Royal Purple not so good? Gear Lube Study
04-21-2010, 11:11 AM
#1
Former Vendor
Thread Starter
Royal Purple not so good? Gear Lube Study
Here is a PDF document entitled "A Study of Automotive Gear Lubes"
Royal Purple did not fare so well, which I found really surprising. I was less surprised that the AmSoil product came out on top, since this is an AmSoil-conducted study (from 2007), so the results should be taken with the requisite "grain of salt".
I also did not care for the final scoring methodology, nor the lack of a weighting component, as some tests would be more important for racing, some more important for hauling, some more important for daily driver usage, etc.
Nevertheless, it's hard to argue the science behind the individual results of each of the tests. Also interesting that the report includes notarized affidavits attesting to the scientific methods used.
I don't know that this report is enough to compel me go drain the $45 worth of fresh Royal Purple I just put into the 941's G31. But I will most definitely be interested to try the AmSoil product when I finish the Club Sport project, and compare the use characteristics and longevity of the two.
Would love to get some feedback on this report as well!
Royal Purple did not fare so well, which I found really surprising. I was less surprised that the AmSoil product came out on top, since this is an AmSoil-conducted study (from 2007), so the results should be taken with the requisite "grain of salt".
I also did not care for the final scoring methodology, nor the lack of a weighting component, as some tests would be more important for racing, some more important for hauling, some more important for daily driver usage, etc.
Nevertheless, it's hard to argue the science behind the individual results of each of the tests. Also interesting that the report includes notarized affidavits attesting to the scientific methods used.
I don't know that this report is enough to compel me go drain the $45 worth of fresh Royal Purple I just put into the 941's G31. But I will most definitely be interested to try the AmSoil product when I finish the Club Sport project, and compare the use characteristics and longevity of the two.
Would love to get some feedback on this report as well!
04-21-2010, 11:23 AM
#2
Drifting
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I have tried a bunch of different gear lubes (Amsoil, Redline, Mobil 1, BG...). You never know which one is really "better" unless you do some sort of analysis of the drained oil to measure metal content, etc.
Based purely on drivetrain noise, my only scientific conclusion is that a particular lube oil will either work well (quieter) when the drivetrain is hot, or when it is cold, and not both. In other words, if the gears engage smoothly when the transmission is cold, then there will be more gear whine when it warms up; and vice versa.
Based purely on drivetrain noise, my only scientific conclusion is that a particular lube oil will either work well (quieter) when the drivetrain is hot, or when it is cold, and not both. In other words, if the gears engage smoothly when the transmission is cold, then there will be more gear whine when it warms up; and vice versa.
04-21-2010, 12:28 PM
#5
04-21-2010, 12:52 PM
#6
Former Vendor
Thread Starter
Anecdotally, there's some evidence to suggest that the G31 synchro-based gearboxes like the Royal Purple stuff better than other GL5s, but that could be psychological as well 
I've used both Redline and Mobil-1 in my G31s, and now Royal Purple in my newly rebuilt LSD-equipped G31 that I just put in the 941. Hard to judge the difference, but there have been some reports that the synchros seem to perform better with Royal Purple, which is why I was surprised that it fared so poorly in the above report. Part of the challenge with interpreting the stuff in the report vs. real world use is that by the author's own admission, it's left up to the reader to determine which tests are more important. Perhaps the RP stuff really is better on old worn-out synchros? Who knows. I just found it really fascinating. I'll be trying AMSoil next once I get my 931 club sport put together.
I've used both Redline and Mobil-1 in my G31s, and now Royal Purple in my newly rebuilt LSD-equipped G31 that I just put in the 941. Hard to judge the difference, but there have been some reports that the synchros seem to perform better with Royal Purple, which is why I was surprised that it fared so poorly in the above report. Part of the challenge with interpreting the stuff in the report vs. real world use is that by the author's own admission, it's left up to the reader to determine which tests are more important. Perhaps the RP stuff really is better on old worn-out synchros? Who knows. I just found it really fascinating. I'll be trying AMSoil next once I get my 931 club sport put together.
04-21-2010, 01:06 PM
#7
Drifting
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I was impressed by the Amsoil test results. I wish they sold it in stores rather than via some weird cult-like process!
It's over my head, but at times, the Redline looked like a performer, but then it would flop on some other test. The GM stuff seemed like decent quality. The Lucas stuff looks like a disaster.
It's over my head, but at times, the Redline looked like a performer, but then it would flop on some other test. The GM stuff seemed like decent quality. The Lucas stuff looks like a disaster.
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04-21-2010, 01:30 PM
#9
Former Vendor
Thread Starter
Maybe there's a reason RP hasn't done ... or published the results of ... a test 
Oops! Did I type that out loud?!
I was pleased to see how well the Mobil-1 performed, as this is what I've been using in my G31 gearboxes up until the most recent installation in my 941. I switched to RP based on some positive feedback from some other G31 owners, figured I'd give it a try. I've got enough of these gearboxes, will be worth trying the AMSoil next.
Oops! Did I type that out loud?!I was pleased to see how well the Mobil-1 performed, as this is what I've been using in my G31 gearboxes up until the most recent installation in my 941. I switched to RP based on some positive feedback from some other G31 owners, figured I'd give it a try. I've got enough of these gearboxes, will be worth trying the AMSoil next.
04-21-2010, 01:34 PM
#10
Former Vendor
Thread Starter
Acutally, the study was purportedly conducted by an independent lab:
And a little more digging indicates this about the independent lab:
SWRI's website: http://www.swri.org/
Fourteen of the most popular brands of gear lube were tested at an independent laboratory in areas such as pour point, 4-ball EP weld point, 4-ball EP load-wear index, Falex extreme pressure and many other tests used in meeting API GL-5 performance requirements and SAE J306 viscosity requirements.
The purpose of the Gear Oil White Paper is to inform consumers about the increasingly severe conditions under which differentials operate and to provide data reflecting the quality and cost differences of many popular synthetic and petroleum gear lubes. With this information, consumers are better prepared to make informed decisions when purchasing gear lubricants. All performance testing was conducted by an independent laboratory. Physical-property testing (viscosity, viscosity index, pour point and foaming after oxidation) was conducted in-house. Gear lube pricing was obtained from the manufacturers or distributors.
This no-frills study is designed to help consumers make informed decisions when selecting gear oils. There is no hype and no sales pitch -- just facts. Never before has so much information on gear oils been delivered in one easy to understand source.
The purpose of the Gear Oil White Paper is to inform consumers about the increasingly severe conditions under which differentials operate and to provide data reflecting the quality and cost differences of many popular synthetic and petroleum gear lubes. With this information, consumers are better prepared to make informed decisions when purchasing gear lubricants. All performance testing was conducted by an independent laboratory. Physical-property testing (viscosity, viscosity index, pour point and foaming after oxidation) was conducted in-house. Gear lube pricing was obtained from the manufacturers or distributors.
This no-frills study is designed to help consumers make informed decisions when selecting gear oils. There is no hype and no sales pitch -- just facts. Never before has so much information on gear oils been delivered in one easy to understand source.
Originally Posted by http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1818780#Post1818780
1) SWRI
2) Texas. San Antonio.
3) Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 12 technical divisions.
4) SwRI's Automotive Engineering (the Fuels and Lubricants Research Division and the Engine, Emissions and Vehicle Research Division) is certified to ISO 9001:2000 "Quality Management Systems - Requirements," accredited to ISO/IEC 17025:2005 "General Requirements for the Competence of Testing and Calibration Laboratories" and certified to ISO 14001:2004 “Environmental Management Systems.” The division has also achieved Ford Tier 1 status for providing engineering services and has received the Ford Q1 Quality Award.
2) Texas. San Antonio.
3) Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 12 technical divisions.
4) SwRI's Automotive Engineering (the Fuels and Lubricants Research Division and the Engine, Emissions and Vehicle Research Division) is certified to ISO 9001:2000 "Quality Management Systems - Requirements," accredited to ISO/IEC 17025:2005 "General Requirements for the Competence of Testing and Calibration Laboratories" and certified to ISO 14001:2004 “Environmental Management Systems.” The division has also achieved Ford Tier 1 status for providing engineering services and has received the Ford Q1 Quality Award.
04-21-2010, 01:47 PM
#11
Drifting
its a mix-up
some people swear by it, others say that it brought up problems (like extra noises) and stuff
I only got to do 2 oil changes and I changed transmission fluid - all with Redline - and I haven't had any weird noises or anything, and I loved how my car ran
some people swear by it, others say that it brought up problems (like extra noises) and stuff
I only got to do 2 oil changes and I changed transmission fluid - all with Redline - and I haven't had any weird noises or anything, and I loved how my car ran
04-21-2010, 02:57 PM
#14
Race Director
For the gearbox run Redline Heavy shockproof. I have been happy with it for years.
04-21-2010, 03:02 PM
#15
Drifting
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If you want AMSOIL go on line and sing up as perferred customer. If you order 4 gallons of racing oil you pay for the perferred membership on your first order. I have been doing this for 5 years never any cult stuff. I do get some paper work in the mail every so often, but I really like their oil for my 944 race motor.
For the gearbox run Redline Heavy shockproof. I have been happy with it for years.
For the gearbox run Redline Heavy shockproof. I have been happy with it for years.
