RP 10w40 2006 STI 3,624mi

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Looks pretty good but for a premium oil it was a waste to only run it 3600 miles. It did have a borderline low viscosity for such a short run but I believe RP tends to shear.
 

DARKSTI

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Reno,NV
 Originally Posted By: ZZman
Looks pretty good but for a premium oil it was a waste to only run it 3600 miles. It did have a borderline low viscosity for such a short run but I believe RP tends to shear.
I try to stay with the recommended interval of 3750mi that Subaru recommends since there was some trouble with oil starvation due to some small filters getting clogged going to the turbo. I also chose RP over Redline since it is a dollar or two cheaper.
 
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DARKSTI

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Reno,NV
 Originally Posted By: d00df00d
Looks like you've got big fuel dilution. Lots of short trips?
A mix, about 40mi every day or so and sometimes 20mi, this also included a trip to San Francisco which was about 500mi total. I also drive in the mountains often and I have a bit of a lead foot on on-ramps and in the mountains :) Also, what part of the UOA shows the fuel dilution? As I am learning ;\)
 
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11,828
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PA
 Originally Posted By: DARKSTI
A mix, about 40mi every day or so and sometimes 20mi, this also included a trip to San Francisco which was about 500mi total. I also drive in the mountains often and I have a bit of a lead foot on on-ramps and in the mountains :)
Right on. Doesn't sound too bad, but remember, highway trips (preferably spirited) are your friend. Do you go WOT when you drive hard? Try not to go past 80-90% on this next OCI and see what happens. I don't know about the STI in particular but most ECUs usually run a little rich at WOT, so that might cut down on your fuel dilution without actually slowing you down.
 Originally Posted By: DARKSTI
Also, what part of the UOA shows the fuel dilution? As I am learning ;\)
Well I can't be sure because I'm only an amateur myself and the report doesn't give all the necessary data. However, I'm guessing there's fuel dilution because: - Both the flash point and the viscosity are much lower than the virgin oil - This happened with every oil you had, including Red Line 5w-30, which never thins out unless it's diluted (as far as I know) - Subaru engines are usually very easy on oil, so they're not likely to cause shearing except maybe with track use
 

DARKSTI

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Reno,NV
Yeap, I do go WOT quite a bit, but mostly around 75%-90% lately to try and up my gas a mileage a bit. Thanks for explaining the ECU bit and the fuel dilution also :) I will try and not go as hard to see what happens this go around.
 Originally Posted By: d00df00d
 Originally Posted By: DARKSTI
A mix, about 40mi every day or so and sometimes 20mi, this also included a trip to San Francisco which was about 500mi total. I also drive in the mountains often and I have a bit of a lead foot on on-ramps and in the mountains :)
Right on. Doesn't sound too bad, but remember, highway trips (preferably spirited) are your friend. Do you go WOT when you drive hard? Try not to go past 80-90% on this next OCI and see what happens. Most ECUs usually run a little rich at WOT, so that might cut down on your fuel dilution without actually slowing you down.
 Originally Posted By: DARKSTI
Also, what part of the UOA shows the fuel dilution? As I am learning ;\)
Well I can't be sure because I'm only an amateur myself and the report doesn't give all the necessary data. However, I'm guessing there's fuel dilution because: - Both the flash point and the viscosity are much lower than the virgin oil - This happened with every oil you had, including Red Line 5w-30, which never thins out unless it's diluted (as far as I know) - Subaru engines are usually very easy on oil, so they're not likely to cause shearing except maybe with track use
 
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You can still go hard, just don't go WOT. If you feel the pedal hit the floor, back off a tiny bit. BTW, don't take what I say as gospel. I'm reasonably confident saying it, but really I'm just guessing based on general info. I would run it by some real experts to be sure.
 

DARKSTI

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Reno,NV
 Originally Posted By: d00df00d
You can still go hard, just don't go WOT. If you feel the pedal hit the floor, back off a tiny bit. BTW, don't take what I say as gospel. I'm reasonably confident saying it, but really I'm just guessing based on general info. I would run it by some real experts to be sure.
Sounds good :)
 

FZ1

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Texas
Looks good. Bet you could try PP with similar results and less $. Don't forget to change the AF.
 

DARKSTI

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Reno,NV
 Originally Posted By: FZ1
Looks good. Bet you could try PP with similar results and less $. Don't forget to change the AF.
I am going to replace the air filter in the next few days, it does get dusty around here
 
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15,056
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Canada
Good call on the OCI if you're under warranty. If you're not, run the oil longer, OR switch to something cheaper - RTS 5W-40 does well here. In your previous run, I'm really, really suprised to see Redline shear down so much in 2500 or so miles.
 
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N.H, U.S.A.
2HP/Cu-in can do a job on an oil, If this was a Chevy small block V8, it be making 700HP so, I dont think I'd put PP in this beast - Super premium stuff only. Does that leave out RP too?;)
 

DARKSTI

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Reno,NV
 Originally Posted By: addyguy
Good call on the OCI if you're under warranty. If you're not, run the oil longer, OR switch to something cheaper - RTS 5W-40 does well here. In your previous run, I'm really, really suprised to see Redline shear down so much in 2500 or so miles.
I am not under warranty but still like to stick to recommended interval just in case although I am going to try to around 4000mi this time. I also want to run a 10w40 as it does get hot here (90+) so I want something a tad thicker just to be safe since I do drive hard.
 

DARKSTI

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Reno,NV
 Originally Posted By: ARCOgraphite
2HP/Cu-in can do a job on an oil, If this was a Chevy small block V8, it be making 700HP so, I dont think I'd put PP in this beast - Super premium stuff only. Does that leave out RP too?;)
Interestingly enough I was using PP 5w30 until about 60K since I had some physical problems that made it so I couldn't change the oil myself and the dealership recommended PP 5w30 it did seem to run OK on that but it seems to run amazingly smoother and quieter with RP 10w40, although it's probably a placebo effect. ;\)
 
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686
Location
PA
DarkSTI - If you want super-duty oil suitable for your temps, try M1 15w50 :) I'm gonna run it in my 08 LGT next OCI, see how it feels and what a UOA says...especially since it won't be going under 60 degrees for the next few months.
 

DARKSTI

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Reno,NV
 Originally Posted By: JoeFromPA
DarkSTI - If you want super-duty oil suitable for your temps, try M1 15w50 :) I'm gonna run it in my 08 LGT next OCI, see how it feels and what a UOA says...especially since it won't be going under 60 degrees for the next few months.
 Originally Posted By: addyguy
I agree with Joe, M1 15W-50 is also a great alternative for hot weather driving.
Thanks for the suggestion guys, but it does get down to below 50 at night especially in the mountains so I am thinking 10w40 should be perfect especially with my shorter OCI.
 
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686
Location
PA
Fair enough. Royal Purple 10w40's flashpoint, per RP's website, is 400 F. It's starting viscosity is 14 cst 100 c, and 75 SUS 210F. In an engine like the STI (known for fuel dilution and hot turbos), I'd want an oil with a little more robustness personally...you can see in your analysis that it sheared (within grade), though the flashpoint either wasn't calculated accurately or it didn't move much. I don't know RP's HTHS though. Just my .02
 

DARKSTI

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Reno,NV
 Originally Posted By: JoeFromPA
Fair enough. Royal Purple 10w40's flashpoint, per RP's website, is 400 F. It's starting viscosity is 14 cst 100 c, and 75 SUS 210F. In an engine like the STI (known for fuel dilution and hot turbos), I'd want an oil with a little more robustness personally...you can see in your analysis that it sheared (within grade), though the flashpoint either wasn't calculated accurately or it didn't move much. I don't know RP's HTHS though. Just my .02
Thanks for the explanation, maybe Redline 10w40 might fair better. I think I will try that after this run on RP.
 
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