and 930 transmissions without understanding the differences between a Borg-Warner cone system and a Porsche balk ring system. The Porsche system needs more friction to work which is why synthetic oils are a problem.
Scott
Scott
Is the problem with synthetics limited to premature wear? I would assume that if the gear oil is too slick, the synchros wouldn't be able to slow down, and one wouldn't be able to shift. But I've not read anything about that.
Like I had said before, this is outside of my area of expertise. I think the guys at EB Motorsports are probably my best bet, as they have several early 70's 911's they race. I know they run Millers engine oils - there is actually an SAE International article that was written in July about the nanotechnology that has one of their cars pictured in the article.
Its kind of like the whole harness at DE's debate - some folks say absolutely do not run a harness without a full roll bar, other folks say run a harness if you possibly can. Everyone has opinions, but no one can actually show stuff to support their assertions.
Regardless, I'm not going to refute any of the claims made here, not trying to. However, I would say that if you are wearing out R&P gears, I would suggest the NT oils as a way to alleviate that problem. I'm trying to learn here. But I would assume that worn synchros would be preferable to broken R&P gears (I know that's the case wiht 944 gearboxes - an order of magnitude cost difference in parts, plus a full reshim of all bearings comes with new R&P - synchro replacement is quick and easy).
Thanks for the link, BTW. Interesting that I'm not finding much about PAG oils, which from what I understand were initially specified, and is what the customer I talked about earlier had the most questions about.
03-02-2013, 02:03 PM
#43
RL Technical Advisor
03-02-2013, 02:04 PM
#44
Three Wheelin'
Of course, another reminder to beware of absolute statements like:
"Synthetics are no good for Porsche-style synchro transmissions-- they are too slippery."
There are quite a few of us here in NorCal that run 915 transmissions with outputs north of 350 bhp (crank) and Red Line lubricant. I think all of these cars have 8:31 crown wheel/pinion set ups. None of these cars have transmission cooling systems. I have been running this way for over 10 years, and have not had issues with premature wear.
I have not been motivated to try Swepco for "lower "slipperiness." I have not reviewed specs or test results, but I think it is possible that the Red Line does better with temperature than Swepco. That is why the box had Red Line in it when I acquired the car.
I think it is possible for additives ("friction modifiers") to be carefully employed by manufacturers like Red Line to get to a range of "slipperiness versus temperature" that meets design specs, including some chosen for Porsche-style synchro tranmissions. See, e.g., the Red Line web site: http://www.redlineoil.com/product.aspx?pid=47&pcid=7
For performance applications, I think that the nut behind the wheel has far greater influence over transmission component life than selection of a good quality lubricant. I have been around long enough to have witnessed in person and via video quite a range of behaviors and practices when it comes to shifting a 915, as well as creating "shock loads." And in my own experience, I have been in situations where I was not as "nice" as I should have been.
901, 944-family, G50 and other transmissions are obviously different from the 915, but I am sure application-specific considerations are just as important for those designs.
"Synthetics are no good for Porsche-style synchro transmissions-- they are too slippery."
There are quite a few of us here in NorCal that run 915 transmissions with outputs north of 350 bhp (crank) and Red Line lubricant. I think all of these cars have 8:31 crown wheel/pinion set ups. None of these cars have transmission cooling systems. I have been running this way for over 10 years, and have not had issues with premature wear.
I have not been motivated to try Swepco for "lower "slipperiness." I have not reviewed specs or test results, but I think it is possible that the Red Line does better with temperature than Swepco. That is why the box had Red Line in it when I acquired the car.
I think it is possible for additives ("friction modifiers") to be carefully employed by manufacturers like Red Line to get to a range of "slipperiness versus temperature" that meets design specs, including some chosen for Porsche-style synchro tranmissions. See, e.g., the Red Line web site: http://www.redlineoil.com/product.aspx?pid=47&pcid=7
For performance applications, I think that the nut behind the wheel has far greater influence over transmission component life than selection of a good quality lubricant. I have been around long enough to have witnessed in person and via video quite a range of behaviors and practices when it comes to shifting a 915, as well as creating "shock loads." And in my own experience, I have been in situations where I was not as "nice" as I should have been.
901, 944-family, G50 and other transmissions are obviously different from the 915, but I am sure application-specific considerations are just as important for those designs.
03-02-2013, 02:55 PM
#45
Mike,
I had a conversation with your favorite transmission builder discussing this very issue. His opinion was that you needed to be double clutching on downshifts and deliberate on upshifts if you use Redline in a 915. Why? So the synchro hardware lives because Redline is too slippery to use the transmission conventionally. That's why my 915 has Swepco in it.
No matter how you slice it, synthetics are too slippery for the balk ring synchromesh system the 901, 915, and 930. This is an accepted fact. Ask Porsche.....
Scott
I had a conversation with your favorite transmission builder discussing this very issue. His opinion was that you needed to be double clutching on downshifts and deliberate on upshifts if you use Redline in a 915. Why? So the synchro hardware lives because Redline is too slippery to use the transmission conventionally. That's why my 915 has Swepco in it.
No matter how you slice it, synthetics are too slippery for the balk ring synchromesh system the 901, 915, and 930. This is an accepted fact. Ask Porsche.....
Scott