Shell Rotella T6 5w-40 3917 oci '12 Subaru WRX

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A little background. First oil change was done at dealer @ 3000 miles then roughly every 3750 until 20,200 miles using Subaru 5w-30 synthetic and Subaru blue oil filters. Since that time I have changed the oil myself roughly every 3750 miles using Rotella T-6 5w-40 and Subaru blue oil filters. Engine was all stock using Cobb OTS stage I map since 4000 miles. Then went Cobb SF Intake and Box with a Cobb downpipe and a custom tune since 20,000 miles. I had not had a UOA on this car until now. I have been using 8 ounces of Torco Accelerator per tank just to make sure that octane stays in the safe range to reduce the chance of knock, I am thinking that is where the Manganese is coming from.
 
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Spotless. I'd stick with this. No reason to extend. Rotella T6 is CHEAP, you sheared almost outta grade, and the report is perfect. I'd run this oil and at interval.
 
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It did shear out of grade. 30 weight goes up to 12.5 cSt. I've never seen RT6 shear down to a 30 weight before. Try something more shear resistant, such as Red Line 10w40 or AMSoil AMO.
 
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Never ever, EVER put octane boost in the fuel tank that contains MMT (a manganese compound) in a lambda control system - This will kill your o2 sensors and then the cat. It may be going now. Look for slow response on the sensor waveform. Sorry but That was a bad choice. Re-Read you manual about fuel and additives. Good luck.
 
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Stick with this oil and OCI. That octane booster is a waste, although I hadn't realized the danger myself. Find a gas station with 93 if you need something higher than 89 or 91.
 
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The Torco web site says it won't hurt the o2 or the cat. If it does then someone would have sued them by now. I don't know what its made of or if it even works but most co.(that has been around as long as Torco has) will not post out right lies on their web page. http://torcoracefuel.net/pro-accelerator.html I used Torco 2 stroke oil back in the early 70's in my race bike, good stuff back then. ROD
 
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Knale

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Originally Posted By: ARCOgraphite
Never ever, EVER put octane boost in the fuel tank that contains MMT (a manganese compound) in a lambda control system - This will kill your o2 sensors and then the cat. It may be going now. Look for slow response on the sensor waveform. Sorry but That was a bad choice. Re-Read you manual about fuel and additives. Good luck.
What you are saying may be true. I have not done any research on reports of Torco killing o2 sensors and cats. Torco classifies the Accelerator as a race gas consentrate for what that matters. Just a little on how I am using it. The weakest dilution instructions they talk about are 16 ounces to 12 gallons of gas. Since 91 octane is the highest available in California without going to a race gas, I thought mixing 8 ounces to my 17 gallon tank would be insurance to battle knock. Granted my custom tune was on 91 octane pump gas. Since seeing this report and the manganese showing up in the oil and some opinions that it may damage my o2 sensor, I may reconsider.
 

Knale

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Originally Posted By: A_Harman
It did shear out of grade. 30 weight goes up to 12.5 cSt. I've never seen RT6 shear down to a 30 weight before. Try something more shear resistant, such as Red Line 10w40 or AMSoil AMO.
I am thinking there is some dilution going on. For the most part the car sees short trips, with an occational longer trip mixed in. This is my daily driver. My commute to work is around 9 miles. Oil pressure does not get to operating pressure during my commute to work, so I am betting the oil is not getting up to operating temp.
 
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Originally Posted By: A_Harman
It did shear out of grade. 30 weight goes up to 12.5 cSt. I've never seen RT6 shear down to a 30 weight before. Try something more shear resistant, such as Red Line 10w40 or AMSoil AMO.
It's not uncommon for WRX's to shear RT6, especially if they are modified. Maybe there's some fuel dilution as well (trace?). OP - Isn't your car tuned for 91 octane? Or is there still a chance of knock happening with 91? -Dennis
 

Knale

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Originally Posted By: bluesubie
Originally Posted By: A_Harman
It did shear out of grade. 30 weight goes up to 12.5 cSt. I've never seen RT6 shear down to a 30 weight before. Try something more shear resistant, such as Red Line 10w40 or AMSoil AMO.
It's not uncommon for WRX's to shear RT6, especially if they are modified. Maybe there's some fuel dilution as well (trace?). OP - Isn't your car tuned for 91 octane? Or is there still a chance of knock happening with 91? -Dennis
Yes my car was tuned (not off the shelf map) with 91 octane. In every data log I have run, there have been no knock occurrences to speak of except for an occasional fine knock learning event that are not considered out of the ordinary. My thinking behind the octane booster was to keep the octane in the safe range, not to raise it to 95 or greater. With the 8 ounces of Torco Accelerator that I am mixing with 17 gallons of 91 octane I almost bet octane is not even reaching 93. But now that I see manganese in the oil sample and people are questioning what it will do the the o2 sensor and or cat, I will probably stop using it.
 
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Originally Posted By: Knale
Originally Posted By: A_Harman
It did shear out of grade. 30 weight goes up to 12.5 cSt. I've never seen RT6 shear down to a 30 weight before. Try something more shear resistant, such as Red Line 10w40 or AMSoil AMO.
I am thinking there is some dilution going on. For the most part the car sees short trips, with an occational longer trip mixed in. This is my daily driver. My commute to work is around 9 miles. Oil pressure does not get to operating pressure during my commute to work, so I am betting the oil is not getting up to operating temp.
The analysis sheet is showing <0.5% fuel in the sample, so I'm not thinking it's fuel dilution.
 
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