gathermewool
Site Donor 2023
Previous run was Rotella T 5W-40. The one before that was Cam2 from a free oil change by the dealer.
Last edited:
Rotella T6/5W-40, 7626mi, 08 Subaru WRX STI
- Thread starter gathermewool
- Start date
- Status
Ouch, that car is pretty tough on the oil. Is your car stock?
Patman
Staff member
I find it odd that this lab has boron listed in the "Contaminant Metals" section! Don't they realize that boron is used as a detergent in a lot of oils? I don't even think boron would ever just show up in a UOA if it wasn't in the oil to begin with, so how could it be classified as a contaminant at all?
gathermewool
Site Donor 2023
Sure is! I'll be backing down to 7000 mile for this next OCI.
ECM is tuned to "stage 1" for 93 oct fuel with a Cobb AccessPort for stock setup. Raises boost from 14.7 stock to 17.8 psi, and has modified fueling, timing, valve control, etc.
One thing to note is that I've been noticing a relatively high long-term fuel trim (LTFT) in my logs. I sprayed the MAF with MAF cleaner, which seemed to help, but I'm still +4% a lot, and even higher on occasion. I might spray down the MAF one more time and possibly take the intercooler off to see if there's a loose connection somewhere.
ECM is tuned to "stage 1" for 93 oct fuel with a Cobb AccessPort for stock setup. Raises boost from 14.7 stock to 17.8 psi, and has modified fueling, timing, valve control, etc.
One thing to note is that I've been noticing a relatively high long-term fuel trim (LTFT) in my logs. I sprayed the MAF with MAF cleaner, which seemed to help, but I'm still +4% a lot, and even higher on occasion. I might spray down the MAF one more time and possibly take the intercooler off to see if there's a loose connection somewhere.
gathermewool
Site Donor 2023
Originally Posted By: Patman
I find it odd that this lab has boron listed in the "Contaminant Metals" section! Don't they realize that boron is used as a detergent in a lot of oils? I don't even think boron would ever just show up in a UOA if it wasn't in the oil to begin with, so how could it be classified as a contaminant at all?
This is the lab that Terry Dyson uses. He warned me not to pay attention to those designations, and to disregard the watch and warning advisory limits. The key thing is that WE know what these anlyses pertain to.
I find it odd that this lab has boron listed in the "Contaminant Metals" section! Don't they realize that boron is used as a detergent in a lot of oils? I don't even think boron would ever just show up in a UOA if it wasn't in the oil to begin with, so how could it be classified as a contaminant at all?
This is the lab that Terry Dyson uses. He warned me not to pay attention to those designations, and to disregard the watch and warning advisory limits. The key thing is that WE know what these anlyses pertain to.
If i read this right there is a lot of fuel in this oil. Wear will be higher with this much fuel in the oil. it almost won't matter what oil you run with that much fuel in it. i'm surprised the lead and tin are not higher than they are.
gathermewool
Site Donor 2023
Originally Posted By: tpitcher
Calcium is only 463?
The sample was reanalyzed and came back as 518 - ~same.
Maybe a bad batch? I'm 6,000 miles into this OCI, so we'll have something to compared it to soon.
Calcium is only 463?
The sample was reanalyzed and came back as 518 - ~same.
Maybe a bad batch? I'm 6,000 miles into this OCI, so we'll have something to compared it to soon.
gathermewool
Site Donor 2023
Originally Posted By: spasm3
If i read this right there is a lot of fuel in this oil. Wear will be higher with this much fuel in the oil. it almost won't matter what oil you run with that much fuel in it. i'm surprised the lead and tin are not higher than they are.
I'm not sure if this has anything to do with it, but I've did drive a little more aggressively on the way to the hobby shop. Also, I mentioned above about my abnormally high (to me at least) LTFT. Both of these might have contributed to the high fuel.
If i read this right there is a lot of fuel in this oil. Wear will be higher with this much fuel in the oil. it almost won't matter what oil you run with that much fuel in it. i'm surprised the lead and tin are not higher than they are.
I'm not sure if this has anything to do with it, but I've did drive a little more aggressively on the way to the hobby shop. Also, I mentioned above about my abnormally high (to me at least) LTFT. Both of these might have contributed to the high fuel.
gathermewool
Site Donor 2023
Originally Posted By: tpitcher
I would like to see more Moly in that engine. You may want to consider a Moly additive, but that may be just me...
I don't know enough about it to comfortably play backyard chemist. Rotella seems to work well with this engine, but I might consider another oil for comparison after this next run.
I would like to see more Moly in that engine. You may want to consider a Moly additive, but that may be just me...
I don't know enough about it to comfortably play backyard chemist. Rotella seems to work well with this engine, but I might consider another oil for comparison after this next run.
Originally Posted By: gathermewool
Also, I mentioned above about my abnormally high (to me at least) LTFT. Both of these might have contributed to the high fuel.
The stage 1 tune has a safe ++ rich fuel trim due to the high boost pressure. It could be dialed back a bit by a tuner. Is the car running a stoich mixture at no boost cruise throttle?
Also, I mentioned above about my abnormally high (to me at least) LTFT. Both of these might have contributed to the high fuel.
The stage 1 tune has a safe ++ rich fuel trim due to the high boost pressure. It could be dialed back a bit by a tuner. Is the car running a stoich mixture at no boost cruise throttle?
gathermewool
Site Donor 2023
Originally Posted By: ARCOgraphite
Originally Posted By: gathermewool
Also, I mentioned above about my abnormally high (to me at least) LTFT. Both of these might have contributed to the high fuel.
The stage 1 tune has a safe ++ rich fuel trim due to the high boost pressure. It could be dialed back a bit by a tuner. Is the car running a stoich mixture at no boost cruise throttle?
I'm just learning about tuning - hoping to start self-tuning within a year or so when I feel comfortable enough - but it's my understanding that the ECM will draw from the primary fueling tables for that load/RPM/Air temp and MAF signal, then add or subtract fuel via STFT and LTFT based on O2 sensor feedback. Regardless, if my tune is set to run rich - which it does, but mostly in open loop under boost, not in closed loop - it should indicate -LTFT as the engine tries to take awake fuel to maintain stoich, right? +LTFT means the ECM is seeing a leaner condition than it expected and is adding fuel to compensate.
In closed loop, at low loads or while cruising, the engine is always trying to maintain stoich. The only time I see it dip below is at the onset of boost. The richest I see is 11.05:1 under high boost, WOT conditions, but even that ramps down from stoich only as boost ramps up.
I hope this helps. I've got a lot to learn and looking at it from multiple angle - logging and UOA - is interesting. Hopefully we'll be able to find some correlations, though one UOA/6 months doesn't have quite the resolution as logging multiple times /second! haha
Originally Posted By: gathermewool
Also, I mentioned above about my abnormally high (to me at least) LTFT. Both of these might have contributed to the high fuel.
The stage 1 tune has a safe ++ rich fuel trim due to the high boost pressure. It could be dialed back a bit by a tuner. Is the car running a stoich mixture at no boost cruise throttle?
I'm just learning about tuning - hoping to start self-tuning within a year or so when I feel comfortable enough - but it's my understanding that the ECM will draw from the primary fueling tables for that load/RPM/Air temp and MAF signal, then add or subtract fuel via STFT and LTFT based on O2 sensor feedback. Regardless, if my tune is set to run rich - which it does, but mostly in open loop under boost, not in closed loop - it should indicate -LTFT as the engine tries to take awake fuel to maintain stoich, right? +LTFT means the ECM is seeing a leaner condition than it expected and is adding fuel to compensate.
In closed loop, at low loads or while cruising, the engine is always trying to maintain stoich. The only time I see it dip below is at the onset of boost. The richest I see is 11.05:1 under high boost, WOT conditions, but even that ramps down from stoich only as boost ramps up.
I hope this helps. I've got a lot to learn and looking at it from multiple angle - logging and UOA - is interesting. Hopefully we'll be able to find some correlations, though one UOA/6 months doesn't have quite the resolution as logging multiple times /second! haha
Last edited:
You have a wideband TFT 02 sensor in the subaru EJ255? OTW, narrow band 02 (typical) are losed loop only, open loop load in a MAF (w/ no MAP) is based on throttle angle/RPM/MAF/GEAR (maf derives previous mat/bar data). I am unaware of any trim capability other than the closed loop trim look across. There is NO mixture feedback capability on a narroband 02 for trim. Sorry but my knowledge stops at 80s GM tech. I'm sure the tuner kids on the WRX/STI tuner pages will help - or not
gathermewool
Site Donor 2023
I'm not sure if the WRX EJ255 employs a wideband, but the EJ257 in the STI does. It's not as good as an aftermarket wideband, but is pretty accurate at lower AFR's. I don't know exactly how accurate it is, since I'm parroting what I've read by tuners who posted abouted. Apparently, it's fine for monitoring down into the high 11's, but not much lower. It's good enough to log and show that I'm approximately reaching the AFR's I want in open loop.
Also, I think at high g/s air flow, the open loop fueling includes some LTFT, but no STFT. I'm really not sure where it's pulling the LTFT from, but I do see LTFT in boost on occasion.
The weird thing is that I was noticing LTFT of +10% Saturday on my way to Boston (2 hrs), but only +5% this morning on my drive down. A half hour into the drive, my LTFT dropped even further to around +2%, which I consider normal. I have no idea what would have my LTFT up so high one day, even after an ECM reset, but down to normal on the very next drive...
Also, I think at high g/s air flow, the open loop fueling includes some LTFT, but no STFT. I'm really not sure where it's pulling the LTFT from, but I do see LTFT in boost on occasion.
The weird thing is that I was noticing LTFT of +10% Saturday on my way to Boston (2 hrs), but only +5% this morning on my drive down. A half hour into the drive, my LTFT dropped even further to around +2%, which I consider normal. I have no idea what would have my LTFT up so high one day, even after an ECM reset, but down to normal on the very next drive...
Sorry for digging up a four-month old thread, but I wanted to go back to the calcium issue -- are we in agreement that T6 tends to use magnesium rather than calcium as its detergent, so low calcium levels are okay in T6 UOAs?
That is my understanding, yes.
- Status
Similar threads
