Quote:
Originally Posted by CoupedUpSubie
As long as both oils are tested in the same fashion with the same chemicals the oil with a TBN of 10 will last longer then an oil with a TBN of 6. I spent 5 months doing daily oil tests on a ship. Granted this was oil used in diesel engines but the same principles apply. The way the test station I was using determined the TBN was based on pressure after a certain amount of reagent was added to the oil. TBN depletion depends more on driving style and maintenance. Gasoline doesn't create as much acid as diesel does.
On the topic of if M1 is fine. The history of M1 in the performance subaru's has not been good. Go to any forum and you will find someone referencing different failures after running M1 in a WRX/STi. This isn't so much consumption but spinning bearings. Maybe it has been improved but I won't even use it in my beater 95 impreza.
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Please show me some data that
all oils with a TBN of 10 will continue to fight acids longer than an oil with a TBN of 6. TBN depletion is non-linear and the rate of depletion will also vary based on base stocks and the oils detergent/dispersant package. Now if you're basing your theory on your uoa's from diesel engines, then it's highly possible. Many diesel oils have a very similar additive packages (the same low calcium, higher magnesium) so I can see the TBN depletion rate being very similar for HDEO's. OTOH, PCMO vary wildly in regards to detergent/dispersant additives.
As to Mobil1, you are
wrong that the failures are due to the brand.
I'm very well aware of the perceived "problem" as I was on the original i-club (pre-nasioc) since 1999 and continue to be very active on nasioc. The spun bearing issues are from knuckleheads modifying their cars, bad tunes, not checking their oil levels regularly,
and using the wrong oil grade for their application.
I've seen guys modify their STI's to 400 whp and continue to use Resource Conserving Mobil1 5W-30. Then they do a rebuild, run RT6, and declare that Mobil1 sucks. Well duh! They should be comparing RT6 to Mobil1 5W-40 Turbo Diesel Truck, not regular M1 5W-30. TDT is thicker than RT6 in all temps. Resource Conserving oils are not ideal for turbos because they have a low High Temp High Shear for fuel economy. I have had a couple of very good uoa's with Mobil1 0W-40 in my modified Forester turbo. There are many other good uoa's out there as well.
Your '95 beater Impreza would probably do very well on Mobil conventional 5W-30. You can find 8k mile uoa's on it at bobistheoilguy.com. Of course, you are welcome to show me some data to prove me wrong instead of believing everything you read on the internet.
What does any of this have to do with the topic? Nothing! It's best to look at data for the FR-S/BRZ.
-Dennis