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NorthWestern, is your Subaru turbocharged?  The general consensus in the late model Subaru forums is that Rotella T6 5w-40 is one of the best budget oils for our engines, and has a lot more ZDDP than other mass-market oils, but not as high an amount as more boutique oils like Motul and Redline.  I've been using T6 5w-40 for about two years now and have nothing but positive things to say about it, it often goes on sale too.

 

That being said, I will never, ever used a 5w-30 in my WRX, too thin, and if you abuse the engine with a poor oil in it, that oil will quickly shear down to practically water.

Edited by carfreak85
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zinc is good for engines as it avoids corrosion and acts as a lubricant agent, but too much of it (like found in Rotella thats meant for diesels) is not a good thing, anything above 800ppm of zinc and you are looking at catalytic converter damage on newer vehicles, anything higher than 1600ppm and it begins to clump, only time i ever saw that Rotella would be needed for was on my friends 1994 3000GT plus the Catalytic converter was removed, burned every type of oil due to the extreme heat and pressure, Rotella stopped all that and worked quite well on it.

 

---(a Turbo model might fit that application too like carfreak85 mentioned)

 

also on the back of the oil bottles theres a seal that has 2 letters on it that say something like API SN and such, that tells you alot about whats in the oil itself. im sure theres a chart somewhere online that you can read about it.

 

quick 2 minute search > http://www.pqiamerica.com/Labels.htm

Edited by Subasaurus
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Subasaurus, I have to sort of disagree with you on the zinc thing.

 

YES, ZDDP can damage a catalytic converter over time, but think about it for a moment.  How would oil get back to the cat?  Sure, piston rings aren't 100% effective at cleaning the cylinder walls and PCV introduces blowby gasses to the combustion chamber.

 

However!  To get enough oil to the cat to damage it, you'd have to have an engine that burns a TON of oil.  I'm talking Bob Marley levels of smoke out the tailpipe.

 

TL;DR - Zinc/ZDDP/et al are only bad for a catalytic converter if your car burns oil.  If you have a late model turbocharged Subaru DO NOT use 5w-30, DO NOT use Resource Conserving (RC) oil.

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Subasaurus, I have to sort of disagree with you on the zinc thing.

 

YES, ZDDP can damage a catalytic converter over time, but think about it for a moment.  How would oil get back to the cat?  Sure, piston rings aren't 100% effective at cleaning the cylinder walls and PCV introduces blowby gasses to the combustion chamber.

 

However!  To get enough oil to the cat to damage it, you'd have to have an engine that burns a TON of oil.  I'm talking Bob Marley levels of smoke out the tailpipe.

 

TL;DR - Zinc/ZDDP/et al are only bad for a catalytic converter if your car burns oil.  If you have a late model turbocharged Subaru DO NOT use 5w-30, DO NOT use Resource Conserving (RC) oil.

 

then again, no one really changes oil viscosity unless they have an issue with their vehicle having oil dissapear on them, goes both ways. but yes, changing to a higher zinc level oil on a newer car would NOT cause catalytic converter damage if everything is working well. plus once a vehicle is 20 years old and burning oil, the last thing you care about is the catalytic converter anyways, unless you live in california.

 

there are a few vehicles out there that do burn a bunch of oil when they are only 2 years old though, for example i witnessed 2013-2015 jeep wranglers mising 2 quarts of oil at only 1,000 miles in on their oil change, fiats missing 1.5 quarts at 5,000 miles in NEW, chrysler 300's and PT Cruisers.... don't even get me started on those, and many more. most were 0w-20 burning all this oil, the one that did the best while i worked at an oil and lube shop was Honda burning around 1/4 of a quart at 7,000miles in, but this is getting off topic..

 

>my brain is just used to talking about older vehicles than newer ones, then again what vehicle are we even talking about here anyways?? all we know is that its a Subaru and its one of these according to his profile EA82, EJ22, EJ251, EJ255, EJ257, EZ30, EZ33. so who knows lol

Edited by Subasaurus
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Cats are cheap. Engines aren't. And most of the turbocharged cars we build either run no cat or have "high flow cats" that are just there for visual.

 

We run high ZDDP oils on virtually anything we care about making power and living. Usually 15w50 or or 10w40 depending on what power level and if it's street or strip use.

 

GD

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