Weird gas mileage change
06-27-2006, 11:34 AM
#46
Rennlist Member
So, is the consensus to stay away from the Mobil One 0W-40 that Porsche now recommends for post-73 911/930s? It sounds like the pros are sticking with the good old 20W-50 or, maybe, the Mobil One 15W-50.
Does anyone run Amsoil 20W-50 in a 930? Results, or opinions?
Does anyone run Amsoil 20W-50 in a 930? Results, or opinions?
06-27-2006, 11:45 AM
#47
Rennlist Member
I would have no qualms running Amsoil Severe Duty 20w50 or their V-Twin formulation. I have used the V-Twin formulation and it's great- it had the highest TBN of any oil I tested. There is nothing wrong with m1 0w40, say for winter service, but for hotter summer months I prefer the 15w50 or 20w50 V-Twin M1.
08-21-2006, 01:03 PM
#48
OK guys. I did find 12 quarters of Valvoline Maxlife for $1 / qt after rebate and did the switch from Castrol 20W50. MaxLife is the high mileage version but I think my '85 with 173K qualifies as "high mileage" 
)
It is a fairly clean test case as I have MPG records for 4 years and the car has had GTX 20W50 almost it's complete life and 'only' GTX since 100K. I have a really good handle on oil consumption which is 1200 miles for first quart and 800 miles on second. OCI is 2700-3000 miles since 100K, 7500 before 100K.
I'm getting 5 more quarts today (free after rebate) to keep it topped off and will carefully watch oil consumption and MPG.
)It is a fairly clean test case as I have MPG records for 4 years and the car has had GTX 20W50 almost it's complete life and 'only' GTX since 100K. I have a really good handle on oil consumption which is 1200 miles for first quart and 800 miles on second. OCI is 2700-3000 miles since 100K, 7500 before 100K.
I'm getting 5 more quarts today (free after rebate) to keep it topped off and will carefully watch oil consumption and MPG.
08-22-2006, 05:24 PM
#49
Burning Brakes
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glenncof ,
Alright, post result latter glenncof .
Just replaced oil. What I see is that oil was not that dirty but dark. Mileage stay similar, yes, better than before. When I play with the dark oil, I feel it's loose. It's not as sticky/yelly as the old Castrol GTX. Well maybe my imagination.
Alright, post result latter glenncof .
Just replaced oil. What I see is that oil was not that dirty but dark. Mileage stay similar, yes, better than before. When I play with the dark oil, I feel it's loose. It's not as sticky/yelly as the old Castrol GTX. Well maybe my imagination.
08-22-2006, 06:17 PM
#50
Team Owner
OK guys. I did find 12 quarters of Valvoline Maxlife for $1 / qt after rebate and did the switch from Castrol 20W50. MaxLife is the high mileage version but I think my '85 with 173K qualifies as "high mileage" )
02-08-2007, 06:38 PM
#51
Results:
I'm at 2700 miles now on the Maxlife and getting ready to change. As expected there was zero improvement in gas mileage.
The oil consumption was more consistent, losing 1qt in 1st 1000 miles and 1 qt in 2nd 1000 miles as opposed to GTX doing 1300 then 800.
I know this is very, very subjective but the engine sounds more mellow (???). With the GTX it always sounds better after changing oil which means it must sound worse before. The Maxlife seems to stay consistent. I'll check this after the next change back to GTX.
<Sorry for delay I had to drive my truck for 3 months due to tranny rebuild.>
I'm at 2700 miles now on the Maxlife and getting ready to change. As expected there was zero improvement in gas mileage.
The oil consumption was more consistent, losing 1qt in 1st 1000 miles and 1 qt in 2nd 1000 miles as opposed to GTX doing 1300 then 800.
I know this is very, very subjective but the engine sounds more mellow (???). With the GTX it always sounds better after changing oil which means it must sound worse before. The Maxlife seems to stay consistent. I'll check this after the next change back to GTX.
<Sorry for delay I had to drive my truck for 3 months due to tranny rebuild.>
02-08-2007, 06:43 PM
#52
Rennlist Member
In my testing I found maxlife to not have sufficient Zn or P - it was in the 600 ppm. If you want a high mileage formulation, Castrol GTX HM is a much superior formulation with the proper Zn and P levels.
02-08-2007, 11:53 PM
#53
Rennlist Member
Originally Posted by Charles Navarro
In my testing I found maxlife to not have sufficient Zn or P - it was in the 600 ppm. If you want a high mileage formulation, Castrol GTX HM is a much superior formulation with the proper Zn and P levels.
02-09-2007, 10:15 AM
#54
Rennlist Member
The new formulation of Rotella sas "Triple Protection". Be sure, once I find it here I will test it. The Rotella site mentions reduced Phosphorus, but no mention of Zinc. Their site also shows the original Rotella T "multigrade", so maybe they will continue selling both, but i'm willing to be it will become hard to find the old formulation.
02-09-2007, 10:25 AM
#55
Rennlist Member
I found this on the lubrizol web site, explaining the changes between the API CI-4 and new CJ-4 standards: http://www.lubrizol.com/CJ-4/faq.asp
The P limit is reduced from .14% (1400ppm) to .12% (1200ppm). There again is no mention of Zn, so I believe for now, the new Rotella is an acceptable replacement for the old one. Another great thing is that the new standard actually sets a limit on sulphur (requiring better base stocks) in the oil and lowers the limit of ASH, both great things IMHO.
I still would recommend a syn over dyno, even Rotella, but for those who don't think a syn is for them, Rotella is still a good option in the 15w40 category.
The P limit is reduced from .14% (1400ppm) to .12% (1200ppm). There again is no mention of Zn, so I believe for now, the new Rotella is an acceptable replacement for the old one. Another great thing is that the new standard actually sets a limit on sulphur (requiring better base stocks) in the oil and lowers the limit of ASH, both great things IMHO.
I still would recommend a syn over dyno, even Rotella, but for those who don't think a syn is for them, Rotella is still a good option in the 15w40 category.
02-09-2007, 12:16 PM
#56
Rennlist Member
Thanks, Charles, but choosing an oil is more difficult than choosing whom you wish to marry. Is there a website that tests all popular oils and rates them? I've been on Amsoil's website and would not mind running that stuff...
02-09-2007, 12:32 PM
#57
Rennlist Member
No, short of what I did to check Zn and P levels, the closest to a real performance test would be a study done by amsoil against various motorcycle products. I believe this most closely resembles the stresses seen in an aircooled engine. It's a good read: http://www.amsoil.com/lit/g2156.pdf
02-09-2007, 02:52 PM
#58
Rennlist Member
Charles, you said you recommend a synthetic over dino oil. Does Mobil 1 15w50 have the additive that Pete Zimmerman suggested I add to my Valvoline 20x50 VR1 oil? I think it is EOS (not sure I got it correct).
02-09-2007, 10:53 PM
#59
Rennlist Member
Yes, M1 (both the 0w40 and 15w50) has enough Zn and P. It is on the fence whether or not VR-1 needs the EOS, since it has enough Zn and is a little low on the P (but equal to the levels in the new CJ-4 standard ~1000ppm P).
I actually just got back today from analysis some back to back tests on castrol gtx (and brad penn racing 20w50 & royal purple 20w50 max cycle for comparison). With 800 controled miles on each sample with a complete oil system flush and new filter, previous oils should not have contaminated the results as best as we could test. Engine was a 185hp 2.3L Porsche 914 engine with no external oil cooling, 4.5 qt oil capacity.
In 800 mi, Castol GTX's tbn dropped from 7.57 to 5.61, down 26%. Viscosity was low for a 20w50, but still higher than SAE 30wt. Starting Zn levels dropped by 30%. P levels dropped by 12.2%. (note that the Zn dropped faster than the P, which leads me back to think that the lowered P levels aren't as critical as the Zn in VR-1). Levels of Moly dropped by a whopping 70%.
I was very suprised to say the least. That said I don't think I'll recommend to my customers going more than 3000 mi on Castrol GTX.
In comparison, Brad Penn Racing 20w50 although starting with less Zn and P than GTX, retained more of it. The level of P was unchanged, and Zn dropped only 10%. Levels of magnesium and sodium (a characteristic of the pennsylvania crude and why it works so well) only dropped about 20%. Levels of iron, copper, and aluminum were about 50% lower. Viscosity even remained in spec for 20w50.
The Royal Purple retained the highest viscosity of the bunch, even after 800 mi it was thicker at temp than either of the other oils new. Zn and P levels were the highest, P remaining unafffected and Zn falling by 19%, but still remaining above the levels found in a virgin sample of m1 15w50. TBN also remained unaffected.
On another engine I sampled, a 170hp 1883cc Porsche 356 engine, with ~3000 mi the Royal Purple used in that engine, exposed to almost constant 230-240F oil temps, the TBN dropped only to 6.93 from the 8.5ish starting point, and retained it's viscosity in spec for a 20w50. Again, only about 4 qt capacity here. Zn and P levels too remained above the levels most oils start with.
Our samples of m1 and amsoil were contaminated and could not be testd unfortuneatly. The RP had about equal levels of aluminum and copper in it as the Brad Penn, and had iron levels just between the Castrol and Brad Penn.
I have some more results to mull over, but I summed them over for the most part.
I actually just got back today from analysis some back to back tests on castrol gtx (and brad penn racing 20w50 & royal purple 20w50 max cycle for comparison). With 800 controled miles on each sample with a complete oil system flush and new filter, previous oils should not have contaminated the results as best as we could test. Engine was a 185hp 2.3L Porsche 914 engine with no external oil cooling, 4.5 qt oil capacity.
In 800 mi, Castol GTX's tbn dropped from 7.57 to 5.61, down 26%. Viscosity was low for a 20w50, but still higher than SAE 30wt. Starting Zn levels dropped by 30%. P levels dropped by 12.2%. (note that the Zn dropped faster than the P, which leads me back to think that the lowered P levels aren't as critical as the Zn in VR-1). Levels of Moly dropped by a whopping 70%.
I was very suprised to say the least. That said I don't think I'll recommend to my customers going more than 3000 mi on Castrol GTX.
In comparison, Brad Penn Racing 20w50 although starting with less Zn and P than GTX, retained more of it. The level of P was unchanged, and Zn dropped only 10%. Levels of magnesium and sodium (a characteristic of the pennsylvania crude and why it works so well) only dropped about 20%. Levels of iron, copper, and aluminum were about 50% lower. Viscosity even remained in spec for 20w50.
The Royal Purple retained the highest viscosity of the bunch, even after 800 mi it was thicker at temp than either of the other oils new. Zn and P levels were the highest, P remaining unafffected and Zn falling by 19%, but still remaining above the levels found in a virgin sample of m1 15w50. TBN also remained unaffected.
On another engine I sampled, a 170hp 1883cc Porsche 356 engine, with ~3000 mi the Royal Purple used in that engine, exposed to almost constant 230-240F oil temps, the TBN dropped only to 6.93 from the 8.5ish starting point, and retained it's viscosity in spec for a 20w50. Again, only about 4 qt capacity here. Zn and P levels too remained above the levels most oils start with.
Our samples of m1 and amsoil were contaminated and could not be testd unfortuneatly. The RP had about equal levels of aluminum and copper in it as the Brad Penn, and had iron levels just between the Castrol and Brad Penn.
I have some more results to mull over, but I summed them over for the most part.