Castrol Full Synthetic 5/w50

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Doktor_Bert

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Located some data... Noticed that the 5/w50 Castrol has 870ppm Calcium whereas the Mobil 1 15/w50 has 2460ppm. The 5/w50 has 1468ppm Magnesium whereas the Mobil 1 15/w50 has 15ppm. Why such a difference in the formulation for oils both in the 'SM' rating????
 
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You want thoughts? The engine is specced for 5W20 or 5W30. You are off the reservation with 5W50. It is not a bad oil, and I have used in in my aircooled 911, but unless I am missing something, it is not for you.
 
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I've used it a few times and it's my favorite oil,runs VERY a smooth,especially at wot. I'd use it exclusively if Walmart sold it in five quart jugs. I just will never pay $10 a quart for motor oil.
 
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Originally Posted By: aquariuscsm
I've used it a few times and it's my favorite oil,runs VERY a smooth,especially at wot. I'd use it exclusively if Walmart sold it in five quart jugs. I just will never pay $10 a quart for motor oil.
Of course it runs "smooth." The question concerns whether it is adequately, efficiently, effectively lubricating the engine. The manufacturer of the Ford does not seem to think so. I am less familiar with the Nissan VQ, but willing to bet that it's not quite the best choice there either, when looking at mfr specs. Loosening Aircooled 911's are a different story, and I have made the mistake in the past of using 5W 30's.
 

Doktor_Bert

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Originally Posted By: TomYoung
You want thoughts? The engine is specced for 5W20 or 5W30. You are off the reservation with 5W50. It is not a bad oil, and I have used in in my aircooled 911, but unless I am missing something, it is not for you.
You know I am fascinated by those that still maintain an engine is 'built' for a certain weight oil, when engines still use .001" per inch of journal diameter oil clearances, as they have since the 1950's and beyond. GM Engineer Gerry Thompson stated that the factory considers only two criterion for oil viscosity selection: 1. The coldest climate the car is likely to be delivered to. 2. CAFE contingency My question was about the difference in formulation between Mobil 1 15/w50 and the Castrol. All other questions of 'suitability' I leave to our dynometer and track testing. Thanks....
 
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Originally Posted By: Doktor_Bert
Located some data... Noticed that the 5/w50 Castrol has 870ppm Calcium whereas the Mobil 1 15/w50 has 2460ppm. The 5/w50 has 1468ppm Magnesium whereas the Mobil 1 15/w50 has 15ppm. Why such a difference in the formulation for oils both in the 'SM' rating????
Nothing in API SM or SN specifications control Calcium and Magnesium content. These are additives that determine the TBN of an oil, and are up to the discretion of the blender, depending on how long they are designing the oil to last. For high performance gasoline engine applications, I prefer all-Calcium detergency. Castrol has been changing their formulations over the past few years to increase Mg and decrease Ca. Mobil has also been using more Mg in some of their gasoline oils, such as EP and HM, but not to the same extent as Castrol. I think the Castrol 5w50 is formulated to meet Ford's Boss Mustang spec, and has lower zddp content than the M1 15w50.
 

Doktor_Bert

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Originally Posted By: A_Harman
Originally Posted By: Doktor_Bert
Located some data... Noticed that the 5/w50 Castrol has 870ppm Calcium whereas the Mobil 1 15/w50 has 2460ppm. The 5/w50 has 1468ppm Magnesium whereas the Mobil 1 15/w50 has 15ppm. Why such a difference in the formulation for oils both in the 'SM' rating????
Nothing in API SM or SN specifications control Calcium and Magnesium content. These are additives that determine the TBN of an oil, and are up to the discretion of the blender, depending on how long they are designing the oil to last. For high performance gasoline engine applications, I prefer all-Calcium detergency. Castrol has been changing their formulations over the past few years to increase Mg and decrease Ca. Mobil has also been using more Mg in some of their gasoline oils, such as EP and HM, but not to the same extent as Castrol. I think the Castrol 5w50 is formulated to meet Ford's Boss Mustang spec, and has lower zddp content than the M1 15w50.
Interesting!!!! Thanks for that data. I didn't understand the differences...
 
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Originally Posted By: Doktor_Bert
Originally Posted By: TomYoung
You want thoughts? The engine is specced for 5W20 or 5W30. You are off the reservation with 5W50. It is not a bad oil, and I have used in in my aircooled 911, but unless I am missing something, it is not for you.
You know I am fascinated by those that still maintain an engine is 'built' for a certain weight oil, when engines still use .001" per inch of journal diameter oil clearances, as they have since the 1950's and beyond. GM Engineer Gerry Thompson stated that the factory considers only two criterion for oil viscosity selection: 1. The coldest climate the car is likely to be delivered to. 2. CAFE contingency My question was about the difference in formulation between Mobil 1 15/w50 and the Castrol. All other questions of 'suitability' I leave to our dynometer and track testing. Thanks....
I've used both the M1 15w50 and Castrol Edge 5w50 and in my experience the Edge wins hands down. Especially at wot,smooth as silk!! Castrol synthetics just run smoother in my car than Mobil synthetics.
 
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